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252b5132 | 1 | \input texinfo @c -*-Texinfo-*- |
219d1afa | 2 | @c Copyright (C) 1991-2018 Free Software Foundation, Inc. |
252b5132 RH |
3 | @c UPDATE!! On future updates-- |
4 | @c (1) check for new machine-dep cmdline options in | |
5 | @c md_parse_option definitions in config/tc-*.c | |
6 | @c (2) for platform-specific directives, examine md_pseudo_op | |
7 | @c in config/tc-*.c | |
8 | @c (3) for object-format specific directives, examine obj_pseudo_op | |
01642c12 | 9 | @c in config/obj-*.c |
252b5132 RH |
10 | @c (4) portable directives in potable[] in read.c |
11 | @c %**start of header | |
12 | @setfilename as.info | |
13 | @c ---config--- | |
a4fb0134 SC |
14 | @macro gcctabopt{body} |
15 | @code{\body\} | |
16 | @end macro | |
252b5132 RH |
17 | @c defaults, config file may override: |
18 | @set have-stabs | |
19 | @c --- | |
4a4c4a1d MR |
20 | @c man begin NAME |
21 | @c --- | |
252b5132 | 22 | @include asconfig.texi |
c428fa83 | 23 | @include bfdver.texi |
252b5132 | 24 | @c --- |
0285c67d | 25 | @c man end |
4a4c4a1d | 26 | @c --- |
252b5132 | 27 | @c common OR combinations of conditions |
c1253627 NC |
28 | @ifset COFF |
29 | @set COFF-ELF | |
30 | @end ifset | |
31 | @ifset ELF | |
32 | @set COFF-ELF | |
33 | @end ifset | |
252b5132 RH |
34 | @ifset AOUT |
35 | @set aout-bout | |
36 | @end ifset | |
37 | @ifset ARM/Thumb | |
38 | @set ARM | |
39 | @end ifset | |
9982501a JZ |
40 | @ifset Blackfin |
41 | @set Blackfin | |
42 | @end ifset | |
252b5132 RH |
43 | @ifset BOUT |
44 | @set aout-bout | |
45 | @end ifset | |
46 | @ifset H8/300 | |
47 | @set H8 | |
48 | @end ifset | |
252b5132 RH |
49 | @ifset SH |
50 | @set H8 | |
51 | @end ifset | |
52 | @ifset HPPA | |
53 | @set abnormal-separator | |
54 | @end ifset | |
55 | @c ------------ | |
56 | @ifset GENERIC | |
57 | @settitle Using @value{AS} | |
58 | @end ifset | |
59 | @ifclear GENERIC | |
60 | @settitle Using @value{AS} (@value{TARGET}) | |
61 | @end ifclear | |
62 | @setchapternewpage odd | |
63 | @c %**end of header | |
64 | ||
65 | @c @smallbook | |
66 | @c @set SMALL | |
67 | @c WARE! Some of the machine-dependent sections contain tables of machine | |
68 | @c instructions. Except in multi-column format, these tables look silly. | |
69 | @c Unfortunately, Texinfo doesn't have a general-purpose multi-col format, so | |
70 | @c the multi-col format is faked within @example sections. | |
01642c12 | 71 | @c |
252b5132 RH |
72 | @c Again unfortunately, the natural size that fits on a page, for these tables, |
73 | @c is different depending on whether or not smallbook is turned on. | |
74 | @c This matters, because of order: text flow switches columns at each page | |
75 | @c break. | |
01642c12 | 76 | @c |
252b5132 RH |
77 | @c The format faked in this source works reasonably well for smallbook, |
78 | @c not well for the default large-page format. This manual expects that if you | |
79 | @c turn on @smallbook, you will also uncomment the "@set SMALL" to enable the | |
80 | @c tables in question. You can turn on one without the other at your | |
01642c12 | 81 | @c discretion, of course. |
252b5132 RH |
82 | @ifinfo |
83 | @set SMALL | |
84 | @c the insn tables look just as silly in info files regardless of smallbook, | |
85 | @c might as well show 'em anyways. | |
86 | @end ifinfo | |
87 | ||
9160ea82 AM |
88 | @ifnottex |
89 | @dircategory Software development | |
90 | @direntry | |
252b5132 | 91 | * As: (as). The GNU assembler. |
59455fb1 | 92 | * Gas: (as). The GNU assembler. |
9160ea82 AM |
93 | @end direntry |
94 | @end ifnottex | |
252b5132 RH |
95 | |
96 | @finalout | |
97 | @syncodeindex ky cp | |
98 | ||
0e9517a9 | 99 | @copying |
252b5132 RH |
100 | This file documents the GNU Assembler "@value{AS}". |
101 | ||
0285c67d | 102 | @c man begin COPYRIGHT |
219d1afa | 103 | Copyright @copyright{} 1991-2018 Free Software Foundation, Inc. |
252b5132 | 104 | |
0285c67d | 105 | Permission is granted to copy, distribute and/or modify this document |
793c5807 | 106 | under the terms of the GNU Free Documentation License, Version 1.3 |
0285c67d NC |
107 | or any later version published by the Free Software Foundation; |
108 | with no Invariant Sections, with no Front-Cover Texts, and with no | |
109 | Back-Cover Texts. A copy of the license is included in the | |
c1253627 | 110 | section entitled ``GNU Free Documentation License''. |
0285c67d NC |
111 | |
112 | @c man end | |
0e9517a9 | 113 | @end copying |
252b5132 RH |
114 | |
115 | @titlepage | |
116 | @title Using @value{AS} | |
117 | @subtitle The @sc{gnu} Assembler | |
118 | @ifclear GENERIC | |
119 | @subtitle for the @value{TARGET} family | |
120 | @end ifclear | |
e49e529d JM |
121 | @ifset VERSION_PACKAGE |
122 | @sp 1 | |
123 | @subtitle @value{VERSION_PACKAGE} | |
124 | @end ifset | |
252b5132 RH |
125 | @sp 1 |
126 | @subtitle Version @value{VERSION} | |
127 | @sp 1 | |
128 | @sp 13 | |
b45619c0 | 129 | The Free Software Foundation Inc.@: thanks The Nice Computer |
252b5132 | 130 | Company of Australia for loaning Dean Elsner to write the |
a4fb0134 | 131 | first (Vax) version of @command{as} for Project @sc{gnu}. |
252b5132 RH |
132 | The proprietors, management and staff of TNCCA thank FSF for |
133 | distracting the boss while they got some work | |
134 | done. | |
135 | @sp 3 | |
136 | @author Dean Elsner, Jay Fenlason & friends | |
137 | @page | |
138 | @tex | |
139 | {\parskip=0pt | |
140 | \hfill {\it Using {\tt @value{AS}}}\par | |
141 | \hfill Edited by Cygnus Support\par | |
142 | } | |
143 | %"boxit" macro for figures: | |
144 | %Modified from Knuth's ``boxit'' macro from TeXbook (answer to exercise 21.3) | |
145 | \gdef\boxit#1#2{\vbox{\hrule\hbox{\vrule\kern3pt | |
146 | \vbox{\parindent=0pt\parskip=0pt\hsize=#1\kern3pt\strut\hfil | |
147 | #2\hfil\strut\kern3pt}\kern3pt\vrule}\hrule}}%box with visible outline | |
148 | \gdef\ibox#1#2{\hbox to #1{#2\hfil}\kern8pt}% invisible box | |
149 | @end tex | |
150 | ||
151 | @vskip 0pt plus 1filll | |
219d1afa | 152 | Copyright @copyright{} 1991-2018 Free Software Foundation, Inc. |
252b5132 | 153 | |
cf055d54 | 154 | Permission is granted to copy, distribute and/or modify this document |
793c5807 | 155 | under the terms of the GNU Free Documentation License, Version 1.3 |
cf055d54 NC |
156 | or any later version published by the Free Software Foundation; |
157 | with no Invariant Sections, with no Front-Cover Texts, and with no | |
158 | Back-Cover Texts. A copy of the license is included in the | |
c1253627 | 159 | section entitled ``GNU Free Documentation License''. |
252b5132 | 160 | |
252b5132 | 161 | @end titlepage |
4ecceb71 | 162 | @contents |
252b5132 | 163 | |
2e64b665 | 164 | @ifnottex |
252b5132 RH |
165 | @node Top |
166 | @top Using @value{AS} | |
167 | ||
e49e529d JM |
168 | This file is a user guide to the @sc{gnu} assembler @command{@value{AS}} |
169 | @ifset VERSION_PACKAGE | |
170 | @value{VERSION_PACKAGE} | |
171 | @end ifset | |
172 | version @value{VERSION}. | |
252b5132 | 173 | @ifclear GENERIC |
a4fb0134 | 174 | This version of the file describes @command{@value{AS}} configured to generate |
252b5132 RH |
175 | code for @value{TARGET} architectures. |
176 | @end ifclear | |
cf055d54 NC |
177 | |
178 | This document is distributed under the terms of the GNU Free | |
179 | Documentation License. A copy of the license is included in the | |
c1253627 | 180 | section entitled ``GNU Free Documentation License''. |
cf055d54 | 181 | |
252b5132 RH |
182 | @menu |
183 | * Overview:: Overview | |
184 | * Invoking:: Command-Line Options | |
185 | * Syntax:: Syntax | |
186 | * Sections:: Sections and Relocation | |
187 | * Symbols:: Symbols | |
188 | * Expressions:: Expressions | |
189 | * Pseudo Ops:: Assembler Directives | |
3a99f02f DJ |
190 | @ifset ELF |
191 | * Object Attributes:: Object Attributes | |
192 | @end ifset | |
252b5132 RH |
193 | * Machine Dependencies:: Machine Dependent Features |
194 | * Reporting Bugs:: Reporting Bugs | |
195 | * Acknowledgements:: Who Did What | |
cf055d54 | 196 | * GNU Free Documentation License:: GNU Free Documentation License |
28c9d252 | 197 | * AS Index:: AS Index |
252b5132 | 198 | @end menu |
2e64b665 | 199 | @end ifnottex |
252b5132 RH |
200 | |
201 | @node Overview | |
202 | @chapter Overview | |
203 | @iftex | |
a4fb0134 | 204 | This manual is a user guide to the @sc{gnu} assembler @command{@value{AS}}. |
252b5132 | 205 | @ifclear GENERIC |
a4fb0134 | 206 | This version of the manual describes @command{@value{AS}} configured to generate |
252b5132 RH |
207 | code for @value{TARGET} architectures. |
208 | @end ifclear | |
209 | @end iftex | |
210 | ||
211 | @cindex invocation summary | |
212 | @cindex option summary | |
213 | @cindex summary of options | |
a4fb0134 | 214 | Here is a brief summary of how to invoke @command{@value{AS}}. For details, |
96e9638b | 215 | see @ref{Invoking,,Command-Line Options}. |
252b5132 | 216 | |
0285c67d NC |
217 | @c man title AS the portable GNU assembler. |
218 | ||
a4fb0134 | 219 | @ignore |
0285c67d NC |
220 | @c man begin SEEALSO |
221 | gcc(1), ld(1), and the Info entries for @file{binutils} and @file{ld}. | |
222 | @c man end | |
a4fb0134 | 223 | @end ignore |
0285c67d | 224 | |
252b5132 RH |
225 | @c We don't use deffn and friends for the following because they seem |
226 | @c to be limited to one line for the header. | |
227 | @smallexample | |
0285c67d | 228 | @c man begin SYNOPSIS |
83f10cb2 | 229 | @value{AS} [@b{-a}[@b{cdghlns}][=@var{file}]] [@b{--alternate}] [@b{-D}] |
955974c6 | 230 | [@b{--compress-debug-sections}] [@b{--nocompress-debug-sections}] |
3d6b762c | 231 | [@b{--debug-prefix-map} @var{old}=@var{new}] |
4bdd3565 | 232 | [@b{--defsym} @var{sym}=@var{val}] [@b{-f}] [@b{-g}] [@b{--gstabs}] |
b40bf0a2 NC |
233 | [@b{--gstabs+}] [@b{--gdwarf-2}] [@b{--gdwarf-sections}] |
234 | [@b{--help}] [@b{-I} @var{dir}] [@b{-J}] | |
4bdd3565 NC |
235 | [@b{-K}] [@b{-L}] [@b{--listing-lhs-width}=@var{NUM}] |
236 | [@b{--listing-lhs-width2}=@var{NUM}] [@b{--listing-rhs-width}=@var{NUM}] | |
d60646b9 | 237 | [@b{--listing-cont-lines}=@var{NUM}] [@b{--keep-locals}] |
2edb36e7 | 238 | [@b{--no-pad-sections}] |
d60646b9 NC |
239 | [@b{-o} @var{objfile}] [@b{-R}] |
240 | [@b{--hash-size}=@var{NUM}] [@b{--reduce-memory-overheads}] | |
241 | [@b{--statistics}] | |
242 | [@b{-v}] [@b{-version}] [@b{--version}] | |
243 | [@b{-W}] [@b{--warn}] [@b{--fatal-warnings}] [@b{-w}] [@b{-x}] | |
244 | [@b{-Z}] [@b{@@@var{FILE}}] | |
451133ce | 245 | [@b{--sectname-subst}] [@b{--size-check=[error|warning]}] |
b8871f35 | 246 | [@b{--elf-stt-common=[no|yes]}] |
a0b7da79 MM |
247 | [@b{--target-help}] [@var{target-options}] |
248 | [@b{--}|@var{files} @dots{}] | |
a4fb0134 | 249 | @c |
6387924a | 250 | @c man end |
a4fb0134 | 251 | @c Target dependent options are listed below. Keep the list sorted. |
01642c12 | 252 | @c Add an empty line for separation. |
6387924a | 253 | @c man begin TARGET |
a06ea964 NC |
254 | @ifset AARCH64 |
255 | ||
256 | @emph{Target AArch64 options:} | |
257 | [@b{-EB}|@b{-EL}] | |
69091a2c | 258 | [@b{-mabi}=@var{ABI}] |
a06ea964 | 259 | @end ifset |
625e1353 RH |
260 | @ifset ALPHA |
261 | ||
262 | @emph{Target Alpha options:} | |
263 | [@b{-m@var{cpu}}] | |
264 | [@b{-mdebug} | @b{-no-mdebug}] | |
198f1251 | 265 | [@b{-replace} | @b{-noreplace}] |
625e1353 RH |
266 | [@b{-relax}] [@b{-g}] [@b{-G@var{size}}] |
267 | [@b{-F}] [@b{-32addr}] | |
268 | @end ifset | |
252b5132 | 269 | @ifset ARC |
a4fb0134 SC |
270 | |
271 | @emph{Target ARC options:} | |
886a2506 NC |
272 | [@b{-mcpu=@var{cpu}}] |
273 | [@b{-mA6}|@b{-mARC600}|@b{-mARC601}|@b{-mA7}|@b{-mARC700}|@b{-mEM}|@b{-mHS}] | |
274 | [@b{-mcode-density}] | |
4670103e | 275 | [@b{-mrelax}] |
a4fb0134 | 276 | [@b{-EB}|@b{-EL}] |
252b5132 RH |
277 | @end ifset |
278 | @ifset ARM | |
a4fb0134 SC |
279 | |
280 | @emph{Target ARM options:} | |
03b1477f | 281 | @c Don't document the deprecated options |
92081f48 HPN |
282 | [@b{-mcpu}=@var{processor}[+@var{extension}@dots{}]] |
283 | [@b{-march}=@var{architecture}[+@var{extension}@dots{}]] | |
33a392fb PB |
284 | [@b{-mfpu}=@var{floating-point-format}] |
285 | [@b{-mfloat-abi}=@var{abi}] | |
d507cf36 | 286 | [@b{-meabi}=@var{ver}] |
03b1477f | 287 | [@b{-mthumb}] |
a4fb0134 SC |
288 | [@b{-EB}|@b{-EL}] |
289 | [@b{-mapcs-32}|@b{-mapcs-26}|@b{-mapcs-float}| | |
290 | @b{-mapcs-reentrant}] | |
7f266840 | 291 | [@b{-mthumb-interwork}] [@b{-k}] |
252b5132 | 292 | @end ifset |
9982501a JZ |
293 | @ifset Blackfin |
294 | ||
295 | @emph{Target Blackfin options:} | |
296 | [@b{-mcpu}=@var{processor}[-@var{sirevision}]] | |
297 | [@b{-mfdpic}] | |
298 | [@b{-mno-fdpic}] | |
299 | [@b{-mnopic}] | |
300 | @end ifset | |
328eb32e HPN |
301 | @ifset CRIS |
302 | ||
303 | @emph{Target CRIS options:} | |
304 | [@b{--underscore} | @b{--no-underscore}] | |
305 | [@b{--pic}] [@b{-N}] | |
306 | [@b{--emulation=criself} | @b{--emulation=crisaout}] | |
ae57792d | 307 | [@b{--march=v0_v10} | @b{--march=v10} | @b{--march=v32} | @b{--march=common_v10_v32}] |
328eb32e HPN |
308 | @c Deprecated -- deliberately not documented. |
309 | @c [@b{-h}] [@b{-H}] | |
310 | @end ifset | |
252b5132 | 311 | @ifset D10V |
a4fb0134 SC |
312 | |
313 | @emph{Target D10V options:} | |
314 | [@b{-O}] | |
252b5132 RH |
315 | @end ifset |
316 | @ifset D30V | |
a4fb0134 SC |
317 | |
318 | @emph{Target D30V options:} | |
319 | [@b{-O}|@b{-n}|@b{-N}] | |
252b5132 | 320 | @end ifset |
cfb8c092 NC |
321 | @ifset EPIPHANY |
322 | ||
323 | @emph{Target EPIPHANY options:} | |
324 | [@b{-mepiphany}|@b{-mepiphany16}] | |
325 | @end ifset | |
252b5132 | 326 | @ifset H8 |
6fd4f6cc DD |
327 | |
328 | @emph{Target H8/300 options:} | |
329 | [-h-tick-hex] | |
252b5132 RH |
330 | @end ifset |
331 | @ifset HPPA | |
332 | @c HPPA has no machine-dependent assembler options (yet). | |
333 | @end ifset | |
a4fb0134 SC |
334 | @ifset I80386 |
335 | ||
336 | @emph{Target i386 options:} | |
542385d9 | 337 | [@b{--32}|@b{--x32}|@b{--64}] [@b{-n}] |
1ef52f49 | 338 | [@b{-march}=@var{CPU}[+@var{EXTENSION}@dots{}]] [@b{-mtune}=@var{CPU}] |
252b5132 RH |
339 | @end ifset |
340 | @ifset I960 | |
a4fb0134 SC |
341 | |
342 | @emph{Target i960 options:} | |
252b5132 | 343 | @c see md_parse_option in tc-i960.c |
a4fb0134 SC |
344 | [@b{-ACA}|@b{-ACA_A}|@b{-ACB}|@b{-ACC}|@b{-AKA}|@b{-AKB}| |
345 | @b{-AKC}|@b{-AMC}] | |
346 | [@b{-b}] [@b{-no-relax}] | |
252b5132 | 347 | @end ifset |
587fe2b3 | 348 | @ifset IA64 |
a4fb0134 | 349 | |
9e32ca89 NC |
350 | @emph{Target IA-64 options:} |
351 | [@b{-mconstant-gp}|@b{-mauto-pic}] | |
352 | [@b{-milp32}|@b{-milp64}|@b{-mlp64}|@b{-mp64}] | |
353 | [@b{-mle}|@b{mbe}] | |
8c2fda1d | 354 | [@b{-mtune=itanium1}|@b{-mtune=itanium2}] |
970d6792 | 355 | [@b{-munwind-check=warning}|@b{-munwind-check=error}] |
91d777ee | 356 | [@b{-mhint.b=ok}|@b{-mhint.b=warning}|@b{-mhint.b=error}] |
9e32ca89 NC |
357 | [@b{-x}|@b{-xexplicit}] [@b{-xauto}] [@b{-xdebug}] |
358 | @end ifset | |
a40cbfa3 NC |
359 | @ifset IP2K |
360 | ||
361 | @emph{Target IP2K options:} | |
362 | [@b{-mip2022}|@b{-mip2022ext}] | |
363 | @end ifset | |
49f58d10 JB |
364 | @ifset M32C |
365 | ||
366 | @emph{Target M32C options:} | |
c54b5932 | 367 | [@b{-m32c}|@b{-m16c}] [-relax] [-h-tick-hex] |
49f58d10 | 368 | @end ifset |
587fe2b3 | 369 | @ifset M32R |
9e32ca89 | 370 | |
a4fb0134 SC |
371 | @emph{Target M32R options:} |
372 | [@b{--m32rx}|@b{--[no-]warn-explicit-parallel-conflicts}| | |
587fe2b3 | 373 | @b{--W[n]p}] |
ec694b89 | 374 | @end ifset |
252b5132 | 375 | @ifset M680X0 |
a4fb0134 SC |
376 | |
377 | @emph{Target M680X0 options:} | |
378 | [@b{-l}] [@b{-m68000}|@b{-m68010}|@b{-m68020}|@dots{}] | |
252b5132 | 379 | @end ifset |
60bcf0fa | 380 | @ifset M68HC11 |
a4fb0134 SC |
381 | |
382 | @emph{Target M68HC11 options:} | |
6927f982 | 383 | [@b{-m68hc11}|@b{-m68hc12}|@b{-m68hcs12}|@b{-mm9s12x}|@b{-mm9s12xg}] |
2f904664 SC |
384 | [@b{-mshort}|@b{-mlong}] |
385 | [@b{-mshort-double}|@b{-mlong-double}] | |
1370e33d | 386 | [@b{--force-long-branches}] [@b{--short-branches}] |
a4fb0134 SC |
387 | [@b{--strict-direct-mode}] [@b{--print-insn-syntax}] |
388 | [@b{--print-opcodes}] [@b{--generate-example}] | |
389 | @end ifset | |
390 | @ifset MCORE | |
391 | ||
392 | @emph{Target MCORE options:} | |
393 | [@b{-jsri2bsr}] [@b{-sifilter}] [@b{-relax}] | |
394 | [@b{-mcpu=[210|340]}] | |
60bcf0fa | 395 | @end ifset |
a3c62988 NC |
396 | @ifset METAG |
397 | ||
398 | @emph{Target Meta options:} | |
399 | [@b{-mcpu=@var{cpu}}] [@b{-mfpu=@var{cpu}}] [@b{-mdsp=@var{cpu}}] | |
400 | @end ifset | |
7ba29e2a NC |
401 | @ifset MICROBLAZE |
402 | @emph{Target MICROBLAZE options:} | |
403 | @c MicroBlaze has no machine-dependent assembler options. | |
404 | @end ifset | |
252b5132 | 405 | @ifset MIPS |
a4fb0134 SC |
406 | |
407 | @emph{Target MIPS options:} | |
78849248 | 408 | [@b{-nocpp}] [@b{-EL}] [@b{-EB}] [@b{-O}[@var{optimization level}]] |
437ee9d5 | 409 | [@b{-g}[@var{debug level}]] [@b{-G} @var{num}] [@b{-KPIC}] [@b{-call_shared}] |
0c000745 | 410 | [@b{-non_shared}] [@b{-xgot} [@b{-mvxworks-pic}] |
437ee9d5 | 411 | [@b{-mabi}=@var{ABI}] [@b{-32}] [@b{-n32}] [@b{-64}] [@b{-mfp32}] [@b{-mgp32}] |
351cdf24 MF |
412 | [@b{-mfp64}] [@b{-mgp64}] [@b{-mfpxx}] |
413 | [@b{-modd-spreg}] [@b{-mno-odd-spreg}] | |
437ee9d5 | 414 | [@b{-march}=@var{CPU}] [@b{-mtune}=@var{CPU}] [@b{-mips1}] [@b{-mips2}] |
af7ee8bf | 415 | [@b{-mips3}] [@b{-mips4}] [@b{-mips5}] [@b{-mips32}] [@b{-mips32r2}] |
7361da2c AB |
416 | [@b{-mips32r3}] [@b{-mips32r5}] [@b{-mips32r6}] [@b{-mips64}] [@b{-mips64r2}] |
417 | [@b{-mips64r3}] [@b{-mips64r5}] [@b{-mips64r6}] | |
437ee9d5 | 418 | [@b{-construct-floats}] [@b{-no-construct-floats}] |
8b10b0b3 | 419 | [@b{-mignore-branch-isa}] [@b{-mno-ignore-branch-isa}] |
ba92f887 | 420 | [@b{-mnan=@var{encoding}}] |
437ee9d5 | 421 | [@b{-trap}] [@b{-no-break}] [@b{-break}] [@b{-no-trap}] |
437ee9d5 | 422 | [@b{-mips16}] [@b{-no-mips16}] |
25499ac7 | 423 | [@b{-mmips16e2}] [@b{-mno-mips16e2}] |
df58fc94 | 424 | [@b{-mmicromips}] [@b{-mno-micromips}] |
e16bfa71 | 425 | [@b{-msmartmips}] [@b{-mno-smartmips}] |
1f25f5d3 | 426 | [@b{-mips3d}] [@b{-no-mips3d}] |
deec1734 | 427 | [@b{-mdmx}] [@b{-no-mdmx}] |
2ef2b9ae | 428 | [@b{-mdsp}] [@b{-mno-dsp}] |
8b082fb1 | 429 | [@b{-mdspr2}] [@b{-mno-dspr2}] |
8f4f9071 | 430 | [@b{-mdspr3}] [@b{-mno-dspr3}] |
56d438b1 | 431 | [@b{-mmsa}] [@b{-mno-msa}] |
7d64c587 | 432 | [@b{-mxpa}] [@b{-mno-xpa}] |
ef2e4d86 | 433 | [@b{-mmt}] [@b{-mno-mt}] |
dec0624d | 434 | [@b{-mmcu}] [@b{-mno-mcu}] |
833794fc | 435 | [@b{-minsn32}] [@b{-mno-insn32}] |
2babba43 | 436 | [@b{-mfix7000}] [@b{-mno-fix7000}] |
a8d14a88 | 437 | [@b{-mfix-rm7000}] [@b{-mno-fix-rm7000}] |
2babba43 MR |
438 | [@b{-mfix-vr4120}] [@b{-mno-fix-vr4120}] |
439 | [@b{-mfix-vr4130}] [@b{-mno-fix-vr4130}] | |
ecb4347a | 440 | [@b{-mdebug}] [@b{-no-mdebug}] |
dcd410fe | 441 | [@b{-mpdr}] [@b{-mno-pdr}] |
3c3bdf30 NC |
442 | @end ifset |
443 | @ifset MMIX | |
a4fb0134 SC |
444 | |
445 | @emph{Target MMIX options:} | |
446 | [@b{--fixed-special-register-names}] [@b{--globalize-symbols}] | |
447 | [@b{--gnu-syntax}] [@b{--relax}] [@b{--no-predefined-symbols}] | |
448 | [@b{--no-expand}] [@b{--no-merge-gregs}] [@b{-x}] | |
973eb340 | 449 | [@b{--linker-allocated-gregs}] |
a4fb0134 | 450 | @end ifset |
36591ba1 SL |
451 | @ifset NIOSII |
452 | ||
453 | @emph{Target Nios II options:} | |
454 | [@b{-relax-all}] [@b{-relax-section}] [@b{-no-relax}] | |
455 | [@b{-EB}] [@b{-EL}] | |
456 | @end ifset | |
35c08157 KLC |
457 | @ifset NDS32 |
458 | ||
459 | @emph{Target NDS32 options:} | |
460 | [@b{-EL}] [@b{-EB}] [@b{-O}] [@b{-Os}] [@b{-mcpu=@var{cpu}}] | |
461 | [@b{-misa=@var{isa}}] [@b{-mabi=@var{abi}}] [@b{-mall-ext}] | |
462 | [@b{-m[no-]16-bit}] [@b{-m[no-]perf-ext}] [@b{-m[no-]perf2-ext}] | |
463 | [@b{-m[no-]string-ext}] [@b{-m[no-]dsp-ext}] [@b{-m[no-]mac}] [@b{-m[no-]div}] | |
464 | [@b{-m[no-]audio-isa-ext}] [@b{-m[no-]fpu-sp-ext}] [@b{-m[no-]fpu-dp-ext}] | |
465 | [@b{-m[no-]fpu-fma}] [@b{-mfpu-freg=@var{FREG}}] [@b{-mreduced-regs}] | |
466 | [@b{-mfull-regs}] [@b{-m[no-]dx-regs}] [@b{-mpic}] [@b{-mno-relax}] | |
467 | [@b{-mb2bb}] | |
468 | @end ifset | |
a4fb0134 SC |
469 | @ifset PDP11 |
470 | ||
471 | @emph{Target PDP11 options:} | |
472 | [@b{-mpic}|@b{-mno-pic}] [@b{-mall}] [@b{-mno-extensions}] | |
473 | [@b{-m}@var{extension}|@b{-mno-}@var{extension}] | |
01642c12 | 474 | [@b{-m}@var{cpu}] [@b{-m}@var{machine}] |
a4fb0134 SC |
475 | @end ifset |
476 | @ifset PJ | |
477 | ||
478 | @emph{Target picoJava options:} | |
479 | [@b{-mb}|@b{-me}] | |
480 | @end ifset | |
481 | @ifset PPC | |
482 | ||
483 | @emph{Target PowerPC options:} | |
b8b738ac AM |
484 | [@b{-a32}|@b{-a64}] |
485 | [@b{-mpwrx}|@b{-mpwr2}|@b{-mpwr}|@b{-m601}|@b{-mppc}|@b{-mppc32}|@b{-m603}|@b{-m604}|@b{-m403}|@b{-m405}| | |
486 | @b{-m440}|@b{-m464}|@b{-m476}|@b{-m7400}|@b{-m7410}|@b{-m7450}|@b{-m7455}|@b{-m750cl}|@b{-mppc64}| | |
aea77599 | 487 | @b{-m620}|@b{-me500}|@b{-e500x2}|@b{-me500mc}|@b{-me500mc64}|@b{-me5500}|@b{-me6500}|@b{-mppc64bridge}| |
b36546d2 | 488 | @b{-mbooke}|@b{-mpower4}|@b{-mpwr4}|@b{-mpower5}|@b{-mpwr5}|@b{-mpwr5x}|@b{-mpower6}|@b{-mpwr6}| |
a680de9a | 489 | @b{-mpower7}|@b{-mpwr7}|@b{-mpower8}|@b{-mpwr8}|@b{-mpower9}|@b{-mpwr9}@b{-ma2}| |
74081948 | 490 | @b{-mcell}|@b{-mspe}|@b{-mspe2}|@b{-mtitan}|@b{-me300}|@b{-mcom}] |
5817ffd1 | 491 | [@b{-many}] [@b{-maltivec}|@b{-mvsx}|@b{-mhtm}|@b{-mvle}] |
a4fb0134 | 492 | [@b{-mregnames}|@b{-mno-regnames}] |
b8b738ac AM |
493 | [@b{-mrelocatable}|@b{-mrelocatable-lib}|@b{-K PIC}] [@b{-memb}] |
494 | [@b{-mlittle}|@b{-mlittle-endian}|@b{-le}|@b{-mbig}|@b{-mbig-endian}|@b{-be}] | |
a4fb0134 | 495 | [@b{-msolaris}|@b{-mno-solaris}] |
b8b738ac | 496 | [@b{-nops=@var{count}}] |
a4fb0134 | 497 | @end ifset |
93f11b16 DD |
498 | @ifset PRU |
499 | ||
500 | @emph{Target PRU options:} | |
501 | [@b{-link-relax}] | |
502 | [@b{-mnolink-relax}] | |
503 | [@b{-mno-warn-regname-label}] | |
504 | @end ifset | |
b57e49f7 JW |
505 | @ifset RISCV |
506 | ||
507 | @emph{Target RISC-V options:} | |
508 | [@b{-fpic}|@b{-fPIC}|@b{-fno-pic}] | |
509 | [@b{-march}=@var{ISA}] | |
510 | [@b{-mabi}=@var{ABI}] | |
511 | @end ifset | |
856ea05c KP |
512 | @ifset RL78 |
513 | ||
514 | @emph{Target RL78 options:} | |
515 | [@b{-mg10}] | |
516 | [@b{-m32bit-doubles}|@b{-m64bit-doubles}] | |
517 | @end ifset | |
c7927a3c NC |
518 | @ifset RX |
519 | ||
520 | @emph{Target RX options:} | |
521 | [@b{-mlittle-endian}|@b{-mbig-endian}] | |
c7927a3c | 522 | [@b{-m32bit-doubles}|@b{-m64bit-doubles}] |
708e2187 NC |
523 | [@b{-muse-conventional-section-names}] |
524 | [@b{-msmall-data-limit}] | |
525 | [@b{-mpid}] | |
526 | [@b{-mrelax}] | |
527 | [@b{-mint-register=@var{number}}] | |
528 | [@b{-mgcc-abi}|@b{-mrx-abi}] | |
c7927a3c | 529 | @end ifset |
11c19e16 MS |
530 | @ifset S390 |
531 | ||
532 | @emph{Target s390 options:} | |
533 | [@b{-m31}|@b{-m64}] [@b{-mesa}|@b{-mzarch}] [@b{-march}=@var{CPU}] | |
534 | [@b{-mregnames}|@b{-mno-regnames}] | |
535 | [@b{-mwarn-areg-zero}] | |
536 | @end ifset | |
c3b7224a NC |
537 | @ifset SCORE |
538 | ||
539 | @emph{Target SCORE options:} | |
540 | [@b{-EB}][@b{-EL}][@b{-FIXDD}][@b{-NWARN}] | |
541 | [@b{-SCORE5}][@b{-SCORE5U}][@b{-SCORE7}][@b{-SCORE3}] | |
542 | [@b{-march=score7}][@b{-march=score3}] | |
543 | [@b{-USE_R1}][@b{-KPIC}][@b{-O0}][@b{-G} @var{num}][@b{-V}] | |
544 | @end ifset | |
a4fb0134 SC |
545 | @ifset SPARC |
546 | ||
547 | @emph{Target SPARC options:} | |
548 | @c The order here is important. See c-sparc.texi. | |
46a2d504 JM |
549 | [@b{-Av6}|@b{-Av7}|@b{-Av8}|@b{-Aleon}|@b{-Asparclet}|@b{-Asparclite} |
550 | @b{-Av8plus}|@b{-Av8plusa}|@b{-Av8plusb}|@b{-Av8plusc}|@b{-Av8plusd} | |
551 | @b{-Av8plusv}|@b{-Av8plusm}|@b{-Av9}|@b{-Av9a}|@b{-Av9b}|@b{-Av9c} | |
552 | @b{-Av9d}|@b{-Av9e}|@b{-Av9v}|@b{-Av9m}|@b{-Asparc}|@b{-Asparcvis} | |
553 | @b{-Asparcvis2}|@b{-Asparcfmaf}|@b{-Asparcima}|@b{-Asparcvis3} | |
554 | @b{-Asparcvisr}|@b{-Asparc5}] | |
555 | [@b{-xarch=v8plus}|@b{-xarch=v8plusa}]|@b{-xarch=v8plusb}|@b{-xarch=v8plusc} | |
556 | @b{-xarch=v8plusd}|@b{-xarch=v8plusv}|@b{-xarch=v8plusm}|@b{-xarch=v9} | |
557 | @b{-xarch=v9a}|@b{-xarch=v9b}|@b{-xarch=v9c}|@b{-xarch=v9d}|@b{-xarch=v9e} | |
558 | @b{-xarch=v9v}|@b{-xarch=v9m}|@b{-xarch=sparc}|@b{-xarch=sparcvis} | |
559 | @b{-xarch=sparcvis2}|@b{-xarch=sparcfmaf}|@b{-xarch=sparcima} | |
560 | @b{-xarch=sparcvis3}|@b{-xarch=sparcvisr}|@b{-xarch=sparc5} | |
561 | @b{-bump}] | |
a4fb0134 | 562 | [@b{-32}|@b{-64}] |
46a2d504 | 563 | [@b{--enforce-aligned-data}][@b{--dcti-couples-detect}] |
a4fb0134 SC |
564 | @end ifset |
565 | @ifset TIC54X | |
566 | ||
567 | @emph{Target TIC54X options:} | |
01642c12 | 568 | [@b{-mcpu=54[123589]}|@b{-mcpu=54[56]lp}] [@b{-mfar-mode}|@b{-mf}] |
a4fb0134 SC |
569 | [@b{-merrors-to-file} @var{<filename>}|@b{-me} @var{<filename>}] |
570 | @end ifset | |
40b36596 JM |
571 | @ifset TIC6X |
572 | ||
573 | @emph{Target TIC6X options:} | |
98d23bef BS |
574 | [@b{-march=@var{arch}}] [@b{-mbig-endian}|@b{-mlittle-endian}] |
575 | [@b{-mdsbt}|@b{-mno-dsbt}] [@b{-mpid=no}|@b{-mpid=near}|@b{-mpid=far}] | |
576 | [@b{-mpic}|@b{-mno-pic}] | |
40b36596 | 577 | @end ifset |
aa137e4d NC |
578 | @ifset TILEGX |
579 | ||
580 | @emph{Target TILE-Gx options:} | |
fb6cedde | 581 | [@b{-m32}|@b{-m64}][@b{-EB}][@b{-EL}] |
aa137e4d NC |
582 | @end ifset |
583 | @ifset TILEPRO | |
584 | @c TILEPro has no machine-dependent assembler options | |
585 | @end ifset | |
b6605ddd | 586 | @ifset VISIUM |
40b36596 | 587 | |
b6605ddd EB |
588 | @emph{Target Visium options:} |
589 | [@b{-mtune=@var{arch}}] | |
590 | @end ifset | |
2d8b84ae SA |
591 | @ifset XTENSA |
592 | ||
593 | @emph{Target Xtensa options:} | |
b46824bd MF |
594 | [@b{--[no-]text-section-literals}] [@b{--[no-]auto-litpools}] |
595 | [@b{--[no-]absolute-literals}] | |
2d8b84ae SA |
596 | [@b{--[no-]target-align}] [@b{--[no-]longcalls}] |
597 | [@b{--[no-]transform}] | |
598 | [@b{--rename-section} @var{oldname}=@var{newname}] | |
a82c7d90 | 599 | [@b{--[no-]trampolines}] |
2d8b84ae | 600 | @end ifset |
3c9b82ba NC |
601 | @ifset Z80 |
602 | ||
603 | @emph{Target Z80 options:} | |
604 | [@b{-z80}] [@b{-r800}] | |
605 | [@b{ -ignore-undocumented-instructions}] [@b{-Wnud}] | |
606 | [@b{ -ignore-unportable-instructions}] [@b{-Wnup}] | |
607 | [@b{ -warn-undocumented-instructions}] [@b{-Wud}] | |
608 | [@b{ -warn-unportable-instructions}] [@b{-Wup}] | |
609 | [@b{ -forbid-undocumented-instructions}] [@b{-Fud}] | |
610 | [@b{ -forbid-unportable-instructions}] [@b{-Fup}] | |
611 | @end ifset | |
a4fb0134 | 612 | @ifset Z8000 |
b6605ddd | 613 | |
a4fb0134 | 614 | @c Z8000 has no machine-dependent assembler options |
252b5132 | 615 | @end ifset |
e0001a05 | 616 | |
0285c67d | 617 | @c man end |
252b5132 RH |
618 | @end smallexample |
619 | ||
0285c67d NC |
620 | @c man begin OPTIONS |
621 | ||
a4fb0134 | 622 | @table @gcctabopt |
38fc1cb1 | 623 | @include at-file.texi |
a0b7da79 | 624 | |
83f10cb2 | 625 | @item -a[cdghlmns] |
252b5132 RH |
626 | Turn on listings, in any of a variety of ways: |
627 | ||
a4fb0134 | 628 | @table @gcctabopt |
252b5132 RH |
629 | @item -ac |
630 | omit false conditionals | |
631 | ||
632 | @item -ad | |
633 | omit debugging directives | |
634 | ||
83f10cb2 NC |
635 | @item -ag |
636 | include general information, like @value{AS} version and options passed | |
637 | ||
252b5132 RH |
638 | @item -ah |
639 | include high-level source | |
640 | ||
641 | @item -al | |
642 | include assembly | |
643 | ||
644 | @item -am | |
645 | include macro expansions | |
646 | ||
647 | @item -an | |
648 | omit forms processing | |
649 | ||
650 | @item -as | |
651 | include symbols | |
652 | ||
653 | @item =file | |
654 | set the name of the listing file | |
655 | @end table | |
656 | ||
657 | You may combine these options; for example, use @samp{-aln} for assembly | |
658 | listing without forms processing. The @samp{=file} option, if used, must be | |
659 | the last one. By itself, @samp{-a} defaults to @samp{-ahls}. | |
660 | ||
caa32fe5 | 661 | @item --alternate |
96e9638b BW |
662 | Begin in alternate macro mode. |
663 | @ifclear man | |
664 | @xref{Altmacro,,@code{.altmacro}}. | |
665 | @end ifclear | |
caa32fe5 | 666 | |
955974c6 | 667 | @item --compress-debug-sections |
19a7fe52 L |
668 | Compress DWARF debug sections using zlib with SHF_COMPRESSED from the |
669 | ELF ABI. The resulting object file may not be compatible with older | |
670 | linkers and object file utilities. Note if compression would make a | |
671 | given section @emph{larger} then it is not compressed. | |
955974c6 | 672 | |
151411f8 L |
673 | @ifset ELF |
674 | @cindex @samp{--compress-debug-sections=} option | |
675 | @item --compress-debug-sections=none | |
676 | @itemx --compress-debug-sections=zlib | |
677 | @itemx --compress-debug-sections=zlib-gnu | |
678 | @itemx --compress-debug-sections=zlib-gabi | |
679 | These options control how DWARF debug sections are compressed. | |
680 | @option{--compress-debug-sections=none} is equivalent to | |
681 | @option{--nocompress-debug-sections}. | |
682 | @option{--compress-debug-sections=zlib} and | |
19a7fe52 | 683 | @option{--compress-debug-sections=zlib-gabi} are equivalent to |
151411f8 | 684 | @option{--compress-debug-sections}. |
19a7fe52 L |
685 | @option{--compress-debug-sections=zlib-gnu} compresses DWARF debug |
686 | sections using zlib. The debug sections are renamed to begin with | |
687 | @samp{.zdebug}. Note if compression would make a given section | |
688 | @emph{larger} then it is not compressed nor renamed. | |
689 | ||
151411f8 L |
690 | @end ifset |
691 | ||
955974c6 | 692 | @item --nocompress-debug-sections |
e12fe555 NC |
693 | Do not compress DWARF debug sections. This is usually the default for all |
694 | targets except the x86/x86_64, but a configure time option can be used to | |
695 | override this. | |
955974c6 | 696 | |
252b5132 RH |
697 | @item -D |
698 | Ignored. This option is accepted for script compatibility with calls to | |
699 | other assemblers. | |
700 | ||
3d6b762c JM |
701 | @item --debug-prefix-map @var{old}=@var{new} |
702 | When assembling files in directory @file{@var{old}}, record debugging | |
703 | information describing them as in @file{@var{new}} instead. | |
704 | ||
252b5132 RH |
705 | @item --defsym @var{sym}=@var{value} |
706 | Define the symbol @var{sym} to be @var{value} before assembling the input file. | |
707 | @var{value} must be an integer constant. As in C, a leading @samp{0x} | |
bf083c64 NC |
708 | indicates a hexadecimal value, and a leading @samp{0} indicates an octal |
709 | value. The value of the symbol can be overridden inside a source file via the | |
710 | use of a @code{.set} pseudo-op. | |
252b5132 RH |
711 | |
712 | @item -f | |
713 | ``fast''---skip whitespace and comment preprocessing (assume source is | |
714 | compiler output). | |
715 | ||
329e276d NC |
716 | @item -g |
717 | @itemx --gen-debug | |
718 | Generate debugging information for each assembler source line using whichever | |
719 | debug format is preferred by the target. This currently means either STABS, | |
720 | ECOFF or DWARF2. | |
721 | ||
252b5132 RH |
722 | @item --gstabs |
723 | Generate stabs debugging information for each assembler line. This | |
724 | may help debugging assembler code, if the debugger can handle it. | |
725 | ||
05da4302 NC |
726 | @item --gstabs+ |
727 | Generate stabs debugging information for each assembler line, with GNU | |
728 | extensions that probably only gdb can handle, and that could make other | |
729 | debuggers crash or refuse to read your program. This | |
730 | may help debugging assembler code. Currently the only GNU extension is | |
731 | the location of the current working directory at assembling time. | |
732 | ||
329e276d | 733 | @item --gdwarf-2 |
cdf82bcf | 734 | Generate DWARF2 debugging information for each assembler line. This |
c1253627 | 735 | may help debugging assembler code, if the debugger can handle it. Note---this |
85a39694 | 736 | option is only supported by some targets, not all of them. |
cdf82bcf | 737 | |
b40bf0a2 NC |
738 | @item --gdwarf-sections |
739 | Instead of creating a .debug_line section, create a series of | |
740 | .debug_line.@var{foo} sections where @var{foo} is the name of the | |
741 | corresponding code section. For example a code section called @var{.text.func} | |
742 | will have its dwarf line number information placed into a section called | |
743 | @var{.debug_line.text.func}. If the code section is just called @var{.text} | |
744 | then debug line section will still be called just @var{.debug_line} without any | |
745 | suffix. | |
746 | ||
b8871f35 | 747 | @ifset ELF |
21be61f5 L |
748 | @item --size-check=error |
749 | @itemx --size-check=warning | |
750 | Issue an error or warning for invalid ELF .size directive. | |
751 | ||
b8871f35 L |
752 | @item --elf-stt-common=no |
753 | @itemx --elf-stt-common=yes | |
754 | These options control whether the ELF assembler should generate common | |
755 | symbols with the @code{STT_COMMON} type. The default can be controlled | |
756 | by a configure option @option{--enable-elf-stt-common}. | |
757 | @end ifset | |
758 | ||
252b5132 RH |
759 | @item --help |
760 | Print a summary of the command line options and exit. | |
761 | ||
ea20a7da CC |
762 | @item --target-help |
763 | Print a summary of all target specific options and exit. | |
764 | ||
252b5132 RH |
765 | @item -I @var{dir} |
766 | Add directory @var{dir} to the search list for @code{.include} directives. | |
767 | ||
768 | @item -J | |
769 | Don't warn about signed overflow. | |
770 | ||
771 | @item -K | |
772 | @ifclear DIFF-TBL-KLUGE | |
773 | This option is accepted but has no effect on the @value{TARGET} family. | |
774 | @end ifclear | |
775 | @ifset DIFF-TBL-KLUGE | |
776 | Issue warnings when difference tables altered for long displacements. | |
777 | @end ifset | |
778 | ||
779 | @item -L | |
780 | @itemx --keep-locals | |
ba83aca1 BW |
781 | Keep (in the symbol table) local symbols. These symbols start with |
782 | system-specific local label prefixes, typically @samp{.L} for ELF systems | |
783 | or @samp{L} for traditional a.out systems. | |
784 | @ifclear man | |
785 | @xref{Symbol Names}. | |
786 | @end ifclear | |
252b5132 | 787 | |
c3a27914 NC |
788 | @item --listing-lhs-width=@var{number} |
789 | Set the maximum width, in words, of the output data column for an assembler | |
790 | listing to @var{number}. | |
791 | ||
792 | @item --listing-lhs-width2=@var{number} | |
793 | Set the maximum width, in words, of the output data column for continuation | |
794 | lines in an assembler listing to @var{number}. | |
795 | ||
796 | @item --listing-rhs-width=@var{number} | |
797 | Set the maximum width of an input source line, as displayed in a listing, to | |
798 | @var{number} bytes. | |
799 | ||
800 | @item --listing-cont-lines=@var{number} | |
801 | Set the maximum number of lines printed in a listing for a single line of input | |
802 | to @var{number} + 1. | |
803 | ||
2edb36e7 NC |
804 | @item --no-pad-sections |
805 | Stop the assembler for padding the ends of output sections to the alignment | |
806 | of that section. The default is to pad the sections, but this can waste space | |
807 | which might be needed on targets which have tight memory constraints. | |
808 | ||
252b5132 | 809 | @item -o @var{objfile} |
a4fb0134 | 810 | Name the object-file output from @command{@value{AS}} @var{objfile}. |
252b5132 RH |
811 | |
812 | @item -R | |
813 | Fold the data section into the text section. | |
814 | ||
d60646b9 | 815 | @item --hash-size=@var{number} |
4bdd3565 NC |
816 | Set the default size of GAS's hash tables to a prime number close to |
817 | @var{number}. Increasing this value can reduce the length of time it takes the | |
818 | assembler to perform its tasks, at the expense of increasing the assembler's | |
819 | memory requirements. Similarly reducing this value can reduce the memory | |
820 | requirements at the expense of speed. | |
821 | ||
822 | @item --reduce-memory-overheads | |
823 | This option reduces GAS's memory requirements, at the expense of making the | |
824 | assembly processes slower. Currently this switch is a synonym for | |
825 | @samp{--hash-size=4051}, but in the future it may have other effects as well. | |
826 | ||
451133ce NP |
827 | @ifset ELF |
828 | @item --sectname-subst | |
829 | Honor substitution sequences in section names. | |
830 | @ifclear man | |
831 | @xref{Section Name Substitutions,,@code{.section @var{name}}}. | |
832 | @end ifclear | |
833 | @end ifset | |
834 | ||
252b5132 RH |
835 | @item --statistics |
836 | Print the maximum space (in bytes) and total time (in seconds) used by | |
837 | assembly. | |
838 | ||
839 | @item --strip-local-absolute | |
840 | Remove local absolute symbols from the outgoing symbol table. | |
841 | ||
842 | @item -v | |
843 | @itemx -version | |
a4fb0134 | 844 | Print the @command{as} version. |
252b5132 RH |
845 | |
846 | @item --version | |
a4fb0134 | 847 | Print the @command{as} version and exit. |
252b5132 RH |
848 | |
849 | @item -W | |
2bdd6cf5 | 850 | @itemx --no-warn |
252b5132 RH |
851 | Suppress warning messages. |
852 | ||
2bdd6cf5 GK |
853 | @item --fatal-warnings |
854 | Treat warnings as errors. | |
855 | ||
856 | @item --warn | |
857 | Don't suppress warning messages or treat them as errors. | |
858 | ||
252b5132 RH |
859 | @item -w |
860 | Ignored. | |
861 | ||
862 | @item -x | |
863 | Ignored. | |
864 | ||
865 | @item -Z | |
866 | Generate an object file even after errors. | |
867 | ||
868 | @item -- | @var{files} @dots{} | |
869 | Standard input, or source files to assemble. | |
870 | ||
871 | @end table | |
2a633939 JM |
872 | @c man end |
873 | ||
a06ea964 NC |
874 | @ifset AARCH64 |
875 | ||
876 | @ifclear man | |
877 | @xref{AArch64 Options}, for the options available when @value{AS} is configured | |
878 | for the 64-bit mode of the ARM Architecture (AArch64). | |
879 | @end ifclear | |
880 | ||
881 | @ifset man | |
882 | @c man begin OPTIONS | |
883 | The following options are available when @value{AS} is configured for the | |
884 | 64-bit mode of the ARM Architecture (AArch64). | |
885 | @c man end | |
886 | @c man begin INCLUDE | |
887 | @include c-aarch64.texi | |
888 | @c ended inside the included file | |
889 | @end ifset | |
890 | ||
891 | @end ifset | |
892 | ||
2a633939 JM |
893 | @ifset ALPHA |
894 | ||
895 | @ifclear man | |
896 | @xref{Alpha Options}, for the options available when @value{AS} is configured | |
897 | for an Alpha processor. | |
898 | @end ifclear | |
899 | ||
900 | @ifset man | |
901 | @c man begin OPTIONS | |
902 | The following options are available when @value{AS} is configured for an Alpha | |
903 | processor. | |
904 | @c man end | |
905 | @c man begin INCLUDE | |
906 | @include c-alpha.texi | |
907 | @c ended inside the included file | |
908 | @end ifset | |
909 | ||
910 | @end ifset | |
252b5132 | 911 | |
2a633939 | 912 | @c man begin OPTIONS |
252b5132 | 913 | @ifset ARC |
886a2506 NC |
914 | The following options are available when @value{AS} is configured for an ARC |
915 | processor. | |
252b5132 | 916 | |
a4fb0134 | 917 | @table @gcctabopt |
886a2506 | 918 | @item -mcpu=@var{cpu} |
0d2bcfaf NC |
919 | This option selects the core processor variant. |
920 | @item -EB | -EL | |
921 | Select either big-endian (-EB) or little-endian (-EL) output. | |
886a2506 NC |
922 | @item -mcode-density |
923 | Enable Code Density extenssion instructions. | |
252b5132 RH |
924 | @end table |
925 | @end ifset | |
926 | ||
927 | @ifset ARM | |
928 | The following options are available when @value{AS} is configured for the ARM | |
929 | processor family. | |
930 | ||
a4fb0134 | 931 | @table @gcctabopt |
92081f48 | 932 | @item -mcpu=@var{processor}[+@var{extension}@dots{}] |
cdf82bcf | 933 | Specify which ARM processor variant is the target. |
92081f48 | 934 | @item -march=@var{architecture}[+@var{extension}@dots{}] |
cdf82bcf | 935 | Specify which ARM architecture variant is used by the target. |
03b1477f | 936 | @item -mfpu=@var{floating-point-format} |
a349d9dd | 937 | Select which Floating Point architecture is the target. |
33a392fb PB |
938 | @item -mfloat-abi=@var{abi} |
939 | Select which floating point ABI is in use. | |
03b1477f RE |
940 | @item -mthumb |
941 | Enable Thumb only instruction decoding. | |
7f266840 | 942 | @item -mapcs-32 | -mapcs-26 | -mapcs-float | -mapcs-reentrant |
252b5132 RH |
943 | Select which procedure calling convention is in use. |
944 | @item -EB | -EL | |
945 | Select either big-endian (-EB) or little-endian (-EL) output. | |
cdf82bcf NC |
946 | @item -mthumb-interwork |
947 | Specify that the code has been generated with interworking between Thumb and | |
948 | ARM code in mind. | |
2e6976a8 DG |
949 | @item -mccs |
950 | Turns on CodeComposer Studio assembly syntax compatibility mode. | |
cdf82bcf NC |
951 | @item -k |
952 | Specify that PIC code has been generated. | |
252b5132 RH |
953 | @end table |
954 | @end ifset | |
635fb38d | 955 | @c man end |
252b5132 | 956 | |
9982501a | 957 | @ifset Blackfin |
8611b8fd MF |
958 | |
959 | @ifclear man | |
960 | @xref{Blackfin Options}, for the options available when @value{AS} is | |
961 | configured for the Blackfin processor family. | |
962 | @end ifclear | |
963 | ||
964 | @ifset man | |
965 | @c man begin OPTIONS | |
9982501a JZ |
966 | The following options are available when @value{AS} is configured for |
967 | the Blackfin processor family. | |
8611b8fd MF |
968 | @c man end |
969 | @c man begin INCLUDE | |
970 | @include c-bfin.texi | |
971 | @c ended inside the included file | |
972 | @end ifset | |
9982501a | 973 | |
9982501a JZ |
974 | @end ifset |
975 | ||
635fb38d | 976 | @c man begin OPTIONS |
328eb32e HPN |
977 | @ifset CRIS |
978 | See the info pages for documentation of the CRIS-specific options. | |
979 | @end ifset | |
980 | ||
252b5132 RH |
981 | @ifset D10V |
982 | The following options are available when @value{AS} is configured for | |
983 | a D10V processor. | |
a4fb0134 | 984 | @table @gcctabopt |
252b5132 RH |
985 | @cindex D10V optimization |
986 | @cindex optimization, D10V | |
987 | @item -O | |
988 | Optimize output by parallelizing instructions. | |
989 | @end table | |
990 | @end ifset | |
991 | ||
992 | @ifset D30V | |
993 | The following options are available when @value{AS} is configured for a D30V | |
994 | processor. | |
a4fb0134 | 995 | @table @gcctabopt |
252b5132 RH |
996 | @cindex D30V optimization |
997 | @cindex optimization, D30V | |
998 | @item -O | |
999 | Optimize output by parallelizing instructions. | |
1000 | ||
1001 | @cindex D30V nops | |
1002 | @item -n | |
1003 | Warn when nops are generated. | |
1004 | ||
1005 | @cindex D30V nops after 32-bit multiply | |
1006 | @item -N | |
1007 | Warn when a nop after a 32-bit multiply instruction is generated. | |
1008 | @end table | |
1009 | @end ifset | |
731caf76 L |
1010 | @c man end |
1011 | ||
cfb8c092 NC |
1012 | @ifset EPIPHANY |
1013 | The following options are available when @value{AS} is configured for the | |
1014 | Adapteva EPIPHANY series. | |
1015 | ||
56b13185 JR |
1016 | @ifclear man |
1017 | @xref{Epiphany Options}, for the options available when @value{AS} is | |
1018 | configured for an Epiphany processor. | |
1019 | @end ifclear | |
cfb8c092 | 1020 | |
56b13185 JR |
1021 | @ifset man |
1022 | @c man begin OPTIONS | |
1023 | The following options are available when @value{AS} is configured for | |
1024 | an Epiphany processor. | |
1025 | @c man end | |
1026 | @c man begin INCLUDE | |
1027 | @include c-epiphany.texi | |
0c76cae8 AM |
1028 | @c ended inside the included file |
1029 | @end ifset | |
1030 | ||
1031 | @end ifset | |
1032 | ||
1033 | @ifset H8300 | |
1034 | ||
1035 | @ifclear man | |
1036 | @xref{H8/300 Options}, for the options available when @value{AS} is configured | |
1037 | for an H8/300 processor. | |
1038 | @end ifclear | |
1039 | ||
1040 | @ifset man | |
1041 | @c man begin OPTIONS | |
1042 | The following options are available when @value{AS} is configured for an H8/300 | |
1043 | processor. | |
1044 | @c man end | |
1045 | @c man begin INCLUDE | |
1046 | @include c-h8300.texi | |
56b13185 JR |
1047 | @c ended inside the included file |
1048 | @end ifset | |
cfb8c092 | 1049 | |
cfb8c092 NC |
1050 | @end ifset |
1051 | ||
731caf76 | 1052 | @ifset I80386 |
252b5132 | 1053 | |
731caf76 L |
1054 | @ifclear man |
1055 | @xref{i386-Options}, for the options available when @value{AS} is | |
1056 | configured for an i386 processor. | |
1057 | @end ifclear | |
1058 | ||
1059 | @ifset man | |
1060 | @c man begin OPTIONS | |
1061 | The following options are available when @value{AS} is configured for | |
1062 | an i386 processor. | |
1063 | @c man end | |
1064 | @c man begin INCLUDE | |
1065 | @include c-i386.texi | |
1066 | @c ended inside the included file | |
1067 | @end ifset | |
1068 | ||
1069 | @end ifset | |
1070 | ||
1071 | @c man begin OPTIONS | |
252b5132 RH |
1072 | @ifset I960 |
1073 | The following options are available when @value{AS} is configured for the | |
1074 | Intel 80960 processor. | |
1075 | ||
a4fb0134 | 1076 | @table @gcctabopt |
252b5132 RH |
1077 | @item -ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC |
1078 | Specify which variant of the 960 architecture is the target. | |
1079 | ||
1080 | @item -b | |
1081 | Add code to collect statistics about branches taken. | |
1082 | ||
1083 | @item -no-relax | |
1084 | Do not alter compare-and-branch instructions for long displacements; | |
1085 | error if necessary. | |
1086 | ||
1087 | @end table | |
1088 | @end ifset | |
1089 | ||
a40cbfa3 NC |
1090 | @ifset IP2K |
1091 | The following options are available when @value{AS} is configured for the | |
ec88d317 | 1092 | Ubicom IP2K series. |
a40cbfa3 NC |
1093 | |
1094 | @table @gcctabopt | |
1095 | ||
1096 | @item -mip2022ext | |
1097 | Specifies that the extended IP2022 instructions are allowed. | |
1098 | ||
1099 | @item -mip2022 | |
8dfa0188 | 1100 | Restores the default behaviour, which restricts the permitted instructions to |
a40cbfa3 NC |
1101 | just the basic IP2022 ones. |
1102 | ||
1103 | @end table | |
1104 | @end ifset | |
1105 | ||
49f58d10 JB |
1106 | @ifset M32C |
1107 | The following options are available when @value{AS} is configured for the | |
1108 | Renesas M32C and M16C processors. | |
1109 | ||
1110 | @table @gcctabopt | |
1111 | ||
1112 | @item -m32c | |
1113 | Assemble M32C instructions. | |
1114 | ||
1115 | @item -m16c | |
1116 | Assemble M16C instructions (the default). | |
1117 | ||
c54b5932 DD |
1118 | @item -relax |
1119 | Enable support for link-time relaxations. | |
1120 | ||
1121 | @item -h-tick-hex | |
1122 | Support H'00 style hex constants in addition to 0x00 style. | |
1123 | ||
49f58d10 JB |
1124 | @end table |
1125 | @end ifset | |
1126 | ||
ec694b89 NC |
1127 | @ifset M32R |
1128 | The following options are available when @value{AS} is configured for the | |
26597c86 | 1129 | Renesas M32R (formerly Mitsubishi M32R) series. |
ec694b89 | 1130 | |
a4fb0134 | 1131 | @table @gcctabopt |
ec694b89 NC |
1132 | |
1133 | @item --m32rx | |
1134 | Specify which processor in the M32R family is the target. The default | |
1135 | is normally the M32R, but this option changes it to the M32RX. | |
1136 | ||
1137 | @item --warn-explicit-parallel-conflicts or --Wp | |
1138 | Produce warning messages when questionable parallel constructs are | |
01642c12 | 1139 | encountered. |
ec694b89 NC |
1140 | |
1141 | @item --no-warn-explicit-parallel-conflicts or --Wnp | |
01642c12 RM |
1142 | Do not produce warning messages when questionable parallel constructs are |
1143 | encountered. | |
ec694b89 NC |
1144 | |
1145 | @end table | |
1146 | @end ifset | |
252b5132 RH |
1147 | |
1148 | @ifset M680X0 | |
1149 | The following options are available when @value{AS} is configured for the | |
1150 | Motorola 68000 series. | |
1151 | ||
a4fb0134 | 1152 | @table @gcctabopt |
252b5132 RH |
1153 | |
1154 | @item -l | |
1155 | Shorten references to undefined symbols, to one word instead of two. | |
1156 | ||
0285c67d NC |
1157 | @item -m68000 | -m68008 | -m68010 | -m68020 | -m68030 |
1158 | @itemx | -m68040 | -m68060 | -m68302 | -m68331 | -m68332 | |
1159 | @itemx | -m68333 | -m68340 | -mcpu32 | -m5200 | |
252b5132 RH |
1160 | Specify what processor in the 68000 family is the target. The default |
1161 | is normally the 68020, but this can be changed at configuration time. | |
1162 | ||
1163 | @item -m68881 | -m68882 | -mno-68881 | -mno-68882 | |
1164 | The target machine does (or does not) have a floating-point coprocessor. | |
1165 | The default is to assume a coprocessor for 68020, 68030, and cpu32. Although | |
1166 | the basic 68000 is not compatible with the 68881, a combination of the | |
1167 | two can be specified, since it's possible to do emulation of the | |
1168 | coprocessor instructions with the main processor. | |
1169 | ||
1170 | @item -m68851 | -mno-68851 | |
1171 | The target machine does (or does not) have a memory-management | |
1172 | unit coprocessor. The default is to assume an MMU for 68020 and up. | |
1173 | ||
1174 | @end table | |
1175 | @end ifset | |
1176 | ||
36591ba1 SL |
1177 | @ifset NIOSII |
1178 | ||
1179 | @ifclear man | |
1180 | @xref{Nios II Options}, for the options available when @value{AS} is configured | |
1181 | for an Altera Nios II processor. | |
1182 | @end ifclear | |
1183 | ||
1184 | @ifset man | |
1185 | @c man begin OPTIONS | |
1186 | The following options are available when @value{AS} is configured for an | |
1187 | Altera Nios II processor. | |
1188 | @c man end | |
1189 | @c man begin INCLUDE | |
1190 | @include c-nios2.texi | |
1191 | @c ended inside the included file | |
1192 | @end ifset | |
1193 | @end ifset | |
1194 | ||
e135f41b NC |
1195 | @ifset PDP11 |
1196 | ||
1197 | For details about the PDP-11 machine dependent features options, | |
1198 | see @ref{PDP-11-Options}. | |
1199 | ||
a4fb0134 | 1200 | @table @gcctabopt |
e135f41b NC |
1201 | @item -mpic | -mno-pic |
1202 | Generate position-independent (or position-dependent) code. The | |
a4fb0134 | 1203 | default is @option{-mpic}. |
e135f41b NC |
1204 | |
1205 | @item -mall | |
1206 | @itemx -mall-extensions | |
1207 | Enable all instruction set extensions. This is the default. | |
1208 | ||
1209 | @item -mno-extensions | |
1210 | Disable all instruction set extensions. | |
1211 | ||
1212 | @item -m@var{extension} | -mno-@var{extension} | |
1213 | Enable (or disable) a particular instruction set extension. | |
1214 | ||
1215 | @item -m@var{cpu} | |
1216 | Enable the instruction set extensions supported by a particular CPU, and | |
1217 | disable all other extensions. | |
1218 | ||
1219 | @item -m@var{machine} | |
1220 | Enable the instruction set extensions supported by a particular machine | |
1221 | model, and disable all other extensions. | |
1222 | @end table | |
1223 | ||
1224 | @end ifset | |
1225 | ||
041dd5a9 ILT |
1226 | @ifset PJ |
1227 | The following options are available when @value{AS} is configured for | |
1228 | a picoJava processor. | |
1229 | ||
a4fb0134 | 1230 | @table @gcctabopt |
041dd5a9 ILT |
1231 | |
1232 | @cindex PJ endianness | |
1233 | @cindex endianness, PJ | |
1234 | @cindex big endian output, PJ | |
1235 | @item -mb | |
1236 | Generate ``big endian'' format output. | |
1237 | ||
1238 | @cindex little endian output, PJ | |
1239 | @item -ml | |
1240 | Generate ``little endian'' format output. | |
1241 | ||
1242 | @end table | |
1243 | @end ifset | |
1244 | ||
93f11b16 DD |
1245 | @ifset PRU |
1246 | ||
1247 | @ifclear man | |
1248 | @xref{PRU Options}, for the options available when @value{AS} is configured | |
1249 | for a PRU processor. | |
1250 | @end ifclear | |
1251 | ||
1252 | @ifset man | |
1253 | @c man begin OPTIONS | |
1254 | The following options are available when @value{AS} is configured for a | |
1255 | PRU processor. | |
1256 | @c man end | |
1257 | @c man begin INCLUDE | |
1258 | @include c-pru.texi | |
1259 | @c ended inside the included file | |
1260 | @end ifset | |
1261 | @end ifset | |
1262 | ||
60bcf0fa NC |
1263 | @ifset M68HC11 |
1264 | The following options are available when @value{AS} is configured for the | |
1265 | Motorola 68HC11 or 68HC12 series. | |
1266 | ||
a4fb0134 | 1267 | @table @gcctabopt |
60bcf0fa | 1268 | |
6927f982 | 1269 | @item -m68hc11 | -m68hc12 | -m68hcs12 | -mm9s12x | -mm9s12xg |
60bcf0fa NC |
1270 | Specify what processor is the target. The default is |
1271 | defined by the configuration option when building the assembler. | |
1272 | ||
6927f982 NC |
1273 | @item --xgate-ramoffset |
1274 | Instruct the linker to offset RAM addresses from S12X address space into | |
1275 | XGATE address space. | |
1276 | ||
2f904664 SC |
1277 | @item -mshort |
1278 | Specify to use the 16-bit integer ABI. | |
1279 | ||
1280 | @item -mlong | |
01642c12 | 1281 | Specify to use the 32-bit integer ABI. |
2f904664 SC |
1282 | |
1283 | @item -mshort-double | |
01642c12 | 1284 | Specify to use the 32-bit double ABI. |
2f904664 SC |
1285 | |
1286 | @item -mlong-double | |
01642c12 | 1287 | Specify to use the 64-bit double ABI. |
2f904664 | 1288 | |
1370e33d | 1289 | @item --force-long-branches |
60bcf0fa NC |
1290 | Relative branches are turned into absolute ones. This concerns |
1291 | conditional branches, unconditional branches and branches to a | |
1292 | sub routine. | |
1293 | ||
1370e33d NC |
1294 | @item -S | --short-branches |
1295 | Do not turn relative branches into absolute ones | |
60bcf0fa NC |
1296 | when the offset is out of range. |
1297 | ||
1298 | @item --strict-direct-mode | |
1299 | Do not turn the direct addressing mode into extended addressing mode | |
1300 | when the instruction does not support direct addressing mode. | |
1301 | ||
1302 | @item --print-insn-syntax | |
1303 | Print the syntax of instruction in case of error. | |
1304 | ||
1305 | @item --print-opcodes | |
6927f982 | 1306 | Print the list of instructions with syntax and then exit. |
60bcf0fa NC |
1307 | |
1308 | @item --generate-example | |
6927f982 | 1309 | Print an example of instruction for each possible instruction and then exit. |
a4fb0134 | 1310 | This option is only useful for testing @command{@value{AS}}. |
60bcf0fa NC |
1311 | |
1312 | @end table | |
1313 | @end ifset | |
1314 | ||
252b5132 | 1315 | @ifset SPARC |
a4fb0134 | 1316 | The following options are available when @command{@value{AS}} is configured |
252b5132 RH |
1317 | for the SPARC architecture: |
1318 | ||
a4fb0134 | 1319 | @table @gcctabopt |
252b5132 RH |
1320 | @item -Av6 | -Av7 | -Av8 | -Asparclet | -Asparclite |
1321 | @itemx -Av8plus | -Av8plusa | -Av9 | -Av9a | |
1322 | Explicitly select a variant of the SPARC architecture. | |
1323 | ||
1324 | @samp{-Av8plus} and @samp{-Av8plusa} select a 32 bit environment. | |
1325 | @samp{-Av9} and @samp{-Av9a} select a 64 bit environment. | |
1326 | ||
1327 | @samp{-Av8plusa} and @samp{-Av9a} enable the SPARC V9 instruction set with | |
1328 | UltraSPARC extensions. | |
1329 | ||
1330 | @item -xarch=v8plus | -xarch=v8plusa | |
1331 | For compatibility with the Solaris v9 assembler. These options are | |
1332 | equivalent to -Av8plus and -Av8plusa, respectively. | |
1333 | ||
1334 | @item -bump | |
1335 | Warn when the assembler switches to another architecture. | |
1336 | @end table | |
1337 | @end ifset | |
1338 | ||
39bec121 TW |
1339 | @ifset TIC54X |
1340 | The following options are available when @value{AS} is configured for the 'c54x | |
01642c12 | 1341 | architecture. |
39bec121 | 1342 | |
a4fb0134 | 1343 | @table @gcctabopt |
39bec121 TW |
1344 | @item -mfar-mode |
1345 | Enable extended addressing mode. All addresses and relocations will assume | |
1346 | extended addressing (usually 23 bits). | |
1347 | @item -mcpu=@var{CPU_VERSION} | |
1348 | Sets the CPU version being compiled for. | |
1349 | @item -merrors-to-file @var{FILENAME} | |
1350 | Redirect error output to a file, for broken systems which don't support such | |
1351 | behaviour in the shell. | |
1352 | @end table | |
1353 | @end ifset | |
1354 | ||
252b5132 | 1355 | @ifset MIPS |
73201331 | 1356 | @c man begin OPTIONS |
252b5132 | 1357 | The following options are available when @value{AS} is configured for |
98508b2a | 1358 | a MIPS processor. |
252b5132 | 1359 | |
a4fb0134 | 1360 | @table @gcctabopt |
252b5132 RH |
1361 | @item -G @var{num} |
1362 | This option sets the largest size of an object that can be referenced | |
1363 | implicitly with the @code{gp} register. It is only accepted for targets that | |
1364 | use ECOFF format, such as a DECstation running Ultrix. The default value is 8. | |
1365 | ||
1366 | @cindex MIPS endianness | |
1367 | @cindex endianness, MIPS | |
1368 | @cindex big endian output, MIPS | |
1369 | @item -EB | |
1370 | Generate ``big endian'' format output. | |
1371 | ||
1372 | @cindex little endian output, MIPS | |
1373 | @item -EL | |
1374 | Generate ``little endian'' format output. | |
1375 | ||
1376 | @cindex MIPS ISA | |
1377 | @item -mips1 | |
1378 | @itemx -mips2 | |
1379 | @itemx -mips3 | |
e7af610e | 1380 | @itemx -mips4 |
437ee9d5 | 1381 | @itemx -mips5 |
e7af610e | 1382 | @itemx -mips32 |
af7ee8bf | 1383 | @itemx -mips32r2 |
ae52f483 AB |
1384 | @itemx -mips32r3 |
1385 | @itemx -mips32r5 | |
7361da2c | 1386 | @itemx -mips32r6 |
4058e45f | 1387 | @itemx -mips64 |
5f74bc13 | 1388 | @itemx -mips64r2 |
ae52f483 AB |
1389 | @itemx -mips64r3 |
1390 | @itemx -mips64r5 | |
7361da2c | 1391 | @itemx -mips64r6 |
98508b2a | 1392 | Generate code for a particular MIPS Instruction Set Architecture level. |
437ee9d5 TS |
1393 | @samp{-mips1} is an alias for @samp{-march=r3000}, @samp{-mips2} is an |
1394 | alias for @samp{-march=r6000}, @samp{-mips3} is an alias for | |
1395 | @samp{-march=r4000} and @samp{-mips4} is an alias for @samp{-march=r8000}. | |
ae52f483 | 1396 | @samp{-mips5}, @samp{-mips32}, @samp{-mips32r2}, @samp{-mips32r3}, |
7361da2c AB |
1397 | @samp{-mips32r5}, @samp{-mips32r6}, @samp{-mips64}, @samp{-mips64r2}, |
1398 | @samp{-mips64r3}, @samp{-mips64r5}, and @samp{-mips64r6} correspond to generic | |
1399 | MIPS V, MIPS32, MIPS32 Release 2, MIPS32 Release 3, MIPS32 Release 5, MIPS32 | |
1400 | Release 6, MIPS64, MIPS64 Release 2, MIPS64 Release 3, MIPS64 Release 5, and | |
1401 | MIPS64 Release 6 ISA processors, respectively. | |
437ee9d5 | 1402 | |
98508b2a RS |
1403 | @item -march=@var{cpu} |
1404 | Generate code for a particular MIPS CPU. | |
437ee9d5 TS |
1405 | |
1406 | @item -mtune=@var{cpu} | |
98508b2a | 1407 | Schedule and tune for a particular MIPS CPU. |
437ee9d5 TS |
1408 | |
1409 | @item -mfix7000 | |
1410 | @itemx -mno-fix7000 | |
1411 | Cause nops to be inserted if the read of the destination register | |
1412 | of an mfhi or mflo instruction occurs in the following two instructions. | |
1413 | ||
a8d14a88 CM |
1414 | @item -mfix-rm7000 |
1415 | @itemx -mno-fix-rm7000 | |
1416 | Cause nops to be inserted if a dmult or dmultu instruction is | |
1417 | followed by a load instruction. | |
1418 | ||
ecb4347a DJ |
1419 | @item -mdebug |
1420 | @itemx -no-mdebug | |
1421 | Cause stabs-style debugging output to go into an ECOFF-style .mdebug | |
1422 | section instead of the standard ELF .stabs sections. | |
1423 | ||
dcd410fe RO |
1424 | @item -mpdr |
1425 | @itemx -mno-pdr | |
1426 | Control generation of @code{.pdr} sections. | |
1427 | ||
437ee9d5 TS |
1428 | @item -mgp32 |
1429 | @itemx -mfp32 | |
1430 | The register sizes are normally inferred from the ISA and ABI, but these | |
1431 | flags force a certain group of registers to be treated as 32 bits wide at | |
1432 | all times. @samp{-mgp32} controls the size of general-purpose registers | |
1433 | and @samp{-mfp32} controls the size of floating-point registers. | |
1434 | ||
351cdf24 MF |
1435 | @item -mgp64 |
1436 | @itemx -mfp64 | |
1437 | The register sizes are normally inferred from the ISA and ABI, but these | |
1438 | flags force a certain group of registers to be treated as 64 bits wide at | |
1439 | all times. @samp{-mgp64} controls the size of general-purpose registers | |
1440 | and @samp{-mfp64} controls the size of floating-point registers. | |
1441 | ||
1442 | @item -mfpxx | |
1443 | The register sizes are normally inferred from the ISA and ABI, but using | |
1444 | this flag in combination with @samp{-mabi=32} enables an ABI variant | |
1445 | which will operate correctly with floating-point registers which are | |
1446 | 32 or 64 bits wide. | |
1447 | ||
1448 | @item -modd-spreg | |
1449 | @itemx -mno-odd-spreg | |
1450 | Enable use of floating-point operations on odd-numbered single-precision | |
1451 | registers when supported by the ISA. @samp{-mfpxx} implies | |
1452 | @samp{-mno-odd-spreg}, otherwise the default is @samp{-modd-spreg}. | |
1453 | ||
437ee9d5 TS |
1454 | @item -mips16 |
1455 | @itemx -no-mips16 | |
1456 | Generate code for the MIPS 16 processor. This is equivalent to putting | |
32035f51 | 1457 | @code{.module mips16} at the start of the assembly file. @samp{-no-mips16} |
437ee9d5 | 1458 | turns off this option. |
252b5132 | 1459 | |
25499ac7 MR |
1460 | @item -mmips16e2 |
1461 | @itemx -mno-mips16e2 | |
1462 | Enable the use of MIPS16e2 instructions in MIPS16 mode. This is equivalent | |
1463 | to putting @code{.module mips16e2} at the start of the assembly file. | |
1464 | @samp{-mno-mips16e2} turns off this option. | |
1465 | ||
df58fc94 RS |
1466 | @item -mmicromips |
1467 | @itemx -mno-micromips | |
1468 | Generate code for the microMIPS processor. This is equivalent to putting | |
32035f51 MR |
1469 | @code{.module micromips} at the start of the assembly file. |
1470 | @samp{-mno-micromips} turns off this option. This is equivalent to putting | |
1471 | @code{.module nomicromips} at the start of the assembly file. | |
df58fc94 | 1472 | |
e16bfa71 TS |
1473 | @item -msmartmips |
1474 | @itemx -mno-smartmips | |
32035f51 MR |
1475 | Enables the SmartMIPS extension to the MIPS32 instruction set. This is |
1476 | equivalent to putting @code{.module smartmips} at the start of the assembly | |
1477 | file. @samp{-mno-smartmips} turns off this option. | |
e16bfa71 | 1478 | |
1f25f5d3 CD |
1479 | @item -mips3d |
1480 | @itemx -no-mips3d | |
1481 | Generate code for the MIPS-3D Application Specific Extension. | |
1482 | This tells the assembler to accept MIPS-3D instructions. | |
1483 | @samp{-no-mips3d} turns off this option. | |
1484 | ||
deec1734 CD |
1485 | @item -mdmx |
1486 | @itemx -no-mdmx | |
1487 | Generate code for the MDMX Application Specific Extension. | |
1488 | This tells the assembler to accept MDMX instructions. | |
1489 | @samp{-no-mdmx} turns off this option. | |
1490 | ||
2ef2b9ae CF |
1491 | @item -mdsp |
1492 | @itemx -mno-dsp | |
8b082fb1 TS |
1493 | Generate code for the DSP Release 1 Application Specific Extension. |
1494 | This tells the assembler to accept DSP Release 1 instructions. | |
2ef2b9ae CF |
1495 | @samp{-mno-dsp} turns off this option. |
1496 | ||
8b082fb1 TS |
1497 | @item -mdspr2 |
1498 | @itemx -mno-dspr2 | |
1499 | Generate code for the DSP Release 2 Application Specific Extension. | |
8f4f9071 | 1500 | This option implies @samp{-mdsp}. |
8b082fb1 TS |
1501 | This tells the assembler to accept DSP Release 2 instructions. |
1502 | @samp{-mno-dspr2} turns off this option. | |
1503 | ||
8f4f9071 MF |
1504 | @item -mdspr3 |
1505 | @itemx -mno-dspr3 | |
1506 | Generate code for the DSP Release 3 Application Specific Extension. | |
1507 | This option implies @samp{-mdsp} and @samp{-mdspr2}. | |
1508 | This tells the assembler to accept DSP Release 3 instructions. | |
1509 | @samp{-mno-dspr3} turns off this option. | |
1510 | ||
56d438b1 CF |
1511 | @item -mmsa |
1512 | @itemx -mno-msa | |
1513 | Generate code for the MIPS SIMD Architecture Extension. | |
1514 | This tells the assembler to accept MSA instructions. | |
1515 | @samp{-mno-msa} turns off this option. | |
1516 | ||
7d64c587 AB |
1517 | @item -mxpa |
1518 | @itemx -mno-xpa | |
1519 | Generate code for the MIPS eXtended Physical Address (XPA) Extension. | |
1520 | This tells the assembler to accept XPA instructions. | |
1521 | @samp{-mno-xpa} turns off this option. | |
1522 | ||
ef2e4d86 CF |
1523 | @item -mmt |
1524 | @itemx -mno-mt | |
1525 | Generate code for the MT Application Specific Extension. | |
1526 | This tells the assembler to accept MT instructions. | |
1527 | @samp{-mno-mt} turns off this option. | |
1528 | ||
dec0624d MR |
1529 | @item -mmcu |
1530 | @itemx -mno-mcu | |
1531 | Generate code for the MCU Application Specific Extension. | |
1532 | This tells the assembler to accept MCU instructions. | |
1533 | @samp{-mno-mcu} turns off this option. | |
1534 | ||
833794fc MR |
1535 | @item -minsn32 |
1536 | @itemx -mno-insn32 | |
1537 | Only use 32-bit instruction encodings when generating code for the | |
1538 | microMIPS processor. This option inhibits the use of any 16-bit | |
1539 | instructions. This is equivalent to putting @code{.set insn32} at | |
1540 | the start of the assembly file. @samp{-mno-insn32} turns off this | |
1541 | option. This is equivalent to putting @code{.set noinsn32} at the | |
1542 | start of the assembly file. By default @samp{-mno-insn32} is | |
1543 | selected, allowing all instructions to be used. | |
1544 | ||
437ee9d5 TS |
1545 | @item --construct-floats |
1546 | @itemx --no-construct-floats | |
1547 | The @samp{--no-construct-floats} option disables the construction of | |
1548 | double width floating point constants by loading the two halves of the | |
1549 | value into the two single width floating point registers that make up | |
1550 | the double width register. By default @samp{--construct-floats} is | |
1551 | selected, allowing construction of these floating point constants. | |
252b5132 | 1552 | |
3bf0dbfb MR |
1553 | @item --relax-branch |
1554 | @itemx --no-relax-branch | |
1555 | The @samp{--relax-branch} option enables the relaxation of out-of-range | |
1556 | branches. By default @samp{--no-relax-branch} is selected, causing any | |
1557 | out-of-range branches to produce an error. | |
1558 | ||
8b10b0b3 MR |
1559 | @item -mignore-branch-isa |
1560 | @itemx -mno-ignore-branch-isa | |
1561 | Ignore branch checks for invalid transitions between ISA modes. The | |
1562 | semantics of branches does not provide for an ISA mode switch, so in | |
1563 | most cases the ISA mode a branch has been encoded for has to be the | |
1564 | same as the ISA mode of the branch's target label. Therefore GAS has | |
1565 | checks implemented that verify in branch assembly that the two ISA | |
1566 | modes match. @samp{-mignore-branch-isa} disables these checks. By | |
1567 | default @samp{-mno-ignore-branch-isa} is selected, causing any invalid | |
1568 | branch requiring a transition between ISA modes to produce an error. | |
1569 | ||
ba92f887 MR |
1570 | @item -mnan=@var{encoding} |
1571 | Select between the IEEE 754-2008 (@option{-mnan=2008}) or the legacy | |
1572 | (@option{-mnan=legacy}) NaN encoding format. The latter is the default. | |
1573 | ||
252b5132 RH |
1574 | @cindex emulation |
1575 | @item --emulation=@var{name} | |
e8044f35 RS |
1576 | This option was formerly used to switch between ELF and ECOFF output |
1577 | on targets like IRIX 5 that supported both. MIPS ECOFF support was | |
1578 | removed in GAS 2.24, so the option now serves little purpose. | |
1579 | It is retained for backwards compatibility. | |
1580 | ||
1581 | The available configuration names are: @samp{mipself}, @samp{mipslelf} and | |
1582 | @samp{mipsbelf}. Choosing @samp{mipself} now has no effect, since the output | |
1583 | is always ELF. @samp{mipslelf} and @samp{mipsbelf} select little- and | |
1584 | big-endian output respectively, but @samp{-EL} and @samp{-EB} are now the | |
1585 | preferred options instead. | |
252b5132 RH |
1586 | |
1587 | @item -nocpp | |
a4fb0134 | 1588 | @command{@value{AS}} ignores this option. It is accepted for compatibility with |
252b5132 RH |
1589 | the native tools. |
1590 | ||
252b5132 RH |
1591 | @item --trap |
1592 | @itemx --no-trap | |
1593 | @itemx --break | |
1594 | @itemx --no-break | |
1595 | Control how to deal with multiplication overflow and division by zero. | |
1596 | @samp{--trap} or @samp{--no-break} (which are synonyms) take a trap exception | |
1597 | (and only work for Instruction Set Architecture level 2 and higher); | |
1598 | @samp{--break} or @samp{--no-trap} (also synonyms, and the default) take a | |
1599 | break exception. | |
63486801 L |
1600 | |
1601 | @item -n | |
a4fb0134 | 1602 | When this option is used, @command{@value{AS}} will issue a warning every |
63486801 | 1603 | time it generates a nop instruction from a macro. |
252b5132 | 1604 | @end table |
73201331 | 1605 | @c man end |
252b5132 RH |
1606 | @end ifset |
1607 | ||
1608 | @ifset MCORE | |
1609 | The following options are available when @value{AS} is configured for | |
1610 | an MCore processor. | |
1611 | ||
a4fb0134 | 1612 | @table @gcctabopt |
252b5132 RH |
1613 | @item -jsri2bsr |
1614 | @itemx -nojsri2bsr | |
1615 | Enable or disable the JSRI to BSR transformation. By default this is enabled. | |
1616 | The command line option @samp{-nojsri2bsr} can be used to disable it. | |
1617 | ||
1618 | @item -sifilter | |
1619 | @itemx -nosifilter | |
1620 | Enable or disable the silicon filter behaviour. By default this is disabled. | |
a349d9dd | 1621 | The default can be overridden by the @samp{-sifilter} command line option. |
252b5132 RH |
1622 | |
1623 | @item -relax | |
1624 | Alter jump instructions for long displacements. | |
1625 | ||
ec694b89 NC |
1626 | @item -mcpu=[210|340] |
1627 | Select the cpu type on the target hardware. This controls which instructions | |
1628 | can be assembled. | |
1629 | ||
1630 | @item -EB | |
1631 | Assemble for a big endian target. | |
1632 | ||
1633 | @item -EL | |
1634 | Assemble for a little endian target. | |
252b5132 RH |
1635 | |
1636 | @end table | |
1637 | @end ifset | |
a3c62988 | 1638 | @c man end |
252b5132 | 1639 | |
a3c62988 NC |
1640 | @ifset METAG |
1641 | ||
1642 | @ifclear man | |
1643 | @xref{Meta Options}, for the options available when @value{AS} is configured | |
1644 | for a Meta processor. | |
1645 | @end ifclear | |
1646 | ||
1647 | @ifset man | |
1648 | @c man begin OPTIONS | |
1649 | The following options are available when @value{AS} is configured for a | |
1650 | Meta processor. | |
1651 | @c man end | |
1652 | @c man begin INCLUDE | |
1653 | @include c-metag.texi | |
1654 | @c ended inside the included file | |
1655 | @end ifset | |
1656 | ||
1657 | @end ifset | |
1658 | ||
1659 | @c man begin OPTIONS | |
3c3bdf30 NC |
1660 | @ifset MMIX |
1661 | See the info pages for documentation of the MMIX-specific options. | |
1662 | @end ifset | |
1663 | ||
35c08157 KLC |
1664 | @ifset NDS32 |
1665 | ||
1666 | @ifclear man | |
1667 | @xref{NDS32 Options}, for the options available when @value{AS} is configured | |
1668 | for a NDS32 processor. | |
1669 | @end ifclear | |
1670 | @c ended inside the included file | |
1671 | @end ifset | |
1672 | ||
1673 | @ifset man | |
1674 | @c man begin OPTIONS | |
1675 | The following options are available when @value{AS} is configured for a | |
1676 | NDS32 processor. | |
1677 | @c man end | |
1678 | @c man begin INCLUDE | |
1679 | @include c-nds32.texi | |
1680 | @c ended inside the included file | |
1681 | @end ifset | |
1682 | ||
635fb38d | 1683 | @c man end |
b8b738ac AM |
1684 | @ifset PPC |
1685 | ||
1686 | @ifclear man | |
1687 | @xref{PowerPC-Opts}, for the options available when @value{AS} is configured | |
1688 | for a PowerPC processor. | |
1689 | @end ifclear | |
1690 | ||
1691 | @ifset man | |
1692 | @c man begin OPTIONS | |
1693 | The following options are available when @value{AS} is configured for a | |
1694 | PowerPC processor. | |
1695 | @c man end | |
1696 | @c man begin INCLUDE | |
1697 | @include c-ppc.texi | |
1698 | @c ended inside the included file | |
1699 | @end ifset | |
1700 | ||
1701 | @end ifset | |
1702 | ||
e23eba97 NC |
1703 | @ifset RISCV |
1704 | ||
1705 | @ifclear man | |
b57e49f7 | 1706 | @xref{RISC-V-Options}, for the options available when @value{AS} is configured |
e23eba97 NC |
1707 | for a RISC-V processor. |
1708 | @end ifclear | |
1709 | ||
1710 | @ifset man | |
1711 | @c man begin OPTIONS | |
1712 | The following options are available when @value{AS} is configured for a | |
b57e49f7 | 1713 | RISC-V processor. |
e23eba97 NC |
1714 | @c man end |
1715 | @c man begin INCLUDE | |
1716 | @include c-riscv.texi | |
1717 | @c ended inside the included file | |
1718 | @end ifset | |
1719 | ||
1720 | @end ifset | |
1721 | ||
635fb38d | 1722 | @c man begin OPTIONS |
046d31c2 NC |
1723 | @ifset RX |
1724 | See the info pages for documentation of the RX-specific options. | |
1725 | @end ifset | |
1726 | ||
11c19e16 MS |
1727 | @ifset S390 |
1728 | The following options are available when @value{AS} is configured for the s390 | |
1729 | processor family. | |
1730 | ||
1731 | @table @gcctabopt | |
1732 | @item -m31 | |
1733 | @itemx -m64 | |
1734 | Select the word size, either 31/32 bits or 64 bits. | |
1735 | @item -mesa | |
1736 | @item -mzarch | |
1737 | Select the architecture mode, either the Enterprise System | |
1738 | Architecture (esa) or the z/Architecture mode (zarch). | |
1739 | @item -march=@var{processor} | |
952c3f51 AK |
1740 | Specify which s390 processor variant is the target, @samp{g5} (or |
1741 | @samp{arch3}), @samp{g6}, @samp{z900} (or @samp{arch5}), @samp{z990} (or | |
1742 | @samp{arch6}), @samp{z9-109}, @samp{z9-ec} (or @samp{arch7}), @samp{z10} (or | |
1743 | @samp{arch8}), @samp{z196} (or @samp{arch9}), @samp{zEC12} (or @samp{arch10}), | |
47826cdb | 1744 | @samp{z13} (or @samp{arch11}), or @samp{z14} (or @samp{arch12}). |
11c19e16 MS |
1745 | @item -mregnames |
1746 | @itemx -mno-regnames | |
1747 | Allow or disallow symbolic names for registers. | |
1748 | @item -mwarn-areg-zero | |
1749 | Warn whenever the operand for a base or index register has been specified | |
1750 | but evaluates to zero. | |
1751 | @end table | |
1752 | @end ifset | |
2a633939 | 1753 | @c man end |
11c19e16 | 1754 | |
40b36596 | 1755 | @ifset TIC6X |
2a633939 JM |
1756 | |
1757 | @ifclear man | |
1758 | @xref{TIC6X Options}, for the options available when @value{AS} is configured | |
1759 | for a TMS320C6000 processor. | |
1760 | @end ifclear | |
1761 | ||
1762 | @ifset man | |
1763 | @c man begin OPTIONS | |
40b36596 JM |
1764 | The following options are available when @value{AS} is configured for a |
1765 | TMS320C6000 processor. | |
2a633939 JM |
1766 | @c man end |
1767 | @c man begin INCLUDE | |
1768 | @include c-tic6x.texi | |
1769 | @c ended inside the included file | |
1770 | @end ifset | |
40b36596 JM |
1771 | |
1772 | @end ifset | |
1773 | ||
aa137e4d NC |
1774 | @ifset TILEGX |
1775 | ||
1776 | @ifclear man | |
1777 | @xref{TILE-Gx Options}, for the options available when @value{AS} is configured | |
1778 | for a TILE-Gx processor. | |
1779 | @end ifclear | |
1780 | ||
1781 | @ifset man | |
1782 | @c man begin OPTIONS | |
1783 | The following options are available when @value{AS} is configured for a TILE-Gx | |
1784 | processor. | |
1785 | @c man end | |
1786 | @c man begin INCLUDE | |
1787 | @include c-tilegx.texi | |
1788 | @c ended inside the included file | |
1789 | @end ifset | |
1790 | ||
1791 | @end ifset | |
1792 | ||
b6605ddd EB |
1793 | @ifset VISIUM |
1794 | ||
1795 | @ifclear man | |
1796 | @xref{Visium Options}, for the options available when @value{AS} is configured | |
1797 | for a Visium processor. | |
1798 | @end ifclear | |
1799 | ||
1800 | @ifset man | |
1801 | @c man begin OPTIONS | |
1802 | The following option is available when @value{AS} is configured for a Visium | |
1803 | processor. | |
1804 | @c man end | |
1805 | @c man begin INCLUDE | |
1806 | @include c-visium.texi | |
1807 | @c ended inside the included file | |
1808 | @end ifset | |
1809 | ||
1810 | @end ifset | |
1811 | ||
e0001a05 | 1812 | @ifset XTENSA |
e0001a05 | 1813 | |
2d8b84ae SA |
1814 | @ifclear man |
1815 | @xref{Xtensa Options}, for the options available when @value{AS} is configured | |
1816 | for an Xtensa processor. | |
1817 | @end ifclear | |
1818 | ||
1819 | @ifset man | |
1820 | @c man begin OPTIONS | |
1821 | The following options are available when @value{AS} is configured for an | |
1822 | Xtensa processor. | |
1823 | @c man end | |
1824 | @c man begin INCLUDE | |
1825 | @include c-xtensa.texi | |
1826 | @c ended inside the included file | |
e0001a05 NC |
1827 | @end ifset |
1828 | ||
2d8b84ae SA |
1829 | @end ifset |
1830 | ||
1831 | @c man begin OPTIONS | |
1832 | ||
3c9b82ba NC |
1833 | @ifset Z80 |
1834 | The following options are available when @value{AS} is configured for | |
1835 | a Z80 family processor. | |
1836 | @table @gcctabopt | |
1837 | @item -z80 | |
1838 | Assemble for Z80 processor. | |
1839 | @item -r800 | |
1840 | Assemble for R800 processor. | |
01642c12 | 1841 | @item -ignore-undocumented-instructions |
3c9b82ba NC |
1842 | @itemx -Wnud |
1843 | Assemble undocumented Z80 instructions that also work on R800 without warning. | |
01642c12 | 1844 | @item -ignore-unportable-instructions |
3c9b82ba NC |
1845 | @itemx -Wnup |
1846 | Assemble all undocumented Z80 instructions without warning. | |
01642c12 | 1847 | @item -warn-undocumented-instructions |
3c9b82ba NC |
1848 | @itemx -Wud |
1849 | Issue a warning for undocumented Z80 instructions that also work on R800. | |
01642c12 | 1850 | @item -warn-unportable-instructions |
3c9b82ba | 1851 | @itemx -Wup |
01642c12 RM |
1852 | Issue a warning for undocumented Z80 instructions that do not work on R800. |
1853 | @item -forbid-undocumented-instructions | |
3c9b82ba NC |
1854 | @itemx -Fud |
1855 | Treat all undocumented instructions as errors. | |
01642c12 | 1856 | @item -forbid-unportable-instructions |
3c9b82ba | 1857 | @itemx -Fup |
b45619c0 | 1858 | Treat undocumented Z80 instructions that do not work on R800 as errors. |
3c9b82ba NC |
1859 | @end table |
1860 | @end ifset | |
1861 | ||
0285c67d NC |
1862 | @c man end |
1863 | ||
252b5132 RH |
1864 | @menu |
1865 | * Manual:: Structure of this Manual | |
1866 | * GNU Assembler:: The GNU Assembler | |
1867 | * Object Formats:: Object File Formats | |
1868 | * Command Line:: Command Line | |
1869 | * Input Files:: Input Files | |
1870 | * Object:: Output (Object) File | |
1871 | * Errors:: Error and Warning Messages | |
1872 | @end menu | |
1873 | ||
1874 | @node Manual | |
1875 | @section Structure of this Manual | |
1876 | ||
1877 | @cindex manual, structure and purpose | |
1878 | This manual is intended to describe what you need to know to use | |
a4fb0134 | 1879 | @sc{gnu} @command{@value{AS}}. We cover the syntax expected in source files, including |
252b5132 | 1880 | notation for symbols, constants, and expressions; the directives that |
a4fb0134 | 1881 | @command{@value{AS}} understands; and of course how to invoke @command{@value{AS}}. |
252b5132 RH |
1882 | |
1883 | @ifclear GENERIC | |
1884 | We also cover special features in the @value{TARGET} | |
a4fb0134 | 1885 | configuration of @command{@value{AS}}, including assembler directives. |
252b5132 RH |
1886 | @end ifclear |
1887 | @ifset GENERIC | |
1888 | This manual also describes some of the machine-dependent features of | |
1889 | various flavors of the assembler. | |
1890 | @end ifset | |
1891 | ||
1892 | @cindex machine instructions (not covered) | |
1893 | On the other hand, this manual is @emph{not} intended as an introduction | |
1894 | to programming in assembly language---let alone programming in general! | |
1895 | In a similar vein, we make no attempt to introduce the machine | |
1896 | architecture; we do @emph{not} describe the instruction set, standard | |
1897 | mnemonics, registers or addressing modes that are standard to a | |
1898 | particular architecture. | |
1899 | @ifset GENERIC | |
1900 | You may want to consult the manufacturer's | |
1901 | machine architecture manual for this information. | |
1902 | @end ifset | |
1903 | @ifclear GENERIC | |
1904 | @ifset H8/300 | |
1905 | For information on the H8/300 machine instruction set, see @cite{H8/300 | |
c2dcd04e NC |
1906 | Series Programming Manual}. For the H8/300H, see @cite{H8/300H Series |
1907 | Programming Manual} (Renesas). | |
252b5132 | 1908 | @end ifset |
252b5132 | 1909 | @ifset SH |
ef230218 JR |
1910 | For information on the Renesas (formerly Hitachi) / SuperH SH machine instruction set, |
1911 | see @cite{SH-Microcomputer User's Manual} (Renesas) or | |
1912 | @cite{SH-4 32-bit CPU Core Architecture} (SuperH) and | |
1913 | @cite{SuperH (SH) 64-Bit RISC Series} (SuperH). | |
252b5132 RH |
1914 | @end ifset |
1915 | @ifset Z8000 | |
1916 | For information on the Z8000 machine instruction set, see @cite{Z8000 CPU Technical Manual} | |
1917 | @end ifset | |
1918 | @end ifclear | |
1919 | ||
1920 | @c I think this is premature---doc@cygnus.com, 17jan1991 | |
1921 | @ignore | |
1922 | Throughout this manual, we assume that you are running @dfn{GNU}, | |
1923 | the portable operating system from the @dfn{Free Software | |
1924 | Foundation, Inc.}. This restricts our attention to certain kinds of | |
1925 | computer (in particular, the kinds of computers that @sc{gnu} can run on); | |
1926 | once this assumption is granted examples and definitions need less | |
1927 | qualification. | |
1928 | ||
a4fb0134 | 1929 | @command{@value{AS}} is part of a team of programs that turn a high-level |
252b5132 RH |
1930 | human-readable series of instructions into a low-level |
1931 | computer-readable series of instructions. Different versions of | |
a4fb0134 | 1932 | @command{@value{AS}} are used for different kinds of computer. |
252b5132 RH |
1933 | @end ignore |
1934 | ||
1935 | @c There used to be a section "Terminology" here, which defined | |
1936 | @c "contents", "byte", "word", and "long". Defining "word" to any | |
1937 | @c particular size is confusing when the .word directive may generate 16 | |
1938 | @c bits on one machine and 32 bits on another; in general, for the user | |
1939 | @c version of this manual, none of these terms seem essential to define. | |
1940 | @c They were used very little even in the former draft of the manual; | |
1941 | @c this draft makes an effort to avoid them (except in names of | |
1942 | @c directives). | |
1943 | ||
1944 | @node GNU Assembler | |
1945 | @section The GNU Assembler | |
1946 | ||
0285c67d NC |
1947 | @c man begin DESCRIPTION |
1948 | ||
a4fb0134 | 1949 | @sc{gnu} @command{as} is really a family of assemblers. |
252b5132 | 1950 | @ifclear GENERIC |
a4fb0134 | 1951 | This manual describes @command{@value{AS}}, a member of that family which is |
252b5132 RH |
1952 | configured for the @value{TARGET} architectures. |
1953 | @end ifclear | |
1954 | If you use (or have used) the @sc{gnu} assembler on one architecture, you | |
1955 | should find a fairly similar environment when you use it on another | |
1956 | architecture. Each version has much in common with the others, | |
1957 | including object file formats, most assembler directives (often called | |
1958 | @dfn{pseudo-ops}) and assembler syntax.@refill | |
1959 | ||
1960 | @cindex purpose of @sc{gnu} assembler | |
a4fb0134 | 1961 | @command{@value{AS}} is primarily intended to assemble the output of the |
252b5132 | 1962 | @sc{gnu} C compiler @code{@value{GCC}} for use by the linker |
a4fb0134 | 1963 | @code{@value{LD}}. Nevertheless, we've tried to make @command{@value{AS}} |
252b5132 RH |
1964 | assemble correctly everything that other assemblers for the same |
1965 | machine would assemble. | |
1966 | @ifset VAX | |
1967 | Any exceptions are documented explicitly (@pxref{Machine Dependencies}). | |
1968 | @end ifset | |
1969 | @ifset M680X0 | |
1970 | @c This remark should appear in generic version of manual; assumption | |
1971 | @c here is that generic version sets M680x0. | |
a4fb0134 | 1972 | This doesn't mean @command{@value{AS}} always uses the same syntax as another |
252b5132 RH |
1973 | assembler for the same architecture; for example, we know of several |
1974 | incompatible versions of 680x0 assembly language syntax. | |
1975 | @end ifset | |
1976 | ||
0285c67d NC |
1977 | @c man end |
1978 | ||
a4fb0134 | 1979 | Unlike older assemblers, @command{@value{AS}} is designed to assemble a source |
252b5132 RH |
1980 | program in one pass of the source file. This has a subtle impact on the |
1981 | @kbd{.org} directive (@pxref{Org,,@code{.org}}). | |
1982 | ||
1983 | @node Object Formats | |
1984 | @section Object File Formats | |
1985 | ||
1986 | @cindex object file format | |
1987 | The @sc{gnu} assembler can be configured to produce several alternative | |
1988 | object file formats. For the most part, this does not affect how you | |
1989 | write assembly language programs; but directives for debugging symbols | |
1990 | are typically different in different file formats. @xref{Symbol | |
1991 | Attributes,,Symbol Attributes}. | |
1992 | @ifclear GENERIC | |
1993 | @ifclear MULTI-OBJ | |
c1253627 | 1994 | For the @value{TARGET} target, @command{@value{AS}} is configured to produce |
252b5132 RH |
1995 | @value{OBJ-NAME} format object files. |
1996 | @end ifclear | |
1997 | @c The following should exhaust all configs that set MULTI-OBJ, ideally | |
252b5132 | 1998 | @ifset I960 |
a4fb0134 | 1999 | On the @value{TARGET}, @command{@value{AS}} can be configured to produce either |
252b5132 RH |
2000 | @code{b.out} or COFF format object files. |
2001 | @end ifset | |
2002 | @ifset HPPA | |
a4fb0134 | 2003 | On the @value{TARGET}, @command{@value{AS}} can be configured to produce either |
252b5132 RH |
2004 | SOM or ELF format object files. |
2005 | @end ifset | |
2006 | @end ifclear | |
2007 | ||
2008 | @node Command Line | |
2009 | @section Command Line | |
2010 | ||
2011 | @cindex command line conventions | |
0285c67d | 2012 | |
a4fb0134 | 2013 | After the program name @command{@value{AS}}, the command line may contain |
252b5132 RH |
2014 | options and file names. Options may appear in any order, and may be |
2015 | before, after, or between file names. The order of file names is | |
2016 | significant. | |
2017 | ||
2018 | @cindex standard input, as input file | |
2019 | @kindex -- | |
2020 | @file{--} (two hyphens) by itself names the standard input file | |
a4fb0134 | 2021 | explicitly, as one of the files for @command{@value{AS}} to assemble. |
252b5132 RH |
2022 | |
2023 | @cindex options, command line | |
2024 | Except for @samp{--} any command line argument that begins with a | |
2025 | hyphen (@samp{-}) is an option. Each option changes the behavior of | |
a4fb0134 | 2026 | @command{@value{AS}}. No option changes the way another option works. An |
252b5132 RH |
2027 | option is a @samp{-} followed by one or more letters; the case of |
2028 | the letter is important. All options are optional. | |
2029 | ||
2030 | Some options expect exactly one file name to follow them. The file | |
2031 | name may either immediately follow the option's letter (compatible | |
2032 | with older assemblers) or it may be the next command argument (@sc{gnu} | |
2033 | standard). These two command lines are equivalent: | |
2034 | ||
2035 | @smallexample | |
2036 | @value{AS} -o my-object-file.o mumble.s | |
2037 | @value{AS} -omy-object-file.o mumble.s | |
2038 | @end smallexample | |
2039 | ||
2040 | @node Input Files | |
2041 | @section Input Files | |
2042 | ||
2043 | @cindex input | |
2044 | @cindex source program | |
2045 | @cindex files, input | |
2046 | We use the phrase @dfn{source program}, abbreviated @dfn{source}, to | |
a4fb0134 | 2047 | describe the program input to one run of @command{@value{AS}}. The program may |
252b5132 RH |
2048 | be in one or more files; how the source is partitioned into files |
2049 | doesn't change the meaning of the source. | |
2050 | ||
2051 | @c I added "con" prefix to "catenation" just to prove I can overcome my | |
2052 | @c APL training... doc@cygnus.com | |
2053 | The source program is a concatenation of the text in all the files, in the | |
2054 | order specified. | |
2055 | ||
0285c67d | 2056 | @c man begin DESCRIPTION |
a4fb0134 | 2057 | Each time you run @command{@value{AS}} it assembles exactly one source |
252b5132 RH |
2058 | program. The source program is made up of one or more files. |
2059 | (The standard input is also a file.) | |
2060 | ||
a4fb0134 | 2061 | You give @command{@value{AS}} a command line that has zero or more input file |
252b5132 RH |
2062 | names. The input files are read (from left file name to right). A |
2063 | command line argument (in any position) that has no special meaning | |
2064 | is taken to be an input file name. | |
2065 | ||
a4fb0134 SC |
2066 | If you give @command{@value{AS}} no file names it attempts to read one input file |
2067 | from the @command{@value{AS}} standard input, which is normally your terminal. You | |
2068 | may have to type @key{ctl-D} to tell @command{@value{AS}} there is no more program | |
252b5132 RH |
2069 | to assemble. |
2070 | ||
2071 | Use @samp{--} if you need to explicitly name the standard input file | |
2072 | in your command line. | |
2073 | ||
a4fb0134 | 2074 | If the source is empty, @command{@value{AS}} produces a small, empty object |
252b5132 RH |
2075 | file. |
2076 | ||
0285c67d NC |
2077 | @c man end |
2078 | ||
252b5132 RH |
2079 | @subheading Filenames and Line-numbers |
2080 | ||
2081 | @cindex input file linenumbers | |
2082 | @cindex line numbers, in input files | |
2083 | There are two ways of locating a line in the input file (or files) and | |
2084 | either may be used in reporting error messages. One way refers to a line | |
2085 | number in a physical file; the other refers to a line number in a | |
2086 | ``logical'' file. @xref{Errors, ,Error and Warning Messages}. | |
2087 | ||
2088 | @dfn{Physical files} are those files named in the command line given | |
a4fb0134 | 2089 | to @command{@value{AS}}. |
252b5132 RH |
2090 | |
2091 | @dfn{Logical files} are simply names declared explicitly by assembler | |
2092 | directives; they bear no relation to physical files. Logical file names help | |
a4fb0134 SC |
2093 | error messages reflect the original source file, when @command{@value{AS}} source |
2094 | is itself synthesized from other files. @command{@value{AS}} understands the | |
252b5132 RH |
2095 | @samp{#} directives emitted by the @code{@value{GCC}} preprocessor. See also |
2096 | @ref{File,,@code{.file}}. | |
2097 | ||
2098 | @node Object | |
2099 | @section Output (Object) File | |
2100 | ||
2101 | @cindex object file | |
2102 | @cindex output file | |
2103 | @kindex a.out | |
2104 | @kindex .o | |
a4fb0134 | 2105 | Every time you run @command{@value{AS}} it produces an output file, which is |
252b5132 RH |
2106 | your assembly language program translated into numbers. This file |
2107 | is the object file. Its default name is | |
2108 | @ifclear BOUT | |
2109 | @code{a.out}. | |
2110 | @end ifclear | |
2111 | @ifset BOUT | |
2112 | @ifset GENERIC | |
01642c12 | 2113 | @code{a.out}, or |
252b5132 | 2114 | @end ifset |
a4fb0134 | 2115 | @code{b.out} when @command{@value{AS}} is configured for the Intel 80960. |
252b5132 | 2116 | @end ifset |
a4fb0134 | 2117 | You can give it another name by using the @option{-o} option. Conventionally, |
252b5132 RH |
2118 | object file names end with @file{.o}. The default name is used for historical |
2119 | reasons: older assemblers were capable of assembling self-contained programs | |
2120 | directly into a runnable program. (For some formats, this isn't currently | |
2121 | possible, but it can be done for the @code{a.out} format.) | |
2122 | ||
2123 | @cindex linker | |
2124 | @kindex ld | |
2125 | The object file is meant for input to the linker @code{@value{LD}}. It contains | |
2126 | assembled program code, information to help @code{@value{LD}} integrate | |
2127 | the assembled program into a runnable file, and (optionally) symbolic | |
2128 | information for the debugger. | |
2129 | ||
2130 | @c link above to some info file(s) like the description of a.out. | |
2131 | @c don't forget to describe @sc{gnu} info as well as Unix lossage. | |
2132 | ||
2133 | @node Errors | |
2134 | @section Error and Warning Messages | |
2135 | ||
0285c67d NC |
2136 | @c man begin DESCRIPTION |
2137 | ||
a349d9dd | 2138 | @cindex error messages |
252b5132 RH |
2139 | @cindex warning messages |
2140 | @cindex messages from assembler | |
a4fb0134 | 2141 | @command{@value{AS}} may write warnings and error messages to the standard error |
252b5132 | 2142 | file (usually your terminal). This should not happen when a compiler |
a4fb0134 SC |
2143 | runs @command{@value{AS}} automatically. Warnings report an assumption made so |
2144 | that @command{@value{AS}} could keep assembling a flawed program; errors report a | |
252b5132 RH |
2145 | grave problem that stops the assembly. |
2146 | ||
0285c67d NC |
2147 | @c man end |
2148 | ||
252b5132 RH |
2149 | @cindex format of warning messages |
2150 | Warning messages have the format | |
2151 | ||
2152 | @smallexample | |
2153 | file_name:@b{NNN}:Warning Message Text | |
2154 | @end smallexample | |
2155 | ||
2156 | @noindent | |
72e0b254 NC |
2157 | @cindex file names and line numbers, in warnings/errors |
2158 | (where @b{NNN} is a line number). If both a logical file name | |
2159 | (@pxref{File,,@code{.file}}) and a logical line number | |
252b5132 RH |
2160 | @ifset GENERIC |
2161 | (@pxref{Line,,@code{.line}}) | |
2162 | @end ifset | |
72e0b254 NC |
2163 | have been given then they will be used, otherwise the file name and line number |
2164 | in the current assembler source file will be used. The message text is | |
2165 | intended to be self explanatory (in the grand Unix tradition). | |
2166 | ||
2167 | Note the file name must be set via the logical version of the @code{.file} | |
2168 | directive, not the DWARF2 version of the @code{.file} directive. For example: | |
2169 | ||
2170 | @smallexample | |
2171 | .file 2 "bar.c" | |
2172 | error_assembler_source | |
2173 | .file "foo.c" | |
2174 | .line 30 | |
2175 | error_c_source | |
2176 | @end smallexample | |
2177 | ||
2178 | produces this output: | |
2179 | ||
2180 | @smallexample | |
2181 | Assembler messages: | |
2182 | asm.s:2: Error: no such instruction: `error_assembler_source' | |
2183 | foo.c:31: Error: no such instruction: `error_c_source' | |
2184 | @end smallexample | |
252b5132 RH |
2185 | |
2186 | @cindex format of error messages | |
2187 | Error messages have the format | |
72e0b254 | 2188 | |
252b5132 RH |
2189 | @smallexample |
2190 | file_name:@b{NNN}:FATAL:Error Message Text | |
2191 | @end smallexample | |
72e0b254 | 2192 | |
252b5132 RH |
2193 | The file name and line number are derived as for warning |
2194 | messages. The actual message text may be rather less explanatory | |
2195 | because many of them aren't supposed to happen. | |
2196 | ||
2197 | @node Invoking | |
2198 | @chapter Command-Line Options | |
2199 | ||
2200 | @cindex options, all versions of assembler | |
2201 | This chapter describes command-line options available in @emph{all} | |
96e9638b BW |
2202 | versions of the @sc{gnu} assembler; see @ref{Machine Dependencies}, |
2203 | for options specific | |
252b5132 | 2204 | @ifclear GENERIC |
c1253627 | 2205 | to the @value{TARGET} target. |
252b5132 RH |
2206 | @end ifclear |
2207 | @ifset GENERIC | |
2208 | to particular machine architectures. | |
2209 | @end ifset | |
2210 | ||
0285c67d NC |
2211 | @c man begin DESCRIPTION |
2212 | ||
c1253627 | 2213 | If you are invoking @command{@value{AS}} via the @sc{gnu} C compiler, |
252b5132 RH |
2214 | you can use the @samp{-Wa} option to pass arguments through to the assembler. |
2215 | The assembler arguments must be separated from each other (and the @samp{-Wa}) | |
2216 | by commas. For example: | |
2217 | ||
2218 | @smallexample | |
2219 | gcc -c -g -O -Wa,-alh,-L file.c | |
2220 | @end smallexample | |
2221 | ||
2222 | @noindent | |
2223 | This passes two options to the assembler: @samp{-alh} (emit a listing to | |
5f5e16be | 2224 | standard output with high-level and assembly source) and @samp{-L} (retain |
252b5132 RH |
2225 | local symbols in the symbol table). |
2226 | ||
2227 | Usually you do not need to use this @samp{-Wa} mechanism, since many compiler | |
2228 | command-line options are automatically passed to the assembler by the compiler. | |
2229 | (You can call the @sc{gnu} compiler driver with the @samp{-v} option to see | |
2230 | precisely what options it passes to each compilation pass, including the | |
2231 | assembler.) | |
2232 | ||
0285c67d NC |
2233 | @c man end |
2234 | ||
252b5132 | 2235 | @menu |
83f10cb2 | 2236 | * a:: -a[cdghlns] enable listings |
caa32fe5 | 2237 | * alternate:: --alternate enable alternate macro syntax |
252b5132 RH |
2238 | * D:: -D for compatibility |
2239 | * f:: -f to work faster | |
2240 | * I:: -I for .include search path | |
2241 | @ifclear DIFF-TBL-KLUGE | |
2242 | * K:: -K for compatibility | |
2243 | @end ifclear | |
2244 | @ifset DIFF-TBL-KLUGE | |
2245 | * K:: -K for difference tables | |
2246 | @end ifset | |
2247 | ||
ba83aca1 | 2248 | * L:: -L to retain local symbols |
c3a27914 | 2249 | * listing:: --listing-XXX to configure listing output |
252b5132 RH |
2250 | * M:: -M or --mri to assemble in MRI compatibility mode |
2251 | * MD:: --MD for dependency tracking | |
2edb36e7 | 2252 | * no-pad-sections:: --no-pad-sections to stop section padding |
252b5132 RH |
2253 | * o:: -o to name the object file |
2254 | * R:: -R to join data and text sections | |
2255 | * statistics:: --statistics to see statistics about assembly | |
2256 | * traditional-format:: --traditional-format for compatible output | |
2257 | * v:: -v to announce version | |
2bdd6cf5 | 2258 | * W:: -W, --no-warn, --warn, --fatal-warnings to control warnings |
252b5132 RH |
2259 | * Z:: -Z to make object file even after errors |
2260 | @end menu | |
2261 | ||
2262 | @node a | |
83f10cb2 | 2263 | @section Enable Listings: @option{-a[cdghlns]} |
252b5132 RH |
2264 | |
2265 | @kindex -a | |
2266 | @kindex -ac | |
2267 | @kindex -ad | |
83f10cb2 | 2268 | @kindex -ag |
252b5132 RH |
2269 | @kindex -ah |
2270 | @kindex -al | |
2271 | @kindex -an | |
2272 | @kindex -as | |
2273 | @cindex listings, enabling | |
2274 | @cindex assembly listings, enabling | |
2275 | ||
2276 | These options enable listing output from the assembler. By itself, | |
2277 | @samp{-a} requests high-level, assembly, and symbols listing. | |
2278 | You can use other letters to select specific options for the list: | |
2279 | @samp{-ah} requests a high-level language listing, | |
2280 | @samp{-al} requests an output-program assembly listing, and | |
2281 | @samp{-as} requests a symbol table listing. | |
2282 | High-level listings require that a compiler debugging option like | |
2283 | @samp{-g} be used, and that assembly listings (@samp{-al}) be requested | |
2284 | also. | |
2285 | ||
83f10cb2 NC |
2286 | Use the @samp{-ag} option to print a first section with general assembly |
2287 | information, like @value{AS} version, switches passed, or time stamp. | |
2288 | ||
252b5132 RH |
2289 | Use the @samp{-ac} option to omit false conditionals from a listing. Any lines |
2290 | which are not assembled because of a false @code{.if} (or @code{.ifdef}, or any | |
2291 | other conditional), or a true @code{.if} followed by an @code{.else}, will be | |
2292 | omitted from the listing. | |
2293 | ||
2294 | Use the @samp{-ad} option to omit debugging directives from the | |
2295 | listing. | |
2296 | ||
2297 | Once you have specified one of these options, you can further control | |
2298 | listing output and its appearance using the directives @code{.list}, | |
2299 | @code{.nolist}, @code{.psize}, @code{.eject}, @code{.title}, and | |
2300 | @code{.sbttl}. | |
2301 | The @samp{-an} option turns off all forms processing. | |
2302 | If you do not request listing output with one of the @samp{-a} options, the | |
2303 | listing-control directives have no effect. | |
2304 | ||
2305 | The letters after @samp{-a} may be combined into one option, | |
2306 | @emph{e.g.}, @samp{-aln}. | |
2307 | ||
96e9638b BW |
2308 | Note if the assembler source is coming from the standard input (e.g., |
2309 | because it | |
c3a27914 NC |
2310 | is being created by @code{@value{GCC}} and the @samp{-pipe} command line switch |
2311 | is being used) then the listing will not contain any comments or preprocessor | |
2312 | directives. This is because the listing code buffers input source lines from | |
2313 | stdin only after they have been preprocessed by the assembler. This reduces | |
2314 | memory usage and makes the code more efficient. | |
2315 | ||
caa32fe5 NC |
2316 | @node alternate |
2317 | @section @option{--alternate} | |
2318 | ||
2319 | @kindex --alternate | |
2320 | Begin in alternate macro mode, see @ref{Altmacro,,@code{.altmacro}}. | |
2321 | ||
252b5132 | 2322 | @node D |
a4fb0134 | 2323 | @section @option{-D} |
252b5132 RH |
2324 | |
2325 | @kindex -D | |
2326 | This option has no effect whatsoever, but it is accepted to make it more | |
2327 | likely that scripts written for other assemblers also work with | |
a4fb0134 | 2328 | @command{@value{AS}}. |
252b5132 RH |
2329 | |
2330 | @node f | |
a4fb0134 | 2331 | @section Work Faster: @option{-f} |
252b5132 RH |
2332 | |
2333 | @kindex -f | |
2334 | @cindex trusted compiler | |
a4fb0134 | 2335 | @cindex faster processing (@option{-f}) |
252b5132 RH |
2336 | @samp{-f} should only be used when assembling programs written by a |
2337 | (trusted) compiler. @samp{-f} stops the assembler from doing whitespace | |
2338 | and comment preprocessing on | |
2339 | the input file(s) before assembling them. @xref{Preprocessing, | |
2340 | ,Preprocessing}. | |
2341 | ||
2342 | @quotation | |
2343 | @emph{Warning:} if you use @samp{-f} when the files actually need to be | |
a4fb0134 | 2344 | preprocessed (if they contain comments, for example), @command{@value{AS}} does |
252b5132 RH |
2345 | not work correctly. |
2346 | @end quotation | |
2347 | ||
2348 | @node I | |
c1253627 | 2349 | @section @code{.include} Search Path: @option{-I} @var{path} |
252b5132 RH |
2350 | |
2351 | @kindex -I @var{path} | |
2352 | @cindex paths for @code{.include} | |
2353 | @cindex search path for @code{.include} | |
2354 | @cindex @code{include} directive search path | |
2355 | Use this option to add a @var{path} to the list of directories | |
a4fb0134 SC |
2356 | @command{@value{AS}} searches for files specified in @code{.include} |
2357 | directives (@pxref{Include,,@code{.include}}). You may use @option{-I} as | |
252b5132 | 2358 | many times as necessary to include a variety of paths. The current |
a4fb0134 | 2359 | working directory is always searched first; after that, @command{@value{AS}} |
252b5132 RH |
2360 | searches any @samp{-I} directories in the same order as they were |
2361 | specified (left to right) on the command line. | |
2362 | ||
2363 | @node K | |
a4fb0134 | 2364 | @section Difference Tables: @option{-K} |
252b5132 RH |
2365 | |
2366 | @kindex -K | |
2367 | @ifclear DIFF-TBL-KLUGE | |
2368 | On the @value{TARGET} family, this option is allowed, but has no effect. It is | |
2369 | permitted for compatibility with the @sc{gnu} assembler on other platforms, | |
2370 | where it can be used to warn when the assembler alters the machine code | |
2371 | generated for @samp{.word} directives in difference tables. The @value{TARGET} | |
2372 | family does not have the addressing limitations that sometimes lead to this | |
2373 | alteration on other platforms. | |
2374 | @end ifclear | |
2375 | ||
2376 | @ifset DIFF-TBL-KLUGE | |
2377 | @cindex difference tables, warning | |
2378 | @cindex warning for altered difference tables | |
96e9638b BW |
2379 | @command{@value{AS}} sometimes alters the code emitted for directives of the |
2380 | form @samp{.word @var{sym1}-@var{sym2}}. @xref{Word,,@code{.word}}. | |
252b5132 RH |
2381 | You can use the @samp{-K} option if you want a warning issued when this |
2382 | is done. | |
2383 | @end ifset | |
2384 | ||
2385 | @node L | |
ba83aca1 | 2386 | @section Include Local Symbols: @option{-L} |
252b5132 RH |
2387 | |
2388 | @kindex -L | |
ba83aca1 BW |
2389 | @cindex local symbols, retaining in output |
2390 | Symbols beginning with system-specific local label prefixes, typically | |
2391 | @samp{.L} for ELF systems or @samp{L} for traditional a.out systems, are | |
2392 | called @dfn{local symbols}. @xref{Symbol Names}. Normally you do not see | |
2393 | such symbols when debugging, because they are intended for the use of | |
2394 | programs (like compilers) that compose assembler programs, not for your | |
2395 | notice. Normally both @command{@value{AS}} and @code{@value{LD}} discard | |
2396 | such symbols, so you do not normally debug with them. | |
2397 | ||
2398 | This option tells @command{@value{AS}} to retain those local symbols | |
252b5132 | 2399 | in the object file. Usually if you do this you also tell the linker |
ba83aca1 | 2400 | @code{@value{LD}} to preserve those symbols. |
252b5132 | 2401 | |
c3a27914 | 2402 | @node listing |
a4fb0134 | 2403 | @section Configuring listing output: @option{--listing} |
c3a27914 NC |
2404 | |
2405 | The listing feature of the assembler can be enabled via the command line switch | |
2406 | @samp{-a} (@pxref{a}). This feature combines the input source file(s) with a | |
2407 | hex dump of the corresponding locations in the output object file, and displays | |
96e9638b BW |
2408 | them as a listing file. The format of this listing can be controlled by |
2409 | directives inside the assembler source (i.e., @code{.list} (@pxref{List}), | |
2410 | @code{.title} (@pxref{Title}), @code{.sbttl} (@pxref{Sbttl}), | |
2411 | @code{.psize} (@pxref{Psize}), and | |
2412 | @code{.eject} (@pxref{Eject}) and also by the following switches: | |
c3a27914 | 2413 | |
a4fb0134 | 2414 | @table @gcctabopt |
c3a27914 NC |
2415 | @item --listing-lhs-width=@samp{number} |
2416 | @kindex --listing-lhs-width | |
2417 | @cindex Width of first line disassembly output | |
2418 | Sets the maximum width, in words, of the first line of the hex byte dump. This | |
2419 | dump appears on the left hand side of the listing output. | |
2420 | ||
2421 | @item --listing-lhs-width2=@samp{number} | |
2422 | @kindex --listing-lhs-width2 | |
2423 | @cindex Width of continuation lines of disassembly output | |
2424 | Sets the maximum width, in words, of any further lines of the hex byte dump for | |
8dfa0188 | 2425 | a given input source line. If this value is not specified, it defaults to being |
c3a27914 NC |
2426 | the same as the value specified for @samp{--listing-lhs-width}. If neither |
2427 | switch is used the default is to one. | |
2428 | ||
2429 | @item --listing-rhs-width=@samp{number} | |
2430 | @kindex --listing-rhs-width | |
2431 | @cindex Width of source line output | |
2432 | Sets the maximum width, in characters, of the source line that is displayed | |
2433 | alongside the hex dump. The default value for this parameter is 100. The | |
2434 | source line is displayed on the right hand side of the listing output. | |
2435 | ||
2436 | @item --listing-cont-lines=@samp{number} | |
2437 | @kindex --listing-cont-lines | |
2438 | @cindex Maximum number of continuation lines | |
2439 | Sets the maximum number of continuation lines of hex dump that will be | |
2440 | displayed for a given single line of source input. The default value is 4. | |
2441 | @end table | |
2442 | ||
252b5132 | 2443 | @node M |
a4fb0134 | 2444 | @section Assemble in MRI Compatibility Mode: @option{-M} |
252b5132 RH |
2445 | |
2446 | @kindex -M | |
2447 | @cindex MRI compatibility mode | |
a4fb0134 SC |
2448 | The @option{-M} or @option{--mri} option selects MRI compatibility mode. This |
2449 | changes the syntax and pseudo-op handling of @command{@value{AS}} to make it | |
252b5132 RH |
2450 | compatible with the @code{ASM68K} or the @code{ASM960} (depending upon the |
2451 | configured target) assembler from Microtec Research. The exact nature of the | |
2452 | MRI syntax will not be documented here; see the MRI manuals for more | |
2453 | information. Note in particular that the handling of macros and macro | |
2454 | arguments is somewhat different. The purpose of this option is to permit | |
a4fb0134 | 2455 | assembling existing MRI assembler code using @command{@value{AS}}. |
252b5132 RH |
2456 | |
2457 | The MRI compatibility is not complete. Certain operations of the MRI assembler | |
2458 | depend upon its object file format, and can not be supported using other object | |
2459 | file formats. Supporting these would require enhancing each object file format | |
2460 | individually. These are: | |
2461 | ||
2462 | @itemize @bullet | |
2463 | @item global symbols in common section | |
2464 | ||
2465 | The m68k MRI assembler supports common sections which are merged by the linker. | |
a4fb0134 | 2466 | Other object file formats do not support this. @command{@value{AS}} handles |
252b5132 RH |
2467 | common sections by treating them as a single common symbol. It permits local |
2468 | symbols to be defined within a common section, but it can not support global | |
2469 | symbols, since it has no way to describe them. | |
2470 | ||
2471 | @item complex relocations | |
2472 | ||
2473 | The MRI assemblers support relocations against a negated section address, and | |
2474 | relocations which combine the start addresses of two or more sections. These | |
2475 | are not support by other object file formats. | |
2476 | ||
2477 | @item @code{END} pseudo-op specifying start address | |
2478 | ||
2479 | The MRI @code{END} pseudo-op permits the specification of a start address. | |
2480 | This is not supported by other object file formats. The start address may | |
a4fb0134 | 2481 | instead be specified using the @option{-e} option to the linker, or in a linker |
252b5132 RH |
2482 | script. |
2483 | ||
2484 | @item @code{IDNT}, @code{.ident} and @code{NAME} pseudo-ops | |
2485 | ||
2486 | The MRI @code{IDNT}, @code{.ident} and @code{NAME} pseudo-ops assign a module | |
2487 | name to the output file. This is not supported by other object file formats. | |
2488 | ||
2489 | @item @code{ORG} pseudo-op | |
2490 | ||
2491 | The m68k MRI @code{ORG} pseudo-op begins an absolute section at a given | |
a4fb0134 | 2492 | address. This differs from the usual @command{@value{AS}} @code{.org} pseudo-op, |
252b5132 RH |
2493 | which changes the location within the current section. Absolute sections are |
2494 | not supported by other object file formats. The address of a section may be | |
2495 | assigned within a linker script. | |
2496 | @end itemize | |
2497 | ||
2498 | There are some other features of the MRI assembler which are not supported by | |
a4fb0134 | 2499 | @command{@value{AS}}, typically either because they are difficult or because they |
252b5132 RH |
2500 | seem of little consequence. Some of these may be supported in future releases. |
2501 | ||
2502 | @itemize @bullet | |
2503 | ||
2504 | @item EBCDIC strings | |
2505 | ||
2506 | EBCDIC strings are not supported. | |
2507 | ||
2508 | @item packed binary coded decimal | |
2509 | ||
2510 | Packed binary coded decimal is not supported. This means that the @code{DC.P} | |
2511 | and @code{DCB.P} pseudo-ops are not supported. | |
2512 | ||
2513 | @item @code{FEQU} pseudo-op | |
2514 | ||
2515 | The m68k @code{FEQU} pseudo-op is not supported. | |
2516 | ||
2517 | @item @code{NOOBJ} pseudo-op | |
2518 | ||
2519 | The m68k @code{NOOBJ} pseudo-op is not supported. | |
2520 | ||
2521 | @item @code{OPT} branch control options | |
2522 | ||
2523 | The m68k @code{OPT} branch control options---@code{B}, @code{BRS}, @code{BRB}, | |
a4fb0134 | 2524 | @code{BRL}, and @code{BRW}---are ignored. @command{@value{AS}} automatically |
252b5132 RH |
2525 | relaxes all branches, whether forward or backward, to an appropriate size, so |
2526 | these options serve no purpose. | |
2527 | ||
2528 | @item @code{OPT} list control options | |
2529 | ||
2530 | The following m68k @code{OPT} list control options are ignored: @code{C}, | |
2531 | @code{CEX}, @code{CL}, @code{CRE}, @code{E}, @code{G}, @code{I}, @code{M}, | |
2532 | @code{MEX}, @code{MC}, @code{MD}, @code{X}. | |
2533 | ||
2534 | @item other @code{OPT} options | |
2535 | ||
2536 | The following m68k @code{OPT} options are ignored: @code{NEST}, @code{O}, | |
2537 | @code{OLD}, @code{OP}, @code{P}, @code{PCO}, @code{PCR}, @code{PCS}, @code{R}. | |
2538 | ||
2539 | @item @code{OPT} @code{D} option is default | |
2540 | ||
2541 | The m68k @code{OPT} @code{D} option is the default, unlike the MRI assembler. | |
2542 | @code{OPT NOD} may be used to turn it off. | |
2543 | ||
2544 | @item @code{XREF} pseudo-op. | |
2545 | ||
2546 | The m68k @code{XREF} pseudo-op is ignored. | |
2547 | ||
2548 | @item @code{.debug} pseudo-op | |
2549 | ||
2550 | The i960 @code{.debug} pseudo-op is not supported. | |
2551 | ||
2552 | @item @code{.extended} pseudo-op | |
2553 | ||
2554 | The i960 @code{.extended} pseudo-op is not supported. | |
2555 | ||
2556 | @item @code{.list} pseudo-op. | |
2557 | ||
2558 | The various options of the i960 @code{.list} pseudo-op are not supported. | |
2559 | ||
2560 | @item @code{.optimize} pseudo-op | |
2561 | ||
2562 | The i960 @code{.optimize} pseudo-op is not supported. | |
2563 | ||
2564 | @item @code{.output} pseudo-op | |
2565 | ||
2566 | The i960 @code{.output} pseudo-op is not supported. | |
2567 | ||
2568 | @item @code{.setreal} pseudo-op | |
2569 | ||
2570 | The i960 @code{.setreal} pseudo-op is not supported. | |
2571 | ||
2572 | @end itemize | |
2573 | ||
2574 | @node MD | |
c1253627 | 2575 | @section Dependency Tracking: @option{--MD} |
252b5132 RH |
2576 | |
2577 | @kindex --MD | |
2578 | @cindex dependency tracking | |
2579 | @cindex make rules | |
2580 | ||
a4fb0134 | 2581 | @command{@value{AS}} can generate a dependency file for the file it creates. This |
252b5132 RH |
2582 | file consists of a single rule suitable for @code{make} describing the |
2583 | dependencies of the main source file. | |
2584 | ||
2585 | The rule is written to the file named in its argument. | |
2586 | ||
2587 | This feature is used in the automatic updating of makefiles. | |
2588 | ||
2edb36e7 NC |
2589 | @node no-pad-sections |
2590 | @section Output Section Padding | |
2591 | @kindex --no-pad-sections | |
2592 | @cindex output section padding | |
2593 | Normally the assembler will pad the end of each output section up to its | |
2594 | alignment boundary. But this can waste space, which can be significant on | |
2595 | memory constrained targets. So the @option{--no-pad-sections} option will | |
2596 | disable this behaviour. | |
2597 | ||
252b5132 | 2598 | @node o |
a4fb0134 | 2599 | @section Name the Object File: @option{-o} |
252b5132 RH |
2600 | |
2601 | @kindex -o | |
2602 | @cindex naming object file | |
2603 | @cindex object file name | |
a4fb0134 | 2604 | There is always one object file output when you run @command{@value{AS}}. By |
252b5132 RH |
2605 | default it has the name |
2606 | @ifset GENERIC | |
2607 | @ifset I960 | |
2608 | @file{a.out} (or @file{b.out}, for Intel 960 targets only). | |
2609 | @end ifset | |
2610 | @ifclear I960 | |
2611 | @file{a.out}. | |
2612 | @end ifclear | |
2613 | @end ifset | |
2614 | @ifclear GENERIC | |
2615 | @ifset I960 | |
2616 | @file{b.out}. | |
2617 | @end ifset | |
2618 | @ifclear I960 | |
2619 | @file{a.out}. | |
2620 | @end ifclear | |
2621 | @end ifclear | |
2622 | You use this option (which takes exactly one filename) to give the | |
2623 | object file a different name. | |
2624 | ||
a4fb0134 | 2625 | Whatever the object file is called, @command{@value{AS}} overwrites any |
252b5132 RH |
2626 | existing file of the same name. |
2627 | ||
2628 | @node R | |
a4fb0134 | 2629 | @section Join Data and Text Sections: @option{-R} |
252b5132 RH |
2630 | |
2631 | @kindex -R | |
2632 | @cindex data and text sections, joining | |
2633 | @cindex text and data sections, joining | |
2634 | @cindex joining text and data sections | |
2635 | @cindex merging text and data sections | |
a4fb0134 | 2636 | @option{-R} tells @command{@value{AS}} to write the object file as if all |
252b5132 RH |
2637 | data-section data lives in the text section. This is only done at |
2638 | the very last moment: your binary data are the same, but data | |
2639 | section parts are relocated differently. The data section part of | |
2640 | your object file is zero bytes long because all its bytes are | |
2641 | appended to the text section. (@xref{Sections,,Sections and Relocation}.) | |
2642 | ||
a4fb0134 | 2643 | When you specify @option{-R} it would be possible to generate shorter |
252b5132 RH |
2644 | address displacements (because we do not have to cross between text and |
2645 | data section). We refrain from doing this simply for compatibility with | |
a4fb0134 | 2646 | older versions of @command{@value{AS}}. In future, @option{-R} may work this way. |
252b5132 | 2647 | |
c1253627 NC |
2648 | @ifset COFF-ELF |
2649 | When @command{@value{AS}} is configured for COFF or ELF output, | |
252b5132 RH |
2650 | this option is only useful if you use sections named @samp{.text} and |
2651 | @samp{.data}. | |
2652 | @end ifset | |
2653 | ||
2654 | @ifset HPPA | |
a4fb0134 SC |
2655 | @option{-R} is not supported for any of the HPPA targets. Using |
2656 | @option{-R} generates a warning from @command{@value{AS}}. | |
252b5132 RH |
2657 | @end ifset |
2658 | ||
2659 | @node statistics | |
a4fb0134 | 2660 | @section Display Assembly Statistics: @option{--statistics} |
252b5132 RH |
2661 | |
2662 | @kindex --statistics | |
2663 | @cindex statistics, about assembly | |
2664 | @cindex time, total for assembly | |
2665 | @cindex space used, maximum for assembly | |
2666 | Use @samp{--statistics} to display two statistics about the resources used by | |
a4fb0134 | 2667 | @command{@value{AS}}: the maximum amount of space allocated during the assembly |
252b5132 RH |
2668 | (in bytes), and the total execution time taken for the assembly (in @sc{cpu} |
2669 | seconds). | |
2670 | ||
2671 | @node traditional-format | |
c1253627 | 2672 | @section Compatible Output: @option{--traditional-format} |
252b5132 RH |
2673 | |
2674 | @kindex --traditional-format | |
a4fb0134 | 2675 | For some targets, the output of @command{@value{AS}} is different in some ways |
252b5132 | 2676 | from the output of some existing assembler. This switch requests |
a4fb0134 | 2677 | @command{@value{AS}} to use the traditional format instead. |
252b5132 RH |
2678 | |
2679 | For example, it disables the exception frame optimizations which | |
a4fb0134 | 2680 | @command{@value{AS}} normally does by default on @code{@value{GCC}} output. |
252b5132 RH |
2681 | |
2682 | @node v | |
a4fb0134 | 2683 | @section Announce Version: @option{-v} |
252b5132 RH |
2684 | |
2685 | @kindex -v | |
2686 | @kindex -version | |
2687 | @cindex assembler version | |
2688 | @cindex version of assembler | |
2689 | You can find out what version of as is running by including the | |
2690 | option @samp{-v} (which you can also spell as @samp{-version}) on the | |
2691 | command line. | |
2692 | ||
2693 | @node W | |
a4fb0134 | 2694 | @section Control Warnings: @option{-W}, @option{--warn}, @option{--no-warn}, @option{--fatal-warnings} |
252b5132 | 2695 | |
a4fb0134 | 2696 | @command{@value{AS}} should never give a warning or error message when |
252b5132 | 2697 | assembling compiler output. But programs written by people often |
a4fb0134 | 2698 | cause @command{@value{AS}} to give a warning that a particular assumption was |
252b5132 | 2699 | made. All such warnings are directed to the standard error file. |
2bdd6cf5 | 2700 | |
c1253627 NC |
2701 | @kindex -W |
2702 | @kindex --no-warn | |
2bdd6cf5 GK |
2703 | @cindex suppressing warnings |
2704 | @cindex warnings, suppressing | |
a4fb0134 | 2705 | If you use the @option{-W} and @option{--no-warn} options, no warnings are issued. |
2bdd6cf5 | 2706 | This only affects the warning messages: it does not change any particular of |
a4fb0134 | 2707 | how @command{@value{AS}} assembles your file. Errors, which stop the assembly, |
2bdd6cf5 GK |
2708 | are still reported. |
2709 | ||
c1253627 | 2710 | @kindex --fatal-warnings |
2bdd6cf5 GK |
2711 | @cindex errors, caused by warnings |
2712 | @cindex warnings, causing error | |
a4fb0134 | 2713 | If you use the @option{--fatal-warnings} option, @command{@value{AS}} considers |
2bdd6cf5 GK |
2714 | files that generate warnings to be in error. |
2715 | ||
c1253627 | 2716 | @kindex --warn |
2bdd6cf5 | 2717 | @cindex warnings, switching on |
a4fb0134 | 2718 | You can switch these options off again by specifying @option{--warn}, which |
2bdd6cf5 | 2719 | causes warnings to be output as usual. |
252b5132 RH |
2720 | |
2721 | @node Z | |
a4fb0134 | 2722 | @section Generate Object File in Spite of Errors: @option{-Z} |
252b5132 RH |
2723 | @cindex object file, after errors |
2724 | @cindex errors, continuing after | |
a4fb0134 | 2725 | After an error message, @command{@value{AS}} normally produces no output. If for |
252b5132 | 2726 | some reason you are interested in object file output even after |
a4fb0134 SC |
2727 | @command{@value{AS}} gives an error message on your program, use the @samp{-Z} |
2728 | option. If there are any errors, @command{@value{AS}} continues anyways, and | |
252b5132 RH |
2729 | writes an object file after a final warning message of the form @samp{@var{n} |
2730 | errors, @var{m} warnings, generating bad object file.} | |
2731 | ||
2732 | @node Syntax | |
2733 | @chapter Syntax | |
2734 | ||
2735 | @cindex machine-independent syntax | |
2736 | @cindex syntax, machine-independent | |
2737 | This chapter describes the machine-independent syntax allowed in a | |
a4fb0134 | 2738 | source file. @command{@value{AS}} syntax is similar to what many other |
252b5132 RH |
2739 | assemblers use; it is inspired by the BSD 4.2 |
2740 | @ifclear VAX | |
2741 | assembler. | |
2742 | @end ifclear | |
2743 | @ifset VAX | |
a4fb0134 | 2744 | assembler, except that @command{@value{AS}} does not assemble Vax bit-fields. |
252b5132 RH |
2745 | @end ifset |
2746 | ||
2747 | @menu | |
7c31ae13 | 2748 | * Preprocessing:: Preprocessing |
252b5132 RH |
2749 | * Whitespace:: Whitespace |
2750 | * Comments:: Comments | |
2751 | * Symbol Intro:: Symbols | |
2752 | * Statements:: Statements | |
2753 | * Constants:: Constants | |
2754 | @end menu | |
2755 | ||
2756 | @node Preprocessing | |
2757 | @section Preprocessing | |
2758 | ||
2759 | @cindex preprocessing | |
a4fb0134 | 2760 | The @command{@value{AS}} internal preprocessor: |
252b5132 RH |
2761 | @itemize @bullet |
2762 | @cindex whitespace, removed by preprocessor | |
2763 | @item | |
2764 | adjusts and removes extra whitespace. It leaves one space or tab before | |
2765 | the keywords on a line, and turns any other whitespace on the line into | |
2766 | a single space. | |
2767 | ||
2768 | @cindex comments, removed by preprocessor | |
2769 | @item | |
2770 | removes all comments, replacing them with a single space, or an | |
2771 | appropriate number of newlines. | |
2772 | ||
2773 | @cindex constants, converted by preprocessor | |
2774 | @item | |
2775 | converts character constants into the appropriate numeric values. | |
2776 | @end itemize | |
2777 | ||
2778 | It does not do macro processing, include file handling, or | |
2779 | anything else you may get from your C compiler's preprocessor. You can | |
2780 | do include file processing with the @code{.include} directive | |
2781 | (@pxref{Include,,@code{.include}}). You can use the @sc{gnu} C compiler driver | |
c1253627 | 2782 | to get other ``CPP'' style preprocessing by giving the input file a |
96e9638b | 2783 | @samp{.S} suffix. @xref{Overall Options, ,Options Controlling the Kind of |
2edb36e7 | 2784 | Output, gcc info, Using GNU CC}. |
252b5132 RH |
2785 | |
2786 | Excess whitespace, comments, and character constants | |
2787 | cannot be used in the portions of the input text that are not | |
2788 | preprocessed. | |
2789 | ||
2790 | @cindex turning preprocessing on and off | |
2791 | @cindex preprocessing, turning on and off | |
2792 | @kindex #NO_APP | |
2793 | @kindex #APP | |
2794 | If the first line of an input file is @code{#NO_APP} or if you use the | |
2795 | @samp{-f} option, whitespace and comments are not removed from the input file. | |
2796 | Within an input file, you can ask for whitespace and comment removal in | |
2797 | specific portions of the by putting a line that says @code{#APP} before the | |
2798 | text that may contain whitespace or comments, and putting a line that says | |
2799 | @code{#NO_APP} after this text. This feature is mainly intend to support | |
2800 | @code{asm} statements in compilers whose output is otherwise free of comments | |
2801 | and whitespace. | |
2802 | ||
2803 | @node Whitespace | |
2804 | @section Whitespace | |
2805 | ||
2806 | @cindex whitespace | |
2807 | @dfn{Whitespace} is one or more blanks or tabs, in any order. | |
2808 | Whitespace is used to separate symbols, and to make programs neater for | |
2809 | people to read. Unless within character constants | |
2810 | (@pxref{Characters,,Character Constants}), any whitespace means the same | |
2811 | as exactly one space. | |
2812 | ||
2813 | @node Comments | |
2814 | @section Comments | |
2815 | ||
2816 | @cindex comments | |
a4fb0134 | 2817 | There are two ways of rendering comments to @command{@value{AS}}. In both |
252b5132 RH |
2818 | cases the comment is equivalent to one space. |
2819 | ||
2820 | Anything from @samp{/*} through the next @samp{*/} is a comment. | |
2821 | This means you may not nest these comments. | |
2822 | ||
2823 | @smallexample | |
2824 | /* | |
2825 | The only way to include a newline ('\n') in a comment | |
2826 | is to use this sort of comment. | |
2827 | */ | |
2828 | ||
2829 | /* This sort of comment does not nest. */ | |
2830 | @end smallexample | |
2831 | ||
2832 | @cindex line comment character | |
7c31ae13 NC |
2833 | Anything from a @dfn{line comment} character up to the next newline is |
2834 | considered a comment and is ignored. The line comment character is target | |
2835 | specific, and some targets multiple comment characters. Some targets also have | |
2836 | line comment characters that only work if they are the first character on a | |
2837 | line. Some targets use a sequence of two characters to introduce a line | |
2838 | comment. Some targets can also change their line comment characters depending | |
2839 | upon command line options that have been used. For more details see the | |
2840 | @emph{Syntax} section in the documentation for individual targets. | |
2841 | ||
2842 | If the line comment character is the hash sign (@samp{#}) then it still has the | |
2843 | special ability to enable and disable preprocessing (@pxref{Preprocessing}) and | |
2844 | to specify logical line numbers: | |
252b5132 RH |
2845 | |
2846 | @kindex # | |
2847 | @cindex lines starting with @code{#} | |
2848 | @cindex logical line numbers | |
2849 | To be compatible with past assemblers, lines that begin with @samp{#} have a | |
2850 | special interpretation. Following the @samp{#} should be an absolute | |
2851 | expression (@pxref{Expressions}): the logical line number of the @emph{next} | |
96e9638b | 2852 | line. Then a string (@pxref{Strings, ,Strings}) is allowed: if present it is a |
252b5132 RH |
2853 | new logical file name. The rest of the line, if any, should be whitespace. |
2854 | ||
2855 | If the first non-whitespace characters on the line are not numeric, | |
2856 | the line is ignored. (Just like a comment.) | |
2857 | ||
2858 | @smallexample | |
2859 | # This is an ordinary comment. | |
2860 | # 42-6 "new_file_name" # New logical file name | |
2861 | # This is logical line # 36. | |
2862 | @end smallexample | |
2863 | This feature is deprecated, and may disappear from future versions | |
a4fb0134 | 2864 | of @command{@value{AS}}. |
252b5132 RH |
2865 | |
2866 | @node Symbol Intro | |
2867 | @section Symbols | |
2868 | ||
2869 | @cindex characters used in symbols | |
2870 | @ifclear SPECIAL-SYMS | |
2871 | A @dfn{symbol} is one or more characters chosen from the set of all | |
2872 | letters (both upper and lower case), digits and the three characters | |
2873 | @samp{_.$}. | |
2874 | @end ifclear | |
2875 | @ifset SPECIAL-SYMS | |
2876 | @ifclear GENERIC | |
2877 | @ifset H8 | |
2878 | A @dfn{symbol} is one or more characters chosen from the set of all | |
2879 | letters (both upper and lower case), digits and the three characters | |
2880 | @samp{._$}. (Save that, on the H8/300 only, you may not use @samp{$} in | |
2881 | symbol names.) | |
2882 | @end ifset | |
2883 | @end ifclear | |
2884 | @end ifset | |
2885 | @ifset GENERIC | |
2886 | On most machines, you can also use @code{$} in symbol names; exceptions | |
2887 | are noted in @ref{Machine Dependencies}. | |
2888 | @end ifset | |
2889 | No symbol may begin with a digit. Case is significant. | |
d02603dc | 2890 | There is no length limit; all characters are significant. Multibyte characters |
7bfd842d NC |
2891 | are supported. Symbols are delimited by characters not in that set, or by the |
2892 | beginning of a file (since the source program must end with a newline, the end | |
2893 | of a file is not a possible symbol delimiter). @xref{Symbols}. | |
d02603dc NC |
2894 | |
2895 | Symbol names may also be enclosed in double quote @code{"} characters. In such | |
2896 | cases any characters are allowed, except for the NUL character. If a double | |
2897 | quote character is to be included in the symbol name it must be preceeded by a | |
2898 | backslash @code{\} character. | |
252b5132 RH |
2899 | @cindex length of symbols |
2900 | ||
2901 | @node Statements | |
2902 | @section Statements | |
2903 | ||
2904 | @cindex statements, structure of | |
2905 | @cindex line separator character | |
2906 | @cindex statement separator character | |
7c31ae13 NC |
2907 | |
2908 | A @dfn{statement} ends at a newline character (@samp{\n}) or a | |
2909 | @dfn{line separator character}. The line separator character is target | |
2910 | specific and described in the @emph{Syntax} section of each | |
2911 | target's documentation. Not all targets support a line separator character. | |
2912 | The newline or line separator character is considered to be part of the | |
2913 | preceding statement. Newlines and separators within character constants are an | |
252b5132 | 2914 | exception: they do not end statements. |
252b5132 RH |
2915 | |
2916 | @cindex newline, required at file end | |
2917 | @cindex EOF, newline must precede | |
2918 | It is an error to end any statement with end-of-file: the last | |
2919 | character of any input file should be a newline.@refill | |
2920 | ||
2921 | An empty statement is allowed, and may include whitespace. It is ignored. | |
2922 | ||
2923 | @cindex instructions and directives | |
2924 | @cindex directives and instructions | |
2925 | @c "key symbol" is not used elsewhere in the document; seems pedantic to | |
2926 | @c @defn{} it in that case, as was done previously... doc@cygnus.com, | |
2927 | @c 13feb91. | |
2928 | A statement begins with zero or more labels, optionally followed by a | |
2929 | key symbol which determines what kind of statement it is. The key | |
2930 | symbol determines the syntax of the rest of the statement. If the | |
2931 | symbol begins with a dot @samp{.} then the statement is an assembler | |
2932 | directive: typically valid for any computer. If the symbol begins with | |
2933 | a letter the statement is an assembly language @dfn{instruction}: it | |
2934 | assembles into a machine language instruction. | |
2935 | @ifset GENERIC | |
a4fb0134 | 2936 | Different versions of @command{@value{AS}} for different computers |
252b5132 RH |
2937 | recognize different instructions. In fact, the same symbol may |
2938 | represent a different instruction in a different computer's assembly | |
2939 | language.@refill | |
2940 | @end ifset | |
2941 | ||
2942 | @cindex @code{:} (label) | |
2943 | @cindex label (@code{:}) | |
2944 | A label is a symbol immediately followed by a colon (@code{:}). | |
2945 | Whitespace before a label or after a colon is permitted, but you may not | |
2946 | have whitespace between a label's symbol and its colon. @xref{Labels}. | |
2947 | ||
2948 | @ifset HPPA | |
01642c12 | 2949 | For HPPA targets, labels need not be immediately followed by a colon, but |
252b5132 RH |
2950 | the definition of a label must begin in column zero. This also implies that |
2951 | only one label may be defined on each line. | |
2952 | @end ifset | |
2953 | ||
2954 | @smallexample | |
2955 | label: .directive followed by something | |
2956 | another_label: # This is an empty statement. | |
2957 | instruction operand_1, operand_2, @dots{} | |
2958 | @end smallexample | |
2959 | ||
2960 | @node Constants | |
2961 | @section Constants | |
2962 | ||
2963 | @cindex constants | |
2964 | A constant is a number, written so that its value is known by | |
2965 | inspection, without knowing any context. Like this: | |
2966 | @smallexample | |
2967 | @group | |
2968 | .byte 74, 0112, 092, 0x4A, 0X4a, 'J, '\J # All the same value. | |
2969 | .ascii "Ring the bell\7" # A string constant. | |
2970 | .octa 0x123456789abcdef0123456789ABCDEF0 # A bignum. | |
2971 | .float 0f-314159265358979323846264338327\ | |
2972 | 95028841971.693993751E-40 # - pi, a flonum. | |
2973 | @end group | |
2974 | @end smallexample | |
2975 | ||
2976 | @menu | |
2977 | * Characters:: Character Constants | |
2978 | * Numbers:: Number Constants | |
2979 | @end menu | |
2980 | ||
2981 | @node Characters | |
2982 | @subsection Character Constants | |
2983 | ||
2984 | @cindex character constants | |
2985 | @cindex constants, character | |
2986 | There are two kinds of character constants. A @dfn{character} stands | |
2987 | for one character in one byte and its value may be used in | |
2988 | numeric expressions. String constants (properly called string | |
2989 | @emph{literals}) are potentially many bytes and their values may not be | |
2990 | used in arithmetic expressions. | |
2991 | ||
2992 | @menu | |
2993 | * Strings:: Strings | |
2994 | * Chars:: Characters | |
2995 | @end menu | |
2996 | ||
2997 | @node Strings | |
2998 | @subsubsection Strings | |
2999 | ||
3000 | @cindex string constants | |
3001 | @cindex constants, string | |
3002 | A @dfn{string} is written between double-quotes. It may contain | |
3003 | double-quotes or null characters. The way to get special characters | |
3004 | into a string is to @dfn{escape} these characters: precede them with | |
3005 | a backslash @samp{\} character. For example @samp{\\} represents | |
3006 | one backslash: the first @code{\} is an escape which tells | |
a4fb0134 SC |
3007 | @command{@value{AS}} to interpret the second character literally as a backslash |
3008 | (which prevents @command{@value{AS}} from recognizing the second @code{\} as an | |
252b5132 RH |
3009 | escape character). The complete list of escapes follows. |
3010 | ||
3011 | @cindex escape codes, character | |
3012 | @cindex character escape codes | |
361fa3a4 NC |
3013 | @c NOTE: Cindex entries must not start with a backlash character. |
3014 | @c NOTE: This confuses the pdf2texi script when it is creating the | |
3015 | @c NOTE: index based upon the first character and so it generates: | |
3016 | @c NOTE: \initial {\\} | |
3017 | @c NOTE: which then results in the error message: | |
3018 | @c NOTE: Argument of \\ has an extra }. | |
3019 | @c NOTE: So in the index entries below a space character has been | |
3020 | @c NOTE: prepended to avoid this problem. | |
252b5132 RH |
3021 | @table @kbd |
3022 | @c @item \a | |
3023 | @c Mnemonic for ACKnowledge; for ASCII this is octal code 007. | |
3024 | @c | |
361fa3a4 | 3025 | @cindex @code{ \b} (backspace character) |
252b5132 RH |
3026 | @cindex backspace (@code{\b}) |
3027 | @item \b | |
3028 | Mnemonic for backspace; for ASCII this is octal code 010. | |
3029 | ||
3030 | @c @item \e | |
3031 | @c Mnemonic for EOText; for ASCII this is octal code 004. | |
3032 | @c | |
361fa3a4 | 3033 | @cindex @code{ \f} (formfeed character) |
252b5132 | 3034 | @cindex formfeed (@code{\f}) |
361fa3a4 | 3035 | @item backslash-f |
252b5132 RH |
3036 | Mnemonic for FormFeed; for ASCII this is octal code 014. |
3037 | ||
361fa3a4 | 3038 | @cindex @code{ \n} (newline character) |
252b5132 RH |
3039 | @cindex newline (@code{\n}) |
3040 | @item \n | |
3041 | Mnemonic for newline; for ASCII this is octal code 012. | |
3042 | ||
3043 | @c @item \p | |
3044 | @c Mnemonic for prefix; for ASCII this is octal code 033, usually known as @code{escape}. | |
3045 | @c | |
361fa3a4 NC |
3046 | @cindex @code{ \r} (carriage return character) |
3047 | @cindex carriage return (@code{backslash-r}) | |
252b5132 RH |
3048 | @item \r |
3049 | Mnemonic for carriage-Return; for ASCII this is octal code 015. | |
3050 | ||
3051 | @c @item \s | |
3052 | @c Mnemonic for space; for ASCII this is octal code 040. Included for compliance with | |
3053 | @c other assemblers. | |
3054 | @c | |
361fa3a4 | 3055 | @cindex @code{ \t} (tab) |
252b5132 RH |
3056 | @cindex tab (@code{\t}) |
3057 | @item \t | |
3058 | Mnemonic for horizontal Tab; for ASCII this is octal code 011. | |
3059 | ||
3060 | @c @item \v | |
3061 | @c Mnemonic for Vertical tab; for ASCII this is octal code 013. | |
3062 | @c @item \x @var{digit} @var{digit} @var{digit} | |
3063 | @c A hexadecimal character code. The numeric code is 3 hexadecimal digits. | |
3064 | @c | |
361fa3a4 | 3065 | @cindex @code{ \@var{ddd}} (octal character code) |
252b5132 RH |
3066 | @cindex octal character code (@code{\@var{ddd}}) |
3067 | @item \ @var{digit} @var{digit} @var{digit} | |
3068 | An octal character code. The numeric code is 3 octal digits. | |
3069 | For compatibility with other Unix systems, 8 and 9 are accepted as digits: | |
3070 | for example, @code{\008} has the value 010, and @code{\009} the value 011. | |
3071 | ||
361fa3a4 | 3072 | @cindex @code{ \@var{xd...}} (hex character code) |
252b5132 RH |
3073 | @cindex hex character code (@code{\@var{xd...}}) |
3074 | @item \@code{x} @var{hex-digits...} | |
3075 | A hex character code. All trailing hex digits are combined. Either upper or | |
3076 | lower case @code{x} works. | |
3077 | ||
361fa3a4 | 3078 | @cindex @code{ \\} (@samp{\} character) |
252b5132 RH |
3079 | @cindex backslash (@code{\\}) |
3080 | @item \\ | |
3081 | Represents one @samp{\} character. | |
3082 | ||
3083 | @c @item \' | |
3084 | @c Represents one @samp{'} (accent acute) character. | |
3085 | @c This is needed in single character literals | |
3086 | @c (@xref{Characters,,Character Constants}.) to represent | |
3087 | @c a @samp{'}. | |
3088 | @c | |
361fa3a4 | 3089 | @cindex @code{ \"} (doublequote character) |
252b5132 RH |
3090 | @cindex doublequote (@code{\"}) |
3091 | @item \" | |
3092 | Represents one @samp{"} character. Needed in strings to represent | |
3093 | this character, because an unescaped @samp{"} would end the string. | |
3094 | ||
3095 | @item \ @var{anything-else} | |
3096 | Any other character when escaped by @kbd{\} gives a warning, but | |
3097 | assembles as if the @samp{\} was not present. The idea is that if | |
3098 | you used an escape sequence you clearly didn't want the literal | |
a4fb0134 SC |
3099 | interpretation of the following character. However @command{@value{AS}} has no |
3100 | other interpretation, so @command{@value{AS}} knows it is giving you the wrong | |
252b5132 RH |
3101 | code and warns you of the fact. |
3102 | @end table | |
3103 | ||
3104 | Which characters are escapable, and what those escapes represent, | |
3105 | varies widely among assemblers. The current set is what we think | |
3106 | the BSD 4.2 assembler recognizes, and is a subset of what most C | |
3107 | compilers recognize. If you are in doubt, do not use an escape | |
3108 | sequence. | |
3109 | ||
3110 | @node Chars | |
3111 | @subsubsection Characters | |
3112 | ||
3113 | @cindex single character constant | |
3114 | @cindex character, single | |
3115 | @cindex constant, single character | |
9962fe29 AM |
3116 | A single character may be written as a single quote immediately followed by |
3117 | that character. Some backslash escapes apply to characters, @code{\b}, | |
3118 | @code{\f}, @code{\n}, @code{\r}, @code{\t}, and @code{\"} with the same meaning | |
3119 | as for strings, plus @code{\'} for a single quote. So if you want to write the | |
3120 | character backslash, you must write @kbd{'\\} where the first @code{\} escapes | |
3121 | the second @code{\}. As you can see, the quote is an acute accent, not a grave | |
3122 | accent. A newline | |
252b5132 RH |
3123 | @ifclear GENERIC |
3124 | @ifclear abnormal-separator | |
3125 | (or semicolon @samp{;}) | |
3126 | @end ifclear | |
3127 | @ifset abnormal-separator | |
252b5132 RH |
3128 | @ifset H8 |
3129 | (or dollar sign @samp{$}, for the H8/300; or semicolon @samp{;} for the | |
7be1c489 | 3130 | Renesas SH) |
252b5132 RH |
3131 | @end ifset |
3132 | @end ifset | |
3133 | @end ifclear | |
3134 | immediately following an acute accent is taken as a literal character | |
3135 | and does not count as the end of a statement. The value of a character | |
3136 | constant in a numeric expression is the machine's byte-wide code for | |
a4fb0134 | 3137 | that character. @command{@value{AS}} assumes your character code is ASCII: |
252b5132 RH |
3138 | @kbd{'A} means 65, @kbd{'B} means 66, and so on. @refill |
3139 | ||
3140 | @node Numbers | |
3141 | @subsection Number Constants | |
3142 | ||
3143 | @cindex constants, number | |
3144 | @cindex number constants | |
a4fb0134 | 3145 | @command{@value{AS}} distinguishes three kinds of numbers according to how they |
252b5132 RH |
3146 | are stored in the target machine. @emph{Integers} are numbers that |
3147 | would fit into an @code{int} in the C language. @emph{Bignums} are | |
3148 | integers, but they are stored in more than 32 bits. @emph{Flonums} | |
3149 | are floating point numbers, described below. | |
3150 | ||
3151 | @menu | |
3152 | * Integers:: Integers | |
3153 | * Bignums:: Bignums | |
3154 | * Flonums:: Flonums | |
3155 | @ifclear GENERIC | |
3156 | @ifset I960 | |
3157 | * Bit Fields:: Bit Fields | |
3158 | @end ifset | |
3159 | @end ifclear | |
3160 | @end menu | |
3161 | ||
3162 | @node Integers | |
3163 | @subsubsection Integers | |
3164 | @cindex integers | |
3165 | @cindex constants, integer | |
3166 | ||
3167 | @cindex binary integers | |
3168 | @cindex integers, binary | |
3169 | A binary integer is @samp{0b} or @samp{0B} followed by zero or more of | |
3170 | the binary digits @samp{01}. | |
3171 | ||
3172 | @cindex octal integers | |
3173 | @cindex integers, octal | |
3174 | An octal integer is @samp{0} followed by zero or more of the octal | |
3175 | digits (@samp{01234567}). | |
3176 | ||
3177 | @cindex decimal integers | |
3178 | @cindex integers, decimal | |
3179 | A decimal integer starts with a non-zero digit followed by zero or | |
3180 | more digits (@samp{0123456789}). | |
3181 | ||
3182 | @cindex hexadecimal integers | |
3183 | @cindex integers, hexadecimal | |
3184 | A hexadecimal integer is @samp{0x} or @samp{0X} followed by one or | |
3185 | more hexadecimal digits chosen from @samp{0123456789abcdefABCDEF}. | |
3186 | ||
3187 | Integers have the usual values. To denote a negative integer, use | |
3188 | the prefix operator @samp{-} discussed under expressions | |
3189 | (@pxref{Prefix Ops,,Prefix Operators}). | |
3190 | ||
3191 | @node Bignums | |
3192 | @subsubsection Bignums | |
3193 | ||
3194 | @cindex bignums | |
3195 | @cindex constants, bignum | |
3196 | A @dfn{bignum} has the same syntax and semantics as an integer | |
3197 | except that the number (or its negative) takes more than 32 bits to | |
3198 | represent in binary. The distinction is made because in some places | |
3199 | integers are permitted while bignums are not. | |
3200 | ||
3201 | @node Flonums | |
3202 | @subsubsection Flonums | |
3203 | @cindex flonums | |
3204 | @cindex floating point numbers | |
3205 | @cindex constants, floating point | |
3206 | ||
3207 | @cindex precision, floating point | |
3208 | A @dfn{flonum} represents a floating point number. The translation is | |
3209 | indirect: a decimal floating point number from the text is converted by | |
a4fb0134 | 3210 | @command{@value{AS}} to a generic binary floating point number of more than |
252b5132 RH |
3211 | sufficient precision. This generic floating point number is converted |
3212 | to a particular computer's floating point format (or formats) by a | |
a4fb0134 | 3213 | portion of @command{@value{AS}} specialized to that computer. |
252b5132 RH |
3214 | |
3215 | A flonum is written by writing (in order) | |
3216 | @itemize @bullet | |
3217 | @item | |
3218 | The digit @samp{0}. | |
3219 | @ifset HPPA | |
3220 | (@samp{0} is optional on the HPPA.) | |
3221 | @end ifset | |
3222 | ||
3223 | @item | |
a4fb0134 | 3224 | A letter, to tell @command{@value{AS}} the rest of the number is a flonum. |
252b5132 RH |
3225 | @ifset GENERIC |
3226 | @kbd{e} is recommended. Case is not important. | |
3227 | @ignore | |
3228 | @c FIXME: verify if flonum syntax really this vague for most cases | |
3229 | (Any otherwise illegal letter works here, but that might be changed. Vax BSD | |
3230 | 4.2 assembler seems to allow any of @samp{defghDEFGH}.) | |
3231 | @end ignore | |
3232 | ||
7be1c489 | 3233 | On the H8/300, Renesas / SuperH SH, |
252b5132 RH |
3234 | and AMD 29K architectures, the letter must be |
3235 | one of the letters @samp{DFPRSX} (in upper or lower case). | |
3236 | ||
3237 | On the ARC, the letter must be one of the letters @samp{DFRS} | |
3238 | (in upper or lower case). | |
3239 | ||
3240 | On the Intel 960 architecture, the letter must be | |
3241 | one of the letters @samp{DFT} (in upper or lower case). | |
3242 | ||
3243 | On the HPPA architecture, the letter must be @samp{E} (upper case only). | |
3244 | @end ifset | |
3245 | @ifclear GENERIC | |
252b5132 RH |
3246 | @ifset ARC |
3247 | One of the letters @samp{DFRS} (in upper or lower case). | |
3248 | @end ifset | |
3249 | @ifset H8 | |
3250 | One of the letters @samp{DFPRSX} (in upper or lower case). | |
3251 | @end ifset | |
3252 | @ifset HPPA | |
3253 | The letter @samp{E} (upper case only). | |
3254 | @end ifset | |
3255 | @ifset I960 | |
3256 | One of the letters @samp{DFT} (in upper or lower case). | |
3257 | @end ifset | |
3258 | @end ifclear | |
3259 | ||
3260 | @item | |
3261 | An optional sign: either @samp{+} or @samp{-}. | |
3262 | ||
3263 | @item | |
3264 | An optional @dfn{integer part}: zero or more decimal digits. | |
3265 | ||
3266 | @item | |
3267 | An optional @dfn{fractional part}: @samp{.} followed by zero | |
3268 | or more decimal digits. | |
3269 | ||
3270 | @item | |
3271 | An optional exponent, consisting of: | |
3272 | ||
3273 | @itemize @bullet | |
3274 | @item | |
3275 | An @samp{E} or @samp{e}. | |
3276 | @c I can't find a config where "EXP_CHARS" is other than 'eE', but in | |
3277 | @c principle this can perfectly well be different on different targets. | |
3278 | @item | |
3279 | Optional sign: either @samp{+} or @samp{-}. | |
3280 | @item | |
3281 | One or more decimal digits. | |
3282 | @end itemize | |
3283 | ||
3284 | @end itemize | |
3285 | ||
3286 | At least one of the integer part or the fractional part must be | |
3287 | present. The floating point number has the usual base-10 value. | |
3288 | ||
a4fb0134 | 3289 | @command{@value{AS}} does all processing using integers. Flonums are computed |
252b5132 | 3290 | independently of any floating point hardware in the computer running |
a4fb0134 | 3291 | @command{@value{AS}}. |
252b5132 RH |
3292 | |
3293 | @ifclear GENERIC | |
3294 | @ifset I960 | |
3295 | @c Bit fields are written as a general facility but are also controlled | |
3296 | @c by a conditional-compilation flag---which is as of now (21mar91) | |
3297 | @c turned on only by the i960 config of GAS. | |
3298 | @node Bit Fields | |
3299 | @subsubsection Bit Fields | |
3300 | ||
3301 | @cindex bit fields | |
3302 | @cindex constants, bit field | |
3303 | You can also define numeric constants as @dfn{bit fields}. | |
b45619c0 | 3304 | Specify two numbers separated by a colon--- |
252b5132 RH |
3305 | @example |
3306 | @var{mask}:@var{value} | |
3307 | @end example | |
3308 | @noindent | |
a4fb0134 | 3309 | @command{@value{AS}} applies a bitwise @sc{and} between @var{mask} and |
252b5132 RH |
3310 | @var{value}. |
3311 | ||
3312 | The resulting number is then packed | |
3313 | @ifset GENERIC | |
3314 | @c this conditional paren in case bit fields turned on elsewhere than 960 | |
3315 | (in host-dependent byte order) | |
3316 | @end ifset | |
3317 | into a field whose width depends on which assembler directive has the | |
3318 | bit-field as its argument. Overflow (a result from the bitwise and | |
3319 | requiring more binary digits to represent) is not an error; instead, | |
3320 | more constants are generated, of the specified width, beginning with the | |
3321 | least significant digits.@refill | |
3322 | ||
3323 | The directives @code{.byte}, @code{.hword}, @code{.int}, @code{.long}, | |
3324 | @code{.short}, and @code{.word} accept bit-field arguments. | |
3325 | @end ifset | |
3326 | @end ifclear | |
3327 | ||
3328 | @node Sections | |
3329 | @chapter Sections and Relocation | |
3330 | @cindex sections | |
3331 | @cindex relocation | |
3332 | ||
3333 | @menu | |
3334 | * Secs Background:: Background | |
3335 | * Ld Sections:: Linker Sections | |
3336 | * As Sections:: Assembler Internal Sections | |
3337 | * Sub-Sections:: Sub-Sections | |
3338 | * bss:: bss Section | |
3339 | @end menu | |
3340 | ||
3341 | @node Secs Background | |
3342 | @section Background | |
3343 | ||
3344 | Roughly, a section is a range of addresses, with no gaps; all data | |
3345 | ``in'' those addresses is treated the same for some particular purpose. | |
3346 | For example there may be a ``read only'' section. | |
3347 | ||
3348 | @cindex linker, and assembler | |
3349 | @cindex assembler, and linker | |
3350 | The linker @code{@value{LD}} reads many object files (partial programs) and | |
a4fb0134 | 3351 | combines their contents to form a runnable program. When @command{@value{AS}} |
252b5132 RH |
3352 | emits an object file, the partial program is assumed to start at address 0. |
3353 | @code{@value{LD}} assigns the final addresses for the partial program, so that | |
3354 | different partial programs do not overlap. This is actually an | |
a4fb0134 | 3355 | oversimplification, but it suffices to explain how @command{@value{AS}} uses |
252b5132 RH |
3356 | sections. |
3357 | ||
3358 | @code{@value{LD}} moves blocks of bytes of your program to their run-time | |
3359 | addresses. These blocks slide to their run-time addresses as rigid | |
3360 | units; their length does not change and neither does the order of bytes | |
3361 | within them. Such a rigid unit is called a @emph{section}. Assigning | |
3362 | run-time addresses to sections is called @dfn{relocation}. It includes | |
3363 | the task of adjusting mentions of object-file addresses so they refer to | |
3364 | the proper run-time addresses. | |
3365 | @ifset H8 | |
7be1c489 | 3366 | For the H8/300, and for the Renesas / SuperH SH, |
a4fb0134 | 3367 | @command{@value{AS}} pads sections if needed to |
252b5132 RH |
3368 | ensure they end on a word (sixteen bit) boundary. |
3369 | @end ifset | |
3370 | ||
3371 | @cindex standard assembler sections | |
a4fb0134 | 3372 | An object file written by @command{@value{AS}} has at least three sections, any |
252b5132 RH |
3373 | of which may be empty. These are named @dfn{text}, @dfn{data} and |
3374 | @dfn{bss} sections. | |
3375 | ||
c1253627 | 3376 | @ifset COFF-ELF |
252b5132 | 3377 | @ifset GENERIC |
c1253627 | 3378 | When it generates COFF or ELF output, |
252b5132 | 3379 | @end ifset |
a4fb0134 | 3380 | @command{@value{AS}} can also generate whatever other named sections you specify |
252b5132 RH |
3381 | using the @samp{.section} directive (@pxref{Section,,@code{.section}}). |
3382 | If you do not use any directives that place output in the @samp{.text} | |
3383 | or @samp{.data} sections, these sections still exist, but are empty. | |
3384 | @end ifset | |
3385 | ||
3386 | @ifset HPPA | |
3387 | @ifset GENERIC | |
a4fb0134 | 3388 | When @command{@value{AS}} generates SOM or ELF output for the HPPA, |
252b5132 | 3389 | @end ifset |
a4fb0134 | 3390 | @command{@value{AS}} can also generate whatever other named sections you |
252b5132 RH |
3391 | specify using the @samp{.space} and @samp{.subspace} directives. See |
3392 | @cite{HP9000 Series 800 Assembly Language Reference Manual} | |
3393 | (HP 92432-90001) for details on the @samp{.space} and @samp{.subspace} | |
3394 | assembler directives. | |
3395 | ||
3396 | @ifset SOM | |
a4fb0134 | 3397 | Additionally, @command{@value{AS}} uses different names for the standard |
252b5132 RH |
3398 | text, data, and bss sections when generating SOM output. Program text |
3399 | is placed into the @samp{$CODE$} section, data into @samp{$DATA$}, and | |
3400 | BSS into @samp{$BSS$}. | |
3401 | @end ifset | |
3402 | @end ifset | |
3403 | ||
3404 | Within the object file, the text section starts at address @code{0}, the | |
3405 | data section follows, and the bss section follows the data section. | |
3406 | ||
3407 | @ifset HPPA | |
3408 | When generating either SOM or ELF output files on the HPPA, the text | |
3409 | section starts at address @code{0}, the data section at address | |
3410 | @code{0x4000000}, and the bss section follows the data section. | |
3411 | @end ifset | |
3412 | ||
3413 | To let @code{@value{LD}} know which data changes when the sections are | |
a4fb0134 | 3414 | relocated, and how to change that data, @command{@value{AS}} also writes to the |
252b5132 RH |
3415 | object file details of the relocation needed. To perform relocation |
3416 | @code{@value{LD}} must know, each time an address in the object | |
3417 | file is mentioned: | |
3418 | @itemize @bullet | |
3419 | @item | |
3420 | Where in the object file is the beginning of this reference to | |
3421 | an address? | |
3422 | @item | |
3423 | How long (in bytes) is this reference? | |
3424 | @item | |
3425 | Which section does the address refer to? What is the numeric value of | |
3426 | @display | |
3427 | (@var{address}) @minus{} (@var{start-address of section})? | |
3428 | @end display | |
3429 | @item | |
3430 | Is the reference to an address ``Program-Counter relative''? | |
3431 | @end itemize | |
3432 | ||
3433 | @cindex addresses, format of | |
3434 | @cindex section-relative addressing | |
a4fb0134 | 3435 | In fact, every address @command{@value{AS}} ever uses is expressed as |
252b5132 RH |
3436 | @display |
3437 | (@var{section}) + (@var{offset into section}) | |
3438 | @end display | |
3439 | @noindent | |
a4fb0134 | 3440 | Further, most expressions @command{@value{AS}} computes have this section-relative |
252b5132 RH |
3441 | nature. |
3442 | @ifset SOM | |
3443 | (For some object formats, such as SOM for the HPPA, some expressions are | |
3444 | symbol-relative instead.) | |
3445 | @end ifset | |
3446 | ||
3447 | In this manual we use the notation @{@var{secname} @var{N}@} to mean ``offset | |
3448 | @var{N} into section @var{secname}.'' | |
3449 | ||
3450 | Apart from text, data and bss sections you need to know about the | |
3451 | @dfn{absolute} section. When @code{@value{LD}} mixes partial programs, | |
3452 | addresses in the absolute section remain unchanged. For example, address | |
3453 | @code{@{absolute 0@}} is ``relocated'' to run-time address 0 by | |
3454 | @code{@value{LD}}. Although the linker never arranges two partial programs' | |
3455 | data sections with overlapping addresses after linking, @emph{by definition} | |
3456 | their absolute sections must overlap. Address @code{@{absolute@ 239@}} in one | |
3457 | part of a program is always the same address when the program is running as | |
3458 | address @code{@{absolute@ 239@}} in any other part of the program. | |
3459 | ||
3460 | The idea of sections is extended to the @dfn{undefined} section. Any | |
3461 | address whose section is unknown at assembly time is by definition | |
3462 | rendered @{undefined @var{U}@}---where @var{U} is filled in later. | |
3463 | Since numbers are always defined, the only way to generate an undefined | |
3464 | address is to mention an undefined symbol. A reference to a named | |
3465 | common block would be such a symbol: its value is unknown at assembly | |
3466 | time so it has section @emph{undefined}. | |
3467 | ||
3468 | By analogy the word @emph{section} is used to describe groups of sections in | |
3469 | the linked program. @code{@value{LD}} puts all partial programs' text | |
3470 | sections in contiguous addresses in the linked program. It is | |
3471 | customary to refer to the @emph{text section} of a program, meaning all | |
3472 | the addresses of all partial programs' text sections. Likewise for | |
3473 | data and bss sections. | |
3474 | ||
3475 | Some sections are manipulated by @code{@value{LD}}; others are invented for | |
a4fb0134 | 3476 | use of @command{@value{AS}} and have no meaning except during assembly. |
252b5132 RH |
3477 | |
3478 | @node Ld Sections | |
3479 | @section Linker Sections | |
3480 | @code{@value{LD}} deals with just four kinds of sections, summarized below. | |
3481 | ||
3482 | @table @strong | |
3483 | ||
c1253627 | 3484 | @ifset COFF-ELF |
252b5132 RH |
3485 | @cindex named sections |
3486 | @cindex sections, named | |
3487 | @item named sections | |
3488 | @end ifset | |
3489 | @ifset aout-bout | |
3490 | @cindex text section | |
3491 | @cindex data section | |
3492 | @itemx text section | |
3493 | @itemx data section | |
3494 | @end ifset | |
a4fb0134 | 3495 | These sections hold your program. @command{@value{AS}} and @code{@value{LD}} treat them as |
252b5132 | 3496 | separate but equal sections. Anything you can say of one section is |
c1253627 NC |
3497 | true of another. |
3498 | @c @ifset aout-bout | |
252b5132 RH |
3499 | When the program is running, however, it is |
3500 | customary for the text section to be unalterable. The | |
3501 | text section is often shared among processes: it contains | |
3502 | instructions, constants and the like. The data section of a running | |
3503 | program is usually alterable: for example, C variables would be stored | |
3504 | in the data section. | |
c1253627 | 3505 | @c @end ifset |
252b5132 RH |
3506 | |
3507 | @cindex bss section | |
3508 | @item bss section | |
3509 | This section contains zeroed bytes when your program begins running. It | |
a349d9dd | 3510 | is used to hold uninitialized variables or common storage. The length of |
252b5132 RH |
3511 | each partial program's bss section is important, but because it starts |
3512 | out containing zeroed bytes there is no need to store explicit zero | |
3513 | bytes in the object file. The bss section was invented to eliminate | |
3514 | those explicit zeros from object files. | |
3515 | ||
3516 | @cindex absolute section | |
3517 | @item absolute section | |
3518 | Address 0 of this section is always ``relocated'' to runtime address 0. | |
3519 | This is useful if you want to refer to an address that @code{@value{LD}} must | |
3520 | not change when relocating. In this sense we speak of absolute | |
3521 | addresses being ``unrelocatable'': they do not change during relocation. | |
3522 | ||
3523 | @cindex undefined section | |
3524 | @item undefined section | |
3525 | This ``section'' is a catch-all for address references to objects not in | |
3526 | the preceding sections. | |
3527 | @c FIXME: ref to some other doc on obj-file formats could go here. | |
3528 | @end table | |
3529 | ||
3530 | @cindex relocation example | |
3531 | An idealized example of three relocatable sections follows. | |
c1253627 | 3532 | @ifset COFF-ELF |
252b5132 RH |
3533 | The example uses the traditional section names @samp{.text} and @samp{.data}. |
3534 | @end ifset | |
3535 | Memory addresses are on the horizontal axis. | |
3536 | ||
3537 | @c TEXI2ROFF-KILL | |
c1253627 | 3538 | @ifnottex |
252b5132 RH |
3539 | @c END TEXI2ROFF-KILL |
3540 | @smallexample | |
3541 | +-----+----+--+ | |
3542 | partial program # 1: |ttttt|dddd|00| | |
3543 | +-----+----+--+ | |
3544 | ||
3545 | text data bss | |
3546 | seg. seg. seg. | |
3547 | ||
3548 | +---+---+---+ | |
3549 | partial program # 2: |TTT|DDD|000| | |
3550 | +---+---+---+ | |
3551 | ||
3552 | +--+---+-----+--+----+---+-----+~~ | |
3553 | linked program: | |TTT|ttttt| |dddd|DDD|00000| | |
3554 | +--+---+-----+--+----+---+-----+~~ | |
3555 | ||
3556 | addresses: 0 @dots{} | |
3557 | @end smallexample | |
3558 | @c TEXI2ROFF-KILL | |
c1253627 | 3559 | @end ifnottex |
252b5132 RH |
3560 | @need 5000 |
3561 | @tex | |
c1253627 | 3562 | \bigskip |
252b5132 RH |
3563 | \line{\it Partial program \#1: \hfil} |
3564 | \line{\ibox{2.5cm}{\tt text}\ibox{2cm}{\tt data}\ibox{1cm}{\tt bss}\hfil} | |
3565 | \line{\boxit{2.5cm}{\tt ttttt}\boxit{2cm}{\tt dddd}\boxit{1cm}{\tt 00}\hfil} | |
3566 | ||
3567 | \line{\it Partial program \#2: \hfil} | |
3568 | \line{\ibox{1cm}{\tt text}\ibox{1.5cm}{\tt data}\ibox{1cm}{\tt bss}\hfil} | |
3569 | \line{\boxit{1cm}{\tt TTT}\boxit{1.5cm}{\tt DDDD}\boxit{1cm}{\tt 000}\hfil} | |
3570 | ||
3571 | \line{\it linked program: \hfil} | |
3572 | \line{\ibox{.5cm}{}\ibox{1cm}{\tt text}\ibox{2.5cm}{}\ibox{.75cm}{}\ibox{2cm}{\tt data}\ibox{1.5cm}{}\ibox{2cm}{\tt bss}\hfil} | |
3573 | \line{\boxit{.5cm}{}\boxit{1cm}{\tt TTT}\boxit{2.5cm}{\tt | |
3574 | ttttt}\boxit{.75cm}{}\boxit{2cm}{\tt dddd}\boxit{1.5cm}{\tt | |
3575 | DDDD}\boxit{2cm}{\tt 00000}\ \dots\hfil} | |
3576 | ||
3577 | \line{\it addresses: \hfil} | |
3578 | \line{0\dots\hfil} | |
3579 | ||
3580 | @end tex | |
3581 | @c END TEXI2ROFF-KILL | |
3582 | ||
3583 | @node As Sections | |
3584 | @section Assembler Internal Sections | |
3585 | ||
3586 | @cindex internal assembler sections | |
3587 | @cindex sections in messages, internal | |
a4fb0134 | 3588 | These sections are meant only for the internal use of @command{@value{AS}}. They |
252b5132 | 3589 | have no meaning at run-time. You do not really need to know about these |
a4fb0134 | 3590 | sections for most purposes; but they can be mentioned in @command{@value{AS}} |
252b5132 | 3591 | warning messages, so it might be helpful to have an idea of their |
a4fb0134 | 3592 | meanings to @command{@value{AS}}. These sections are used to permit the |
252b5132 RH |
3593 | value of every expression in your assembly language program to be a |
3594 | section-relative address. | |
3595 | ||
3596 | @table @b | |
3597 | @cindex assembler internal logic error | |
3598 | @item ASSEMBLER-INTERNAL-LOGIC-ERROR! | |
3599 | An internal assembler logic error has been found. This means there is a | |
3600 | bug in the assembler. | |
3601 | ||
3602 | @cindex expr (internal section) | |
3603 | @item expr section | |
3604 | The assembler stores complex expression internally as combinations of | |
3605 | symbols. When it needs to represent an expression as a symbol, it puts | |
3606 | it in the expr section. | |
3607 | @c FIXME item debug | |
3608 | @c FIXME item transfer[t] vector preload | |
3609 | @c FIXME item transfer[t] vector postload | |
3610 | @c FIXME item register | |
3611 | @end table | |
3612 | ||
3613 | @node Sub-Sections | |
3614 | @section Sub-Sections | |
3615 | ||
3616 | @cindex numbered subsections | |
3617 | @cindex grouping data | |
3618 | @ifset aout-bout | |
3619 | Assembled bytes | |
c1253627 | 3620 | @ifset COFF-ELF |
252b5132 RH |
3621 | conventionally |
3622 | @end ifset | |
3623 | fall into two sections: text and data. | |
3624 | @end ifset | |
3625 | You may have separate groups of | |
3626 | @ifset GENERIC | |
3627 | data in named sections | |
3628 | @end ifset | |
3629 | @ifclear GENERIC | |
3630 | @ifclear aout-bout | |
3631 | data in named sections | |
3632 | @end ifclear | |
3633 | @ifset aout-bout | |
3634 | text or data | |
3635 | @end ifset | |
3636 | @end ifclear | |
3637 | that you want to end up near to each other in the object file, even though they | |
a4fb0134 | 3638 | are not contiguous in the assembler source. @command{@value{AS}} allows you to |
252b5132 RH |
3639 | use @dfn{subsections} for this purpose. Within each section, there can be |
3640 | numbered subsections with values from 0 to 8192. Objects assembled into the | |
3641 | same subsection go into the object file together with other objects in the same | |
3642 | subsection. For example, a compiler might want to store constants in the text | |
3643 | section, but might not want to have them interspersed with the program being | |
3644 | assembled. In this case, the compiler could issue a @samp{.text 0} before each | |
3645 | section of code being output, and a @samp{.text 1} before each group of | |
3646 | constants being output. | |
3647 | ||
3648 | Subsections are optional. If you do not use subsections, everything | |
3649 | goes in subsection number zero. | |
3650 | ||
3651 | @ifset GENERIC | |
3652 | Each subsection is zero-padded up to a multiple of four bytes. | |
3653 | (Subsections may be padded a different amount on different flavors | |
a4fb0134 | 3654 | of @command{@value{AS}}.) |
252b5132 RH |
3655 | @end ifset |
3656 | @ifclear GENERIC | |
3657 | @ifset H8 | |
7be1c489 | 3658 | On the H8/300 platform, each subsection is zero-padded to a word |
252b5132 | 3659 | boundary (two bytes). |
c2dcd04e | 3660 | The same is true on the Renesas SH. |
252b5132 RH |
3661 | @end ifset |
3662 | @ifset I960 | |
3663 | @c FIXME section padding (alignment)? | |
3664 | @c Rich Pixley says padding here depends on target obj code format; that | |
3665 | @c doesn't seem particularly useful to say without further elaboration, | |
3666 | @c so for now I say nothing about it. If this is a generic BFD issue, | |
3667 | @c these paragraphs might need to vanish from this manual, and be | |
3668 | @c discussed in BFD chapter of binutils (or some such). | |
3669 | @end ifset | |
252b5132 RH |
3670 | @end ifclear |
3671 | ||
3672 | Subsections appear in your object file in numeric order, lowest numbered | |
3673 | to highest. (All this to be compatible with other people's assemblers.) | |
3674 | The object file contains no representation of subsections; @code{@value{LD}} and | |
3675 | other programs that manipulate object files see no trace of them. | |
3676 | They just see all your text subsections as a text section, and all your | |
3677 | data subsections as a data section. | |
3678 | ||
3679 | To specify which subsection you want subsequent statements assembled | |
3680 | into, use a numeric argument to specify it, in a @samp{.text | |
3681 | @var{expression}} or a @samp{.data @var{expression}} statement. | |
ed9589d4 | 3682 | @ifset COFF |
252b5132 | 3683 | @ifset GENERIC |
ed9589d4 | 3684 | When generating COFF output, you |
252b5132 RH |
3685 | @end ifset |
3686 | @ifclear GENERIC | |
3687 | You | |
3688 | @end ifclear | |
3689 | can also use an extra subsection | |
3690 | argument with arbitrary named sections: @samp{.section @var{name}, | |
3691 | @var{expression}}. | |
3692 | @end ifset | |
ed9589d4 BW |
3693 | @ifset ELF |
3694 | @ifset GENERIC | |
3695 | When generating ELF output, you | |
3696 | @end ifset | |
3697 | @ifclear GENERIC | |
3698 | You | |
3699 | @end ifclear | |
3700 | can also use the @code{.subsection} directive (@pxref{SubSection}) | |
3701 | to specify a subsection: @samp{.subsection @var{expression}}. | |
3702 | @end ifset | |
96e9638b BW |
3703 | @var{Expression} should be an absolute expression |
3704 | (@pxref{Expressions}). If you just say @samp{.text} then @samp{.text 0} | |
252b5132 RH |
3705 | is assumed. Likewise @samp{.data} means @samp{.data 0}. Assembly |
3706 | begins in @code{text 0}. For instance: | |
3707 | @smallexample | |
3708 | .text 0 # The default subsection is text 0 anyway. | |
3709 | .ascii "This lives in the first text subsection. *" | |
3710 | .text 1 | |
3711 | .ascii "But this lives in the second text subsection." | |
3712 | .data 0 | |
3713 | .ascii "This lives in the data section," | |
3714 | .ascii "in the first data subsection." | |
3715 | .text 0 | |
3716 | .ascii "This lives in the first text section," | |
3717 | .ascii "immediately following the asterisk (*)." | |
3718 | @end smallexample | |
3719 | ||
3720 | Each section has a @dfn{location counter} incremented by one for every byte | |
3721 | assembled into that section. Because subsections are merely a convenience | |
a4fb0134 | 3722 | restricted to @command{@value{AS}} there is no concept of a subsection location |
252b5132 RH |
3723 | counter. There is no way to directly manipulate a location counter---but the |
3724 | @code{.align} directive changes it, and any label definition captures its | |
3725 | current value. The location counter of the section where statements are being | |
3726 | assembled is said to be the @dfn{active} location counter. | |
3727 | ||
3728 | @node bss | |
3729 | @section bss Section | |
3730 | ||
3731 | @cindex bss section | |
3732 | @cindex common variable storage | |
3733 | The bss section is used for local common variable storage. | |
3734 | You may allocate address space in the bss section, but you may | |
3735 | not dictate data to load into it before your program executes. When | |
3736 | your program starts running, all the contents of the bss | |
3737 | section are zeroed bytes. | |
3738 | ||
3739 | The @code{.lcomm} pseudo-op defines a symbol in the bss section; see | |
3740 | @ref{Lcomm,,@code{.lcomm}}. | |
3741 | ||
3742 | The @code{.comm} pseudo-op may be used to declare a common symbol, which is | |
96e9638b | 3743 | another form of uninitialized symbol; see @ref{Comm,,@code{.comm}}. |
252b5132 RH |
3744 | |
3745 | @ifset GENERIC | |
3746 | When assembling for a target which supports multiple sections, such as ELF or | |
3747 | COFF, you may switch into the @code{.bss} section and define symbols as usual; | |
3748 | see @ref{Section,,@code{.section}}. You may only assemble zero values into the | |
3749 | section. Typically the section will only contain symbol definitions and | |
3750 | @code{.skip} directives (@pxref{Skip,,@code{.skip}}). | |
3751 | @end ifset | |
3752 | ||
3753 | @node Symbols | |
3754 | @chapter Symbols | |
3755 | ||
3756 | @cindex symbols | |
3757 | Symbols are a central concept: the programmer uses symbols to name | |
3758 | things, the linker uses symbols to link, and the debugger uses symbols | |
3759 | to debug. | |
3760 | ||
3761 | @quotation | |
3762 | @cindex debuggers, and symbol order | |
a4fb0134 | 3763 | @emph{Warning:} @command{@value{AS}} does not place symbols in the object file in |
252b5132 RH |
3764 | the same order they were declared. This may break some debuggers. |
3765 | @end quotation | |
3766 | ||
3767 | @menu | |
3768 | * Labels:: Labels | |
3769 | * Setting Symbols:: Giving Symbols Other Values | |
3770 | * Symbol Names:: Symbol Names | |
3771 | * Dot:: The Special Dot Symbol | |
3772 | * Symbol Attributes:: Symbol Attributes | |
3773 | @end menu | |
3774 | ||
3775 | @node Labels | |
3776 | @section Labels | |
3777 | ||
3778 | @cindex labels | |
3779 | A @dfn{label} is written as a symbol immediately followed by a colon | |
3780 | @samp{:}. The symbol then represents the current value of the | |
3781 | active location counter, and is, for example, a suitable instruction | |
3782 | operand. You are warned if you use the same symbol to represent two | |
3783 | different locations: the first definition overrides any other | |
3784 | definitions. | |
3785 | ||
3786 | @ifset HPPA | |
3787 | On the HPPA, the usual form for a label need not be immediately followed by a | |
3788 | colon, but instead must start in column zero. Only one label may be defined on | |
a4fb0134 | 3789 | a single line. To work around this, the HPPA version of @command{@value{AS}} also |
252b5132 RH |
3790 | provides a special directive @code{.label} for defining labels more flexibly. |
3791 | @end ifset | |
3792 | ||
3793 | @node Setting Symbols | |
3794 | @section Giving Symbols Other Values | |
3795 | ||
3796 | @cindex assigning values to symbols | |
3797 | @cindex symbol values, assigning | |
3798 | A symbol can be given an arbitrary value by writing a symbol, followed | |
3799 | by an equals sign @samp{=}, followed by an expression | |
3800 | (@pxref{Expressions}). This is equivalent to using the @code{.set} | |
9497f5ac NC |
3801 | directive. @xref{Set,,@code{.set}}. In the same way, using a double |
3802 | equals sign @samp{=}@samp{=} here represents an equivalent of the | |
3803 | @code{.eqv} directive. @xref{Eqv,,@code{.eqv}}. | |
252b5132 | 3804 | |
f8739b83 JZ |
3805 | @ifset Blackfin |
3806 | Blackfin does not support symbol assignment with @samp{=}. | |
3807 | @end ifset | |
3808 | ||
252b5132 RH |
3809 | @node Symbol Names |
3810 | @section Symbol Names | |
3811 | ||
3812 | @cindex symbol names | |
3813 | @cindex names, symbol | |
3814 | @ifclear SPECIAL-SYMS | |
3815 | Symbol names begin with a letter or with one of @samp{._}. On most | |
3816 | machines, you can also use @code{$} in symbol names; exceptions are | |
3817 | noted in @ref{Machine Dependencies}. That character may be followed by any | |
96e9638b BW |
3818 | string of digits, letters, dollar signs (unless otherwise noted for a |
3819 | particular target machine), and underscores. | |
252b5132 | 3820 | @end ifclear |
252b5132 RH |
3821 | @ifset SPECIAL-SYMS |
3822 | @ifset H8 | |
3823 | Symbol names begin with a letter or with one of @samp{._}. On the | |
7be1c489 | 3824 | Renesas SH you can also use @code{$} in symbol names. That |
c2dcd04e NC |
3825 | character may be followed by any string of digits, letters, dollar signs (save |
3826 | on the H8/300), and underscores. | |
252b5132 RH |
3827 | @end ifset |
3828 | @end ifset | |
3829 | ||
3830 | Case of letters is significant: @code{foo} is a different symbol name | |
3831 | than @code{Foo}. | |
3832 | ||
ed1fcdd1 NC |
3833 | Symbol names do not start with a digit. An exception to this rule is made for |
3834 | Local Labels. See below. | |
3835 | ||
7bfd842d NC |
3836 | Multibyte characters are supported. To generate a symbol name containing |
3837 | multibyte characters enclose it within double quotes and use escape codes. cf | |
3838 | @xref{Strings}. Generating a multibyte symbol name from a label is not | |
3839 | currently supported. | |
3840 | ||
252b5132 RH |
3841 | Each symbol has exactly one name. Each name in an assembly language program |
3842 | refers to exactly one symbol. You may use that symbol name any number of times | |
3843 | in a program. | |
3844 | ||
3845 | @subheading Local Symbol Names | |
3846 | ||
3847 | @cindex local symbol names | |
3848 | @cindex symbol names, local | |
ba83aca1 BW |
3849 | A local symbol is any symbol beginning with certain local label prefixes. |
3850 | By default, the local label prefix is @samp{.L} for ELF systems or | |
3851 | @samp{L} for traditional a.out systems, but each target may have its own | |
3852 | set of local label prefixes. | |
3853 | @ifset HPPA | |
3854 | On the HPPA local symbols begin with @samp{L$}. | |
3855 | @end ifset | |
3856 | ||
3857 | Local symbols are defined and used within the assembler, but they are | |
3858 | normally not saved in object files. Thus, they are not visible when debugging. | |
5c9352f3 AM |
3859 | You may use the @samp{-L} option (@pxref{L, ,Include Local Symbols}) |
3860 | to retain the local symbols in the object files. | |
ba83aca1 BW |
3861 | |
3862 | @subheading Local Labels | |
3863 | ||
3864 | @cindex local labels | |
252b5132 RH |
3865 | @cindex temporary symbol names |
3866 | @cindex symbol names, temporary | |
ed1fcdd1 NC |
3867 | Local labels are different from local symbols. Local labels help compilers and |
3868 | programmers use names temporarily. They create symbols which are guaranteed to | |
3869 | be unique over the entire scope of the input source code and which can be | |
3870 | referred to by a simple notation. To define a local label, write a label of | |
9791c250 AM |
3871 | the form @samp{@b{N}:} (where @b{N} represents any non-negative integer). |
3872 | To refer to the most recent previous definition of that label write | |
3873 | @samp{@b{N}b}, using the same number as when you defined the label. To refer | |
3874 | to the next definition of a local label, write @samp{@b{N}f}. The @samp{b} | |
3875 | stands for ``backwards'' and the @samp{f} stands for ``forwards''. | |
2d5aaba0 NC |
3876 | |
3877 | There is no restriction on how you can use these labels, and you can reuse them | |
3878 | too. So that it is possible to repeatedly define the same local label (using | |
3879 | the same number @samp{@b{N}}), although you can only refer to the most recently | |
3880 | defined local label of that number (for a backwards reference) or the next | |
3881 | definition of a specific local label for a forward reference. It is also worth | |
3882 | noting that the first 10 local labels (@samp{@b{0:}}@dots{}@samp{@b{9:}}) are | |
3883 | implemented in a slightly more efficient manner than the others. | |
3884 | ||
3885 | Here is an example: | |
3886 | ||
3887 | @smallexample | |
3888 | 1: branch 1f | |
3889 | 2: branch 1b | |
3890 | 1: branch 2f | |
3891 | 2: branch 1b | |
3892 | @end smallexample | |
3893 | ||
3894 | Which is the equivalent of: | |
3895 | ||
3896 | @smallexample | |
3897 | label_1: branch label_3 | |
3898 | label_2: branch label_1 | |
3899 | label_3: branch label_4 | |
3900 | label_4: branch label_3 | |
3901 | @end smallexample | |
3902 | ||
ba83aca1 | 3903 | Local label names are only a notational device. They are immediately |
2d5aaba0 | 3904 | transformed into more conventional symbol names before the assembler uses them. |
96e9638b BW |
3905 | The symbol names are stored in the symbol table, appear in error messages, and |
3906 | are optionally emitted to the object file. The names are constructed using | |
3907 | these parts: | |
252b5132 RH |
3908 | |
3909 | @table @code | |
ba83aca1 BW |
3910 | @item @emph{local label prefix} |
3911 | All local symbols begin with the system-specific local label prefix. | |
3912 | Normally both @command{@value{AS}} and @code{@value{LD}} forget symbols | |
3913 | that start with the local label prefix. These labels are | |
252b5132 | 3914 | used for symbols you are never intended to see. If you use the |
a4fb0134 | 3915 | @samp{-L} option then @command{@value{AS}} retains these symbols in the |
252b5132 RH |
3916 | object file. If you also instruct @code{@value{LD}} to retain these symbols, |
3917 | you may use them in debugging. | |
3918 | ||
2d5aaba0 NC |
3919 | @item @var{number} |
3920 | This is the number that was used in the local label definition. So if the | |
01642c12 | 3921 | label is written @samp{55:} then the number is @samp{55}. |
252b5132 | 3922 | |
2d5aaba0 NC |
3923 | @item @kbd{C-B} |
3924 | This unusual character is included so you do not accidentally invent a symbol | |
3925 | of the same name. The character has ASCII value of @samp{\002} (control-B). | |
252b5132 RH |
3926 | |
3927 | @item @emph{ordinal number} | |
2d5aaba0 | 3928 | This is a serial number to keep the labels distinct. The first definition of |
01642c12 | 3929 | @samp{0:} gets the number @samp{1}. The 15th definition of @samp{0:} gets the |
2d5aaba0 | 3930 | number @samp{15}, and so on. Likewise the first definition of @samp{1:} gets |
b45619c0 | 3931 | the number @samp{1} and its 15th definition gets @samp{15} as well. |
252b5132 RH |
3932 | @end table |
3933 | ||
ba83aca1 BW |
3934 | So for example, the first @code{1:} may be named @code{.L1@kbd{C-B}1}, and |
3935 | the 44th @code{3:} may be named @code{.L3@kbd{C-B}44}. | |
2d5aaba0 NC |
3936 | |
3937 | @subheading Dollar Local Labels | |
3938 | @cindex dollar local symbols | |
3939 | ||
ed1fcdd1 NC |
3940 | On some targets @code{@value{AS}} also supports an even more local form of |
3941 | local labels called dollar labels. These labels go out of scope (i.e., they | |
3942 | become undefined) as soon as a non-local label is defined. Thus they remain | |
3943 | valid for only a small region of the input source code. Normal local labels, | |
3944 | by contrast, remain in scope for the entire file, or until they are redefined | |
3945 | by another occurrence of the same local label. | |
2d5aaba0 NC |
3946 | |
3947 | Dollar labels are defined in exactly the same way as ordinary local labels, | |
77cca80f NC |
3948 | except that they have a dollar sign suffix to their numeric value, e.g., |
3949 | @samp{@b{55$:}}. | |
2d5aaba0 NC |
3950 | |
3951 | They can also be distinguished from ordinary local labels by their transformed | |
96e9638b BW |
3952 | names which use ASCII character @samp{\001} (control-A) as the magic character |
3953 | to distinguish them from ordinary labels. For example, the fifth definition of | |
ba83aca1 | 3954 | @samp{6$} may be named @samp{.L6@kbd{C-A}5}. |
252b5132 RH |
3955 | |
3956 | @node Dot | |
3957 | @section The Special Dot Symbol | |
3958 | ||
3959 | @cindex dot (symbol) | |
3960 | @cindex @code{.} (symbol) | |
3961 | @cindex current address | |
3962 | @cindex location counter | |
3963 | The special symbol @samp{.} refers to the current address that | |
a4fb0134 | 3964 | @command{@value{AS}} is assembling into. Thus, the expression @samp{melvin: |
252b5132 RH |
3965 | .long .} defines @code{melvin} to contain its own address. |
3966 | Assigning a value to @code{.} is treated the same as a @code{.org} | |
884f0d36 | 3967 | directive. |
252b5132 | 3968 | @ifclear no-space-dir |
884f0d36 | 3969 | Thus, the expression @samp{.=.+4} is the same as saying |
252b5132 RH |
3970 | @samp{.space 4}. |
3971 | @end ifclear | |
252b5132 RH |
3972 | |
3973 | @node Symbol Attributes | |
3974 | @section Symbol Attributes | |
3975 | ||
3976 | @cindex symbol attributes | |
3977 | @cindex attributes, symbol | |
3978 | Every symbol has, as well as its name, the attributes ``Value'' and | |
3979 | ``Type''. Depending on output format, symbols can also have auxiliary | |
3980 | attributes. | |
3981 | @ifset INTERNALS | |
3982 | The detailed definitions are in @file{a.out.h}. | |
3983 | @end ifset | |
3984 | ||
a4fb0134 | 3985 | If you use a symbol without defining it, @command{@value{AS}} assumes zero for |
252b5132 RH |
3986 | all these attributes, and probably won't warn you. This makes the |
3987 | symbol an externally defined symbol, which is generally what you | |
3988 | would want. | |
3989 | ||
3990 | @menu | |
3991 | * Symbol Value:: Value | |
3992 | * Symbol Type:: Type | |
3993 | @ifset aout-bout | |
3994 | @ifset GENERIC | |
3995 | * a.out Symbols:: Symbol Attributes: @code{a.out} | |
3996 | @end ifset | |
3997 | @ifclear GENERIC | |
3998 | @ifclear BOUT | |
3999 | * a.out Symbols:: Symbol Attributes: @code{a.out} | |
4000 | @end ifclear | |
4001 | @ifset BOUT | |
4002 | * a.out Symbols:: Symbol Attributes: @code{a.out}, @code{b.out} | |
4003 | @end ifset | |
4004 | @end ifclear | |
4005 | @end ifset | |
4006 | @ifset COFF | |
4007 | * COFF Symbols:: Symbol Attributes for COFF | |
4008 | @end ifset | |
4009 | @ifset SOM | |
4010 | * SOM Symbols:: Symbol Attributes for SOM | |
4011 | @end ifset | |
4012 | @end menu | |
4013 | ||
4014 | @node Symbol Value | |
4015 | @subsection Value | |
4016 | ||
4017 | @cindex value of a symbol | |
4018 | @cindex symbol value | |
4019 | The value of a symbol is (usually) 32 bits. For a symbol which labels a | |
4020 | location in the text, data, bss or absolute sections the value is the | |
4021 | number of addresses from the start of that section to the label. | |
4022 | Naturally for text, data and bss sections the value of a symbol changes | |
4023 | as @code{@value{LD}} changes section base addresses during linking. Absolute | |
4024 | symbols' values do not change during linking: that is why they are | |
4025 | called absolute. | |
4026 | ||
4027 | The value of an undefined symbol is treated in a special way. If it is | |
4028 | 0 then the symbol is not defined in this assembler source file, and | |
4029 | @code{@value{LD}} tries to determine its value from other files linked into the | |
4030 | same program. You make this kind of symbol simply by mentioning a symbol | |
4031 | name without defining it. A non-zero value represents a @code{.comm} | |
4032 | common declaration. The value is how much common storage to reserve, in | |
4033 | bytes (addresses). The symbol refers to the first address of the | |
4034 | allocated storage. | |
4035 | ||
4036 | @node Symbol Type | |
4037 | @subsection Type | |
4038 | ||
4039 | @cindex type of a symbol | |
4040 | @cindex symbol type | |
4041 | The type attribute of a symbol contains relocation (section) | |
4042 | information, any flag settings indicating that a symbol is external, and | |
4043 | (optionally), other information for linkers and debuggers. The exact | |
4044 | format depends on the object-code output format in use. | |
4045 | ||
4046 | @ifset aout-bout | |
4047 | @ifclear GENERIC | |
4048 | @ifset BOUT | |
4049 | @c The following avoids a "widow" subsection title. @group would be | |
4050 | @c better if it were available outside examples. | |
4051 | @need 1000 | |
4052 | @node a.out Symbols | |
4053 | @subsection Symbol Attributes: @code{a.out}, @code{b.out} | |
4054 | ||
4055 | @cindex @code{b.out} symbol attributes | |
4056 | @cindex symbol attributes, @code{b.out} | |
a4fb0134 | 4057 | These symbol attributes appear only when @command{@value{AS}} is configured for |
252b5132 RH |
4058 | one of the Berkeley-descended object output formats---@code{a.out} or |
4059 | @code{b.out}. | |
4060 | ||
4061 | @end ifset | |
4062 | @ifclear BOUT | |
4063 | @node a.out Symbols | |
4064 | @subsection Symbol Attributes: @code{a.out} | |
4065 | ||
4066 | @cindex @code{a.out} symbol attributes | |
4067 | @cindex symbol attributes, @code{a.out} | |
4068 | ||
4069 | @end ifclear | |
4070 | @end ifclear | |
4071 | @ifset GENERIC | |
4072 | @node a.out Symbols | |
4073 | @subsection Symbol Attributes: @code{a.out} | |
4074 | ||
4075 | @cindex @code{a.out} symbol attributes | |
4076 | @cindex symbol attributes, @code{a.out} | |
4077 | ||
4078 | @end ifset | |
4079 | @menu | |
4080 | * Symbol Desc:: Descriptor | |
4081 | * Symbol Other:: Other | |
4082 | @end menu | |
4083 | ||
4084 | @node Symbol Desc | |
4085 | @subsubsection Descriptor | |
4086 | ||
4087 | @cindex descriptor, of @code{a.out} symbol | |
4088 | This is an arbitrary 16-bit value. You may establish a symbol's | |
4089 | descriptor value by using a @code{.desc} statement | |
4090 | (@pxref{Desc,,@code{.desc}}). A descriptor value means nothing to | |
a4fb0134 | 4091 | @command{@value{AS}}. |
252b5132 RH |
4092 | |
4093 | @node Symbol Other | |
4094 | @subsubsection Other | |
4095 | ||
4096 | @cindex other attribute, of @code{a.out} symbol | |
a4fb0134 | 4097 | This is an arbitrary 8-bit value. It means nothing to @command{@value{AS}}. |
252b5132 RH |
4098 | @end ifset |
4099 | ||
4100 | @ifset COFF | |
4101 | @node COFF Symbols | |
4102 | @subsection Symbol Attributes for COFF | |
4103 | ||
4104 | @cindex COFF symbol attributes | |
4105 | @cindex symbol attributes, COFF | |
4106 | ||
4107 | The COFF format supports a multitude of auxiliary symbol attributes; | |
4108 | like the primary symbol attributes, they are set between @code{.def} and | |
4109 | @code{.endef} directives. | |
4110 | ||
4111 | @subsubsection Primary Attributes | |
4112 | ||
4113 | @cindex primary attributes, COFF symbols | |
4114 | The symbol name is set with @code{.def}; the value and type, | |
4115 | respectively, with @code{.val} and @code{.type}. | |
4116 | ||
4117 | @subsubsection Auxiliary Attributes | |
4118 | ||
4119 | @cindex auxiliary attributes, COFF symbols | |
a4fb0134 | 4120 | The @command{@value{AS}} directives @code{.dim}, @code{.line}, @code{.scl}, |
c87db184 CF |
4121 | @code{.size}, @code{.tag}, and @code{.weak} can generate auxiliary symbol |
4122 | table information for COFF. | |
252b5132 RH |
4123 | @end ifset |
4124 | ||
4125 | @ifset SOM | |
4126 | @node SOM Symbols | |
4127 | @subsection Symbol Attributes for SOM | |
4128 | ||
4129 | @cindex SOM symbol attributes | |
4130 | @cindex symbol attributes, SOM | |
4131 | ||
4132 | The SOM format for the HPPA supports a multitude of symbol attributes set with | |
4133 | the @code{.EXPORT} and @code{.IMPORT} directives. | |
4134 | ||
01642c12 | 4135 | The attributes are described in @cite{HP9000 Series 800 Assembly |
252b5132 RH |
4136 | Language Reference Manual} (HP 92432-90001) under the @code{IMPORT} and |
4137 | @code{EXPORT} assembler directive documentation. | |
4138 | @end ifset | |
4139 | ||
4140 | @node Expressions | |
4141 | @chapter Expressions | |
4142 | ||
4143 | @cindex expressions | |
4144 | @cindex addresses | |
4145 | @cindex numeric values | |
4146 | An @dfn{expression} specifies an address or numeric value. | |
4147 | Whitespace may precede and/or follow an expression. | |
4148 | ||
4149 | The result of an expression must be an absolute number, or else an offset into | |
4150 | a particular section. If an expression is not absolute, and there is not | |
a4fb0134 | 4151 | enough information when @command{@value{AS}} sees the expression to know its |
252b5132 RH |
4152 | section, a second pass over the source program might be necessary to interpret |
4153 | the expression---but the second pass is currently not implemented. | |
a4fb0134 | 4154 | @command{@value{AS}} aborts with an error message in this situation. |
252b5132 RH |
4155 | |
4156 | @menu | |
4157 | * Empty Exprs:: Empty Expressions | |
4158 | * Integer Exprs:: Integer Expressions | |
4159 | @end menu | |
4160 | ||
4161 | @node Empty Exprs | |
4162 | @section Empty Expressions | |
4163 | ||
4164 | @cindex empty expressions | |
4165 | @cindex expressions, empty | |
4166 | An empty expression has no value: it is just whitespace or null. | |
4167 | Wherever an absolute expression is required, you may omit the | |
a4fb0134 | 4168 | expression, and @command{@value{AS}} assumes a value of (absolute) 0. This |
252b5132 RH |
4169 | is compatible with other assemblers. |
4170 | ||
4171 | @node Integer Exprs | |
4172 | @section Integer Expressions | |
4173 | ||
4174 | @cindex integer expressions | |
4175 | @cindex expressions, integer | |
4176 | An @dfn{integer expression} is one or more @emph{arguments} delimited | |
4177 | by @emph{operators}. | |
4178 | ||
4179 | @menu | |
4180 | * Arguments:: Arguments | |
4181 | * Operators:: Operators | |
4182 | * Prefix Ops:: Prefix Operators | |
4183 | * Infix Ops:: Infix Operators | |
4184 | @end menu | |
4185 | ||
4186 | @node Arguments | |
4187 | @subsection Arguments | |
4188 | ||
4189 | @cindex expression arguments | |
4190 | @cindex arguments in expressions | |
4191 | @cindex operands in expressions | |
4192 | @cindex arithmetic operands | |
4193 | @dfn{Arguments} are symbols, numbers or subexpressions. In other | |
4194 | contexts arguments are sometimes called ``arithmetic operands''. In | |
4195 | this manual, to avoid confusing them with the ``instruction operands'' of | |
4196 | the machine language, we use the term ``argument'' to refer to parts of | |
4197 | expressions only, reserving the word ``operand'' to refer only to machine | |
4198 | instruction operands. | |
4199 | ||
4200 | Symbols are evaluated to yield @{@var{section} @var{NNN}@} where | |
4201 | @var{section} is one of text, data, bss, absolute, | |
4202 | or undefined. @var{NNN} is a signed, 2's complement 32 bit | |
4203 | integer. | |
4204 | ||
4205 | Numbers are usually integers. | |
4206 | ||
4207 | A number can be a flonum or bignum. In this case, you are warned | |
a4fb0134 | 4208 | that only the low order 32 bits are used, and @command{@value{AS}} pretends |
252b5132 RH |
4209 | these 32 bits are an integer. You may write integer-manipulating |
4210 | instructions that act on exotic constants, compatible with other | |
4211 | assemblers. | |
4212 | ||
4213 | @cindex subexpressions | |
4214 | Subexpressions are a left parenthesis @samp{(} followed by an integer | |
4215 | expression, followed by a right parenthesis @samp{)}; or a prefix | |
4216 | operator followed by an argument. | |
4217 | ||
4218 | @node Operators | |
4219 | @subsection Operators | |
4220 | ||
4221 | @cindex operators, in expressions | |
4222 | @cindex arithmetic functions | |
4223 | @cindex functions, in expressions | |
4224 | @dfn{Operators} are arithmetic functions, like @code{+} or @code{%}. Prefix | |
4225 | operators are followed by an argument. Infix operators appear | |
4226 | between their arguments. Operators may be preceded and/or followed by | |
4227 | whitespace. | |
4228 | ||
4229 | @node Prefix Ops | |
4230 | @subsection Prefix Operator | |
4231 | ||
4232 | @cindex prefix operators | |
a4fb0134 | 4233 | @command{@value{AS}} has the following @dfn{prefix operators}. They each take |
252b5132 RH |
4234 | one argument, which must be absolute. |
4235 | ||
4236 | @c the tex/end tex stuff surrounding this small table is meant to make | |
4237 | @c it align, on the printed page, with the similar table in the next | |
4238 | @c section (which is inside an enumerate). | |
4239 | @tex | |
4240 | \global\advance\leftskip by \itemindent | |
4241 | @end tex | |
4242 | ||
4243 | @table @code | |
4244 | @item - | |
4245 | @dfn{Negation}. Two's complement negation. | |
4246 | @item ~ | |
4247 | @dfn{Complementation}. Bitwise not. | |
4248 | @end table | |
4249 | ||
4250 | @tex | |
4251 | \global\advance\leftskip by -\itemindent | |
4252 | @end tex | |
4253 | ||
4254 | @node Infix Ops | |
4255 | @subsection Infix Operators | |
4256 | ||
4257 | @cindex infix operators | |
4258 | @cindex operators, permitted arguments | |
4259 | @dfn{Infix operators} take two arguments, one on either side. Operators | |
4260 | have precedence, but operations with equal precedence are performed left | |
a4fb0134 | 4261 | to right. Apart from @code{+} or @option{-}, both arguments must be |
252b5132 RH |
4262 | absolute, and the result is absolute. |
4263 | ||
4264 | @enumerate | |
4265 | @cindex operator precedence | |
4266 | @cindex precedence of operators | |
4267 | ||
4268 | @item | |
4269 | Highest Precedence | |
4270 | ||
4271 | @table @code | |
4272 | @item * | |
4273 | @dfn{Multiplication}. | |
4274 | ||
4275 | @item / | |
4276 | @dfn{Division}. Truncation is the same as the C operator @samp{/} | |
4277 | ||
4278 | @item % | |
4279 | @dfn{Remainder}. | |
4280 | ||
d1eac9d9 | 4281 | @item << |
252b5132 RH |
4282 | @dfn{Shift Left}. Same as the C operator @samp{<<}. |
4283 | ||
d1eac9d9 | 4284 | @item >> |
252b5132 RH |
4285 | @dfn{Shift Right}. Same as the C operator @samp{>>}. |
4286 | @end table | |
4287 | ||
4288 | @item | |
4289 | Intermediate precedence | |
4290 | ||
4291 | @table @code | |
4292 | @item | | |
4293 | ||
4294 | @dfn{Bitwise Inclusive Or}. | |
4295 | ||
4296 | @item & | |
4297 | @dfn{Bitwise And}. | |
4298 | ||
4299 | @item ^ | |
4300 | @dfn{Bitwise Exclusive Or}. | |
4301 | ||
4302 | @item ! | |
4303 | @dfn{Bitwise Or Not}. | |
4304 | @end table | |
4305 | ||
4306 | @item | |
b131d4dc | 4307 | Low Precedence |
252b5132 RH |
4308 | |
4309 | @table @code | |
4310 | @cindex addition, permitted arguments | |
4311 | @cindex plus, permitted arguments | |
4312 | @cindex arguments for addition | |
4313 | @item + | |
4314 | @dfn{Addition}. If either argument is absolute, the result has the section of | |
4315 | the other argument. You may not add together arguments from different | |
4316 | sections. | |
4317 | ||
4318 | @cindex subtraction, permitted arguments | |
4319 | @cindex minus, permitted arguments | |
4320 | @cindex arguments for subtraction | |
4321 | @item - | |
4322 | @dfn{Subtraction}. If the right argument is absolute, the | |
4323 | result has the section of the left argument. | |
4324 | If both arguments are in the same section, the result is absolute. | |
4325 | You may not subtract arguments from different sections. | |
4326 | @c FIXME is there still something useful to say about undefined - undefined ? | |
b131d4dc NC |
4327 | |
4328 | @cindex comparison expressions | |
4329 | @cindex expressions, comparison | |
4330 | @item == | |
4331 | @dfn{Is Equal To} | |
4332 | @item <> | |
723a8472 | 4333 | @itemx != |
b131d4dc NC |
4334 | @dfn{Is Not Equal To} |
4335 | @item < | |
4336 | @dfn{Is Less Than} | |
d1eac9d9 | 4337 | @item > |
b131d4dc | 4338 | @dfn{Is Greater Than} |
d1eac9d9 | 4339 | @item >= |
b131d4dc | 4340 | @dfn{Is Greater Than Or Equal To} |
d1eac9d9 | 4341 | @item <= |
b131d4dc NC |
4342 | @dfn{Is Less Than Or Equal To} |
4343 | ||
4344 | The comparison operators can be used as infix operators. A true results has a | |
4345 | value of -1 whereas a false result has a value of 0. Note, these operators | |
4346 | perform signed comparisons. | |
4347 | @end table | |
4348 | ||
4349 | @item Lowest Precedence | |
4350 | ||
4351 | @table @code | |
4352 | @item && | |
4353 | @dfn{Logical And}. | |
4354 | ||
4355 | @item || | |
4356 | @dfn{Logical Or}. | |
4357 | ||
4358 | These two logical operations can be used to combine the results of sub | |
4359 | expressions. Note, unlike the comparison operators a true result returns a | |
4360 | value of 1 but a false results does still return 0. Also note that the logical | |
4361 | or operator has a slightly lower precedence than logical and. | |
4362 | ||
252b5132 RH |
4363 | @end table |
4364 | @end enumerate | |
4365 | ||
4366 | In short, it's only meaningful to add or subtract the @emph{offsets} in an | |
4367 | address; you can only have a defined section in one of the two arguments. | |
4368 | ||
4369 | @node Pseudo Ops | |
4370 | @chapter Assembler Directives | |
4371 | ||
4372 | @cindex directives, machine independent | |
4373 | @cindex pseudo-ops, machine independent | |
4374 | @cindex machine independent directives | |
4375 | All assembler directives have names that begin with a period (@samp{.}). | |
7e302352 RS |
4376 | The names are case insensitive for most targets, and usually written |
4377 | in lower case. | |
252b5132 RH |
4378 | |
4379 | This chapter discusses directives that are available regardless of the | |
4380 | target machine configuration for the @sc{gnu} assembler. | |
4381 | @ifset GENERIC | |
4382 | Some machine configurations provide additional directives. | |
4383 | @xref{Machine Dependencies}. | |
4384 | @end ifset | |
4385 | @ifclear GENERIC | |
4386 | @ifset machine-directives | |
96e9638b | 4387 | @xref{Machine Dependencies}, for additional directives. |
252b5132 RH |
4388 | @end ifset |
4389 | @end ifclear | |
4390 | ||
4391 | @menu | |
4392 | * Abort:: @code{.abort} | |
4393 | @ifset COFF | |
38a57ae7 | 4394 | * ABORT (COFF):: @code{.ABORT} |
252b5132 | 4395 | @end ifset |
f0dc282c | 4396 | |
252b5132 | 4397 | * Align:: @code{.align @var{abs-expr} , @var{abs-expr}} |
caa32fe5 | 4398 | * Altmacro:: @code{.altmacro} |
252b5132 RH |
4399 | * Ascii:: @code{.ascii "@var{string}"}@dots{} |
4400 | * Asciz:: @code{.asciz "@var{string}"}@dots{} | |
4401 | * Balign:: @code{.balign @var{abs-expr} , @var{abs-expr}} | |
d3b47e2b | 4402 | * Bundle directives:: @code{.bundle_align_mode @var{abs-expr}}, etc |
252b5132 | 4403 | * Byte:: @code{.byte @var{expressions}} |
4b7d318b | 4404 | * CFI directives:: @code{.cfi_startproc [simple]}, @code{.cfi_endproc}, etc. |
ccf8a69b | 4405 | * Comm:: @code{.comm @var{symbol} , @var{length} } |
252b5132 | 4406 | * Data:: @code{.data @var{subsection}} |
340d33e5 NC |
4407 | * Dc:: @code{.dc[@var{size}] @var{expressions}} |
4408 | * Dcb:: @code{.dcb[@var{size}] @var{number} [,@var{fill}]} | |
4409 | * Ds:: @code{.ds[@var{size}] @var{number} [,@var{fill}]} | |
252b5132 RH |
4410 | @ifset COFF |
4411 | * Def:: @code{.def @var{name}} | |
4412 | @end ifset | |
4413 | @ifset aout-bout | |
4414 | * Desc:: @code{.desc @var{symbol}, @var{abs-expression}} | |
4415 | @end ifset | |
4416 | @ifset COFF | |
4417 | * Dim:: @code{.dim} | |
4418 | @end ifset | |
f0dc282c | 4419 | |
252b5132 RH |
4420 | * Double:: @code{.double @var{flonums}} |
4421 | * Eject:: @code{.eject} | |
4422 | * Else:: @code{.else} | |
3fd9f047 | 4423 | * Elseif:: @code{.elseif} |
252b5132 RH |
4424 | * End:: @code{.end} |
4425 | @ifset COFF | |
4426 | * Endef:: @code{.endef} | |
4427 | @end ifset | |
f0dc282c | 4428 | |
252b5132 RH |
4429 | * Endfunc:: @code{.endfunc} |
4430 | * Endif:: @code{.endif} | |
4431 | * Equ:: @code{.equ @var{symbol}, @var{expression}} | |
4432 | * Equiv:: @code{.equiv @var{symbol}, @var{expression}} | |
9497f5ac | 4433 | * Eqv:: @code{.eqv @var{symbol}, @var{expression}} |
252b5132 | 4434 | * Err:: @code{.err} |
d190d046 | 4435 | * Error:: @code{.error @var{string}} |
252b5132 RH |
4436 | * Exitm:: @code{.exitm} |
4437 | * Extern:: @code{.extern} | |
4438 | * Fail:: @code{.fail} | |
14082c76 | 4439 | * File:: @code{.file} |
252b5132 RH |
4440 | * Fill:: @code{.fill @var{repeat} , @var{size} , @var{value}} |
4441 | * Float:: @code{.float @var{flonums}} | |
01642c12 | 4442 | * Func:: @code{.func} |
252b5132 | 4443 | * Global:: @code{.global @var{symbol}}, @code{.globl @var{symbol}} |
c91d2e08 | 4444 | @ifset ELF |
3a99f02f | 4445 | * Gnu_attribute:: @code{.gnu_attribute @var{tag},@var{value}} |
c91d2e08 NC |
4446 | * Hidden:: @code{.hidden @var{names}} |
4447 | @end ifset | |
f0dc282c | 4448 | |
252b5132 RH |
4449 | * hword:: @code{.hword @var{expressions}} |
4450 | * Ident:: @code{.ident} | |
4451 | * If:: @code{.if @var{absolute expression}} | |
7e005732 | 4452 | * Incbin:: @code{.incbin "@var{file}"[,@var{skip}[,@var{count}]]} |
252b5132 RH |
4453 | * Include:: @code{.include "@var{file}"} |
4454 | * Int:: @code{.int @var{expressions}} | |
c91d2e08 NC |
4455 | @ifset ELF |
4456 | * Internal:: @code{.internal @var{names}} | |
4457 | @end ifset | |
f0dc282c | 4458 | |
252b5132 RH |
4459 | * Irp:: @code{.irp @var{symbol},@var{values}}@dots{} |
4460 | * Irpc:: @code{.irpc @var{symbol},@var{values}}@dots{} | |
4461 | * Lcomm:: @code{.lcomm @var{symbol} , @var{length}} | |
4462 | * Lflags:: @code{.lflags} | |
4463 | @ifclear no-line-dir | |
4464 | * Line:: @code{.line @var{line-number}} | |
4465 | @end ifclear | |
f0dc282c | 4466 | |
252b5132 RH |
4467 | * Linkonce:: @code{.linkonce [@var{type}]} |
4468 | * List:: @code{.list} | |
bd0eb99b | 4469 | * Ln:: @code{.ln @var{line-number}} |
14082c76 BW |
4470 | * Loc:: @code{.loc @var{fileno} @var{lineno}} |
4471 | * Loc_mark_labels:: @code{.loc_mark_labels @var{enable}} | |
4d4175af BW |
4472 | @ifset ELF |
4473 | * Local:: @code{.local @var{names}} | |
4474 | @end ifset | |
bd0eb99b | 4475 | |
252b5132 RH |
4476 | * Long:: @code{.long @var{expressions}} |
4477 | @ignore | |
4478 | * Lsym:: @code{.lsym @var{symbol}, @var{expression}} | |
4479 | @end ignore | |
f0dc282c | 4480 | |
252b5132 RH |
4481 | * Macro:: @code{.macro @var{name} @var{args}}@dots{} |
4482 | * MRI:: @code{.mri @var{val}} | |
caa32fe5 | 4483 | * Noaltmacro:: @code{.noaltmacro} |
252b5132 | 4484 | * Nolist:: @code{.nolist} |
62a02d25 | 4485 | * Nop:: @code{.nop @var{size}[, @var{control}]} |
252b5132 | 4486 | * Octa:: @code{.octa @var{bignums}} |
9aec2026 | 4487 | * Offset:: @code{.offset @var{loc}} |
85234291 L |
4488 | * Org:: @code{.org @var{new-lc}, @var{fill}} |
4489 | * P2align:: @code{.p2align @var{abs-expr}, @var{abs-expr}, @var{abs-expr}} | |
c91d2e08 NC |
4490 | @ifset ELF |
4491 | * PopSection:: @code{.popsection} | |
4492 | * Previous:: @code{.previous} | |
4493 | @end ifset | |
f0dc282c | 4494 | |
252b5132 | 4495 | * Print:: @code{.print @var{string}} |
c91d2e08 NC |
4496 | @ifset ELF |
4497 | * Protected:: @code{.protected @var{names}} | |
4498 | @end ifset | |
f0dc282c | 4499 | |
252b5132 RH |
4500 | * Psize:: @code{.psize @var{lines}, @var{columns}} |
4501 | * Purgem:: @code{.purgem @var{name}} | |
c91d2e08 NC |
4502 | @ifset ELF |
4503 | * PushSection:: @code{.pushsection @var{name}} | |
4504 | @end ifset | |
f0dc282c | 4505 | |
252b5132 | 4506 | * Quad:: @code{.quad @var{bignums}} |
05e9452c | 4507 | * Reloc:: @code{.reloc @var{offset}, @var{reloc_name}[, @var{expression}]} |
252b5132 RH |
4508 | * Rept:: @code{.rept @var{count}} |
4509 | * Sbttl:: @code{.sbttl "@var{subheading}"} | |
4510 | @ifset COFF | |
4511 | * Scl:: @code{.scl @var{class}} | |
c1253627 NC |
4512 | @end ifset |
4513 | @ifset COFF-ELF | |
7337fc21 | 4514 | * Section:: @code{.section @var{name}[, @var{flags}]} |
252b5132 | 4515 | @end ifset |
f0dc282c | 4516 | |
252b5132 RH |
4517 | * Set:: @code{.set @var{symbol}, @var{expression}} |
4518 | * Short:: @code{.short @var{expressions}} | |
4519 | * Single:: @code{.single @var{flonums}} | |
c1253627 | 4520 | @ifset COFF-ELF |
c91d2e08 | 4521 | * Size:: @code{.size [@var{name} , @var{expression}]} |
c1253627 | 4522 | @end ifset |
884f0d36 | 4523 | @ifclear no-space-dir |
340d33e5 | 4524 | * Skip:: @code{.skip @var{size} [,@var{fill}]} |
884f0d36 BW |
4525 | @end ifclear |
4526 | ||
252b5132 | 4527 | * Sleb128:: @code{.sleb128 @var{expressions}} |
884f0d36 | 4528 | @ifclear no-space-dir |
340d33e5 | 4529 | * Space:: @code{.space @var{size} [,@var{fill}]} |
884f0d36 | 4530 | @end ifclear |
252b5132 RH |
4531 | @ifset have-stabs |
4532 | * Stab:: @code{.stabd, .stabn, .stabs} | |
4533 | @end ifset | |
f0dc282c | 4534 | |
38a57ae7 | 4535 | * String:: @code{.string "@var{str}"}, @code{.string8 "@var{str}"}, @code{.string16 "@var{str}"}, @code{.string32 "@var{str}"}, @code{.string64 "@var{str}"} |
252b5132 RH |
4536 | * Struct:: @code{.struct @var{expression}} |
4537 | @ifset ELF | |
c91d2e08 | 4538 | * SubSection:: @code{.subsection} |
252b5132 RH |
4539 | * Symver:: @code{.symver @var{name},@var{name2@@nodename}} |
4540 | @end ifset | |
f0dc282c | 4541 | |
252b5132 RH |
4542 | @ifset COFF |
4543 | * Tag:: @code{.tag @var{structname}} | |
4544 | @end ifset | |
f0dc282c | 4545 | |
252b5132 RH |
4546 | * Text:: @code{.text @var{subsection}} |
4547 | * Title:: @code{.title "@var{heading}"} | |
c1253627 | 4548 | @ifset COFF-ELF |
c91d2e08 | 4549 | * Type:: @code{.type <@var{int} | @var{name} , @var{type description}>} |
c1253627 NC |
4550 | @end ifset |
4551 | ||
c91d2e08 | 4552 | * Uleb128:: @code{.uleb128 @var{expressions}} |
252b5132 | 4553 | @ifset COFF |
252b5132 RH |
4554 | * Val:: @code{.val @var{addr}} |
4555 | @end ifset | |
f0dc282c | 4556 | |
2e13b764 | 4557 | @ifset ELF |
c91d2e08 | 4558 | * Version:: @code{.version "@var{string}"} |
c91d2e08 NC |
4559 | * VTableEntry:: @code{.vtable_entry @var{table}, @var{offset}} |
4560 | * VTableInherit:: @code{.vtable_inherit @var{child}, @var{parent}} | |
2e13b764 | 4561 | @end ifset |
f0dc282c | 4562 | |
d190d046 | 4563 | * Warning:: @code{.warning @var{string}} |
c87db184 | 4564 | * Weak:: @code{.weak @var{names}} |
06e77878 | 4565 | * Weakref:: @code{.weakref @var{alias}, @var{symbol}} |
252b5132 | 4566 | * Word:: @code{.word @var{expressions}} |
7ce98c16 NC |
4567 | @ifclear no-space-dir |
4568 | * Zero:: @code{.zero @var{size}} | |
4569 | @end ifclear | |
2b841ec2 AM |
4570 | @ifset ELF |
4571 | * 2byte:: @code{.2byte @var{expressions}} | |
4572 | * 4byte:: @code{.4byte @var{expressions}} | |
4573 | * 8byte:: @code{.8byte @var{bignums}} | |
4574 | @end ifset | |
252b5132 RH |
4575 | * Deprecated:: Deprecated Directives |
4576 | @end menu | |
4577 | ||
4578 | @node Abort | |
4579 | @section @code{.abort} | |
4580 | ||
4581 | @cindex @code{abort} directive | |
4582 | @cindex stopping the assembly | |
4583 | This directive stops the assembly immediately. It is for | |
4584 | compatibility with other assemblers. The original idea was that the | |
4585 | assembly language source would be piped into the assembler. If the sender | |
a4fb0134 | 4586 | of the source quit, it could use this directive tells @command{@value{AS}} to |
252b5132 RH |
4587 | quit also. One day @code{.abort} will not be supported. |
4588 | ||
4589 | @ifset COFF | |
370b66a1 CD |
4590 | @node ABORT (COFF) |
4591 | @section @code{.ABORT} (COFF) | |
252b5132 RH |
4592 | |
4593 | @cindex @code{ABORT} directive | |
a4fb0134 | 4594 | When producing COFF output, @command{@value{AS}} accepts this directive as a |
252b5132 RH |
4595 | synonym for @samp{.abort}. |
4596 | ||
4597 | @ifset BOUT | |
a4fb0134 | 4598 | When producing @code{b.out} output, @command{@value{AS}} accepts this directive, |
252b5132 RH |
4599 | but ignores it. |
4600 | @end ifset | |
4601 | @end ifset | |
4602 | ||
4603 | @node Align | |
4604 | @section @code{.align @var{abs-expr}, @var{abs-expr}, @var{abs-expr}} | |
4605 | ||
4606 | @cindex padding the location counter | |
4607 | @cindex @code{align} directive | |
4608 | Pad the location counter (in the current subsection) to a particular storage | |
4609 | boundary. The first expression (which must be absolute) is the alignment | |
4610 | required, as described below. | |
4611 | ||
4612 | The second expression (also absolute) gives the fill value to be stored in the | |
4613 | padding bytes. It (and the comma) may be omitted. If it is omitted, the | |
2ca23e65 | 4614 | padding bytes are normally zero. However, on most systems, if the section is |
252b5132 RH |
4615 | marked as containing code and the fill value is omitted, the space is filled |
4616 | with no-op instructions. | |
4617 | ||
4618 | The third expression is also absolute, and is also optional. If it is present, | |
4619 | it is the maximum number of bytes that should be skipped by this alignment | |
4620 | directive. If doing the alignment would require skipping more bytes than the | |
4621 | specified maximum, then the alignment is not done at all. You can omit the | |
4622 | fill value (the second argument) entirely by simply using two commas after the | |
4623 | required alignment; this can be useful if you want the alignment to be filled | |
4624 | with no-op instructions when appropriate. | |
4625 | ||
4626 | The way the required alignment is specified varies from system to system. | |
73589c9d | 4627 | For the arc, hppa, i386 using ELF, i860, iq2000, m68k, or1k, |
60946ad0 | 4628 | s390, sparc, tic4x, tic80 and xtensa, the first expression is the |
252b5132 RH |
4629 | alignment request in bytes. For example @samp{.align 8} advances |
4630 | the location counter until it is a multiple of 8. If the location counter | |
60946ad0 AM |
4631 | is already a multiple of 8, no change is needed. For the tic54x, the |
4632 | first expression is the alignment request in words. | |
252b5132 | 4633 | |
9e9a9798 | 4634 | For other systems, including ppc, i386 using a.out format, arm and |
adcf07e6 | 4635 | strongarm, it is the |
252b5132 RH |
4636 | number of low-order zero bits the location counter must have after |
4637 | advancement. For example @samp{.align 3} advances the location | |
4638 | counter until it a multiple of 8. If the location counter is already a | |
4639 | multiple of 8, no change is needed. | |
4640 | ||
4641 | This inconsistency is due to the different behaviors of the various | |
4642 | native assemblers for these systems which GAS must emulate. | |
4643 | GAS also provides @code{.balign} and @code{.p2align} directives, | |
4644 | described later, which have a consistent behavior across all | |
4645 | architectures (but are specific to GAS). | |
4646 | ||
ccf8a69b BW |
4647 | @node Altmacro |
4648 | @section @code{.altmacro} | |
4649 | Enable alternate macro mode, enabling: | |
4650 | ||
4651 | @ftable @code | |
4652 | @item LOCAL @var{name} [ , @dots{} ] | |
4653 | One additional directive, @code{LOCAL}, is available. It is used to | |
4654 | generate a string replacement for each of the @var{name} arguments, and | |
4655 | replace any instances of @var{name} in each macro expansion. The | |
4656 | replacement string is unique in the assembly, and different for each | |
4657 | separate macro expansion. @code{LOCAL} allows you to write macros that | |
4658 | define symbols, without fear of conflict between separate macro expansions. | |
4659 | ||
4660 | @item String delimiters | |
4661 | You can write strings delimited in these other ways besides | |
4662 | @code{"@var{string}"}: | |
4663 | ||
4664 | @table @code | |
4665 | @item '@var{string}' | |
4666 | You can delimit strings with single-quote characters. | |
4667 | ||
4668 | @item <@var{string}> | |
4669 | You can delimit strings with matching angle brackets. | |
4670 | @end table | |
4671 | ||
4672 | @item single-character string escape | |
4673 | To include any single character literally in a string (even if the | |
4674 | character would otherwise have some special meaning), you can prefix the | |
4675 | character with @samp{!} (an exclamation mark). For example, you can | |
4676 | write @samp{<4.3 !> 5.4!!>} to get the literal text @samp{4.3 > 5.4!}. | |
4677 | ||
4678 | @item Expression results as strings | |
4679 | You can write @samp{%@var{expr}} to evaluate the expression @var{expr} | |
01642c12 | 4680 | and use the result as a string. |
ccf8a69b BW |
4681 | @end ftable |
4682 | ||
252b5132 RH |
4683 | @node Ascii |
4684 | @section @code{.ascii "@var{string}"}@dots{} | |
4685 | ||
4686 | @cindex @code{ascii} directive | |
4687 | @cindex string literals | |
4688 | @code{.ascii} expects zero or more string literals (@pxref{Strings}) | |
4689 | separated by commas. It assembles each string (with no automatic | |
4690 | trailing zero byte) into consecutive addresses. | |
4691 | ||
4692 | @node Asciz | |
4693 | @section @code{.asciz "@var{string}"}@dots{} | |
4694 | ||
4695 | @cindex @code{asciz} directive | |
4696 | @cindex zero-terminated strings | |
4697 | @cindex null-terminated strings | |
4698 | @code{.asciz} is just like @code{.ascii}, but each string is followed by | |
4699 | a zero byte. The ``z'' in @samp{.asciz} stands for ``zero''. | |
4700 | ||
4701 | @node Balign | |
4702 | @section @code{.balign[wl] @var{abs-expr}, @var{abs-expr}, @var{abs-expr}} | |
4703 | ||
4704 | @cindex padding the location counter given number of bytes | |
4705 | @cindex @code{balign} directive | |
4706 | Pad the location counter (in the current subsection) to a particular | |
4707 | storage boundary. The first expression (which must be absolute) is the | |
4708 | alignment request in bytes. For example @samp{.balign 8} advances | |
4709 | the location counter until it is a multiple of 8. If the location counter | |
4710 | is already a multiple of 8, no change is needed. | |
4711 | ||
4712 | The second expression (also absolute) gives the fill value to be stored in the | |
4713 | padding bytes. It (and the comma) may be omitted. If it is omitted, the | |
2ca23e65 | 4714 | padding bytes are normally zero. However, on most systems, if the section is |
252b5132 RH |
4715 | marked as containing code and the fill value is omitted, the space is filled |
4716 | with no-op instructions. | |
4717 | ||
4718 | The third expression is also absolute, and is also optional. If it is present, | |
4719 | it is the maximum number of bytes that should be skipped by this alignment | |
4720 | directive. If doing the alignment would require skipping more bytes than the | |
4721 | specified maximum, then the alignment is not done at all. You can omit the | |
4722 | fill value (the second argument) entirely by simply using two commas after the | |
4723 | required alignment; this can be useful if you want the alignment to be filled | |
4724 | with no-op instructions when appropriate. | |
4725 | ||
4726 | @cindex @code{balignw} directive | |
4727 | @cindex @code{balignl} directive | |
4728 | The @code{.balignw} and @code{.balignl} directives are variants of the | |
4729 | @code{.balign} directive. The @code{.balignw} directive treats the fill | |
4730 | pattern as a two byte word value. The @code{.balignl} directives treats the | |
4731 | fill pattern as a four byte longword value. For example, @code{.balignw | |
4732 | 4,0x368d} will align to a multiple of 4. If it skips two bytes, they will be | |
4733 | filled in with the value 0x368d (the exact placement of the bytes depends upon | |
4734 | the endianness of the processor). If it skips 1 or 3 bytes, the fill value is | |
4735 | undefined. | |
4736 | ||
fa94de6b | 4737 | @node Bundle directives |
d3b47e2b L |
4738 | @section Bundle directives |
4739 | @subsection @code{.bundle_align_mode @var{abs-expr}} | |
fa94de6b RM |
4740 | @cindex @code{bundle_align_mode} directive |
4741 | @cindex bundle | |
4742 | @cindex instruction bundle | |
4743 | @cindex aligned instruction bundle | |
ec82c18e | 4744 | @code{.bundle_align_mode} enables or disables @dfn{aligned instruction |
fa94de6b | 4745 | bundle} mode. In this mode, sequences of adjacent instructions are grouped |
ec82c18e | 4746 | into fixed-sized @dfn{bundles}. If the argument is zero, this mode is |
27dcf5c0 | 4747 | disabled (which is the default state). If the argument it not zero, it |
fa94de6b RM |
4748 | gives the size of an instruction bundle as a power of two (as for the |
4749 | @code{.p2align} directive, @pxref{P2align}). | |
4750 | ||
4751 | For some targets, it's an ABI requirement that no instruction may span a | |
ec82c18e | 4752 | certain aligned boundary. A @dfn{bundle} is simply a sequence of |
fa94de6b RM |
4753 | instructions that starts on an aligned boundary. For example, if |
4754 | @var{abs-expr} is @code{5} then the bundle size is 32, so each aligned | |
4755 | chunk of 32 bytes is a bundle. When aligned instruction bundle mode is in | |
4756 | effect, no single instruction may span a boundary between bundles. If an | |
4757 | instruction would start too close to the end of a bundle for the length of | |
4758 | that particular instruction to fit within the bundle, then the space at the | |
4759 | end of that bundle is filled with no-op instructions so the instruction | |
4760 | starts in the next bundle. As a corollary, it's an error if any single | |
4761 | instruction's encoding is longer than the bundle size. | |
4762 | ||
d3b47e2b | 4763 | @subsection @code{.bundle_lock} and @code{.bundle_unlock} |
fa94de6b RM |
4764 | @cindex @code{bundle_lock} directive |
4765 | @cindex @code{bundle_unlock} directive | |
4766 | The @code{.bundle_lock} and directive @code{.bundle_unlock} directives | |
4767 | allow explicit control over instruction bundle padding. These directives | |
4768 | are only valid when @code{.bundle_align_mode} has been used to enable | |
4769 | aligned instruction bundle mode. It's an error if they appear when | |
4770 | @code{.bundle_align_mode} has not been used at all, or when the last | |
4771 | directive was @w{@code{.bundle_align_mode 0}}. | |
4772 | ||
4773 | @cindex bundle-locked | |
4774 | For some targets, it's an ABI requirement that certain instructions may | |
4775 | appear only as part of specified permissible sequences of multiple | |
4776 | instructions, all within the same bundle. A pair of @code{.bundle_lock} | |
ec82c18e | 4777 | and @code{.bundle_unlock} directives define a @dfn{bundle-locked} |
fa94de6b RM |
4778 | instruction sequence. For purposes of aligned instruction bundle mode, a |
4779 | sequence starting with @code{.bundle_lock} and ending with | |
4780 | @code{.bundle_unlock} is treated as a single instruction. That is, the | |
4781 | entire sequence must fit into a single bundle and may not span a bundle | |
4782 | boundary. If necessary, no-op instructions will be inserted before the | |
4783 | first instruction of the sequence so that the whole sequence starts on an | |
4784 | aligned bundle boundary. It's an error if the sequence is longer than the | |
4785 | bundle size. | |
4786 | ||
d416e51d RM |
4787 | For convenience when using @code{.bundle_lock} and @code{.bundle_unlock} |
4788 | inside assembler macros (@pxref{Macro}), bundle-locked sequences may be | |
4789 | nested. That is, a second @code{.bundle_lock} directive before the next | |
4790 | @code{.bundle_unlock} directive has no effect except that it must be | |
4791 | matched by another closing @code{.bundle_unlock} so that there is the | |
4792 | same number of @code{.bundle_lock} and @code{.bundle_unlock} directives. | |
fa94de6b | 4793 | |
252b5132 RH |
4794 | @node Byte |
4795 | @section @code{.byte @var{expressions}} | |
4796 | ||
4797 | @cindex @code{byte} directive | |
4798 | @cindex integers, one byte | |
4799 | @code{.byte} expects zero or more expressions, separated by commas. | |
4800 | Each expression is assembled into the next byte. | |
4801 | ||
54cfded0 | 4802 | @node CFI directives |
d3b47e2b L |
4803 | @section CFI directives |
4804 | @subsection @code{.cfi_sections @var{section_list}} | |
38462edf JJ |
4805 | @cindex @code{cfi_sections} directive |
4806 | @code{.cfi_sections} may be used to specify whether CFI directives | |
4807 | should emit @code{.eh_frame} section and/or @code{.debug_frame} section. | |
4808 | If @var{section_list} is @code{.eh_frame}, @code{.eh_frame} is emitted, | |
4809 | if @var{section_list} is @code{.debug_frame}, @code{.debug_frame} is emitted. | |
4810 | To emit both use @code{.eh_frame, .debug_frame}. The default if this | |
4811 | directive is not used is @code{.cfi_sections .eh_frame}. | |
4812 | ||
2f0c68f2 CM |
4813 | On targets that support compact unwinding tables these can be generated |
4814 | by specifying @code{.eh_frame_entry} instead of @code{.eh_frame}. | |
4815 | ||
bd5608dc NC |
4816 | Some targets may support an additional name, such as @code{.c6xabi.exidx} |
4817 | which is used by the @value{TIC6X} target. | |
4818 | ||
4819 | The @code{.cfi_sections} directive can be repeated, with the same or different | |
4820 | arguments, provided that CFI generation has not yet started. Once CFI | |
4821 | generation has started however the section list is fixed and any attempts to | |
4822 | redefine it will result in an error. | |
4823 | ||
d3b47e2b | 4824 | @subsection @code{.cfi_startproc [simple]} |
54cfded0 AM |
4825 | @cindex @code{cfi_startproc} directive |
4826 | @code{.cfi_startproc} is used at the beginning of each function that | |
4827 | should have an entry in @code{.eh_frame}. It initializes some internal | |
4b7d318b | 4828 | data structures. Don't forget to close the function by |
54cfded0 AM |
4829 | @code{.cfi_endproc}. |
4830 | ||
01642c12 | 4831 | Unless @code{.cfi_startproc} is used along with parameter @code{simple} |
4b7d318b | 4832 | it also emits some architecture dependent initial CFI instructions. |
01642c12 | 4833 | |
d3b47e2b | 4834 | @subsection @code{.cfi_endproc} |
54cfded0 AM |
4835 | @cindex @code{cfi_endproc} directive |
4836 | @code{.cfi_endproc} is used at the end of a function where it closes its | |
4837 | unwind entry previously opened by | |
b45619c0 | 4838 | @code{.cfi_startproc}, and emits it to @code{.eh_frame}. |
54cfded0 | 4839 | |
d3b47e2b | 4840 | @subsection @code{.cfi_personality @var{encoding} [, @var{exp}]} |
2f0c68f2 | 4841 | @cindex @code{cfi_personality} directive |
9b8ae42e JJ |
4842 | @code{.cfi_personality} defines personality routine and its encoding. |
4843 | @var{encoding} must be a constant determining how the personality | |
4844 | should be encoded. If it is 255 (@code{DW_EH_PE_omit}), second | |
4845 | argument is not present, otherwise second argument should be | |
4846 | a constant or a symbol name. When using indirect encodings, | |
4847 | the symbol provided should be the location where personality | |
4848 | can be loaded from, not the personality routine itself. | |
4849 | The default after @code{.cfi_startproc} is @code{.cfi_personality 0xff}, | |
4850 | no personality routine. | |
4851 | ||
2f0c68f2 CM |
4852 | @subsection @code{.cfi_personality_id @var{id}} |
4853 | @cindex @code{cfi_personality_id} directive | |
4854 | @code{cfi_personality_id} defines a personality routine by its index as | |
4855 | defined in a compact unwinding format. | |
4856 | Only valid when generating compact EH frames (i.e. | |
4857 | with @code{.cfi_sections eh_frame_entry}. | |
4858 | ||
4859 | @subsection @code{.cfi_fde_data [@var{opcode1} [, @dots{}]]} | |
4860 | @cindex @code{cfi_fde_data} directive | |
4861 | @code{cfi_fde_data} is used to describe the compact unwind opcodes to be | |
4862 | used for the current function. These are emitted inline in the | |
4863 | @code{.eh_frame_entry} section if small enough and there is no LSDA, or | |
4864 | in the @code{.gnu.extab} section otherwise. | |
4865 | Only valid when generating compact EH frames (i.e. | |
4866 | with @code{.cfi_sections eh_frame_entry}. | |
4867 | ||
d3b47e2b | 4868 | @subsection @code{.cfi_lsda @var{encoding} [, @var{exp}]} |
9b8ae42e JJ |
4869 | @code{.cfi_lsda} defines LSDA and its encoding. |
4870 | @var{encoding} must be a constant determining how the LSDA | |
2f0c68f2 CM |
4871 | should be encoded. If it is 255 (@code{DW_EH_PE_omit}), the second |
4872 | argument is not present, otherwise the second argument should be a constant | |
9b8ae42e | 4873 | or a symbol name. The default after @code{.cfi_startproc} is @code{.cfi_lsda 0xff}, |
2f0c68f2 CM |
4874 | meaning that no LSDA is present. |
4875 | ||
4876 | @subsection @code{.cfi_inline_lsda} [@var{align}] | |
4877 | @code{.cfi_inline_lsda} marks the start of a LSDA data section and | |
4878 | switches to the corresponding @code{.gnu.extab} section. | |
4879 | Must be preceded by a CFI block containing a @code{.cfi_lsda} directive. | |
4880 | Only valid when generating compact EH frames (i.e. | |
4881 | with @code{.cfi_sections eh_frame_entry}. | |
4882 | ||
4883 | The table header and unwinding opcodes will be generated at this point, | |
4884 | so that they are immediately followed by the LSDA data. The symbol | |
4885 | referenced by the @code{.cfi_lsda} directive should still be defined | |
4886 | in case a fallback FDE based encoding is used. The LSDA data is terminated | |
4887 | by a section directive. | |
4888 | ||
4889 | The optional @var{align} argument specifies the alignment required. | |
4890 | The alignment is specified as a power of two, as with the | |
4891 | @code{.p2align} directive. | |
9b8ae42e | 4892 | |
d3b47e2b | 4893 | @subsection @code{.cfi_def_cfa @var{register}, @var{offset}} |
01642c12 | 4894 | @code{.cfi_def_cfa} defines a rule for computing CFA as: @i{take |
54cfded0 AM |
4895 | address from @var{register} and add @var{offset} to it}. |
4896 | ||
d3b47e2b | 4897 | @subsection @code{.cfi_def_cfa_register @var{register}} |
54cfded0 AM |
4898 | @code{.cfi_def_cfa_register} modifies a rule for computing CFA. From |
4899 | now on @var{register} will be used instead of the old one. Offset | |
4900 | remains the same. | |
4901 | ||
d3b47e2b | 4902 | @subsection @code{.cfi_def_cfa_offset @var{offset}} |
54cfded0 AM |
4903 | @code{.cfi_def_cfa_offset} modifies a rule for computing CFA. Register |
4904 | remains the same, but @var{offset} is new. Note that it is the | |
4905 | absolute offset that will be added to a defined register to compute | |
4906 | CFA address. | |
4907 | ||
d3b47e2b | 4908 | @subsection @code{.cfi_adjust_cfa_offset @var{offset}} |
54cfded0 | 4909 | Same as @code{.cfi_def_cfa_offset} but @var{offset} is a relative |
33eaf5de | 4910 | value that is added/subtracted from the previous offset. |
54cfded0 | 4911 | |
d3b47e2b | 4912 | @subsection @code{.cfi_offset @var{register}, @var{offset}} |
54cfded0 | 4913 | Previous value of @var{register} is saved at offset @var{offset} from |
01642c12 | 4914 | CFA. |
54cfded0 | 4915 | |
084303b8 AK |
4916 | @subsection @code{.cfi_val_offset @var{register}, @var{offset}} |
4917 | Previous value of @var{register} is CFA + @var{offset}. | |
4918 | ||
d3b47e2b | 4919 | @subsection @code{.cfi_rel_offset @var{register}, @var{offset}} |
17076204 RH |
4920 | Previous value of @var{register} is saved at offset @var{offset} from |
4921 | the current CFA register. This is transformed to @code{.cfi_offset} | |
4922 | using the known displacement of the CFA register from the CFA. | |
4923 | This is often easier to use, because the number will match the | |
4924 | code it's annotating. | |
54cfded0 | 4925 | |
d3b47e2b | 4926 | @subsection @code{.cfi_register @var{register1}, @var{register2}} |
4b7d318b L |
4927 | Previous value of @var{register1} is saved in register @var{register2}. |
4928 | ||
d3b47e2b | 4929 | @subsection @code{.cfi_restore @var{register}} |
01642c12 RM |
4930 | @code{.cfi_restore} says that the rule for @var{register} is now the |
4931 | same as it was at the beginning of the function, after all initial | |
4b7d318b L |
4932 | instruction added by @code{.cfi_startproc} were executed. |
4933 | ||
d3b47e2b | 4934 | @subsection @code{.cfi_undefined @var{register}} |
4b7d318b L |
4935 | From now on the previous value of @var{register} can't be restored anymore. |
4936 | ||
d3b47e2b | 4937 | @subsection @code{.cfi_same_value @var{register}} |
01642c12 | 4938 | Current value of @var{register} is the same like in the previous frame, |
4b7d318b L |
4939 | i.e. no restoration needed. |
4940 | ||
48eac74c MG |
4941 | @subsection @code{.cfi_remember_state} and @code{.cfi_restore_state} |
4942 | @code{.cfi_remember_state} pushes the set of rules for every register onto an | |
4943 | implicit stack, while @code{.cfi_restore_state} pops them off the stack and | |
4944 | places them in the current row. This is useful for situations where you have | |
4945 | multiple @code{.cfi_*} directives that need to be undone due to the control | |
4946 | flow of the program. For example, we could have something like this (assuming | |
4947 | the CFA is the value of @code{rbp}): | |
4948 | ||
4949 | @smallexample | |
4950 | je label | |
4951 | popq %rbx | |
4952 | .cfi_restore %rbx | |
4953 | popq %r12 | |
4954 | .cfi_restore %r12 | |
4955 | popq %rbp | |
4956 | .cfi_restore %rbp | |
4957 | .cfi_def_cfa %rsp, 8 | |
4958 | ret | |
4959 | label: | |
4960 | /* Do something else */ | |
4961 | @end smallexample | |
4962 | ||
4963 | Here, we want the @code{.cfi} directives to affect only the rows corresponding | |
4964 | to the instructions before @code{label}. This means we'd have to add multiple | |
4965 | @code{.cfi} directives after @code{label} to recreate the original save | |
4966 | locations of the registers, as well as setting the CFA back to the value of | |
4967 | @code{rbp}. This would be clumsy, and result in a larger binary size. Instead, | |
4968 | we can write: | |
4969 | ||
4970 | @smallexample | |
4971 | je label | |
4972 | popq %rbx | |
4973 | .cfi_remember_state | |
4974 | .cfi_restore %rbx | |
4975 | popq %r12 | |
4976 | .cfi_restore %r12 | |
4977 | popq %rbp | |
4978 | .cfi_restore %rbp | |
4979 | .cfi_def_cfa %rsp, 8 | |
4980 | ret | |
4981 | label: | |
4982 | .cfi_restore_state | |
4983 | /* Do something else */ | |
4984 | @end smallexample | |
4985 | ||
4986 | That way, the rules for the instructions after @code{label} will be the same | |
4987 | as before the first @code{.cfi_restore} without having to use multiple | |
4988 | @code{.cfi} directives. | |
4b7d318b | 4989 | |
d3b47e2b | 4990 | @subsection @code{.cfi_return_column @var{register}} |
01642c12 | 4991 | Change return column @var{register}, i.e. the return address is either |
4b7d318b L |
4992 | directly in @var{register} or can be accessed by rules for @var{register}. |
4993 | ||
d3b47e2b | 4994 | @subsection @code{.cfi_signal_frame} |
63752a75 JJ |
4995 | Mark current function as signal trampoline. |
4996 | ||
d3b47e2b | 4997 | @subsection @code{.cfi_window_save} |
364b6d8b JJ |
4998 | SPARC register window has been saved. |
4999 | ||
d3b47e2b | 5000 | @subsection @code{.cfi_escape} @var{expression}[, @dots{}] |
cdfbf930 RH |
5001 | Allows the user to add arbitrary bytes to the unwind info. One |
5002 | might use this to add OS-specific CFI opcodes, or generic CFI | |
5003 | opcodes that GAS does not yet support. | |
252b5132 | 5004 | |
d3b47e2b | 5005 | @subsection @code{.cfi_val_encoded_addr @var{register}, @var{encoding}, @var{label}} |
f1c4cc75 RH |
5006 | The current value of @var{register} is @var{label}. The value of @var{label} |
5007 | will be encoded in the output file according to @var{encoding}; see the | |
5008 | description of @code{.cfi_personality} for details on this encoding. | |
5009 | ||
5010 | The usefulness of equating a register to a fixed label is probably | |
5011 | limited to the return address register. Here, it can be useful to | |
5012 | mark a code segment that has only one return address which is reached | |
5013 | by a direct branch and no copy of the return address exists in memory | |
5014 | or another register. | |
5015 | ||
ccf8a69b BW |
5016 | @node Comm |
5017 | @section @code{.comm @var{symbol} , @var{length} } | |
bd0eb99b | 5018 | |
ccf8a69b BW |
5019 | @cindex @code{comm} directive |
5020 | @cindex symbol, common | |
5021 | @code{.comm} declares a common symbol named @var{symbol}. When linking, a | |
5022 | common symbol in one object file may be merged with a defined or common symbol | |
5023 | of the same name in another object file. If @code{@value{LD}} does not see a | |
5024 | definition for the symbol--just one or more common symbols--then it will | |
5025 | allocate @var{length} bytes of uninitialized memory. @var{length} must be an | |
5026 | absolute expression. If @code{@value{LD}} sees multiple common symbols with | |
5027 | the same name, and they do not all have the same size, it will allocate space | |
5028 | using the largest size. | |
07a53e5c | 5029 | |
c1711530 DK |
5030 | @ifset COFF-ELF |
5031 | When using ELF or (as a GNU extension) PE, the @code{.comm} directive takes | |
01642c12 | 5032 | an optional third argument. This is the desired alignment of the symbol, |
c1711530 DK |
5033 | specified for ELF as a byte boundary (for example, an alignment of 16 means |
5034 | that the least significant 4 bits of the address should be zero), and for PE | |
5035 | as a power of two (for example, an alignment of 5 means aligned to a 32-byte | |
01642c12 | 5036 | boundary). The alignment must be an absolute expression, and it must be a |
c1711530 | 5037 | power of two. If @code{@value{LD}} allocates uninitialized memory for the |
01642c12 | 5038 | common symbol, it will use the alignment when placing the symbol. If no |
c1711530 | 5039 | alignment is specified, @command{@value{AS}} will set the alignment to the |
ccf8a69b | 5040 | largest power of two less than or equal to the size of the symbol, up to a |
c1711530 DK |
5041 | maximum of 16 on ELF, or the default section alignment of 4 on PE@footnote{This |
5042 | is not the same as the executable image file alignment controlled by @code{@value{LD}}'s | |
5043 | @samp{--section-alignment} option; image file sections in PE are aligned to | |
5044 | multiples of 4096, which is far too large an alignment for ordinary variables. | |
5045 | It is rather the default alignment for (non-debug) sections within object | |
5046 | (@samp{*.o}) files, which are less strictly aligned.}. | |
ccf8a69b | 5047 | @end ifset |
cd1fcb49 | 5048 | |
ccf8a69b BW |
5049 | @ifset HPPA |
5050 | The syntax for @code{.comm} differs slightly on the HPPA. The syntax is | |
5051 | @samp{@var{symbol} .comm, @var{length}}; @var{symbol} is optional. | |
5052 | @end ifset | |
07a53e5c | 5053 | |
252b5132 RH |
5054 | @node Data |
5055 | @section @code{.data @var{subsection}} | |
252b5132 | 5056 | @cindex @code{data} directive |
340d33e5 | 5057 | |
a4fb0134 | 5058 | @code{.data} tells @command{@value{AS}} to assemble the following statements onto the |
252b5132 RH |
5059 | end of the data subsection numbered @var{subsection} (which is an |
5060 | absolute expression). If @var{subsection} is omitted, it defaults | |
5061 | to zero. | |
5062 | ||
340d33e5 NC |
5063 | @node Dc |
5064 | @section @code{.dc[@var{size}] @var{expressions}} | |
5065 | @cindex @code{dc} directive | |
5066 | ||
46c685ac | 5067 | The @code{.dc} directive expects zero or more @var{expressions} separated by |
340d33e5 NC |
5068 | commas. These expressions are evaluated and their values inserted into the |
5069 | current section. The size of the emitted value depends upon the suffix to the | |
5070 | @code{.dc} directive: | |
5071 | ||
5072 | @table @code | |
5073 | @item @samp{.a} | |
5074 | Emits N-bit values, where N is the size of an address on the target system. | |
5075 | @item @samp{.b} | |
5076 | Emits 8-bit values. | |
5077 | @item @samp{.d} | |
5078 | Emits double precision floating-point values. | |
5079 | @item @samp{.l} | |
5080 | Emits 32-bit values. | |
5081 | @item @samp{.s} | |
5082 | Emits single precision floating-point values. | |
5083 | @item @samp{.w} | |
5084 | Emits 16-bit values. | |
5085 | Note - this is true even on targets where the @code{.word} directive would emit | |
5086 | 32-bit values. | |
5087 | @item @samp{.x} | |
5088 | Emits long double precision floating-point values. | |
5089 | @end table | |
5090 | ||
5091 | If no suffix is used then @samp{.w} is assumed. | |
5092 | ||
5093 | The byte ordering is still target dependent, as is the size and format of | |
5094 | floating point values. | |
5095 | ||
5096 | @node Dcb | |
5097 | @section @code{.dcb[@var{size}] @var{number} [,@var{fill}]} | |
5098 | @cindex @code{dcb} directive | |
5099 | This directive emits @var{number} copies of @var{fill}, each of @var{size} | |
5100 | bytes. Both @var{number} and @var{fill} are absolute expressions. If the | |
5101 | comma and @var{fill} are omitted, @var{fill} is assumed to be zero. The | |
5102 | @var{size} suffix, if present, must be one of: | |
5103 | ||
5104 | @table @code | |
5105 | @item @samp{.b} | |
5106 | Emits single byte values. | |
5107 | @item @samp{.d} | |
5108 | Emits double-precision floating point values. | |
5109 | @item @samp{.l} | |
5110 | Emits 4-byte values. | |
5111 | @item @samp{.s} | |
5112 | Emits single-precision floating point values. | |
5113 | @item @samp{.w} | |
5114 | Emits 2-byte values. | |
5115 | @item @samp{.x} | |
5116 | Emits long double-precision floating point values. | |
5117 | @end table | |
5118 | ||
5119 | If the @var{size} suffix is omitted then @samp{.w} is assumed. | |
5120 | ||
5121 | The byte ordering is target dependent, as is the size and format of floating | |
5122 | point values. | |
5123 | ||
5124 | @node Ds | |
5125 | @section @code{.ds[@var{size}] @var{number} [,@var{fill}]} | |
5126 | @cindex @code{ds} directive | |
5127 | This directive emits @var{number} copies of @var{fill}, each of @var{size} | |
5128 | bytes. Both @var{number} and @var{fill} are absolute expressions. If the | |
5129 | comma and @var{fill} are omitted, @var{fill} is assumed to be zero. The | |
5130 | @var{size} suffix, if present, must be one of: | |
5131 | ||
5132 | @table @code | |
5133 | @item @samp{.b} | |
5134 | Emits single byte values. | |
5135 | @item @samp{.d} | |
5136 | Emits 8-byte values. | |
5137 | @item @samp{.l} | |
5138 | Emits 4-byte values. | |
5139 | @item @samp{.p} | |
5140 | Emits 12-byte values. | |
5141 | @item @samp{.s} | |
5142 | Emits 4-byte values. | |
5143 | @item @samp{.w} | |
5144 | Emits 2-byte values. | |
5145 | @item @samp{.x} | |
5146 | Emits 12-byte values. | |
5147 | @end table | |
5148 | ||
5149 | Note - unlike the @code{.dcb} directive the @samp{.d}, @samp{.s} and @samp{.x} | |
5150 | suffixes do not indicate that floating-point values are to inserted. | |
5151 | ||
5152 | If the @var{size} suffix is omitted then @samp{.w} is assumed. | |
5153 | ||
5154 | The byte ordering is target dependent, as is the size and format of floating | |
5155 | point values. | |
5156 | ||
5157 | ||
252b5132 RH |
5158 | @ifset COFF |
5159 | @node Def | |
5160 | @section @code{.def @var{name}} | |
5161 | ||
5162 | @cindex @code{def} directive | |
5163 | @cindex COFF symbols, debugging | |
5164 | @cindex debugging COFF symbols | |
5165 | Begin defining debugging information for a symbol @var{name}; the | |
5166 | definition extends until the @code{.endef} directive is encountered. | |
5167 | @ifset BOUT | |
5168 | ||
a4fb0134 | 5169 | This directive is only observed when @command{@value{AS}} is configured for COFF |
252b5132 RH |
5170 | format output; when producing @code{b.out}, @samp{.def} is recognized, |
5171 | but ignored. | |
5172 | @end ifset | |
5173 | @end ifset | |
5174 | ||
5175 | @ifset aout-bout | |
5176 | @node Desc | |
5177 | @section @code{.desc @var{symbol}, @var{abs-expression}} | |
5178 | ||
5179 | @cindex @code{desc} directive | |
5180 | @cindex COFF symbol descriptor | |
5181 | @cindex symbol descriptor, COFF | |
5182 | This directive sets the descriptor of the symbol (@pxref{Symbol Attributes}) | |
5183 | to the low 16 bits of an absolute expression. | |
5184 | ||
5185 | @ifset COFF | |
a4fb0134 | 5186 | The @samp{.desc} directive is not available when @command{@value{AS}} is |
252b5132 | 5187 | configured for COFF output; it is only for @code{a.out} or @code{b.out} |
a4fb0134 | 5188 | object format. For the sake of compatibility, @command{@value{AS}} accepts |
252b5132 RH |
5189 | it, but produces no output, when configured for COFF. |
5190 | @end ifset | |
5191 | @end ifset | |
5192 | ||
5193 | @ifset COFF | |
5194 | @node Dim | |
5195 | @section @code{.dim} | |
5196 | ||
5197 | @cindex @code{dim} directive | |
5198 | @cindex COFF auxiliary symbol information | |
5199 | @cindex auxiliary symbol information, COFF | |
5200 | This directive is generated by compilers to include auxiliary debugging | |
5201 | information in the symbol table. It is only permitted inside | |
5202 | @code{.def}/@code{.endef} pairs. | |
5203 | @ifset BOUT | |
5204 | ||
5205 | @samp{.dim} is only meaningful when generating COFF format output; when | |
a4fb0134 | 5206 | @command{@value{AS}} is generating @code{b.out}, it accepts this directive but |
252b5132 RH |
5207 | ignores it. |
5208 | @end ifset | |
5209 | @end ifset | |
5210 | ||
5211 | @node Double | |
5212 | @section @code{.double @var{flonums}} | |
5213 | ||
5214 | @cindex @code{double} directive | |
5215 | @cindex floating point numbers (double) | |
5216 | @code{.double} expects zero or more flonums, separated by commas. It | |
5217 | assembles floating point numbers. | |
5218 | @ifset GENERIC | |
5219 | The exact kind of floating point numbers emitted depends on how | |
a4fb0134 | 5220 | @command{@value{AS}} is configured. @xref{Machine Dependencies}. |
252b5132 RH |
5221 | @end ifset |
5222 | @ifclear GENERIC | |
5223 | @ifset IEEEFLOAT | |
5224 | On the @value{TARGET} family @samp{.double} emits 64-bit floating-point numbers | |
5225 | in @sc{ieee} format. | |
5226 | @end ifset | |
5227 | @end ifclear | |
5228 | ||
5229 | @node Eject | |
5230 | @section @code{.eject} | |
5231 | ||
5232 | @cindex @code{eject} directive | |
5233 | @cindex new page, in listings | |
5234 | @cindex page, in listings | |
5235 | @cindex listing control: new page | |
5236 | Force a page break at this point, when generating assembly listings. | |
5237 | ||
5238 | @node Else | |
5239 | @section @code{.else} | |
5240 | ||
5241 | @cindex @code{else} directive | |
a4fb0134 | 5242 | @code{.else} is part of the @command{@value{AS}} support for conditional |
96e9638b | 5243 | assembly; see @ref{If,,@code{.if}}. It marks the beginning of a section |
252b5132 RH |
5244 | of code to be assembled if the condition for the preceding @code{.if} |
5245 | was false. | |
5246 | ||
3fd9f047 TW |
5247 | @node Elseif |
5248 | @section @code{.elseif} | |
5249 | ||
5250 | @cindex @code{elseif} directive | |
a4fb0134 | 5251 | @code{.elseif} is part of the @command{@value{AS}} support for conditional |
96e9638b | 5252 | assembly; see @ref{If,,@code{.if}}. It is shorthand for beginning a new |
3fd9f047 TW |
5253 | @code{.if} block that would otherwise fill the entire @code{.else} section. |
5254 | ||
252b5132 RH |
5255 | @node End |
5256 | @section @code{.end} | |
5257 | ||
5258 | @cindex @code{end} directive | |
a4fb0134 | 5259 | @code{.end} marks the end of the assembly file. @command{@value{AS}} does not |
252b5132 RH |
5260 | process anything in the file past the @code{.end} directive. |
5261 | ||
5262 | @ifset COFF | |
5263 | @node Endef | |
5264 | @section @code{.endef} | |
5265 | ||
5266 | @cindex @code{endef} directive | |
5267 | This directive flags the end of a symbol definition begun with | |
5268 | @code{.def}. | |
5269 | @ifset BOUT | |
5270 | ||
5271 | @samp{.endef} is only meaningful when generating COFF format output; if | |
a4fb0134 | 5272 | @command{@value{AS}} is configured to generate @code{b.out}, it accepts this |
252b5132 RH |
5273 | directive but ignores it. |
5274 | @end ifset | |
5275 | @end ifset | |
5276 | ||
5277 | @node Endfunc | |
5278 | @section @code{.endfunc} | |
5279 | @cindex @code{endfunc} directive | |
5280 | @code{.endfunc} marks the end of a function specified with @code{.func}. | |
5281 | ||
5282 | @node Endif | |
5283 | @section @code{.endif} | |
5284 | ||
5285 | @cindex @code{endif} directive | |
a4fb0134 | 5286 | @code{.endif} is part of the @command{@value{AS}} support for conditional assembly; |
252b5132 RH |
5287 | it marks the end of a block of code that is only assembled |
5288 | conditionally. @xref{If,,@code{.if}}. | |
5289 | ||
5290 | @node Equ | |
5291 | @section @code{.equ @var{symbol}, @var{expression}} | |
5292 | ||
5293 | @cindex @code{equ} directive | |
5294 | @cindex assigning values to symbols | |
5295 | @cindex symbols, assigning values to | |
5296 | This directive sets the value of @var{symbol} to @var{expression}. | |
96e9638b | 5297 | It is synonymous with @samp{.set}; see @ref{Set,,@code{.set}}. |
252b5132 RH |
5298 | |
5299 | @ifset HPPA | |
01642c12 | 5300 | The syntax for @code{equ} on the HPPA is |
252b5132 RH |
5301 | @samp{@var{symbol} .equ @var{expression}}. |
5302 | @end ifset | |
5303 | ||
3c9b82ba | 5304 | @ifset Z80 |
01642c12 RM |
5305 | The syntax for @code{equ} on the Z80 is |
5306 | @samp{@var{symbol} equ @var{expression}}. | |
33eaf5de | 5307 | On the Z80 it is an error if @var{symbol} is already defined, |
01642c12 | 5308 | but the symbol is not protected from later redefinition. |
96e9638b | 5309 | Compare @ref{Equiv}. |
3c9b82ba NC |
5310 | @end ifset |
5311 | ||
252b5132 RH |
5312 | @node Equiv |
5313 | @section @code{.equiv @var{symbol}, @var{expression}} | |
5314 | @cindex @code{equiv} directive | |
5315 | The @code{.equiv} directive is like @code{.equ} and @code{.set}, except that | |
8dfa0188 NC |
5316 | the assembler will signal an error if @var{symbol} is already defined. Note a |
5317 | symbol which has been referenced but not actually defined is considered to be | |
5318 | undefined. | |
252b5132 | 5319 | |
01642c12 | 5320 | Except for the contents of the error message, this is roughly equivalent to |
252b5132 RH |
5321 | @smallexample |
5322 | .ifdef SYM | |
5323 | .err | |
5324 | .endif | |
5325 | .equ SYM,VAL | |
5326 | @end smallexample | |
9497f5ac NC |
5327 | plus it protects the symbol from later redefinition. |
5328 | ||
5329 | @node Eqv | |
5330 | @section @code{.eqv @var{symbol}, @var{expression}} | |
5331 | @cindex @code{eqv} directive | |
5332 | The @code{.eqv} directive is like @code{.equiv}, but no attempt is made to | |
5333 | evaluate the expression or any part of it immediately. Instead each time | |
5334 | the resulting symbol is used in an expression, a snapshot of its current | |
5335 | value is taken. | |
252b5132 RH |
5336 | |
5337 | @node Err | |
5338 | @section @code{.err} | |
5339 | @cindex @code{err} directive | |
a4fb0134 SC |
5340 | If @command{@value{AS}} assembles a @code{.err} directive, it will print an error |
5341 | message and, unless the @option{-Z} option was used, it will not generate an | |
f9eb6721 | 5342 | object file. This can be used to signal an error in conditionally compiled code. |
252b5132 | 5343 | |
d190d046 HPN |
5344 | @node Error |
5345 | @section @code{.error "@var{string}"} | |
5346 | @cindex error directive | |
5347 | ||
5348 | Similarly to @code{.err}, this directive emits an error, but you can specify a | |
5349 | string that will be emitted as the error message. If you don't specify the | |
5350 | message, it defaults to @code{".error directive invoked in source file"}. | |
5351 | @xref{Errors, ,Error and Warning Messages}. | |
5352 | ||
5353 | @smallexample | |
5354 | .error "This code has not been assembled and tested." | |
5355 | @end smallexample | |
5356 | ||
252b5132 RH |
5357 | @node Exitm |
5358 | @section @code{.exitm} | |
5359 | Exit early from the current macro definition. @xref{Macro}. | |
5360 | ||
5361 | @node Extern | |
5362 | @section @code{.extern} | |
5363 | ||
5364 | @cindex @code{extern} directive | |
5365 | @code{.extern} is accepted in the source program---for compatibility | |
a4fb0134 | 5366 | with other assemblers---but it is ignored. @command{@value{AS}} treats |
252b5132 RH |
5367 | all undefined symbols as external. |
5368 | ||
5369 | @node Fail | |
5370 | @section @code{.fail @var{expression}} | |
5371 | ||
5372 | @cindex @code{fail} directive | |
5373 | Generates an error or a warning. If the value of the @var{expression} is 500 | |
a4fb0134 SC |
5374 | or more, @command{@value{AS}} will print a warning message. If the value is less |
5375 | than 500, @command{@value{AS}} will print an error message. The message will | |
252b5132 RH |
5376 | include the value of @var{expression}. This can occasionally be useful inside |
5377 | complex nested macros or conditional assembly. | |
5378 | ||
252b5132 | 5379 | @node File |
14082c76 | 5380 | @section @code{.file} |
252b5132 | 5381 | @cindex @code{file} directive |
14082c76 BW |
5382 | |
5383 | @ifclear no-file-dir | |
5384 | There are two different versions of the @code{.file} directive. Targets | |
5385 | that support DWARF2 line number information use the DWARF2 version of | |
5386 | @code{.file}. Other targets use the default version. | |
5387 | ||
5388 | @subheading Default Version | |
5389 | ||
252b5132 RH |
5390 | @cindex logical file name |
5391 | @cindex file name, logical | |
14082c76 BW |
5392 | This version of the @code{.file} directive tells @command{@value{AS}} that we |
5393 | are about to start a new logical file. The syntax is: | |
5394 | ||
5395 | @smallexample | |
5396 | .file @var{string} | |
5397 | @end smallexample | |
5398 | ||
5399 | @var{string} is the new file name. In general, the filename is | |
252b5132 RH |
5400 | recognized whether or not it is surrounded by quotes @samp{"}; but if you wish |
5401 | to specify an empty file name, you must give the quotes--@code{""}. This | |
5402 | statement may go away in future: it is only recognized to be compatible with | |
a4fb0134 | 5403 | old @command{@value{AS}} programs. |
14082c76 BW |
5404 | |
5405 | @subheading DWARF2 Version | |
252b5132 RH |
5406 | @end ifclear |
5407 | ||
14082c76 BW |
5408 | When emitting DWARF2 line number information, @code{.file} assigns filenames |
5409 | to the @code{.debug_line} file name table. The syntax is: | |
5410 | ||
5411 | @smallexample | |
5412 | .file @var{fileno} @var{filename} | |
5413 | @end smallexample | |
5414 | ||
5415 | The @var{fileno} operand should be a unique positive integer to use as the | |
5416 | index of the entry in the table. The @var{filename} operand is a C string | |
5417 | literal. | |
5418 | ||
5419 | The detail of filename indices is exposed to the user because the filename | |
5420 | table is shared with the @code{.debug_info} section of the DWARF2 debugging | |
5421 | information, and thus the user must know the exact indices that table | |
5422 | entries will have. | |
5423 | ||
252b5132 RH |
5424 | @node Fill |
5425 | @section @code{.fill @var{repeat} , @var{size} , @var{value}} | |
5426 | ||
5427 | @cindex @code{fill} directive | |
5428 | @cindex writing patterns in memory | |
5429 | @cindex patterns, writing in memory | |
bc64be0c | 5430 | @var{repeat}, @var{size} and @var{value} are absolute expressions. |
252b5132 RH |
5431 | This emits @var{repeat} copies of @var{size} bytes. @var{Repeat} |
5432 | may be zero or more. @var{Size} may be zero or more, but if it is | |
5433 | more than 8, then it is deemed to have the value 8, compatible with | |
5434 | other people's assemblers. The contents of each @var{repeat} bytes | |
5435 | is taken from an 8-byte number. The highest order 4 bytes are | |
5436 | zero. The lowest order 4 bytes are @var{value} rendered in the | |
a4fb0134 | 5437 | byte-order of an integer on the computer @command{@value{AS}} is assembling for. |
252b5132 RH |
5438 | Each @var{size} bytes in a repetition is taken from the lowest order |
5439 | @var{size} bytes of this number. Again, this bizarre behavior is | |
5440 | compatible with other people's assemblers. | |
5441 | ||
5442 | @var{size} and @var{value} are optional. | |
5443 | If the second comma and @var{value} are absent, @var{value} is | |
5444 | assumed zero. If the first comma and following tokens are absent, | |
5445 | @var{size} is assumed to be 1. | |
5446 | ||
5447 | @node Float | |
5448 | @section @code{.float @var{flonums}} | |
5449 | ||
5450 | @cindex floating point numbers (single) | |
5451 | @cindex @code{float} directive | |
5452 | This directive assembles zero or more flonums, separated by commas. It | |
5453 | has the same effect as @code{.single}. | |
5454 | @ifset GENERIC | |
5455 | The exact kind of floating point numbers emitted depends on how | |
a4fb0134 | 5456 | @command{@value{AS}} is configured. |
252b5132 RH |
5457 | @xref{Machine Dependencies}. |
5458 | @end ifset | |
5459 | @ifclear GENERIC | |
5460 | @ifset IEEEFLOAT | |
5461 | On the @value{TARGET} family, @code{.float} emits 32-bit floating point numbers | |
5462 | in @sc{ieee} format. | |
5463 | @end ifset | |
5464 | @end ifclear | |
5465 | ||
5466 | @node Func | |
5467 | @section @code{.func @var{name}[,@var{label}]} | |
5468 | @cindex @code{func} directive | |
5469 | @code{.func} emits debugging information to denote function @var{name}, and | |
5470 | is ignored unless the file is assembled with debugging enabled. | |
05da4302 | 5471 | Only @samp{--gstabs[+]} is currently supported. |
252b5132 RH |
5472 | @var{label} is the entry point of the function and if omitted @var{name} |
5473 | prepended with the @samp{leading char} is used. | |
5474 | @samp{leading char} is usually @code{_} or nothing, depending on the target. | |
5475 | All functions are currently defined to have @code{void} return type. | |
5476 | The function must be terminated with @code{.endfunc}. | |
5477 | ||
5478 | @node Global | |
5479 | @section @code{.global @var{symbol}}, @code{.globl @var{symbol}} | |
5480 | ||
5481 | @cindex @code{global} directive | |
5482 | @cindex symbol, making visible to linker | |
5483 | @code{.global} makes the symbol visible to @code{@value{LD}}. If you define | |
5484 | @var{symbol} in your partial program, its value is made available to | |
5485 | other partial programs that are linked with it. Otherwise, | |
5486 | @var{symbol} takes its attributes from a symbol of the same name | |
5487 | from another file linked into the same program. | |
5488 | ||
5489 | Both spellings (@samp{.globl} and @samp{.global}) are accepted, for | |
5490 | compatibility with other assemblers. | |
5491 | ||
5492 | @ifset HPPA | |
5493 | On the HPPA, @code{.global} is not always enough to make it accessible to other | |
5494 | partial programs. You may need the HPPA-only @code{.EXPORT} directive as well. | |
96e9638b | 5495 | @xref{HPPA Directives, ,HPPA Assembler Directives}. |
252b5132 RH |
5496 | @end ifset |
5497 | ||
c91d2e08 | 5498 | @ifset ELF |
3a99f02f DJ |
5499 | @node Gnu_attribute |
5500 | @section @code{.gnu_attribute @var{tag},@var{value}} | |
5501 | Record a @sc{gnu} object attribute for this file. @xref{Object Attributes}. | |
5502 | ||
c91d2e08 NC |
5503 | @node Hidden |
5504 | @section @code{.hidden @var{names}} | |
5505 | ||
c1253627 NC |
5506 | @cindex @code{hidden} directive |
5507 | @cindex visibility | |
ed9589d4 | 5508 | This is one of the ELF visibility directives. The other two are |
01642c12 | 5509 | @code{.internal} (@pxref{Internal,,@code{.internal}}) and |
a349d9dd | 5510 | @code{.protected} (@pxref{Protected,,@code{.protected}}). |
c91d2e08 NC |
5511 | |
5512 | This directive overrides the named symbols default visibility (which is set by | |
5513 | their binding: local, global or weak). The directive sets the visibility to | |
5514 | @code{hidden} which means that the symbols are not visible to other components. | |
01642c12 | 5515 | Such symbols are always considered to be @code{protected} as well. |
c91d2e08 NC |
5516 | @end ifset |
5517 | ||
252b5132 RH |
5518 | @node hword |
5519 | @section @code{.hword @var{expressions}} | |
5520 | ||
5521 | @cindex @code{hword} directive | |
5522 | @cindex integers, 16-bit | |
5523 | @cindex numbers, 16-bit | |
5524 | @cindex sixteen bit integers | |
5525 | This expects zero or more @var{expressions}, and emits | |
5526 | a 16 bit number for each. | |
5527 | ||
5528 | @ifset GENERIC | |
5529 | This directive is a synonym for @samp{.short}; depending on the target | |
5530 | architecture, it may also be a synonym for @samp{.word}. | |
5531 | @end ifset | |
5532 | @ifclear GENERIC | |
5533 | @ifset W32 | |
5534 | This directive is a synonym for @samp{.short}. | |
5535 | @end ifset | |
5536 | @ifset W16 | |
5537 | This directive is a synonym for both @samp{.short} and @samp{.word}. | |
5538 | @end ifset | |
5539 | @end ifclear | |
5540 | ||
5541 | @node Ident | |
5542 | @section @code{.ident} | |
5543 | ||
5544 | @cindex @code{ident} directive | |
cb4c78d6 BE |
5545 | |
5546 | This directive is used by some assemblers to place tags in object files. The | |
5547 | behavior of this directive varies depending on the target. When using the | |
5548 | a.out object file format, @command{@value{AS}} simply accepts the directive for | |
5549 | source-file compatibility with existing assemblers, but does not emit anything | |
5550 | for it. When using COFF, comments are emitted to the @code{.comment} or | |
5551 | @code{.rdata} section, depending on the target. When using ELF, comments are | |
5552 | emitted to the @code{.comment} section. | |
252b5132 RH |
5553 | |
5554 | @node If | |
5555 | @section @code{.if @var{absolute expression}} | |
5556 | ||
5557 | @cindex conditional assembly | |
5558 | @cindex @code{if} directive | |
5559 | @code{.if} marks the beginning of a section of code which is only | |
5560 | considered part of the source program being assembled if the argument | |
5561 | (which must be an @var{absolute expression}) is non-zero. The end of | |
5562 | the conditional section of code must be marked by @code{.endif} | |
5563 | (@pxref{Endif,,@code{.endif}}); optionally, you may include code for the | |
5564 | alternative condition, flagged by @code{.else} (@pxref{Else,,@code{.else}}). | |
3fd9f047 TW |
5565 | If you have several conditions to check, @code{.elseif} may be used to avoid |
5566 | nesting blocks if/else within each subsequent @code{.else} block. | |
252b5132 RH |
5567 | |
5568 | The following variants of @code{.if} are also supported: | |
5569 | @table @code | |
5570 | @cindex @code{ifdef} directive | |
5571 | @item .ifdef @var{symbol} | |
5572 | Assembles the following section of code if the specified @var{symbol} | |
8dfa0188 NC |
5573 | has been defined. Note a symbol which has been referenced but not yet defined |
5574 | is considered to be undefined. | |
252b5132 | 5575 | |
26aca5f6 JB |
5576 | @cindex @code{ifb} directive |
5577 | @item .ifb @var{text} | |
5578 | Assembles the following section of code if the operand is blank (empty). | |
5579 | ||
252b5132 RH |
5580 | @cindex @code{ifc} directive |
5581 | @item .ifc @var{string1},@var{string2} | |
5582 | Assembles the following section of code if the two strings are the same. The | |
5583 | strings may be optionally quoted with single quotes. If they are not quoted, | |
5584 | the first string stops at the first comma, and the second string stops at the | |
5585 | end of the line. Strings which contain whitespace should be quoted. The | |
5586 | string comparison is case sensitive. | |
5587 | ||
5588 | @cindex @code{ifeq} directive | |
5589 | @item .ifeq @var{absolute expression} | |
5590 | Assembles the following section of code if the argument is zero. | |
5591 | ||
5592 | @cindex @code{ifeqs} directive | |
5593 | @item .ifeqs @var{string1},@var{string2} | |
5594 | Another form of @code{.ifc}. The strings must be quoted using double quotes. | |
5595 | ||
5596 | @cindex @code{ifge} directive | |
5597 | @item .ifge @var{absolute expression} | |
5598 | Assembles the following section of code if the argument is greater than or | |
5599 | equal to zero. | |
5600 | ||
5601 | @cindex @code{ifgt} directive | |
5602 | @item .ifgt @var{absolute expression} | |
5603 | Assembles the following section of code if the argument is greater than zero. | |
5604 | ||
5605 | @cindex @code{ifle} directive | |
5606 | @item .ifle @var{absolute expression} | |
5607 | Assembles the following section of code if the argument is less than or equal | |
5608 | to zero. | |
5609 | ||
5610 | @cindex @code{iflt} directive | |
5611 | @item .iflt @var{absolute expression} | |
5612 | Assembles the following section of code if the argument is less than zero. | |
5613 | ||
26aca5f6 JB |
5614 | @cindex @code{ifnb} directive |
5615 | @item .ifnb @var{text} | |
5616 | Like @code{.ifb}, but the sense of the test is reversed: this assembles the | |
5617 | following section of code if the operand is non-blank (non-empty). | |
5618 | ||
252b5132 RH |
5619 | @cindex @code{ifnc} directive |
5620 | @item .ifnc @var{string1},@var{string2}. | |
5621 | Like @code{.ifc}, but the sense of the test is reversed: this assembles the | |
5622 | following section of code if the two strings are not the same. | |
5623 | ||
5624 | @cindex @code{ifndef} directive | |
5625 | @cindex @code{ifnotdef} directive | |
5626 | @item .ifndef @var{symbol} | |
5627 | @itemx .ifnotdef @var{symbol} | |
5628 | Assembles the following section of code if the specified @var{symbol} | |
8dfa0188 NC |
5629 | has not been defined. Both spelling variants are equivalent. Note a symbol |
5630 | which has been referenced but not yet defined is considered to be undefined. | |
252b5132 RH |
5631 | |
5632 | @cindex @code{ifne} directive | |
5633 | @item .ifne @var{absolute expression} | |
5634 | Assembles the following section of code if the argument is not equal to zero | |
5635 | (in other words, this is equivalent to @code{.if}). | |
5636 | ||
5637 | @cindex @code{ifnes} directive | |
5638 | @item .ifnes @var{string1},@var{string2} | |
5639 | Like @code{.ifeqs}, but the sense of the test is reversed: this assembles the | |
5640 | following section of code if the two strings are not the same. | |
5641 | @end table | |
5642 | ||
7e005732 NC |
5643 | @node Incbin |
5644 | @section @code{.incbin "@var{file}"[,@var{skip}[,@var{count}]]} | |
5645 | ||
5646 | @cindex @code{incbin} directive | |
5647 | @cindex binary files, including | |
5648 | The @code{incbin} directive includes @var{file} verbatim at the current | |
5649 | location. You can control the search paths used with the @samp{-I} command-line | |
5650 | option (@pxref{Invoking,,Command-Line Options}). Quotation marks are required | |
5651 | around @var{file}. | |
5652 | ||
5653 | The @var{skip} argument skips a number of bytes from the start of the | |
5654 | @var{file}. The @var{count} argument indicates the maximum number of bytes to | |
15dcfbc3 NC |
5655 | read. Note that the data is not aligned in any way, so it is the user's |
5656 | responsibility to make sure that proper alignment is provided both before and | |
5657 | after the @code{incbin} directive. | |
7e005732 | 5658 | |
252b5132 RH |
5659 | @node Include |
5660 | @section @code{.include "@var{file}"} | |
5661 | ||
5662 | @cindex @code{include} directive | |
5663 | @cindex supporting files, including | |
5664 | @cindex files, including | |
5665 | This directive provides a way to include supporting files at specified | |
5666 | points in your source program. The code from @var{file} is assembled as | |
5667 | if it followed the point of the @code{.include}; when the end of the | |
5668 | included file is reached, assembly of the original file continues. You | |
5669 | can control the search paths used with the @samp{-I} command-line option | |
5670 | (@pxref{Invoking,,Command-Line Options}). Quotation marks are required | |
5671 | around @var{file}. | |
5672 | ||
5673 | @node Int | |
5674 | @section @code{.int @var{expressions}} | |
5675 | ||
5676 | @cindex @code{int} directive | |
5677 | @cindex integers, 32-bit | |
5678 | Expect zero or more @var{expressions}, of any section, separated by commas. | |
5679 | For each expression, emit a number that, at run time, is the value of that | |
5680 | expression. The byte order and bit size of the number depends on what kind | |
5681 | of target the assembly is for. | |
5682 | ||
5683 | @ifclear GENERIC | |
5684 | @ifset H8 | |
7be1c489 | 5685 | On most forms of the H8/300, @code{.int} emits 16-bit |
c2dcd04e | 5686 | integers. On the H8/300H and the Renesas SH, however, @code{.int} emits |
252b5132 RH |
5687 | 32-bit integers. |
5688 | @end ifset | |
5689 | @end ifclear | |
5690 | ||
c91d2e08 NC |
5691 | @ifset ELF |
5692 | @node Internal | |
5693 | @section @code{.internal @var{names}} | |
5694 | ||
c1253627 NC |
5695 | @cindex @code{internal} directive |
5696 | @cindex visibility | |
ed9589d4 | 5697 | This is one of the ELF visibility directives. The other two are |
01642c12 | 5698 | @code{.hidden} (@pxref{Hidden,,@code{.hidden}}) and |
a349d9dd | 5699 | @code{.protected} (@pxref{Protected,,@code{.protected}}). |
c91d2e08 NC |
5700 | |
5701 | This directive overrides the named symbols default visibility (which is set by | |
5702 | their binding: local, global or weak). The directive sets the visibility to | |
5703 | @code{internal} which means that the symbols are considered to be @code{hidden} | |
c1253627 | 5704 | (i.e., not visible to other components), and that some extra, processor specific |
c91d2e08 NC |
5705 | processing must also be performed upon the symbols as well. |
5706 | @end ifset | |
5707 | ||
252b5132 RH |
5708 | @node Irp |
5709 | @section @code{.irp @var{symbol},@var{values}}@dots{} | |
5710 | ||
5711 | @cindex @code{irp} directive | |
5712 | Evaluate a sequence of statements assigning different values to @var{symbol}. | |
5713 | The sequence of statements starts at the @code{.irp} directive, and is | |
5714 | terminated by an @code{.endr} directive. For each @var{value}, @var{symbol} is | |
5715 | set to @var{value}, and the sequence of statements is assembled. If no | |
5716 | @var{value} is listed, the sequence of statements is assembled once, with | |
5717 | @var{symbol} set to the null string. To refer to @var{symbol} within the | |
5718 | sequence of statements, use @var{\symbol}. | |
5719 | ||
5720 | For example, assembling | |
5721 | ||
5722 | @example | |
5723 | .irp param,1,2,3 | |
5724 | move d\param,sp@@- | |
5725 | .endr | |
5726 | @end example | |
5727 | ||
5728 | is equivalent to assembling | |
5729 | ||
5730 | @example | |
5731 | move d1,sp@@- | |
5732 | move d2,sp@@- | |
5733 | move d3,sp@@- | |
5734 | @end example | |
5735 | ||
96e9638b | 5736 | For some caveats with the spelling of @var{symbol}, see also @ref{Macro}. |
5e75c3ab | 5737 | |
252b5132 RH |
5738 | @node Irpc |
5739 | @section @code{.irpc @var{symbol},@var{values}}@dots{} | |
5740 | ||
5741 | @cindex @code{irpc} directive | |
5742 | Evaluate a sequence of statements assigning different values to @var{symbol}. | |
5743 | The sequence of statements starts at the @code{.irpc} directive, and is | |
5744 | terminated by an @code{.endr} directive. For each character in @var{value}, | |
5745 | @var{symbol} is set to the character, and the sequence of statements is | |
5746 | assembled. If no @var{value} is listed, the sequence of statements is | |
5747 | assembled once, with @var{symbol} set to the null string. To refer to | |
5748 | @var{symbol} within the sequence of statements, use @var{\symbol}. | |
5749 | ||
5750 | For example, assembling | |
5751 | ||
5752 | @example | |
5753 | .irpc param,123 | |
5754 | move d\param,sp@@- | |
5755 | .endr | |
5756 | @end example | |
5757 | ||
5758 | is equivalent to assembling | |
5759 | ||
5760 | @example | |
5761 | move d1,sp@@- | |
5762 | move d2,sp@@- | |
5763 | move d3,sp@@- | |
5764 | @end example | |
5765 | ||
5e75c3ab JB |
5766 | For some caveats with the spelling of @var{symbol}, see also the discussion |
5767 | at @xref{Macro}. | |
5768 | ||
252b5132 RH |
5769 | @node Lcomm |
5770 | @section @code{.lcomm @var{symbol} , @var{length}} | |
5771 | ||
5772 | @cindex @code{lcomm} directive | |
5773 | @cindex local common symbols | |
5774 | @cindex symbols, local common | |
5775 | Reserve @var{length} (an absolute expression) bytes for a local common | |
5776 | denoted by @var{symbol}. The section and value of @var{symbol} are | |
5777 | those of the new local common. The addresses are allocated in the bss | |
5778 | section, so that at run-time the bytes start off zeroed. @var{Symbol} | |
5779 | is not declared global (@pxref{Global,,@code{.global}}), so is normally | |
5780 | not visible to @code{@value{LD}}. | |
5781 | ||
5782 | @ifset GENERIC | |
5783 | Some targets permit a third argument to be used with @code{.lcomm}. This | |
5784 | argument specifies the desired alignment of the symbol in the bss section. | |
5785 | @end ifset | |
5786 | ||
5787 | @ifset HPPA | |
5788 | The syntax for @code{.lcomm} differs slightly on the HPPA. The syntax is | |
5789 | @samp{@var{symbol} .lcomm, @var{length}}; @var{symbol} is optional. | |
5790 | @end ifset | |
5791 | ||
5792 | @node Lflags | |
5793 | @section @code{.lflags} | |
5794 | ||
5795 | @cindex @code{lflags} directive (ignored) | |
a4fb0134 | 5796 | @command{@value{AS}} accepts this directive, for compatibility with other |
252b5132 RH |
5797 | assemblers, but ignores it. |
5798 | ||
5799 | @ifclear no-line-dir | |
5800 | @node Line | |
5801 | @section @code{.line @var{line-number}} | |
5802 | ||
5803 | @cindex @code{line} directive | |
252b5132 RH |
5804 | @cindex logical line number |
5805 | @ifset aout-bout | |
5806 | Change the logical line number. @var{line-number} must be an absolute | |
5807 | expression. The next line has that logical line number. Therefore any other | |
5808 | statements on the current line (after a statement separator character) are | |
5809 | reported as on logical line number @var{line-number} @minus{} 1. One day | |
a4fb0134 | 5810 | @command{@value{AS}} will no longer support this directive: it is recognized only |
252b5132 | 5811 | for compatibility with existing assembler programs. |
252b5132 RH |
5812 | @end ifset |
5813 | ||
252b5132 | 5814 | Even though this is a directive associated with the @code{a.out} or |
a4fb0134 | 5815 | @code{b.out} object-code formats, @command{@value{AS}} still recognizes it |
252b5132 RH |
5816 | when producing COFF output, and treats @samp{.line} as though it |
5817 | were the COFF @samp{.ln} @emph{if} it is found outside a | |
5818 | @code{.def}/@code{.endef} pair. | |
5819 | ||
5820 | Inside a @code{.def}, @samp{.line} is, instead, one of the directives | |
5821 | used by compilers to generate auxiliary symbol information for | |
5822 | debugging. | |
5823 | @end ifclear | |
5824 | ||
5825 | @node Linkonce | |
5826 | @section @code{.linkonce [@var{type}]} | |
5827 | @cindex COMDAT | |
5828 | @cindex @code{linkonce} directive | |
5829 | @cindex common sections | |
5830 | Mark the current section so that the linker only includes a single copy of it. | |
5831 | This may be used to include the same section in several different object files, | |
5832 | but ensure that the linker will only include it once in the final output file. | |
5833 | The @code{.linkonce} pseudo-op must be used for each instance of the section. | |
5834 | Duplicate sections are detected based on the section name, so it should be | |
5835 | unique. | |
5836 | ||
5837 | This directive is only supported by a few object file formats; as of this | |
5838 | writing, the only object file format which supports it is the Portable | |
5839 | Executable format used on Windows NT. | |
5840 | ||
5841 | The @var{type} argument is optional. If specified, it must be one of the | |
5842 | following strings. For example: | |
5843 | @smallexample | |
5844 | .linkonce same_size | |
5845 | @end smallexample | |
5846 | Not all types may be supported on all object file formats. | |
5847 | ||
5848 | @table @code | |
5849 | @item discard | |
5850 | Silently discard duplicate sections. This is the default. | |
5851 | ||
5852 | @item one_only | |
5853 | Warn if there are duplicate sections, but still keep only one copy. | |
5854 | ||
5855 | @item same_size | |
5856 | Warn if any of the duplicates have different sizes. | |
5857 | ||
5858 | @item same_contents | |
5859 | Warn if any of the duplicates do not have exactly the same contents. | |
5860 | @end table | |
5861 | ||
ccf8a69b BW |
5862 | @node List |
5863 | @section @code{.list} | |
5864 | ||
5865 | @cindex @code{list} directive | |
5866 | @cindex listing control, turning on | |
5867 | Control (in conjunction with the @code{.nolist} directive) whether or | |
5868 | not assembly listings are generated. These two directives maintain an | |
5869 | internal counter (which is zero initially). @code{.list} increments the | |
5870 | counter, and @code{.nolist} decrements it. Assembly listings are | |
5871 | generated whenever the counter is greater than zero. | |
5872 | ||
5873 | By default, listings are disabled. When you enable them (with the | |
5874 | @samp{-a} command line option; @pxref{Invoking,,Command-Line Options}), | |
5875 | the initial value of the listing counter is one. | |
5876 | ||
252b5132 RH |
5877 | @node Ln |
5878 | @section @code{.ln @var{line-number}} | |
5879 | ||
5880 | @cindex @code{ln} directive | |
5881 | @ifclear no-line-dir | |
5882 | @samp{.ln} is a synonym for @samp{.line}. | |
5883 | @end ifclear | |
5884 | @ifset no-line-dir | |
a4fb0134 | 5885 | Tell @command{@value{AS}} to change the logical line number. @var{line-number} |
252b5132 RH |
5886 | must be an absolute expression. The next line has that logical |
5887 | line number, so any other statements on the current line (after a | |
5888 | statement separator character @code{;}) are reported as on logical | |
5889 | line number @var{line-number} @minus{} 1. | |
5890 | @ifset BOUT | |
5891 | ||
a4fb0134 | 5892 | This directive is accepted, but ignored, when @command{@value{AS}} is |
252b5132 RH |
5893 | configured for @code{b.out}; its effect is only associated with COFF |
5894 | output format. | |
5895 | @end ifset | |
5896 | @end ifset | |
5897 | ||
ccf8a69b BW |
5898 | @node Loc |
5899 | @section @code{.loc @var{fileno} @var{lineno} [@var{column}] [@var{options}]} | |
5900 | @cindex @code{loc} directive | |
5901 | When emitting DWARF2 line number information, | |
5902 | the @code{.loc} directive will add a row to the @code{.debug_line} line | |
5903 | number matrix corresponding to the immediately following assembly | |
5904 | instruction. The @var{fileno}, @var{lineno}, and optional @var{column} | |
5905 | arguments will be applied to the @code{.debug_line} state machine before | |
5906 | the row is added. | |
252b5132 | 5907 | |
ccf8a69b BW |
5908 | The @var{options} are a sequence of the following tokens in any order: |
5909 | ||
5910 | @table @code | |
5911 | @item basic_block | |
5912 | This option will set the @code{basic_block} register in the | |
5913 | @code{.debug_line} state machine to @code{true}. | |
5914 | ||
5915 | @item prologue_end | |
5916 | This option will set the @code{prologue_end} register in the | |
5917 | @code{.debug_line} state machine to @code{true}. | |
5918 | ||
5919 | @item epilogue_begin | |
5920 | This option will set the @code{epilogue_begin} register in the | |
5921 | @code{.debug_line} state machine to @code{true}. | |
5922 | ||
5923 | @item is_stmt @var{value} | |
5924 | This option will set the @code{is_stmt} register in the | |
01642c12 | 5925 | @code{.debug_line} state machine to @code{value}, which must be |
ccf8a69b BW |
5926 | either 0 or 1. |
5927 | ||
5928 | @item isa @var{value} | |
5929 | This directive will set the @code{isa} register in the @code{.debug_line} | |
5930 | state machine to @var{value}, which must be an unsigned integer. | |
5931 | ||
92846e72 CC |
5932 | @item discriminator @var{value} |
5933 | This directive will set the @code{discriminator} register in the @code{.debug_line} | |
5934 | state machine to @var{value}, which must be an unsigned integer. | |
5935 | ||
ba8826a8 AO |
5936 | @item view @var{value} |
5937 | This option causes a row to be added to @code{.debug_line} in reference to the | |
5938 | current address (which might not be the same as that of the following assembly | |
5939 | instruction), and to associate @var{value} with the @code{view} register in the | |
5940 | @code{.debug_line} state machine. If @var{value} is a label, both the | |
5941 | @code{view} register and the label are set to the number of prior @code{.loc} | |
5942 | directives at the same program location. If @var{value} is the literal | |
5943 | @code{0}, the @code{view} register is set to zero, and the assembler asserts | |
5944 | that there aren't any prior @code{.loc} directives at the same program | |
5945 | location. If @var{value} is the literal @code{-0}, the assembler arrange for | |
5946 | the @code{view} register to be reset in this row, even if there are prior | |
5947 | @code{.loc} directives at the same program location. | |
5948 | ||
ccf8a69b BW |
5949 | @end table |
5950 | ||
5951 | @node Loc_mark_labels | |
5952 | @section @code{.loc_mark_labels @var{enable}} | |
5953 | @cindex @code{loc_mark_labels} directive | |
5954 | When emitting DWARF2 line number information, | |
5955 | the @code{.loc_mark_labels} directive makes the assembler emit an entry | |
5956 | to the @code{.debug_line} line number matrix with the @code{basic_block} | |
5957 | register in the state machine set whenever a code label is seen. | |
5958 | The @var{enable} argument should be either 1 or 0, to enable or disable | |
5959 | this function respectively. | |
252b5132 | 5960 | |
4d4175af BW |
5961 | @ifset ELF |
5962 | @node Local | |
5963 | @section @code{.local @var{names}} | |
5964 | ||
5965 | @cindex @code{local} directive | |
5966 | This directive, which is available for ELF targets, marks each symbol in | |
5967 | the comma-separated list of @code{names} as a local symbol so that it | |
5968 | will not be externally visible. If the symbols do not already exist, | |
5969 | they will be created. | |
5970 | ||
5971 | For targets where the @code{.lcomm} directive (@pxref{Lcomm}) does not | |
5972 | accept an alignment argument, which is the case for most ELF targets, | |
5973 | the @code{.local} directive can be used in combination with @code{.comm} | |
5974 | (@pxref{Comm}) to define aligned local common data. | |
5975 | @end ifset | |
5976 | ||
252b5132 RH |
5977 | @node Long |
5978 | @section @code{.long @var{expressions}} | |
5979 | ||
5980 | @cindex @code{long} directive | |
96e9638b | 5981 | @code{.long} is the same as @samp{.int}. @xref{Int,,@code{.int}}. |
252b5132 RH |
5982 | |
5983 | @ignore | |
5984 | @c no one seems to know what this is for or whether this description is | |
5985 | @c what it really ought to do | |
5986 | @node Lsym | |
5987 | @section @code{.lsym @var{symbol}, @var{expression}} | |
5988 | ||
5989 | @cindex @code{lsym} directive | |
5990 | @cindex symbol, not referenced in assembly | |
5991 | @code{.lsym} creates a new symbol named @var{symbol}, but does not put it in | |
5992 | the hash table, ensuring it cannot be referenced by name during the | |
5993 | rest of the assembly. This sets the attributes of the symbol to be | |
5994 | the same as the expression value: | |
5995 | @smallexample | |
5996 | @var{other} = @var{descriptor} = 0 | |
5997 | @var{type} = @r{(section of @var{expression})} | |
5998 | @var{value} = @var{expression} | |
5999 | @end smallexample | |
6000 | @noindent | |
6001 | The new symbol is not flagged as external. | |
6002 | @end ignore | |
6003 | ||
6004 | @node Macro | |
6005 | @section @code{.macro} | |
6006 | ||
6007 | @cindex macros | |
6008 | The commands @code{.macro} and @code{.endm} allow you to define macros that | |
6009 | generate assembly output. For example, this definition specifies a macro | |
6010 | @code{sum} that puts a sequence of numbers into memory: | |
6011 | ||
6012 | @example | |
6013 | .macro sum from=0, to=5 | |
6014 | .long \from | |
6015 | .if \to-\from | |
6016 | sum "(\from+1)",\to | |
6017 | .endif | |
6018 | .endm | |
6019 | @end example | |
6020 | ||
6021 | @noindent | |
6022 | With that definition, @samp{SUM 0,5} is equivalent to this assembly input: | |
6023 | ||
6024 | @example | |
6025 | .long 0 | |
6026 | .long 1 | |
6027 | .long 2 | |
6028 | .long 3 | |
6029 | .long 4 | |
6030 | .long 5 | |
6031 | @end example | |
6032 | ||
6033 | @ftable @code | |
6034 | @item .macro @var{macname} | |
6035 | @itemx .macro @var{macname} @var{macargs} @dots{} | |
6036 | @cindex @code{macro} directive | |
6037 | Begin the definition of a macro called @var{macname}. If your macro | |
6038 | definition requires arguments, specify their names after the macro name, | |
6eaeac8a JB |
6039 | separated by commas or spaces. You can qualify the macro argument to |
6040 | indicate whether all invocations must specify a non-blank value (through | |
6041 | @samp{:@code{req}}), or whether it takes all of the remaining arguments | |
6042 | (through @samp{:@code{vararg}}). You can supply a default value for any | |
fffeaa5f JB |
6043 | macro argument by following the name with @samp{=@var{deflt}}. You |
6044 | cannot define two macros with the same @var{macname} unless it has been | |
96e9638b | 6045 | subject to the @code{.purgem} directive (@pxref{Purgem}) between the two |
fffeaa5f | 6046 | definitions. For example, these are all valid @code{.macro} statements: |
252b5132 RH |
6047 | |
6048 | @table @code | |
6049 | @item .macro comm | |
6050 | Begin the definition of a macro called @code{comm}, which takes no | |
6051 | arguments. | |
6052 | ||
6258339f | 6053 | @item .macro plus1 p, p1 |
252b5132 RH |
6054 | @itemx .macro plus1 p p1 |
6055 | Either statement begins the definition of a macro called @code{plus1}, | |
6056 | which takes two arguments; within the macro definition, write | |
6057 | @samp{\p} or @samp{\p1} to evaluate the arguments. | |
6058 | ||
6059 | @item .macro reserve_str p1=0 p2 | |
6060 | Begin the definition of a macro called @code{reserve_str}, with two | |
6061 | arguments. The first argument has a default value, but not the second. | |
6062 | After the definition is complete, you can call the macro either as | |
6063 | @samp{reserve_str @var{a},@var{b}} (with @samp{\p1} evaluating to | |
6064 | @var{a} and @samp{\p2} evaluating to @var{b}), or as @samp{reserve_str | |
6065 | ,@var{b}} (with @samp{\p1} evaluating as the default, in this case | |
6066 | @samp{0}, and @samp{\p2} evaluating to @var{b}). | |
252b5132 | 6067 | |
6eaeac8a JB |
6068 | @item .macro m p1:req, p2=0, p3:vararg |
6069 | Begin the definition of a macro called @code{m}, with at least three | |
6070 | arguments. The first argument must always have a value specified, but | |
6071 | not the second, which instead has a default value. The third formal | |
6072 | will get assigned all remaining arguments specified at invocation time. | |
6073 | ||
252b5132 RH |
6074 | When you call a macro, you can specify the argument values either by |
6075 | position, or by keyword. For example, @samp{sum 9,17} is equivalent to | |
6076 | @samp{sum to=17, from=9}. | |
6077 | ||
6258339f NC |
6078 | @end table |
6079 | ||
5e75c3ab JB |
6080 | Note that since each of the @var{macargs} can be an identifier exactly |
6081 | as any other one permitted by the target architecture, there may be | |
6082 | occasional problems if the target hand-crafts special meanings to certain | |
6258339f | 6083 | characters when they occur in a special position. For example, if the colon |
5e75c3ab | 6084 | (@code{:}) is generally permitted to be part of a symbol name, but the |
6258339f | 6085 | architecture specific code special-cases it when occurring as the final |
5e75c3ab JB |
6086 | character of a symbol (to denote a label), then the macro parameter |
6087 | replacement code will have no way of knowing that and consider the whole | |
6088 | construct (including the colon) an identifier, and check only this | |
6258339f NC |
6089 | identifier for being the subject to parameter substitution. So for example |
6090 | this macro definition: | |
6091 | ||
6092 | @example | |
6093 | .macro label l | |
6094 | \l: | |
6095 | .endm | |
6096 | @end example | |
6097 | ||
6098 | might not work as expected. Invoking @samp{label foo} might not create a label | |
6099 | called @samp{foo} but instead just insert the text @samp{\l:} into the | |
6100 | assembler source, probably generating an error about an unrecognised | |
6101 | identifier. | |
6102 | ||
6103 | Similarly problems might occur with the period character (@samp{.}) | |
6104 | which is often allowed inside opcode names (and hence identifier names). So | |
6105 | for example constructing a macro to build an opcode from a base name and a | |
6106 | length specifier like this: | |
6107 | ||
6108 | @example | |
6109 | .macro opcode base length | |
6110 | \base.\length | |
6111 | .endm | |
6112 | @end example | |
6113 | ||
6114 | and invoking it as @samp{opcode store l} will not create a @samp{store.l} | |
6115 | instruction but instead generate some kind of error as the assembler tries to | |
6116 | interpret the text @samp{\base.\length}. | |
6117 | ||
6118 | There are several possible ways around this problem: | |
6119 | ||
6120 | @table @code | |
6121 | @item Insert white space | |
6122 | If it is possible to use white space characters then this is the simplest | |
6123 | solution. eg: | |
6124 | ||
6125 | @example | |
6126 | .macro label l | |
6127 | \l : | |
6128 | .endm | |
6129 | @end example | |
6130 | ||
6131 | @item Use @samp{\()} | |
6132 | The string @samp{\()} can be used to separate the end of a macro argument from | |
6133 | the following text. eg: | |
6134 | ||
6135 | @example | |
6136 | .macro opcode base length | |
6137 | \base\().\length | |
6138 | .endm | |
6139 | @end example | |
6140 | ||
6141 | @item Use the alternate macro syntax mode | |
6142 | In the alternative macro syntax mode the ampersand character (@samp{&}) can be | |
6143 | used as a separator. eg: | |
5e75c3ab JB |
6144 | |
6145 | @example | |
6146 | .altmacro | |
6147 | .macro label l | |
6148 | l&: | |
6149 | .endm | |
6150 | @end example | |
6258339f | 6151 | @end table |
5e75c3ab | 6152 | |
96e9638b | 6153 | Note: this problem of correctly identifying string parameters to pseudo ops |
01642c12 | 6154 | also applies to the identifiers used in @code{.irp} (@pxref{Irp}) |
96e9638b | 6155 | and @code{.irpc} (@pxref{Irpc}) as well. |
5e75c3ab | 6156 | |
252b5132 RH |
6157 | @item .endm |
6158 | @cindex @code{endm} directive | |
6159 | Mark the end of a macro definition. | |
6160 | ||
6161 | @item .exitm | |
6162 | @cindex @code{exitm} directive | |
6163 | Exit early from the current macro definition. | |
6164 | ||
6165 | @cindex number of macros executed | |
6166 | @cindex macros, count executed | |
6167 | @item \@@ | |
a4fb0134 | 6168 | @command{@value{AS}} maintains a counter of how many macros it has |
252b5132 RH |
6169 | executed in this pseudo-variable; you can copy that number to your |
6170 | output with @samp{\@@}, but @emph{only within a macro definition}. | |
6171 | ||
252b5132 RH |
6172 | @item LOCAL @var{name} [ , @dots{} ] |
6173 | @emph{Warning: @code{LOCAL} is only available if you select ``alternate | |
caa32fe5 NC |
6174 | macro syntax'' with @samp{--alternate} or @code{.altmacro}.} |
6175 | @xref{Altmacro,,@code{.altmacro}}. | |
6176 | @end ftable | |
252b5132 | 6177 | |
ccf8a69b BW |
6178 | @node MRI |
6179 | @section @code{.mri @var{val}} | |
caa32fe5 | 6180 | |
ccf8a69b BW |
6181 | @cindex @code{mri} directive |
6182 | @cindex MRI mode, temporarily | |
6183 | If @var{val} is non-zero, this tells @command{@value{AS}} to enter MRI mode. If | |
6184 | @var{val} is zero, this tells @command{@value{AS}} to exit MRI mode. This change | |
6185 | affects code assembled until the next @code{.mri} directive, or until the end | |
6186 | of the file. @xref{M, MRI mode, MRI mode}. | |
252b5132 | 6187 | |
caa32fe5 NC |
6188 | @node Noaltmacro |
6189 | @section @code{.noaltmacro} | |
96e9638b | 6190 | Disable alternate macro mode. @xref{Altmacro}. |
caa32fe5 | 6191 | |
252b5132 RH |
6192 | @node Nolist |
6193 | @section @code{.nolist} | |
6194 | ||
6195 | @cindex @code{nolist} directive | |
6196 | @cindex listing control, turning off | |
6197 | Control (in conjunction with the @code{.list} directive) whether or | |
6198 | not assembly listings are generated. These two directives maintain an | |
6199 | internal counter (which is zero initially). @code{.list} increments the | |
6200 | counter, and @code{.nolist} decrements it. Assembly listings are | |
6201 | generated whenever the counter is greater than zero. | |
6202 | ||
62a02d25 L |
6203 | @node Nop |
6204 | @section @code{.nop @var{size}[, @var{control}]} | |
6205 | ||
6206 | @cindex @code{nop} directive | |
6207 | @cindex filling memory with no-op instructions | |
6208 | This directive emits @var{size} bytes filled with no-op instructions. | |
6209 | @var{size} is absolute expression, which must be a positve value. | |
6210 | @var{control} controls how no-op instructions should be generated. If | |
6211 | the comma and @var{control} are omitted, @var{control} is assumed to be | |
6212 | zero. | |
6213 | ||
6214 | Note: For Intel 80386 and AMD x86-64 targets, @var{control} specifies | |
6215 | the size limit of a no-op instruction. The valid values of @var{control} | |
6216 | are between 0 and 8 for 16-bit mode, between 0 and 10 for 32-bit mode, | |
6217 | between 0 and 11 for 64-bit mode. When 0 is used, the no-op instruction | |
6218 | size limit is set to the maximum supported size. | |
6219 | ||
252b5132 RH |
6220 | @node Octa |
6221 | @section @code{.octa @var{bignums}} | |
6222 | ||
6223 | @c FIXME: double size emitted for "octa" on i960, others? Or warn? | |
6224 | @cindex @code{octa} directive | |
6225 | @cindex integer, 16-byte | |
6226 | @cindex sixteen byte integer | |
6227 | This directive expects zero or more bignums, separated by commas. For each | |
6228 | bignum, it emits a 16-byte integer. | |
6229 | ||
6230 | The term ``octa'' comes from contexts in which a ``word'' is two bytes; | |
6231 | hence @emph{octa}-word for 16 bytes. | |
6232 | ||
9aec2026 NC |
6233 | @node Offset |
6234 | @section @code{.offset @var{loc}} | |
6235 | ||
6236 | @cindex @code{offset} directive | |
6237 | Set the location counter to @var{loc} in the absolute section. @var{loc} must | |
6238 | be an absolute expression. This directive may be useful for defining | |
6239 | symbols with absolute values. Do not confuse it with the @code{.org} | |
fa94de6b | 6240 | directive. |
9aec2026 | 6241 | |
252b5132 RH |
6242 | @node Org |
6243 | @section @code{.org @var{new-lc} , @var{fill}} | |
6244 | ||
6245 | @cindex @code{org} directive | |
6246 | @cindex location counter, advancing | |
6247 | @cindex advancing location counter | |
6248 | @cindex current address, advancing | |
6249 | Advance the location counter of the current section to | |
6250 | @var{new-lc}. @var{new-lc} is either an absolute expression or an | |
6251 | expression with the same section as the current subsection. That is, | |
6252 | you can't use @code{.org} to cross sections: if @var{new-lc} has the | |
6253 | wrong section, the @code{.org} directive is ignored. To be compatible | |
6254 | with former assemblers, if the section of @var{new-lc} is absolute, | |
a4fb0134 | 6255 | @command{@value{AS}} issues a warning, then pretends the section of @var{new-lc} |
252b5132 RH |
6256 | is the same as the current subsection. |
6257 | ||
6258 | @code{.org} may only increase the location counter, or leave it | |
6259 | unchanged; you cannot use @code{.org} to move the location counter | |
6260 | backwards. | |
6261 | ||
6262 | @c double negative used below "not undefined" because this is a specific | |
6263 | @c reference to "undefined" (as SEG_UNKNOWN is called in this manual) | |
6264 | @c section. doc@cygnus.com 18feb91 | |
a4fb0134 | 6265 | Because @command{@value{AS}} tries to assemble programs in one pass, @var{new-lc} |
252b5132 RH |
6266 | may not be undefined. If you really detest this restriction we eagerly await |
6267 | a chance to share your improved assembler. | |
6268 | ||
6269 | Beware that the origin is relative to the start of the section, not | |
6270 | to the start of the subsection. This is compatible with other | |
6271 | people's assemblers. | |
6272 | ||
6273 | When the location counter (of the current subsection) is advanced, the | |
6274 | intervening bytes are filled with @var{fill} which should be an | |
6275 | absolute expression. If the comma and @var{fill} are omitted, | |
6276 | @var{fill} defaults to zero. | |
6277 | ||
6278 | @node P2align | |
6279 | @section @code{.p2align[wl] @var{abs-expr}, @var{abs-expr}, @var{abs-expr}} | |
6280 | ||
6281 | @cindex padding the location counter given a power of two | |
6282 | @cindex @code{p2align} directive | |
6283 | Pad the location counter (in the current subsection) to a particular | |
6284 | storage boundary. The first expression (which must be absolute) is the | |
6285 | number of low-order zero bits the location counter must have after | |
6286 | advancement. For example @samp{.p2align 3} advances the location | |
6287 | counter until it a multiple of 8. If the location counter is already a | |
6288 | multiple of 8, no change is needed. | |
6289 | ||
6290 | The second expression (also absolute) gives the fill value to be stored in the | |
6291 | padding bytes. It (and the comma) may be omitted. If it is omitted, the | |
2ca23e65 | 6292 | padding bytes are normally zero. However, on most systems, if the section is |
252b5132 RH |
6293 | marked as containing code and the fill value is omitted, the space is filled |
6294 | with no-op instructions. | |
6295 | ||
6296 | The third expression is also absolute, and is also optional. If it is present, | |
6297 | it is the maximum number of bytes that should be skipped by this alignment | |
6298 | directive. If doing the alignment would require skipping more bytes than the | |
6299 | specified maximum, then the alignment is not done at all. You can omit the | |
6300 | fill value (the second argument) entirely by simply using two commas after the | |
6301 | required alignment; this can be useful if you want the alignment to be filled | |
6302 | with no-op instructions when appropriate. | |
6303 | ||
6304 | @cindex @code{p2alignw} directive | |
6305 | @cindex @code{p2alignl} directive | |
6306 | The @code{.p2alignw} and @code{.p2alignl} directives are variants of the | |
6307 | @code{.p2align} directive. The @code{.p2alignw} directive treats the fill | |
6308 | pattern as a two byte word value. The @code{.p2alignl} directives treats the | |
6309 | fill pattern as a four byte longword value. For example, @code{.p2alignw | |
6310 | 2,0x368d} will align to a multiple of 4. If it skips two bytes, they will be | |
6311 | filled in with the value 0x368d (the exact placement of the bytes depends upon | |
6312 | the endianness of the processor). If it skips 1 or 3 bytes, the fill value is | |
6313 | undefined. | |
6314 | ||
ccf8a69b BW |
6315 | @ifset ELF |
6316 | @node PopSection | |
6317 | @section @code{.popsection} | |
6318 | ||
6319 | @cindex @code{popsection} directive | |
6320 | @cindex Section Stack | |
6321 | This is one of the ELF section stack manipulation directives. The others are | |
01642c12 RM |
6322 | @code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}), |
6323 | @code{.pushsection} (@pxref{PushSection}), and @code{.previous} | |
ccf8a69b BW |
6324 | (@pxref{Previous}). |
6325 | ||
6326 | This directive replaces the current section (and subsection) with the top | |
6327 | section (and subsection) on the section stack. This section is popped off the | |
01642c12 | 6328 | stack. |
ccf8a69b BW |
6329 | @end ifset |
6330 | ||
c91d2e08 NC |
6331 | @ifset ELF |
6332 | @node Previous | |
6333 | @section @code{.previous} | |
6334 | ||
c1253627 | 6335 | @cindex @code{previous} directive |
c91d2e08 NC |
6336 | @cindex Section Stack |
6337 | This is one of the ELF section stack manipulation directives. The others are | |
a349d9dd PB |
6338 | @code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}), |
6339 | @code{.pushsection} (@pxref{PushSection}), and @code{.popsection} | |
6340 | (@pxref{PopSection}). | |
c91d2e08 NC |
6341 | |
6342 | This directive swaps the current section (and subsection) with most recently | |
8b040e0a | 6343 | referenced section/subsection pair prior to this one. Multiple |
c91d2e08 | 6344 | @code{.previous} directives in a row will flip between two sections (and their |
8b040e0a NC |
6345 | subsections). For example: |
6346 | ||
6347 | @smallexample | |
6348 | .section A | |
6349 | .subsection 1 | |
6350 | .word 0x1234 | |
6351 | .subsection 2 | |
6352 | .word 0x5678 | |
6353 | .previous | |
6354 | .word 0x9abc | |
6355 | @end smallexample | |
6356 | ||
6357 | Will place 0x1234 and 0x9abc into subsection 1 and 0x5678 into subsection 2 of | |
6358 | section A. Whilst: | |
6359 | ||
6360 | @smallexample | |
6361 | .section A | |
6362 | .subsection 1 | |
6363 | # Now in section A subsection 1 | |
6364 | .word 0x1234 | |
6365 | .section B | |
6366 | .subsection 0 | |
6367 | # Now in section B subsection 0 | |
6368 | .word 0x5678 | |
6369 | .subsection 1 | |
6370 | # Now in section B subsection 1 | |
6371 | .word 0x9abc | |
6372 | .previous | |
6373 | # Now in section B subsection 0 | |
6374 | .word 0xdef0 | |
6375 | @end smallexample | |
6376 | ||
6377 | Will place 0x1234 into section A, 0x5678 and 0xdef0 into subsection 0 of | |
6378 | section B and 0x9abc into subsection 1 of section B. | |
c91d2e08 NC |
6379 | |
6380 | In terms of the section stack, this directive swaps the current section with | |
6381 | the top section on the section stack. | |
6382 | @end ifset | |
6383 | ||
252b5132 RH |
6384 | @node Print |
6385 | @section @code{.print @var{string}} | |
6386 | ||
6387 | @cindex @code{print} directive | |
a4fb0134 | 6388 | @command{@value{AS}} will print @var{string} on the standard output during |
252b5132 RH |
6389 | assembly. You must put @var{string} in double quotes. |
6390 | ||
c91d2e08 NC |
6391 | @ifset ELF |
6392 | @node Protected | |
6393 | @section @code{.protected @var{names}} | |
6394 | ||
c1253627 NC |
6395 | @cindex @code{protected} directive |
6396 | @cindex visibility | |
ed9589d4 | 6397 | This is one of the ELF visibility directives. The other two are |
a349d9dd | 6398 | @code{.hidden} (@pxref{Hidden}) and @code{.internal} (@pxref{Internal}). |
c91d2e08 NC |
6399 | |
6400 | This directive overrides the named symbols default visibility (which is set by | |
6401 | their binding: local, global or weak). The directive sets the visibility to | |
6402 | @code{protected} which means that any references to the symbols from within the | |
6403 | components that defines them must be resolved to the definition in that | |
6404 | component, even if a definition in another component would normally preempt | |
01642c12 | 6405 | this. |
c91d2e08 NC |
6406 | @end ifset |
6407 | ||
252b5132 RH |
6408 | @node Psize |
6409 | @section @code{.psize @var{lines} , @var{columns}} | |
6410 | ||
6411 | @cindex @code{psize} directive | |
6412 | @cindex listing control: paper size | |
6413 | @cindex paper size, for listings | |
6414 | Use this directive to declare the number of lines---and, optionally, the | |
6415 | number of columns---to use for each page, when generating listings. | |
6416 | ||
6417 | If you do not use @code{.psize}, listings use a default line-count | |
6418 | of 60. You may omit the comma and @var{columns} specification; the | |
6419 | default width is 200 columns. | |
6420 | ||
a4fb0134 | 6421 | @command{@value{AS}} generates formfeeds whenever the specified number of |
252b5132 RH |
6422 | lines is exceeded (or whenever you explicitly request one, using |
6423 | @code{.eject}). | |
6424 | ||
6425 | If you specify @var{lines} as @code{0}, no formfeeds are generated save | |
6426 | those explicitly specified with @code{.eject}. | |
6427 | ||
6428 | @node Purgem | |
6429 | @section @code{.purgem @var{name}} | |
6430 | ||
6431 | @cindex @code{purgem} directive | |
6432 | Undefine the macro @var{name}, so that later uses of the string will not be | |
6433 | expanded. @xref{Macro}. | |
6434 | ||
c91d2e08 NC |
6435 | @ifset ELF |
6436 | @node PushSection | |
9cfc3331 | 6437 | @section @code{.pushsection @var{name} [, @var{subsection}] [, "@var{flags}"[, @@@var{type}[,@var{arguments}]]]} |
c91d2e08 | 6438 | |
c1253627 | 6439 | @cindex @code{pushsection} directive |
c91d2e08 NC |
6440 | @cindex Section Stack |
6441 | This is one of the ELF section stack manipulation directives. The others are | |
01642c12 RM |
6442 | @code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}), |
6443 | @code{.popsection} (@pxref{PopSection}), and @code{.previous} | |
a349d9dd | 6444 | (@pxref{Previous}). |
c91d2e08 | 6445 | |
e9863d7f DJ |
6446 | This directive pushes the current section (and subsection) onto the |
6447 | top of the section stack, and then replaces the current section and | |
9cfc3331 L |
6448 | subsection with @code{name} and @code{subsection}. The optional |
6449 | @code{flags}, @code{type} and @code{arguments} are treated the same | |
6450 | as in the @code{.section} (@pxref{Section}) directive. | |
c91d2e08 NC |
6451 | @end ifset |
6452 | ||
252b5132 RH |
6453 | @node Quad |
6454 | @section @code{.quad @var{bignums}} | |
6455 | ||
6456 | @cindex @code{quad} directive | |
6457 | @code{.quad} expects zero or more bignums, separated by commas. For | |
6458 | each bignum, it emits | |
6459 | @ifclear bignum-16 | |
6460 | an 8-byte integer. If the bignum won't fit in 8 bytes, it prints a | |
6461 | warning message; and just takes the lowest order 8 bytes of the bignum. | |
6462 | @cindex eight-byte integer | |
6463 | @cindex integer, 8-byte | |
6464 | ||
6465 | The term ``quad'' comes from contexts in which a ``word'' is two bytes; | |
6466 | hence @emph{quad}-word for 8 bytes. | |
6467 | @end ifclear | |
6468 | @ifset bignum-16 | |
6469 | a 16-byte integer. If the bignum won't fit in 16 bytes, it prints a | |
6470 | warning message; and just takes the lowest order 16 bytes of the bignum. | |
6471 | @cindex sixteen-byte integer | |
6472 | @cindex integer, 16-byte | |
6473 | @end ifset | |
6474 | ||
05e9452c AM |
6475 | @node Reloc |
6476 | @section @code{.reloc @var{offset}, @var{reloc_name}[, @var{expression}]} | |
6477 | ||
6478 | @cindex @code{reloc} directive | |
6479 | Generate a relocation at @var{offset} of type @var{reloc_name} with value | |
6480 | @var{expression}. If @var{offset} is a number, the relocation is generated in | |
6481 | the current section. If @var{offset} is an expression that resolves to a | |
6482 | symbol plus offset, the relocation is generated in the given symbol's section. | |
6483 | @var{expression}, if present, must resolve to a symbol plus addend or to an | |
6484 | absolute value, but note that not all targets support an addend. e.g. ELF REL | |
6485 | targets such as i386 store an addend in the section contents rather than in the | |
6486 | relocation. This low level interface does not support addends stored in the | |
6487 | section. | |
6488 | ||
252b5132 RH |
6489 | @node Rept |
6490 | @section @code{.rept @var{count}} | |
6491 | ||
6492 | @cindex @code{rept} directive | |
6493 | Repeat the sequence of lines between the @code{.rept} directive and the next | |
6494 | @code{.endr} directive @var{count} times. | |
6495 | ||
6496 | For example, assembling | |
6497 | ||
6498 | @example | |
6499 | .rept 3 | |
6500 | .long 0 | |
6501 | .endr | |
6502 | @end example | |
6503 | ||
6504 | is equivalent to assembling | |
6505 | ||
6506 | @example | |
6507 | .long 0 | |
6508 | .long 0 | |
6509 | .long 0 | |
6510 | @end example | |
6511 | ||
808811a3 NC |
6512 | A count of zero is allowed, but nothing is generated. Negative counts are not |
6513 | allowed and if encountered will be treated as if they were zero. | |
6514 | ||
252b5132 RH |
6515 | @node Sbttl |
6516 | @section @code{.sbttl "@var{subheading}"} | |
6517 | ||
6518 | @cindex @code{sbttl} directive | |
6519 | @cindex subtitles for listings | |
6520 | @cindex listing control: subtitle | |
6521 | Use @var{subheading} as the title (third line, immediately after the | |
6522 | title line) when generating assembly listings. | |
6523 | ||
6524 | This directive affects subsequent pages, as well as the current page if | |
6525 | it appears within ten lines of the top of a page. | |
6526 | ||
6527 | @ifset COFF | |
6528 | @node Scl | |
6529 | @section @code{.scl @var{class}} | |
6530 | ||
6531 | @cindex @code{scl} directive | |
6532 | @cindex symbol storage class (COFF) | |
6533 | @cindex COFF symbol storage class | |
6534 | Set the storage-class value for a symbol. This directive may only be | |
6535 | used inside a @code{.def}/@code{.endef} pair. Storage class may flag | |
6536 | whether a symbol is static or external, or it may record further | |
6537 | symbolic debugging information. | |
6538 | @ifset BOUT | |
6539 | ||
6540 | The @samp{.scl} directive is primarily associated with COFF output; when | |
a4fb0134 | 6541 | configured to generate @code{b.out} output format, @command{@value{AS}} |
252b5132 RH |
6542 | accepts this directive but ignores it. |
6543 | @end ifset | |
6544 | @end ifset | |
6545 | ||
c1253627 | 6546 | @ifset COFF-ELF |
252b5132 | 6547 | @node Section |
c1253627 | 6548 | @section @code{.section @var{name}} |
252b5132 | 6549 | |
252b5132 RH |
6550 | @cindex named section |
6551 | Use the @code{.section} directive to assemble the following code into a section | |
6552 | named @var{name}. | |
6553 | ||
6554 | This directive is only supported for targets that actually support arbitrarily | |
6555 | named sections; on @code{a.out} targets, for example, it is not accepted, even | |
6556 | with a standard @code{a.out} section name. | |
6557 | ||
c1253627 NC |
6558 | @ifset COFF |
6559 | @ifset ELF | |
6560 | @c only print the extra heading if both COFF and ELF are set | |
6561 | @subheading COFF Version | |
6562 | @end ifset | |
6563 | ||
6564 | @cindex @code{section} directive (COFF version) | |
252b5132 RH |
6565 | For COFF targets, the @code{.section} directive is used in one of the following |
6566 | ways: | |
c91d2e08 | 6567 | |
252b5132 RH |
6568 | @smallexample |
6569 | .section @var{name}[, "@var{flags}"] | |
4e188d17 | 6570 | .section @var{name}[, @var{subsection}] |
252b5132 RH |
6571 | @end smallexample |
6572 | ||
6573 | If the optional argument is quoted, it is taken as flags to use for the | |
6574 | section. Each flag is a single character. The following flags are recognized: | |
eda683bb | 6575 | |
252b5132 RH |
6576 | @table @code |
6577 | @item b | |
6578 | bss section (uninitialized data) | |
6579 | @item n | |
6580 | section is not loaded | |
6581 | @item w | |
6582 | writable section | |
6583 | @item d | |
6584 | data section | |
70e0ee1a KT |
6585 | @item e |
6586 | exclude section from linking | |
252b5132 RH |
6587 | @item r |
6588 | read-only section | |
6589 | @item x | |
6590 | executable section | |
2dcc60be ILT |
6591 | @item s |
6592 | shared section (meaningful for PE targets) | |
6ff96af6 NC |
6593 | @item a |
6594 | ignored. (For compatibility with the ELF version) | |
63ad59ae KT |
6595 | @item y |
6596 | section is not readable (meaningful for PE targets) | |
31907d5e DK |
6597 | @item 0-9 |
6598 | single-digit power-of-two section alignment (GNU extension) | |
252b5132 RH |
6599 | @end table |
6600 | ||
6601 | If no flags are specified, the default flags depend upon the section name. If | |
6602 | the section name is not recognized, the default will be for the section to be | |
7e84d676 NC |
6603 | loaded and writable. Note the @code{n} and @code{w} flags remove attributes |
6604 | from the section, rather than adding them, so if they are used on their own it | |
6605 | will be as if no flags had been specified at all. | |
252b5132 RH |
6606 | |
6607 | If the optional argument to the @code{.section} directive is not quoted, it is | |
4e188d17 | 6608 | taken as a subsection number (@pxref{Sub-Sections}). |
c1253627 | 6609 | @end ifset |
252b5132 RH |
6610 | |
6611 | @ifset ELF | |
c1253627 NC |
6612 | @ifset COFF |
6613 | @c only print the extra heading if both COFF and ELF are set | |
6614 | @subheading ELF Version | |
6615 | @end ifset | |
6616 | ||
c91d2e08 NC |
6617 | @cindex Section Stack |
6618 | This is one of the ELF section stack manipulation directives. The others are | |
01642c12 | 6619 | @code{.subsection} (@pxref{SubSection}), @code{.pushsection} |
a349d9dd PB |
6620 | (@pxref{PushSection}), @code{.popsection} (@pxref{PopSection}), and |
6621 | @code{.previous} (@pxref{Previous}). | |
c91d2e08 | 6622 | |
c1253627 | 6623 | @cindex @code{section} directive (ELF version) |
252b5132 | 6624 | For ELF targets, the @code{.section} directive is used like this: |
c91d2e08 | 6625 | |
252b5132 | 6626 | @smallexample |
7047dd1e | 6627 | .section @var{name} [, "@var{flags}"[, @@@var{type}[,@var{flag_specific_arguments}]]] |
252b5132 | 6628 | @end smallexample |
c91d2e08 | 6629 | |
451133ce NP |
6630 | @anchor{Section Name Substitutions} |
6631 | @kindex --sectname-subst | |
6632 | @cindex section name substitution | |
6633 | If the @samp{--sectname-subst} command-line option is provided, the @var{name} | |
6634 | argument may contain a substitution sequence. Only @code{%S} is supported | |
6635 | at the moment, and substitutes the current section name. For example: | |
6636 | ||
6637 | @smallexample | |
6638 | .macro exception_code | |
6639 | .section %S.exception | |
6640 | [exception code here] | |
6641 | .previous | |
6642 | .endm | |
6643 | ||
6644 | .text | |
6645 | [code] | |
6646 | exception_code | |
6647 | [...] | |
6648 | ||
6649 | .section .init | |
6650 | [init code] | |
6651 | exception_code | |
6652 | [...] | |
6653 | @end smallexample | |
6654 | ||
6655 | The two @code{exception_code} invocations above would create the | |
6656 | @code{.text.exception} and @code{.init.exception} sections respectively. | |
33eaf5de NC |
6657 | This is useful e.g. to discriminate between ancillary sections that are |
6658 | tied to setup code to be discarded after use from ancillary sections that | |
451133ce NP |
6659 | need to stay resident without having to define multiple @code{exception_code} |
6660 | macros just for that purpose. | |
6661 | ||
252b5132 | 6662 | The optional @var{flags} argument is a quoted string which may contain any |
a349d9dd | 6663 | combination of the following characters: |
eda683bb | 6664 | |
252b5132 RH |
6665 | @table @code |
6666 | @item a | |
6667 | section is allocatable | |
a91e1603 L |
6668 | @item d |
6669 | section is a GNU_MBIND section | |
18ae9cc1 L |
6670 | @item e |
6671 | section is excluded from executable and shared library. | |
252b5132 RH |
6672 | @item w |
6673 | section is writable | |
6674 | @item x | |
6675 | section is executable | |
ec38dd05 JJ |
6676 | @item M |
6677 | section is mergeable | |
6678 | @item S | |
6679 | section contains zero terminated strings | |
22fe14ad NC |
6680 | @item G |
6681 | section is a member of a section group | |
6682 | @item T | |
6683 | section is used for thread-local-storage | |
01642c12 RM |
6684 | @item ? |
6685 | section is a member of the previously-current section's group, if any | |
eda683bb | 6686 | @item @code{<number>} |
9fb71ee4 NC |
6687 | a numeric value indicating the bits to be set in the ELF section header's flags |
6688 | field. Note - if one or more of the alphabetic characters described above is | |
6689 | also included in the flags field, their bit values will be ORed into the | |
6690 | resulting value. | |
eda683bb NC |
6691 | @item @code{<target specific>} |
6692 | some targets extend this list with their own flag characters | |
252b5132 RH |
6693 | @end table |
6694 | ||
9fb71ee4 NC |
6695 | Note - once a section's flags have been set they cannot be changed. There are |
6696 | a few exceptions to this rule however. Processor and application specific | |
6697 | flags can be added to an already defined section. The @code{.interp}, | |
6698 | @code{.strtab} and @code{.symtab} sections can have the allocate flag | |
6699 | (@code{a}) set after they are initially defined, and the @code{.note-GNU-stack} | |
eda683bb | 6700 | section may have the executable (@code{x}) flag added. |
9fb71ee4 | 6701 | |
252b5132 | 6702 | The optional @var{type} argument may contain one of the following constants: |
eda683bb | 6703 | |
252b5132 RH |
6704 | @table @code |
6705 | @item @@progbits | |
6706 | section contains data | |
6707 | @item @@nobits | |
6708 | section does not contain data (i.e., section only occupies space) | |
22fe14ad NC |
6709 | @item @@note |
6710 | section contains data which is used by things other than the program | |
10b016c2 PB |
6711 | @item @@init_array |
6712 | section contains an array of pointers to init functions | |
6713 | @item @@fini_array | |
6714 | section contains an array of pointers to finish functions | |
6715 | @item @@preinit_array | |
6716 | section contains an array of pointers to pre-init functions | |
eda683bb | 6717 | @item @@@code{<number>} |
9fb71ee4 | 6718 | a numeric value to be set as the ELF section header's type field. |
eda683bb | 6719 | @item @@@code{<target specific>} |
9fb71ee4 | 6720 | some targets extend this list with their own types |
252b5132 RH |
6721 | @end table |
6722 | ||
9fb71ee4 NC |
6723 | Many targets only support the first three section types. The type may be |
6724 | enclosed in double quotes if necessary. | |
10b016c2 | 6725 | |
ececec60 NC |
6726 | Note on targets where the @code{@@} character is the start of a comment (eg |
6727 | ARM) then another character is used instead. For example the ARM port uses the | |
6728 | @code{%} character. | |
6729 | ||
9fb71ee4 NC |
6730 | Note - some sections, eg @code{.text} and @code{.data} are considered to be |
6731 | special and have fixed types. Any attempt to declare them with a different | |
6732 | type will generate an error from the assembler. | |
6733 | ||
22fe14ad | 6734 | If @var{flags} contains the @code{M} symbol then the @var{type} argument must |
96e9638b | 6735 | be specified as well as an extra argument---@var{entsize}---like this: |
22fe14ad NC |
6736 | |
6737 | @smallexample | |
6738 | .section @var{name} , "@var{flags}"M, @@@var{type}, @var{entsize} | |
6739 | @end smallexample | |
6740 | ||
6741 | Sections with the @code{M} flag but not @code{S} flag must contain fixed size | |
6742 | constants, each @var{entsize} octets long. Sections with both @code{M} and | |
6743 | @code{S} must contain zero terminated strings where each character is | |
6744 | @var{entsize} bytes long. The linker may remove duplicates within sections with | |
6745 | the same name, same entity size and same flags. @var{entsize} must be an | |
90dce00a AM |
6746 | absolute expression. For sections with both @code{M} and @code{S}, a string |
6747 | which is a suffix of a larger string is considered a duplicate. Thus | |
6748 | @code{"def"} will be merged with @code{"abcdef"}; A reference to the first | |
6749 | @code{"def"} will be changed to a reference to @code{"abcdef"+3}. | |
22fe14ad NC |
6750 | |
6751 | If @var{flags} contains the @code{G} symbol then the @var{type} argument must | |
6752 | be present along with an additional field like this: | |
6753 | ||
6754 | @smallexample | |
6755 | .section @var{name} , "@var{flags}"G, @@@var{type}, @var{GroupName}[, @var{linkage}] | |
6756 | @end smallexample | |
6757 | ||
6758 | The @var{GroupName} field specifies the name of the section group to which this | |
6759 | particular section belongs. The optional linkage field can contain: | |
eda683bb | 6760 | |
22fe14ad NC |
6761 | @table @code |
6762 | @item comdat | |
6763 | indicates that only one copy of this section should be retained | |
6764 | @item .gnu.linkonce | |
6765 | an alias for comdat | |
6766 | @end table | |
6767 | ||
96e9638b | 6768 | Note: if both the @var{M} and @var{G} flags are present then the fields for |
22fe14ad NC |
6769 | the Merge flag should come first, like this: |
6770 | ||
6771 | @smallexample | |
6772 | .section @var{name} , "@var{flags}"MG, @@@var{type}, @var{entsize}, @var{GroupName}[, @var{linkage}] | |
6773 | @end smallexample | |
ec38dd05 | 6774 | |
01642c12 RM |
6775 | If @var{flags} contains the @code{?} symbol then it may not also contain the |
6776 | @code{G} symbol and the @var{GroupName} or @var{linkage} fields should not be | |
6777 | present. Instead, @code{?} says to consider the section that's current before | |
6778 | this directive. If that section used @code{G}, then the new section will use | |
6779 | @code{G} with those same @var{GroupName} and @var{linkage} fields implicitly. | |
6780 | If not, then the @code{?} symbol has no effect. | |
6781 | ||
252b5132 RH |
6782 | If no flags are specified, the default flags depend upon the section name. If |
6783 | the section name is not recognized, the default will be for the section to have | |
6784 | none of the above flags: it will not be allocated in memory, nor writable, nor | |
6785 | executable. The section will contain data. | |
6786 | ||
6787 | For ELF targets, the assembler supports another type of @code{.section} | |
6788 | directive for compatibility with the Solaris assembler: | |
c91d2e08 | 6789 | |
252b5132 RH |
6790 | @smallexample |
6791 | .section "@var{name}"[, @var{flags}...] | |
6792 | @end smallexample | |
c91d2e08 | 6793 | |
252b5132 RH |
6794 | Note that the section name is quoted. There may be a sequence of comma |
6795 | separated flags: | |
eda683bb | 6796 | |
252b5132 RH |
6797 | @table @code |
6798 | @item #alloc | |
6799 | section is allocatable | |
6800 | @item #write | |
6801 | section is writable | |
6802 | @item #execinstr | |
6803 | section is executable | |
18ae9cc1 L |
6804 | @item #exclude |
6805 | section is excluded from executable and shared library. | |
22fe14ad NC |
6806 | @item #tls |
6807 | section is used for thread local storage | |
252b5132 | 6808 | @end table |
c91d2e08 | 6809 | |
e9863d7f DJ |
6810 | This directive replaces the current section and subsection. See the |
6811 | contents of the gas testsuite directory @code{gas/testsuite/gas/elf} for | |
6812 | some examples of how this directive and the other section stack directives | |
6813 | work. | |
c1253627 NC |
6814 | @end ifset |
6815 | @end ifset | |
252b5132 RH |
6816 | |
6817 | @node Set | |
6818 | @section @code{.set @var{symbol}, @var{expression}} | |
6819 | ||
6820 | @cindex @code{set} directive | |
6821 | @cindex symbol value, setting | |
6822 | Set the value of @var{symbol} to @var{expression}. This | |
6823 | changes @var{symbol}'s value and type to conform to | |
6824 | @var{expression}. If @var{symbol} was flagged as external, it remains | |
6825 | flagged (@pxref{Symbol Attributes}). | |
6826 | ||
5d239759 NC |
6827 | You may @code{.set} a symbol many times in the same assembly provided that the |
6828 | values given to the symbol are constants. Values that are based on expressions | |
6829 | involving other symbols are allowed, but some targets may restrict this to only | |
6830 | being done once per assembly. This is because those targets do not set the | |
6831 | addresses of symbols at assembly time, but rather delay the assignment until a | |
6832 | final link is performed. This allows the linker a chance to change the code in | |
6833 | the files, changing the location of, and the relative distance between, various | |
6834 | different symbols. | |
252b5132 RH |
6835 | |
6836 | If you @code{.set} a global symbol, the value stored in the object | |
6837 | file is the last value stored into it. | |
6838 | ||
3c9b82ba NC |
6839 | @ifset Z80 |
6840 | On Z80 @code{set} is a real instruction, use | |
6841 | @samp{@var{symbol} defl @var{expression}} instead. | |
6842 | @end ifset | |
6843 | ||
252b5132 RH |
6844 | @node Short |
6845 | @section @code{.short @var{expressions}} | |
6846 | ||
6847 | @cindex @code{short} directive | |
6848 | @ifset GENERIC | |
6849 | @code{.short} is normally the same as @samp{.word}. | |
6850 | @xref{Word,,@code{.word}}. | |
6851 | ||
6852 | In some configurations, however, @code{.short} and @code{.word} generate | |
96e9638b | 6853 | numbers of different lengths. @xref{Machine Dependencies}. |
252b5132 RH |
6854 | @end ifset |
6855 | @ifclear GENERIC | |
6856 | @ifset W16 | |
6857 | @code{.short} is the same as @samp{.word}. @xref{Word,,@code{.word}}. | |
6858 | @end ifset | |
6859 | @ifset W32 | |
6860 | This expects zero or more @var{expressions}, and emits | |
6861 | a 16 bit number for each. | |
6862 | @end ifset | |
6863 | @end ifclear | |
6864 | ||
6865 | @node Single | |
6866 | @section @code{.single @var{flonums}} | |
6867 | ||
6868 | @cindex @code{single} directive | |
6869 | @cindex floating point numbers (single) | |
6870 | This directive assembles zero or more flonums, separated by commas. It | |
6871 | has the same effect as @code{.float}. | |
6872 | @ifset GENERIC | |
6873 | The exact kind of floating point numbers emitted depends on how | |
a4fb0134 | 6874 | @command{@value{AS}} is configured. @xref{Machine Dependencies}. |
252b5132 RH |
6875 | @end ifset |
6876 | @ifclear GENERIC | |
6877 | @ifset IEEEFLOAT | |
6878 | On the @value{TARGET} family, @code{.single} emits 32-bit floating point | |
6879 | numbers in @sc{ieee} format. | |
6880 | @end ifset | |
6881 | @end ifclear | |
6882 | ||
c1253627 | 6883 | @ifset COFF-ELF |
252b5132 | 6884 | @node Size |
c1253627 | 6885 | @section @code{.size} |
c91d2e08 | 6886 | |
c1253627 NC |
6887 | This directive is used to set the size associated with a symbol. |
6888 | ||
6889 | @ifset COFF | |
6890 | @ifset ELF | |
6891 | @c only print the extra heading if both COFF and ELF are set | |
6892 | @subheading COFF Version | |
6893 | @end ifset | |
6894 | ||
6895 | @cindex @code{size} directive (COFF version) | |
6896 | For COFF targets, the @code{.size} directive is only permitted inside | |
6897 | @code{.def}/@code{.endef} pairs. It is used like this: | |
6898 | ||
6899 | @smallexample | |
6900 | .size @var{expression} | |
6901 | @end smallexample | |
252b5132 | 6902 | |
c91d2e08 | 6903 | @ifset BOUT |
252b5132 | 6904 | @samp{.size} is only meaningful when generating COFF format output; when |
a4fb0134 | 6905 | @command{@value{AS}} is generating @code{b.out}, it accepts this directive but |
252b5132 RH |
6906 | ignores it. |
6907 | @end ifset | |
c1253627 | 6908 | @end ifset |
c91d2e08 | 6909 | |
c1253627 NC |
6910 | @ifset ELF |
6911 | @ifset COFF | |
6912 | @c only print the extra heading if both COFF and ELF are set | |
6913 | @subheading ELF Version | |
6914 | @end ifset | |
6915 | ||
6916 | @cindex @code{size} directive (ELF version) | |
6917 | For ELF targets, the @code{.size} directive is used like this: | |
c91d2e08 | 6918 | |
c1253627 NC |
6919 | @smallexample |
6920 | .size @var{name} , @var{expression} | |
6921 | @end smallexample | |
6922 | ||
6923 | This directive sets the size associated with a symbol @var{name}. | |
c91d2e08 NC |
6924 | The size in bytes is computed from @var{expression} which can make use of label |
6925 | arithmetic. This directive is typically used to set the size of function | |
6926 | symbols. | |
c1253627 NC |
6927 | @end ifset |
6928 | @end ifset | |
252b5132 | 6929 | |
252b5132 RH |
6930 | @ifclear no-space-dir |
6931 | @node Skip | |
340d33e5 | 6932 | @section @code{.skip @var{size} [,@var{fill}]} |
252b5132 RH |
6933 | |
6934 | @cindex @code{skip} directive | |
6935 | @cindex filling memory | |
6936 | This directive emits @var{size} bytes, each of value @var{fill}. Both | |
6937 | @var{size} and @var{fill} are absolute expressions. If the comma and | |
6938 | @var{fill} are omitted, @var{fill} is assumed to be zero. This is the same as | |
6939 | @samp{.space}. | |
884f0d36 | 6940 | @end ifclear |
252b5132 | 6941 | |
ccf8a69b BW |
6942 | @node Sleb128 |
6943 | @section @code{.sleb128 @var{expressions}} | |
6944 | ||
6945 | @cindex @code{sleb128} directive | |
01642c12 | 6946 | @var{sleb128} stands for ``signed little endian base 128.'' This is a |
ccf8a69b BW |
6947 | compact, variable length representation of numbers used by the DWARF |
6948 | symbolic debugging format. @xref{Uleb128, ,@code{.uleb128}}. | |
6949 | ||
884f0d36 | 6950 | @ifclear no-space-dir |
252b5132 | 6951 | @node Space |
340d33e5 | 6952 | @section @code{.space @var{size} [,@var{fill}]} |
252b5132 RH |
6953 | |
6954 | @cindex @code{space} directive | |
6955 | @cindex filling memory | |
6956 | This directive emits @var{size} bytes, each of value @var{fill}. Both | |
6957 | @var{size} and @var{fill} are absolute expressions. If the comma | |
6958 | and @var{fill} are omitted, @var{fill} is assumed to be zero. This is the same | |
6959 | as @samp{.skip}. | |
6960 | ||
6961 | @ifset HPPA | |
6962 | @quotation | |
6963 | @emph{Warning:} @code{.space} has a completely different meaning for HPPA | |
6964 | targets; use @code{.block} as a substitute. See @cite{HP9000 Series 800 | |
6965 | Assembly Language Reference Manual} (HP 92432-90001) for the meaning of the | |
6966 | @code{.space} directive. @xref{HPPA Directives,,HPPA Assembler Directives}, | |
6967 | for a summary. | |
6968 | @end quotation | |
6969 | @end ifset | |
6970 | @end ifclear | |
6971 | ||
252b5132 RH |
6972 | @ifset have-stabs |
6973 | @node Stab | |
6974 | @section @code{.stabd, .stabn, .stabs} | |
6975 | ||
6976 | @cindex symbolic debuggers, information for | |
6977 | @cindex @code{stab@var{x}} directives | |
6978 | There are three directives that begin @samp{.stab}. | |
6979 | All emit symbols (@pxref{Symbols}), for use by symbolic debuggers. | |
a4fb0134 | 6980 | The symbols are not entered in the @command{@value{AS}} hash table: they |
252b5132 RH |
6981 | cannot be referenced elsewhere in the source file. |
6982 | Up to five fields are required: | |
6983 | ||
6984 | @table @var | |
6985 | @item string | |
6986 | This is the symbol's name. It may contain any character except | |
6987 | @samp{\000}, so is more general than ordinary symbol names. Some | |
6988 | debuggers used to code arbitrarily complex structures into symbol names | |
6989 | using this field. | |
6990 | ||
6991 | @item type | |
6992 | An absolute expression. The symbol's type is set to the low 8 bits of | |
6993 | this expression. Any bit pattern is permitted, but @code{@value{LD}} | |
6994 | and debuggers choke on silly bit patterns. | |
6995 | ||
6996 | @item other | |
6997 | An absolute expression. The symbol's ``other'' attribute is set to the | |
6998 | low 8 bits of this expression. | |
6999 | ||
7000 | @item desc | |
7001 | An absolute expression. The symbol's descriptor is set to the low 16 | |
7002 | bits of this expression. | |
7003 | ||
7004 | @item value | |
7005 | An absolute expression which becomes the symbol's value. | |
7006 | @end table | |
7007 | ||
7008 | If a warning is detected while reading a @code{.stabd}, @code{.stabn}, | |
7009 | or @code{.stabs} statement, the symbol has probably already been created; | |
7010 | you get a half-formed symbol in your object file. This is | |
7011 | compatible with earlier assemblers! | |
7012 | ||
7013 | @table @code | |
7014 | @cindex @code{stabd} directive | |
7015 | @item .stabd @var{type} , @var{other} , @var{desc} | |
7016 | ||
7017 | The ``name'' of the symbol generated is not even an empty string. | |
7018 | It is a null pointer, for compatibility. Older assemblers used a | |
7019 | null pointer so they didn't waste space in object files with empty | |
7020 | strings. | |
7021 | ||
7022 | The symbol's value is set to the location counter, | |
7023 | relocatably. When your program is linked, the value of this symbol | |
7024 | is the address of the location counter when the @code{.stabd} was | |
7025 | assembled. | |
7026 | ||
7027 | @cindex @code{stabn} directive | |
7028 | @item .stabn @var{type} , @var{other} , @var{desc} , @var{value} | |
7029 | The name of the symbol is set to the empty string @code{""}. | |
7030 | ||
7031 | @cindex @code{stabs} directive | |
7032 | @item .stabs @var{string} , @var{type} , @var{other} , @var{desc} , @var{value} | |
7033 | All five fields are specified. | |
7034 | @end table | |
7035 | @end ifset | |
7036 | @c end have-stabs | |
7037 | ||
7038 | @node String | |
38a57ae7 | 7039 | @section @code{.string} "@var{str}", @code{.string8} "@var{str}", @code{.string16} |
01642c12 | 7040 | "@var{str}", @code{.string32} "@var{str}", @code{.string64} "@var{str}" |
252b5132 RH |
7041 | |
7042 | @cindex string, copying to object file | |
38a57ae7 NC |
7043 | @cindex string8, copying to object file |
7044 | @cindex string16, copying to object file | |
7045 | @cindex string32, copying to object file | |
7046 | @cindex string64, copying to object file | |
252b5132 | 7047 | @cindex @code{string} directive |
38a57ae7 NC |
7048 | @cindex @code{string8} directive |
7049 | @cindex @code{string16} directive | |
7050 | @cindex @code{string32} directive | |
7051 | @cindex @code{string64} directive | |
252b5132 RH |
7052 | |
7053 | Copy the characters in @var{str} to the object file. You may specify more than | |
7054 | one string to copy, separated by commas. Unless otherwise specified for a | |
7055 | particular machine, the assembler marks the end of each string with a 0 byte. | |
7056 | You can use any of the escape sequences described in @ref{Strings,,Strings}. | |
7057 | ||
01642c12 | 7058 | The variants @code{string16}, @code{string32} and @code{string64} differ from |
38a57ae7 NC |
7059 | the @code{string} pseudo opcode in that each 8-bit character from @var{str} is |
7060 | copied and expanded to 16, 32 or 64 bits respectively. The expanded characters | |
7061 | are stored in target endianness byte order. | |
7062 | ||
7063 | Example: | |
7064 | @smallexample | |
7065 | .string32 "BYE" | |
7066 | expands to: | |
7067 | .string "B\0\0\0Y\0\0\0E\0\0\0" /* On little endian targets. */ | |
7068 | .string "\0\0\0B\0\0\0Y\0\0\0E" /* On big endian targets. */ | |
7069 | @end smallexample | |
7070 | ||
7071 | ||
252b5132 RH |
7072 | @node Struct |
7073 | @section @code{.struct @var{expression}} | |
7074 | ||
7075 | @cindex @code{struct} directive | |
7076 | Switch to the absolute section, and set the section offset to @var{expression}, | |
7077 | which must be an absolute expression. You might use this as follows: | |
7078 | @smallexample | |
7079 | .struct 0 | |
7080 | field1: | |
7081 | .struct field1 + 4 | |
7082 | field2: | |
7083 | .struct field2 + 4 | |
7084 | field3: | |
7085 | @end smallexample | |
7086 | This would define the symbol @code{field1} to have the value 0, the symbol | |
7087 | @code{field2} to have the value 4, and the symbol @code{field3} to have the | |
7088 | value 8. Assembly would be left in the absolute section, and you would need to | |
7089 | use a @code{.section} directive of some sort to change to some other section | |
7090 | before further assembly. | |
7091 | ||
c91d2e08 NC |
7092 | @ifset ELF |
7093 | @node SubSection | |
7094 | @section @code{.subsection @var{name}} | |
7095 | ||
c1253627 | 7096 | @cindex @code{subsection} directive |
c91d2e08 NC |
7097 | @cindex Section Stack |
7098 | This is one of the ELF section stack manipulation directives. The others are | |
01642c12 RM |
7099 | @code{.section} (@pxref{Section}), @code{.pushsection} (@pxref{PushSection}), |
7100 | @code{.popsection} (@pxref{PopSection}), and @code{.previous} | |
a349d9dd | 7101 | (@pxref{Previous}). |
c91d2e08 NC |
7102 | |
7103 | This directive replaces the current subsection with @code{name}. The current | |
7104 | section is not changed. The replaced subsection is put onto the section stack | |
7105 | in place of the then current top of stack subsection. | |
c91d2e08 NC |
7106 | @end ifset |
7107 | ||
252b5132 RH |
7108 | @ifset ELF |
7109 | @node Symver | |
7110 | @section @code{.symver} | |
7111 | @cindex @code{symver} directive | |
7112 | @cindex symbol versioning | |
7113 | @cindex versions of symbols | |
7114 | Use the @code{.symver} directive to bind symbols to specific version nodes | |
7115 | within a source file. This is only supported on ELF platforms, and is | |
7116 | typically used when assembling files to be linked into a shared library. | |
7117 | There are cases where it may make sense to use this in objects to be bound | |
7118 | into an application itself so as to override a versioned symbol from a | |
7119 | shared library. | |
7120 | ||
79082ff0 | 7121 | For ELF targets, the @code{.symver} directive can be used like this: |
252b5132 RH |
7122 | @smallexample |
7123 | .symver @var{name}, @var{name2@@nodename} | |
7124 | @end smallexample | |
339681c0 | 7125 | If the symbol @var{name} is defined within the file |
79082ff0 | 7126 | being assembled, the @code{.symver} directive effectively creates a symbol |
252b5132 RH |
7127 | alias with the name @var{name2@@nodename}, and in fact the main reason that we |
7128 | just don't try and create a regular alias is that the @var{@@} character isn't | |
7129 | permitted in symbol names. The @var{name2} part of the name is the actual name | |
7130 | of the symbol by which it will be externally referenced. The name @var{name} | |
7131 | itself is merely a name of convenience that is used so that it is possible to | |
7132 | have definitions for multiple versions of a function within a single source | |
7133 | file, and so that the compiler can unambiguously know which version of a | |
7134 | function is being mentioned. The @var{nodename} portion of the alias should be | |
7135 | the name of a node specified in the version script supplied to the linker when | |
7136 | building a shared library. If you are attempting to override a versioned | |
7137 | symbol from a shared library, then @var{nodename} should correspond to the | |
7138 | nodename of the symbol you are trying to override. | |
339681c0 L |
7139 | |
7140 | If the symbol @var{name} is not defined within the file being assembled, all | |
7141 | references to @var{name} will be changed to @var{name2@@nodename}. If no | |
7142 | reference to @var{name} is made, @var{name2@@nodename} will be removed from the | |
7143 | symbol table. | |
79082ff0 L |
7144 | |
7145 | Another usage of the @code{.symver} directive is: | |
7146 | @smallexample | |
7147 | .symver @var{name}, @var{name2@@@@nodename} | |
7148 | @end smallexample | |
7149 | In this case, the symbol @var{name} must exist and be defined within | |
a349d9dd | 7150 | the file being assembled. It is similar to @var{name2@@nodename}. The |
79082ff0 L |
7151 | difference is @var{name2@@@@nodename} will also be used to resolve |
7152 | references to @var{name2} by the linker. | |
7153 | ||
7154 | The third usage of the @code{.symver} directive is: | |
7155 | @smallexample | |
7156 | .symver @var{name}, @var{name2@@@@@@nodename} | |
7157 | @end smallexample | |
7158 | When @var{name} is not defined within the | |
7159 | file being assembled, it is treated as @var{name2@@nodename}. When | |
7160 | @var{name} is defined within the file being assembled, the symbol | |
7161 | name, @var{name}, will be changed to @var{name2@@@@nodename}. | |
252b5132 RH |
7162 | @end ifset |
7163 | ||
7164 | @ifset COFF | |
7165 | @node Tag | |
7166 | @section @code{.tag @var{structname}} | |
7167 | ||
7168 | @cindex COFF structure debugging | |
7169 | @cindex structure debugging, COFF | |
7170 | @cindex @code{tag} directive | |
7171 | This directive is generated by compilers to include auxiliary debugging | |
7172 | information in the symbol table. It is only permitted inside | |
7173 | @code{.def}/@code{.endef} pairs. Tags are used to link structure | |
7174 | definitions in the symbol table with instances of those structures. | |
7175 | @ifset BOUT | |
7176 | ||
7177 | @samp{.tag} is only used when generating COFF format output; when | |
a4fb0134 | 7178 | @command{@value{AS}} is generating @code{b.out}, it accepts this directive but |
252b5132 RH |
7179 | ignores it. |
7180 | @end ifset | |
7181 | @end ifset | |
7182 | ||
7183 | @node Text | |
7184 | @section @code{.text @var{subsection}} | |
7185 | ||
7186 | @cindex @code{text} directive | |
a4fb0134 | 7187 | Tells @command{@value{AS}} to assemble the following statements onto the end of |
252b5132 RH |
7188 | the text subsection numbered @var{subsection}, which is an absolute |
7189 | expression. If @var{subsection} is omitted, subsection number zero | |
7190 | is used. | |
7191 | ||
7192 | @node Title | |
7193 | @section @code{.title "@var{heading}"} | |
7194 | ||
7195 | @cindex @code{title} directive | |
7196 | @cindex listing control: title line | |
7197 | Use @var{heading} as the title (second line, immediately after the | |
7198 | source file name and pagenumber) when generating assembly listings. | |
7199 | ||
7200 | This directive affects subsequent pages, as well as the current page if | |
7201 | it appears within ten lines of the top of a page. | |
7202 | ||
c1253627 | 7203 | @ifset COFF-ELF |
252b5132 | 7204 | @node Type |
c1253627 NC |
7205 | @section @code{.type} |
7206 | ||
7207 | This directive is used to set the type of a symbol. | |
7208 | ||
7209 | @ifset COFF | |
7210 | @ifset ELF | |
7211 | @c only print the extra heading if both COFF and ELF are set | |
7212 | @subheading COFF Version | |
7213 | @end ifset | |
252b5132 RH |
7214 | |
7215 | @cindex COFF symbol type | |
7216 | @cindex symbol type, COFF | |
c1253627 NC |
7217 | @cindex @code{type} directive (COFF version) |
7218 | For COFF targets, this directive is permitted only within | |
7219 | @code{.def}/@code{.endef} pairs. It is used like this: | |
7220 | ||
7221 | @smallexample | |
7222 | .type @var{int} | |
7223 | @end smallexample | |
7224 | ||
7225 | This records the integer @var{int} as the type attribute of a symbol table | |
7226 | entry. | |
252b5132 | 7227 | |
c91d2e08 | 7228 | @ifset BOUT |
252b5132 | 7229 | @samp{.type} is associated only with COFF format output; when |
a4fb0134 | 7230 | @command{@value{AS}} is configured for @code{b.out} output, it accepts this |
252b5132 RH |
7231 | directive but ignores it. |
7232 | @end ifset | |
c1253627 | 7233 | @end ifset |
c91d2e08 | 7234 | |
c1253627 NC |
7235 | @ifset ELF |
7236 | @ifset COFF | |
7237 | @c only print the extra heading if both COFF and ELF are set | |
7238 | @subheading ELF Version | |
7239 | @end ifset | |
c91d2e08 NC |
7240 | |
7241 | @cindex ELF symbol type | |
7242 | @cindex symbol type, ELF | |
c1253627 NC |
7243 | @cindex @code{type} directive (ELF version) |
7244 | For ELF targets, the @code{.type} directive is used like this: | |
7245 | ||
7246 | @smallexample | |
7247 | .type @var{name} , @var{type description} | |
7248 | @end smallexample | |
7249 | ||
7250 | This sets the type of symbol @var{name} to be either a | |
a349d9dd | 7251 | function symbol or an object symbol. There are five different syntaxes |
c91d2e08 | 7252 | supported for the @var{type description} field, in order to provide |
28c9d252 | 7253 | compatibility with various other assemblers. |
58ab4f3d MM |
7254 | |
7255 | Because some of the characters used in these syntaxes (such as @samp{@@} and | |
7256 | @samp{#}) are comment characters for some architectures, some of the syntaxes | |
7257 | below do not work on all architectures. The first variant will be accepted by | |
7258 | the GNU assembler on all architectures so that variant should be used for | |
7259 | maximum portability, if you do not need to assemble your code with other | |
7260 | assemblers. | |
7261 | ||
7262 | The syntaxes supported are: | |
c91d2e08 NC |
7263 | |
7264 | @smallexample | |
5671778d NC |
7265 | .type <name> STT_<TYPE_IN_UPPER_CASE> |
7266 | .type <name>,#<type> | |
7267 | .type <name>,@@<type> | |
e7c33416 | 7268 | .type <name>,%<type> |
5671778d NC |
7269 | .type <name>,"<type>" |
7270 | @end smallexample | |
7271 | ||
7272 | The types supported are: | |
58ab4f3d | 7273 | |
5671778d NC |
7274 | @table @gcctabopt |
7275 | @item STT_FUNC | |
7276 | @itemx function | |
7277 | Mark the symbol as being a function name. | |
c91d2e08 | 7278 | |
d8045f23 NC |
7279 | @item STT_GNU_IFUNC |
7280 | @itemx gnu_indirect_function | |
7281 | Mark the symbol as an indirect function when evaluated during reloc | |
9c55345c | 7282 | processing. (This is only supported on assemblers targeting GNU systems). |
d8045f23 | 7283 | |
5671778d NC |
7284 | @item STT_OBJECT |
7285 | @itemx object | |
7286 | Mark the symbol as being a data object. | |
7287 | ||
7288 | @item STT_TLS | |
7289 | @itemx tls_object | |
33eaf5de | 7290 | Mark the symbol as being a thread-local data object. |
5671778d NC |
7291 | |
7292 | @item STT_COMMON | |
7293 | @itemx common | |
7294 | Mark the symbol as being a common data object. | |
e7c33416 NC |
7295 | |
7296 | @item STT_NOTYPE | |
7297 | @itemx notype | |
7298 | Does not mark the symbol in any way. It is supported just for completeness. | |
7299 | ||
3e7a7d11 NC |
7300 | @item gnu_unique_object |
7301 | Marks the symbol as being a globally unique data object. The dynamic linker | |
7302 | will make sure that in the entire process there is just one symbol with this | |
9c55345c TS |
7303 | name and type in use. (This is only supported on assemblers targeting GNU |
7304 | systems). | |
3e7a7d11 | 7305 | |
5671778d NC |
7306 | @end table |
7307 | ||
7308 | Note: Some targets support extra types in addition to those listed above. | |
c91d2e08 | 7309 | |
c1253627 NC |
7310 | @end ifset |
7311 | @end ifset | |
c91d2e08 NC |
7312 | |
7313 | @node Uleb128 | |
7314 | @section @code{.uleb128 @var{expressions}} | |
7315 | ||
7316 | @cindex @code{uleb128} directive | |
01642c12 | 7317 | @var{uleb128} stands for ``unsigned little endian base 128.'' This is a |
c91d2e08 | 7318 | compact, variable length representation of numbers used by the DWARF |
96e9638b | 7319 | symbolic debugging format. @xref{Sleb128, ,@code{.sleb128}}. |
252b5132 RH |
7320 | |
7321 | @ifset COFF | |
7322 | @node Val | |
7323 | @section @code{.val @var{addr}} | |
7324 | ||
7325 | @cindex @code{val} directive | |
7326 | @cindex COFF value attribute | |
7327 | @cindex value attribute, COFF | |
7328 | This directive, permitted only within @code{.def}/@code{.endef} pairs, | |
7329 | records the address @var{addr} as the value attribute of a symbol table | |
7330 | entry. | |
7331 | @ifset BOUT | |
7332 | ||
a4fb0134 | 7333 | @samp{.val} is used only for COFF output; when @command{@value{AS}} is |
252b5132 RH |
7334 | configured for @code{b.out}, it accepts this directive but ignores it. |
7335 | @end ifset | |
7336 | @end ifset | |
7337 | ||
2e13b764 | 7338 | @ifset ELF |
c91d2e08 NC |
7339 | @node Version |
7340 | @section @code{.version "@var{string}"} | |
2e13b764 | 7341 | |
c1253627 | 7342 | @cindex @code{version} directive |
c91d2e08 NC |
7343 | This directive creates a @code{.note} section and places into it an ELF |
7344 | formatted note of type NT_VERSION. The note's name is set to @code{string}. | |
9a297610 | 7345 | @end ifset |
2e13b764 | 7346 | |
c91d2e08 NC |
7347 | @ifset ELF |
7348 | @node VTableEntry | |
7349 | @section @code{.vtable_entry @var{table}, @var{offset}} | |
2e13b764 | 7350 | |
653cfe85 | 7351 | @cindex @code{vtable_entry} directive |
c91d2e08 NC |
7352 | This directive finds or creates a symbol @code{table} and creates a |
7353 | @code{VTABLE_ENTRY} relocation for it with an addend of @code{offset}. | |
2e13b764 | 7354 | |
c91d2e08 NC |
7355 | @node VTableInherit |
7356 | @section @code{.vtable_inherit @var{child}, @var{parent}} | |
2e13b764 | 7357 | |
653cfe85 | 7358 | @cindex @code{vtable_inherit} directive |
c91d2e08 NC |
7359 | This directive finds the symbol @code{child} and finds or creates the symbol |
7360 | @code{parent} and then creates a @code{VTABLE_INHERIT} relocation for the | |
a349d9dd | 7361 | parent whose addend is the value of the child symbol. As a special case the |
96e9638b | 7362 | parent name of @code{0} is treated as referring to the @code{*ABS*} section. |
c91d2e08 | 7363 | @end ifset |
2e13b764 | 7364 | |
d190d046 HPN |
7365 | @node Warning |
7366 | @section @code{.warning "@var{string}"} | |
7367 | @cindex warning directive | |
7368 | Similar to the directive @code{.error} | |
7369 | (@pxref{Error,,@code{.error "@var{string}"}}), but just emits a warning. | |
7370 | ||
c91d2e08 NC |
7371 | @node Weak |
7372 | @section @code{.weak @var{names}} | |
2e13b764 | 7373 | |
c1253627 | 7374 | @cindex @code{weak} directive |
a349d9dd | 7375 | This directive sets the weak attribute on the comma separated list of symbol |
c91d2e08 | 7376 | @code{names}. If the symbols do not already exist, they will be created. |
c87db184 | 7377 | |
01642c12 | 7378 | On COFF targets other than PE, weak symbols are a GNU extension. This |
977cdf5a | 7379 | directive sets the weak attribute on the comma separated list of symbol |
c87db184 CF |
7380 | @code{names}. If the symbols do not already exist, they will be created. |
7381 | ||
977cdf5a | 7382 | On the PE target, weak symbols are supported natively as weak aliases. |
01642c12 | 7383 | When a weak symbol is created that is not an alias, GAS creates an |
977cdf5a | 7384 | alternate symbol to hold the default value. |
2e13b764 | 7385 | |
06e77878 AO |
7386 | @node Weakref |
7387 | @section @code{.weakref @var{alias}, @var{target}} | |
7388 | ||
7389 | @cindex @code{weakref} directive | |
7390 | This directive creates an alias to the target symbol that enables the symbol to | |
7391 | be referenced with weak-symbol semantics, but without actually making it weak. | |
7392 | If direct references or definitions of the symbol are present, then the symbol | |
7393 | will not be weak, but if all references to it are through weak references, the | |
7394 | symbol will be marked as weak in the symbol table. | |
7395 | ||
7396 | The effect is equivalent to moving all references to the alias to a separate | |
7397 | assembly source file, renaming the alias to the symbol in it, declaring the | |
7398 | symbol as weak there, and running a reloadable link to merge the object files | |
7399 | resulting from the assembly of the new source file and the old source file that | |
7400 | had the references to the alias removed. | |
7401 | ||
7402 | The alias itself never makes to the symbol table, and is entirely handled | |
7403 | within the assembler. | |
7404 | ||
252b5132 RH |
7405 | @node Word |
7406 | @section @code{.word @var{expressions}} | |
7407 | ||
7408 | @cindex @code{word} directive | |
7409 | This directive expects zero or more @var{expressions}, of any section, | |
7410 | separated by commas. | |
7411 | @ifclear GENERIC | |
7412 | @ifset W32 | |
a4fb0134 | 7413 | For each expression, @command{@value{AS}} emits a 32-bit number. |
252b5132 RH |
7414 | @end ifset |
7415 | @ifset W16 | |
a4fb0134 | 7416 | For each expression, @command{@value{AS}} emits a 16-bit number. |
252b5132 RH |
7417 | @end ifset |
7418 | @end ifclear | |
7419 | @ifset GENERIC | |
7420 | ||
7421 | The size of the number emitted, and its byte order, | |
7422 | depend on what target computer the assembly is for. | |
7423 | @end ifset | |
7424 | ||
7425 | @c on amd29k, i960, sparc the "special treatment to support compilers" doesn't | |
7426 | @c happen---32-bit addressability, period; no long/short jumps. | |
7427 | @ifset DIFF-TBL-KLUGE | |
7428 | @cindex difference tables altered | |
7429 | @cindex altered difference tables | |
7430 | @quotation | |
7431 | @emph{Warning: Special Treatment to support Compilers} | |
7432 | @end quotation | |
7433 | ||
7434 | @ifset GENERIC | |
7435 | Machines with a 32-bit address space, but that do less than 32-bit | |
7436 | addressing, require the following special treatment. If the machine of | |
7437 | interest to you does 32-bit addressing (or doesn't require it; | |
7438 | @pxref{Machine Dependencies}), you can ignore this issue. | |
7439 | ||
7440 | @end ifset | |
7441 | In order to assemble compiler output into something that works, | |
a4fb0134 | 7442 | @command{@value{AS}} occasionally does strange things to @samp{.word} directives. |
252b5132 | 7443 | Directives of the form @samp{.word sym1-sym2} are often emitted by |
a4fb0134 | 7444 | compilers as part of jump tables. Therefore, when @command{@value{AS}} assembles a |
252b5132 | 7445 | directive of the form @samp{.word sym1-sym2}, and the difference between |
a4fb0134 | 7446 | @code{sym1} and @code{sym2} does not fit in 16 bits, @command{@value{AS}} |
252b5132 RH |
7447 | creates a @dfn{secondary jump table}, immediately before the next label. |
7448 | This secondary jump table is preceded by a short-jump to the | |
7449 | first byte after the secondary table. This short-jump prevents the flow | |
7450 | of control from accidentally falling into the new table. Inside the | |
7451 | table is a long-jump to @code{sym2}. The original @samp{.word} | |
7452 | contains @code{sym1} minus the address of the long-jump to | |
7453 | @code{sym2}. | |
7454 | ||
7455 | If there were several occurrences of @samp{.word sym1-sym2} before the | |
7456 | secondary jump table, all of them are adjusted. If there was a | |
7457 | @samp{.word sym3-sym4}, that also did not fit in sixteen bits, a | |
7458 | long-jump to @code{sym4} is included in the secondary jump table, | |
7459 | and the @code{.word} directives are adjusted to contain @code{sym3} | |
7460 | minus the address of the long-jump to @code{sym4}; and so on, for as many | |
7461 | entries in the original jump table as necessary. | |
7462 | ||
7463 | @ifset INTERNALS | |
a4fb0134 | 7464 | @emph{This feature may be disabled by compiling @command{@value{AS}} with the |
252b5132 RH |
7465 | @samp{-DWORKING_DOT_WORD} option.} This feature is likely to confuse |
7466 | assembly language programmers. | |
7467 | @end ifset | |
7468 | @end ifset | |
7469 | @c end DIFF-TBL-KLUGE | |
7470 | ||
7ce98c16 NC |
7471 | @ifclear no-space-dir |
7472 | @node Zero | |
7473 | @section @code{.zero @var{size}} | |
7474 | ||
7475 | @cindex @code{zero} directive | |
7476 | @cindex filling memory with zero bytes | |
7477 | This directive emits @var{size} 0-valued bytes. @var{size} must be an absolute | |
7478 | expression. This directive is actually an alias for the @samp{.skip} directive | |
7479 | so in can take an optional second argument of the value to store in the bytes | |
7480 | instead of zero. Using @samp{.zero} in this way would be confusing however. | |
7481 | @end ifclear | |
7482 | ||
2b841ec2 AM |
7483 | @ifset ELF |
7484 | @node 2byte | |
ea86f534 | 7485 | @section @code{.2byte @var{expression} [, @var{expression}]*} |
2b841ec2 AM |
7486 | @cindex @code{2byte} directive |
7487 | @cindex two-byte integer | |
7488 | @cindex integer, 2-byte | |
2b841ec2 | 7489 | |
e406e428 NC |
7490 | This directive expects zero or more expressions, separated by commas. If there |
7491 | are no expressions then the directive does nothing. Otherwise each expression | |
7492 | is evaluated in turn and placed in the next two bytes of the current output | |
7493 | section, using the endian model of the target. If an expression will not fit | |
7494 | in two bytes, a warning message is displayed and the least significant two | |
7495 | bytes of the expression's value are used. If an expression cannot be evaluated | |
7496 | at assembly time then relocations will be generated in order to compute the | |
7497 | value at link time. | |
7498 | ||
7499 | This directive does not apply any alignment before or after inserting the | |
7500 | values. As a result of this, if relocations are generated, they may be | |
7501 | different from those used for inserting values with a guaranteed alignment. | |
7502 | ||
8b1e5da1 | 7503 | This directive is only available for ELF targets, |
2b841ec2 AM |
7504 | |
7505 | @node 4byte | |
ea86f534 | 7506 | @section @code{.4byte @var{expression} [, @var{expression}]*} |
2b841ec2 AM |
7507 | @cindex @code{4byte} directive |
7508 | @cindex four-byte integer | |
7509 | @cindex integer, 4-byte | |
2b841ec2 | 7510 | |
e406e428 NC |
7511 | Like the @option{.2byte} directive, except that it inserts unaligned, four byte |
7512 | long values into the output. | |
2b841ec2 AM |
7513 | |
7514 | @node 8byte | |
ea86f534 | 7515 | @section @code{.8byte @var{expression} [, @var{expression}]*} |
2b841ec2 AM |
7516 | @cindex @code{8byte} directive |
7517 | @cindex eight-byte integer | |
7518 | @cindex integer, 8-byte | |
2b841ec2 | 7519 | |
e21126b7 | 7520 | Like the @option{.2byte} directive, except that it inserts unaligned, eight |
e406e428 NC |
7521 | byte long bignum values into the output. |
7522 | ||
2b841ec2 AM |
7523 | @end ifset |
7524 | ||
252b5132 RH |
7525 | @node Deprecated |
7526 | @section Deprecated Directives | |
7527 | ||
7528 | @cindex deprecated directives | |
7529 | @cindex obsolescent directives | |
7530 | One day these directives won't work. | |
7531 | They are included for compatibility with older assemblers. | |
7532 | @table @t | |
7533 | @item .abort | |
7534 | @item .line | |
7535 | @end table | |
7536 | ||
3a99f02f DJ |
7537 | @ifset ELF |
7538 | @node Object Attributes | |
7539 | @chapter Object Attributes | |
7540 | @cindex object attributes | |
7541 | ||
7542 | @command{@value{AS}} assembles source files written for a specific architecture | |
7543 | into object files for that architecture. But not all object files are alike. | |
7544 | Many architectures support incompatible variations. For instance, floating | |
7545 | point arguments might be passed in floating point registers if the object file | |
7546 | requires hardware floating point support---or floating point arguments might be | |
7547 | passed in integer registers if the object file supports processors with no | |
7548 | hardware floating point unit. Or, if two objects are built for different | |
7549 | generations of the same architecture, the combination may require the | |
7550 | newer generation at run-time. | |
7551 | ||
7552 | This information is useful during and after linking. At link time, | |
7553 | @command{@value{LD}} can warn about incompatible object files. After link | |
7554 | time, tools like @command{gdb} can use it to process the linked file | |
7555 | correctly. | |
7556 | ||
7557 | Compatibility information is recorded as a series of object attributes. Each | |
7558 | attribute has a @dfn{vendor}, @dfn{tag}, and @dfn{value}. The vendor is a | |
7559 | string, and indicates who sets the meaning of the tag. The tag is an integer, | |
7560 | and indicates what property the attribute describes. The value may be a string | |
7561 | or an integer, and indicates how the property affects this object. Missing | |
7562 | attributes are the same as attributes with a zero value or empty string value. | |
7563 | ||
7564 | Object attributes were developed as part of the ABI for the ARM Architecture. | |
7565 | The file format is documented in @cite{ELF for the ARM Architecture}. | |
7566 | ||
7567 | @menu | |
7568 | * GNU Object Attributes:: @sc{gnu} Object Attributes | |
7569 | * Defining New Object Attributes:: Defining New Object Attributes | |
7570 | @end menu | |
7571 | ||
7572 | @node GNU Object Attributes | |
7573 | @section @sc{gnu} Object Attributes | |
7574 | ||
7575 | The @code{.gnu_attribute} directive records an object attribute | |
7576 | with vendor @samp{gnu}. | |
7577 | ||
7578 | Except for @samp{Tag_compatibility}, which has both an integer and a string for | |
7579 | its value, @sc{gnu} attributes have a string value if the tag number is odd and | |
7580 | an integer value if the tag number is even. The second bit (@code{@var{tag} & | |
7581 | 2} is set for architecture-independent attributes and clear for | |
7582 | architecture-dependent ones. | |
7583 | ||
7584 | @subsection Common @sc{gnu} attributes | |
7585 | ||
7586 | These attributes are valid on all architectures. | |
7587 | ||
7588 | @table @r | |
7589 | @item Tag_compatibility (32) | |
7590 | The compatibility attribute takes an integer flag value and a vendor name. If | |
7591 | the flag value is 0, the file is compatible with other toolchains. If it is 1, | |
7592 | then the file is only compatible with the named toolchain. If it is greater | |
7593 | than 1, the file can only be processed by other toolchains under some private | |
7594 | arrangement indicated by the flag value and the vendor name. | |
7595 | @end table | |
7596 | ||
7597 | @subsection MIPS Attributes | |
7598 | ||
7599 | @table @r | |
7600 | @item Tag_GNU_MIPS_ABI_FP (4) | |
7601 | The floating-point ABI used by this object file. The value will be: | |
7602 | ||
7603 | @itemize @bullet | |
7604 | @item | |
7605 | 0 for files not affected by the floating-point ABI. | |
7606 | @item | |
f179c512 MF |
7607 | 1 for files using the hardware floating-point ABI with a standard |
7608 | double-precision FPU. | |
3a99f02f DJ |
7609 | @item |
7610 | 2 for files using the hardware floating-point ABI with a single-precision FPU. | |
7611 | @item | |
7612 | 3 for files using the software floating-point ABI. | |
42554f6a | 7613 | @item |
f179c512 MF |
7614 | 4 for files using the deprecated hardware floating-point ABI which used 64-bit |
7615 | floating-point registers, 32-bit general-purpose registers and increased the | |
7616 | number of callee-saved floating-point registers. | |
7617 | @item | |
7618 | 5 for files using the hardware floating-point ABI with a double-precision FPU | |
7619 | with either 32-bit or 64-bit floating-point registers and 32-bit | |
7620 | general-purpose registers. | |
7621 | @item | |
7622 | 6 for files using the hardware floating-point ABI with 64-bit floating-point | |
7623 | registers and 32-bit general-purpose registers. | |
7624 | @item | |
7625 | 7 for files using the hardware floating-point ABI with 64-bit floating-point | |
7626 | registers, 32-bit general-purpose registers and a rule that forbids the | |
7627 | direct use of odd-numbered single-precision floating-point registers. | |
3a99f02f DJ |
7628 | @end itemize |
7629 | @end table | |
7630 | ||
7631 | @subsection PowerPC Attributes | |
7632 | ||
7633 | @table @r | |
7634 | @item Tag_GNU_Power_ABI_FP (4) | |
7635 | The floating-point ABI used by this object file. The value will be: | |
7636 | ||
7637 | @itemize @bullet | |
7638 | @item | |
7639 | 0 for files not affected by the floating-point ABI. | |
7640 | @item | |
3c7b9897 | 7641 | 1 for files using double-precision hardware floating-point ABI. |
3a99f02f DJ |
7642 | @item |
7643 | 2 for files using the software floating-point ABI. | |
3c7b9897 AM |
7644 | @item |
7645 | 3 for files using single-precision hardware floating-point ABI. | |
3a99f02f DJ |
7646 | @end itemize |
7647 | ||
7648 | @item Tag_GNU_Power_ABI_Vector (8) | |
7649 | The vector ABI used by this object file. The value will be: | |
7650 | ||
7651 | @itemize @bullet | |
7652 | @item | |
7653 | 0 for files not affected by the vector ABI. | |
7654 | @item | |
7655 | 1 for files using general purpose registers to pass vectors. | |
7656 | @item | |
7657 | 2 for files using AltiVec registers to pass vectors. | |
7658 | @item | |
7659 | 3 for files using SPE registers to pass vectors. | |
7660 | @end itemize | |
7661 | @end table | |
7662 | ||
643f7afb AK |
7663 | @subsection IBM z Systems Attributes |
7664 | ||
7665 | @table @r | |
7666 | @item Tag_GNU_S390_ABI_Vector (8) | |
7667 | The vector ABI used by this object file. The value will be: | |
7668 | ||
7669 | @itemize @bullet | |
7670 | @item | |
7671 | 0 for files not affected by the vector ABI. | |
7672 | @item | |
7673 | 1 for files using software vector ABI. | |
7674 | @item | |
7675 | 2 for files using hardware vector ABI. | |
7676 | @end itemize | |
7677 | @end table | |
7678 | ||
3a99f02f DJ |
7679 | @node Defining New Object Attributes |
7680 | @section Defining New Object Attributes | |
7681 | ||
7682 | If you want to define a new @sc{gnu} object attribute, here are the places you | |
7683 | will need to modify. New attributes should be discussed on the @samp{binutils} | |
7684 | mailing list. | |
7685 | ||
7686 | @itemize @bullet | |
7687 | @item | |
7688 | This manual, which is the official register of attributes. | |
7689 | @item | |
7690 | The header for your architecture @file{include/elf}, to define the tag. | |
7691 | @item | |
7692 | The @file{bfd} support file for your architecture, to merge the attribute | |
7693 | and issue any appropriate link warnings. | |
7694 | @item | |
7695 | Test cases in @file{ld/testsuite} for merging and link warnings. | |
7696 | @item | |
7697 | @file{binutils/readelf.c} to display your attribute. | |
7698 | @item | |
7699 | GCC, if you want the compiler to mark the attribute automatically. | |
7700 | @end itemize | |
7701 | ||
7702 | @end ifset | |
7703 | ||
252b5132 RH |
7704 | @ifset GENERIC |
7705 | @node Machine Dependencies | |
7706 | @chapter Machine Dependent Features | |
7707 | ||
7708 | @cindex machine dependencies | |
7709 | The machine instruction sets are (almost by definition) different on | |
a4fb0134 SC |
7710 | each machine where @command{@value{AS}} runs. Floating point representations |
7711 | vary as well, and @command{@value{AS}} often supports a few additional | |
252b5132 RH |
7712 | directives or command-line options for compatibility with other |
7713 | assemblers on a particular platform. Finally, some versions of | |
a4fb0134 | 7714 | @command{@value{AS}} support special pseudo-instructions for branch |
252b5132 RH |
7715 | optimization. |
7716 | ||
7717 | This chapter discusses most of these differences, though it does not | |
7718 | include details on any machine's instruction set. For details on that | |
7719 | subject, see the hardware manufacturer's manual. | |
7720 | ||
7721 | @menu | |
a06ea964 NC |
7722 | @ifset AARCH64 |
7723 | * AArch64-Dependent:: AArch64 Dependent Features | |
7724 | @end ifset | |
625e1353 RH |
7725 | @ifset ALPHA |
7726 | * Alpha-Dependent:: Alpha Dependent Features | |
7727 | @end ifset | |
252b5132 RH |
7728 | @ifset ARC |
7729 | * ARC-Dependent:: ARC Dependent Features | |
7730 | @end ifset | |
7731 | @ifset ARM | |
7732 | * ARM-Dependent:: ARM Dependent Features | |
7733 | @end ifset | |
8473f7a4 DC |
7734 | @ifset AVR |
7735 | * AVR-Dependent:: AVR Dependent Features | |
7736 | @end ifset | |
3b4e1885 JZ |
7737 | @ifset Blackfin |
7738 | * Blackfin-Dependent:: Blackfin Dependent Features | |
07c1b327 | 7739 | @end ifset |
3d3d428f NC |
7740 | @ifset CR16 |
7741 | * CR16-Dependent:: CR16 Dependent Features | |
7742 | @end ifset | |
8bf549a8 | 7743 | @ifset CRIS |
328eb32e HPN |
7744 | * CRIS-Dependent:: CRIS Dependent Features |
7745 | @end ifset | |
252b5132 RH |
7746 | @ifset D10V |
7747 | * D10V-Dependent:: D10V Dependent Features | |
7748 | @end ifset | |
7749 | @ifset D30V | |
7750 | * D30V-Dependent:: D30V Dependent Features | |
7751 | @end ifset | |
cfb8c092 NC |
7752 | @ifset EPIPHANY |
7753 | * Epiphany-Dependent:: EPIPHANY Dependent Features | |
7754 | @end ifset | |
252b5132 | 7755 | @ifset H8/300 |
c2dcd04e | 7756 | * H8/300-Dependent:: Renesas H8/300 Dependent Features |
252b5132 | 7757 | @end ifset |
252b5132 RH |
7758 | @ifset HPPA |
7759 | * HPPA-Dependent:: HPPA Dependent Features | |
7760 | @end ifset | |
5b93d8bb AM |
7761 | @ifset I370 |
7762 | * ESA/390-Dependent:: IBM ESA/390 Dependent Features | |
7763 | @end ifset | |
252b5132 | 7764 | @ifset I80386 |
55b62671 | 7765 | * i386-Dependent:: Intel 80386 and AMD x86-64 Dependent Features |
252b5132 | 7766 | @end ifset |
e3308d0d JE |
7767 | @ifset I860 |
7768 | * i860-Dependent:: Intel 80860 Dependent Features | |
7769 | @end ifset | |
252b5132 RH |
7770 | @ifset I960 |
7771 | * i960-Dependent:: Intel 80960 Dependent Features | |
7772 | @end ifset | |
5cb53c21 L |
7773 | @ifset IA64 |
7774 | * IA-64-Dependent:: Intel IA-64 Dependent Features | |
7775 | @end ifset | |
a40cbfa3 NC |
7776 | @ifset IP2K |
7777 | * IP2K-Dependent:: IP2K Dependent Features | |
7778 | @end ifset | |
84e94c90 NC |
7779 | @ifset LM32 |
7780 | * LM32-Dependent:: LM32 Dependent Features | |
7781 | @end ifset | |
49f58d10 JB |
7782 | @ifset M32C |
7783 | * M32C-Dependent:: M32C Dependent Features | |
7784 | @end ifset | |
ec694b89 NC |
7785 | @ifset M32R |
7786 | * M32R-Dependent:: M32R Dependent Features | |
7787 | @end ifset | |
252b5132 RH |
7788 | @ifset M680X0 |
7789 | * M68K-Dependent:: M680x0 Dependent Features | |
7790 | @end ifset | |
60bcf0fa NC |
7791 | @ifset M68HC11 |
7792 | * M68HC11-Dependent:: M68HC11 and 68HC12 Dependent Features | |
7793 | @end ifset | |
a3c62988 NC |
7794 | @ifset METAG |
7795 | * Meta-Dependent :: Meta Dependent Features | |
7796 | @end ifset | |
7ba29e2a NC |
7797 | @ifset MICROBLAZE |
7798 | * MicroBlaze-Dependent:: MICROBLAZE Dependent Features | |
7799 | @end ifset | |
252b5132 RH |
7800 | @ifset MIPS |
7801 | * MIPS-Dependent:: MIPS Dependent Features | |
7802 | @end ifset | |
3c3bdf30 NC |
7803 | @ifset MMIX |
7804 | * MMIX-Dependent:: MMIX Dependent Features | |
7805 | @end ifset | |
2469cfa2 NC |
7806 | @ifset MSP430 |
7807 | * MSP430-Dependent:: MSP430 Dependent Features | |
7808 | @end ifset | |
35c08157 KLC |
7809 | @ifset NDS32 |
7810 | * NDS32-Dependent:: Andes NDS32 Dependent Features | |
7811 | @end ifset | |
36591ba1 SL |
7812 | @ifset NIOSII |
7813 | * NiosII-Dependent:: Altera Nios II Dependent Features | |
7814 | @end ifset | |
7c31ae13 NC |
7815 | @ifset NS32K |
7816 | * NS32K-Dependent:: NS32K Dependent Features | |
7817 | @end ifset | |
e135f41b NC |
7818 | @ifset PDP11 |
7819 | * PDP-11-Dependent:: PDP-11 Dependent Features | |
7820 | @end ifset | |
041dd5a9 ILT |
7821 | @ifset PJ |
7822 | * PJ-Dependent:: picoJava Dependent Features | |
7823 | @end ifset | |
418c1742 MG |
7824 | @ifset PPC |
7825 | * PPC-Dependent:: PowerPC Dependent Features | |
7826 | @end ifset | |
93f11b16 DD |
7827 | @ifset PRU |
7828 | * PRU-Dependent:: PRU Dependent Features | |
7829 | @end ifset | |
4f7eddc4 PD |
7830 | @ifset RISCV |
7831 | * RISC-V-Dependent:: RISC-V Dependent Features | |
7832 | @end ifset | |
b57e49f7 JW |
7833 | @ifset RL78 |
7834 | * RL78-Dependent:: RL78 Dependent Features | |
7835 | @end ifset | |
046d31c2 NC |
7836 | @ifset RX |
7837 | * RX-Dependent:: RX Dependent Features | |
7838 | @end ifset | |
11c19e16 MS |
7839 | @ifset S390 |
7840 | * S/390-Dependent:: IBM S/390 Dependent Features | |
7841 | @end ifset | |
c0157db4 NC |
7842 | @ifset SCORE |
7843 | * SCORE-Dependent:: SCORE Dependent Features | |
7844 | @end ifset | |
d3b47e2b L |
7845 | @ifset SH |
7846 | * SH-Dependent:: Renesas / SuperH SH Dependent Features | |
7847 | * SH64-Dependent:: SuperH SH64 Dependent Features | |
7848 | @end ifset | |
252b5132 RH |
7849 | @ifset SPARC |
7850 | * Sparc-Dependent:: SPARC Dependent Features | |
7851 | @end ifset | |
39bec121 TW |
7852 | @ifset TIC54X |
7853 | * TIC54X-Dependent:: TI TMS320C54x Dependent Features | |
7854 | @end ifset | |
40b36596 JM |
7855 | @ifset TIC6X |
7856 | * TIC6X-Dependent :: TI TMS320C6x Dependent Features | |
7857 | @end ifset | |
aa137e4d NC |
7858 | @ifset TILEGX |
7859 | * TILE-Gx-Dependent :: Tilera TILE-Gx Dependent Features | |
7860 | @end ifset | |
7861 | @ifset TILEPRO | |
7862 | * TILEPro-Dependent :: Tilera TILEPro Dependent Features | |
7863 | @end ifset | |
252b5132 RH |
7864 | @ifset V850 |
7865 | * V850-Dependent:: V850 Dependent Features | |
7866 | @end ifset | |
b6605ddd EB |
7867 | @ifset VAX |
7868 | * Vax-Dependent:: VAX Dependent Features | |
7869 | @end ifset | |
7870 | @ifset VISIUM | |
7871 | * Visium-Dependent:: Visium Dependent Features | |
7872 | @end ifset | |
f96bd6c2 PC |
7873 | @ifset WASM32 |
7874 | * WebAssembly-Dependent:: WebAssembly Dependent Features | |
7875 | @end ifset | |
f6c1a2d5 | 7876 | @ifset XGATE |
f96bd6c2 | 7877 | * XGATE-Dependent:: XGATE Dependent Features |
f6c1a2d5 | 7878 | @end ifset |
6753e72f NC |
7879 | @ifset XSTORMY16 |
7880 | * XSTORMY16-Dependent:: XStormy16 Dependent Features | |
7881 | @end ifset | |
e0001a05 NC |
7882 | @ifset XTENSA |
7883 | * Xtensa-Dependent:: Xtensa Dependent Features | |
7884 | @end ifset | |
3c9b82ba NC |
7885 | @ifset Z80 |
7886 | * Z80-Dependent:: Z80 Dependent Features | |
7887 | @end ifset | |
252b5132 RH |
7888 | @ifset Z8000 |
7889 | * Z8000-Dependent:: Z8000 Dependent Features | |
7890 | @end ifset | |
252b5132 RH |
7891 | @end menu |
7892 | ||
7893 | @lowersections | |
7894 | @end ifset | |
7895 | ||
7896 | @c The following major nodes are *sections* in the GENERIC version, *chapters* | |
7897 | @c in single-cpu versions. This is mainly achieved by @lowersections. There is a | |
7898 | @c peculiarity: to preserve cross-references, there must be a node called | |
7899 | @c "Machine Dependencies". Hence the conditional nodenames in each | |
7900 | @c major node below. Node defaulting in makeinfo requires adjacency of | |
7901 | @c node and sectioning commands; hence the repetition of @chapter BLAH | |
7902 | @c in both conditional blocks. | |
7903 | ||
a06ea964 NC |
7904 | @ifset AARCH64 |
7905 | @include c-aarch64.texi | |
7906 | @end ifset | |
7907 | ||
625e1353 RH |
7908 | @ifset ALPHA |
7909 | @include c-alpha.texi | |
7910 | @end ifset | |
7911 | ||
7912 | @ifset ARC | |
7913 | @include c-arc.texi | |
7914 | @end ifset | |
7915 | ||
252b5132 RH |
7916 | @ifset ARM |
7917 | @include c-arm.texi | |
7918 | @end ifset | |
7919 | ||
8473f7a4 DC |
7920 | @ifset AVR |
7921 | @include c-avr.texi | |
7922 | @end ifset | |
7923 | ||
3b4e1885 | 7924 | @ifset Blackfin |
07c1b327 CM |
7925 | @include c-bfin.texi |
7926 | @end ifset | |
7927 | ||
3d3d428f NC |
7928 | @ifset CR16 |
7929 | @include c-cr16.texi | |
7930 | @end ifset | |
7931 | ||
328eb32e HPN |
7932 | @ifset CRIS |
7933 | @include c-cris.texi | |
7934 | @end ifset | |
7935 | ||
c2dcd04e | 7936 | @ifset Renesas-all |
252b5132 RH |
7937 | @ifclear GENERIC |
7938 | @node Machine Dependencies | |
7939 | @chapter Machine Dependent Features | |
7940 | ||
c2dcd04e | 7941 | The machine instruction sets are different on each Renesas chip family, |
252b5132 | 7942 | and there are also some syntax differences among the families. This |
a4fb0134 | 7943 | chapter describes the specific @command{@value{AS}} features for each |
252b5132 RH |
7944 | family. |
7945 | ||
7946 | @menu | |
c2dcd04e | 7947 | * H8/300-Dependent:: Renesas H8/300 Dependent Features |
c2dcd04e | 7948 | * SH-Dependent:: Renesas SH Dependent Features |
252b5132 RH |
7949 | @end menu |
7950 | @lowersections | |
7951 | @end ifclear | |
7952 | @end ifset | |
7953 | ||
7954 | @ifset D10V | |
7955 | @include c-d10v.texi | |
7956 | @end ifset | |
7957 | ||
7958 | @ifset D30V | |
7959 | @include c-d30v.texi | |
7960 | @end ifset | |
7961 | ||
cfb8c092 NC |
7962 | @ifset EPIPHANY |
7963 | @include c-epiphany.texi | |
7964 | @end ifset | |
7965 | ||
252b5132 RH |
7966 | @ifset H8/300 |
7967 | @include c-h8300.texi | |
7968 | @end ifset | |
7969 | ||
252b5132 RH |
7970 | @ifset HPPA |
7971 | @include c-hppa.texi | |
7972 | @end ifset | |
7973 | ||
5b93d8bb AM |
7974 | @ifset I370 |
7975 | @include c-i370.texi | |
7976 | @end ifset | |
7977 | ||
252b5132 RH |
7978 | @ifset I80386 |
7979 | @include c-i386.texi | |
7980 | @end ifset | |
7981 | ||
e3308d0d JE |
7982 | @ifset I860 |
7983 | @include c-i860.texi | |
7984 | @end ifset | |
7985 | ||
252b5132 RH |
7986 | @ifset I960 |
7987 | @include c-i960.texi | |
7988 | @end ifset | |
7989 | ||
9e32ca89 NC |
7990 | @ifset IA64 |
7991 | @include c-ia64.texi | |
7992 | @end ifset | |
7993 | ||
a40cbfa3 NC |
7994 | @ifset IP2K |
7995 | @include c-ip2k.texi | |
7996 | @end ifset | |
7997 | ||
84e94c90 NC |
7998 | @ifset LM32 |
7999 | @include c-lm32.texi | |
8000 | @end ifset | |
8001 | ||
49f58d10 JB |
8002 | @ifset M32C |
8003 | @include c-m32c.texi | |
8004 | @end ifset | |
8005 | ||
ec694b89 NC |
8006 | @ifset M32R |
8007 | @include c-m32r.texi | |
8008 | @end ifset | |
252b5132 RH |
8009 | |
8010 | @ifset M680X0 | |
8011 | @include c-m68k.texi | |
8012 | @end ifset | |
8013 | ||
60bcf0fa NC |
8014 | @ifset M68HC11 |
8015 | @include c-m68hc11.texi | |
8016 | @end ifset | |
8017 | ||
a3c62988 NC |
8018 | @ifset METAG |
8019 | @include c-metag.texi | |
8020 | @end ifset | |
8021 | ||
01642c12 | 8022 | @ifset MICROBLAZE |
7ba29e2a NC |
8023 | @include c-microblaze.texi |
8024 | @end ifset | |
8025 | ||
252b5132 RH |
8026 | @ifset MIPS |
8027 | @include c-mips.texi | |
8028 | @end ifset | |
8029 | ||
3c3bdf30 NC |
8030 | @ifset MMIX |
8031 | @include c-mmix.texi | |
8032 | @end ifset | |
8033 | ||
2469cfa2 NC |
8034 | @ifset MSP430 |
8035 | @include c-msp430.texi | |
8036 | @end ifset | |
8037 | ||
35c08157 KLC |
8038 | @ifset NDS32 |
8039 | @include c-nds32.texi | |
8040 | @end ifset | |
8041 | ||
36591ba1 SL |
8042 | @ifset NIOSII |
8043 | @include c-nios2.texi | |
8044 | @end ifset | |
8045 | ||
252b5132 RH |
8046 | @ifset NS32K |
8047 | @include c-ns32k.texi | |
8048 | @end ifset | |
8049 | ||
e135f41b NC |
8050 | @ifset PDP11 |
8051 | @include c-pdp11.texi | |
8052 | @end ifset | |
8053 | ||
041dd5a9 ILT |
8054 | @ifset PJ |
8055 | @include c-pj.texi | |
8056 | @end ifset | |
8057 | ||
418c1742 MG |
8058 | @ifset PPC |
8059 | @include c-ppc.texi | |
8060 | @end ifset | |
8061 | ||
93f11b16 DD |
8062 | @ifset PRU |
8063 | @include c-pru.texi | |
8064 | @end ifset | |
8065 | ||
4f7eddc4 PD |
8066 | @ifset RISCV |
8067 | @include c-riscv.texi | |
8068 | @end ifset | |
8069 | ||
b57e49f7 JW |
8070 | @ifset RL78 |
8071 | @include c-rl78.texi | |
8072 | @end ifset | |
8073 | ||
046d31c2 NC |
8074 | @ifset RX |
8075 | @include c-rx.texi | |
8076 | @end ifset | |
8077 | ||
11c19e16 MS |
8078 | @ifset S390 |
8079 | @include c-s390.texi | |
8080 | @end ifset | |
8081 | ||
c0157db4 NC |
8082 | @ifset SCORE |
8083 | @include c-score.texi | |
8084 | @end ifset | |
8085 | ||
252b5132 RH |
8086 | @ifset SH |
8087 | @include c-sh.texi | |
324bfcf3 | 8088 | @include c-sh64.texi |
252b5132 RH |
8089 | @end ifset |
8090 | ||
8091 | @ifset SPARC | |
8092 | @include c-sparc.texi | |
8093 | @end ifset | |
8094 | ||
39bec121 TW |
8095 | @ifset TIC54X |
8096 | @include c-tic54x.texi | |
8097 | @end ifset | |
8098 | ||
40b36596 JM |
8099 | @ifset TIC6X |
8100 | @include c-tic6x.texi | |
8101 | @end ifset | |
8102 | ||
aa137e4d NC |
8103 | @ifset TILEGX |
8104 | @include c-tilegx.texi | |
8105 | @end ifset | |
8106 | ||
8107 | @ifset TILEPRO | |
8108 | @include c-tilepro.texi | |
8109 | @end ifset | |
8110 | ||
b6605ddd EB |
8111 | @ifset V850 |
8112 | @include c-v850.texi | |
252b5132 RH |
8113 | @end ifset |
8114 | ||
8115 | @ifset VAX | |
8116 | @include c-vax.texi | |
8117 | @end ifset | |
8118 | ||
b6605ddd EB |
8119 | @ifset VISIUM |
8120 | @include c-visium.texi | |
252b5132 RH |
8121 | @end ifset |
8122 | ||
f96bd6c2 PC |
8123 | @ifset WASM32 |
8124 | @include c-wasm32.texi | |
8125 | @end ifset | |
8126 | ||
f6c1a2d5 NC |
8127 | @ifset XGATE |
8128 | @include c-xgate.texi | |
8129 | @end ifset | |
8130 | ||
6753e72f NC |
8131 | @ifset XSTORMY16 |
8132 | @include c-xstormy16.texi | |
8133 | @end ifset | |
8134 | ||
e0001a05 NC |
8135 | @ifset XTENSA |
8136 | @include c-xtensa.texi | |
8137 | @end ifset | |
8138 | ||
b6605ddd EB |
8139 | @ifset Z80 |
8140 | @include c-z80.texi | |
8141 | @end ifset | |
8142 | ||
8143 | @ifset Z8000 | |
8144 | @include c-z8k.texi | |
8145 | @end ifset | |
8146 | ||
252b5132 RH |
8147 | @ifset GENERIC |
8148 | @c reverse effect of @down at top of generic Machine-Dep chapter | |
8149 | @raisesections | |
8150 | @end ifset | |
8151 | ||
8152 | @node Reporting Bugs | |
8153 | @chapter Reporting Bugs | |
8154 | @cindex bugs in assembler | |
8155 | @cindex reporting bugs in assembler | |
8156 | ||
a4fb0134 | 8157 | Your bug reports play an essential role in making @command{@value{AS}} reliable. |
252b5132 RH |
8158 | |
8159 | Reporting a bug may help you by bringing a solution to your problem, or it may | |
8160 | not. But in any case the principal function of a bug report is to help the | |
a4fb0134 SC |
8161 | entire community by making the next version of @command{@value{AS}} work better. |
8162 | Bug reports are your contribution to the maintenance of @command{@value{AS}}. | |
252b5132 RH |
8163 | |
8164 | In order for a bug report to serve its purpose, you must include the | |
8165 | information that enables us to fix the bug. | |
8166 | ||
8167 | @menu | |
8168 | * Bug Criteria:: Have you found a bug? | |
8169 | * Bug Reporting:: How to report bugs | |
8170 | @end menu | |
8171 | ||
8172 | @node Bug Criteria | |
c1253627 | 8173 | @section Have You Found a Bug? |
252b5132 RH |
8174 | @cindex bug criteria |
8175 | ||
8176 | If you are not sure whether you have found a bug, here are some guidelines: | |
8177 | ||
8178 | @itemize @bullet | |
8179 | @cindex fatal signal | |
8180 | @cindex assembler crash | |
8181 | @cindex crash of assembler | |
8182 | @item | |
8183 | If the assembler gets a fatal signal, for any input whatever, that is a | |
a4fb0134 | 8184 | @command{@value{AS}} bug. Reliable assemblers never crash. |
252b5132 RH |
8185 | |
8186 | @cindex error on valid input | |
8187 | @item | |
a4fb0134 | 8188 | If @command{@value{AS}} produces an error message for valid input, that is a bug. |
252b5132 RH |
8189 | |
8190 | @cindex invalid input | |
8191 | @item | |
a4fb0134 | 8192 | If @command{@value{AS}} does not produce an error message for invalid input, that |
252b5132 RH |
8193 | is a bug. However, you should note that your idea of ``invalid input'' might |
8194 | be our idea of ``an extension'' or ``support for traditional practice''. | |
8195 | ||
8196 | @item | |
8197 | If you are an experienced user of assemblers, your suggestions for improvement | |
a4fb0134 | 8198 | of @command{@value{AS}} are welcome in any case. |
252b5132 RH |
8199 | @end itemize |
8200 | ||
8201 | @node Bug Reporting | |
c1253627 | 8202 | @section How to Report Bugs |
252b5132 RH |
8203 | @cindex bug reports |
8204 | @cindex assembler bugs, reporting | |
8205 | ||
8206 | A number of companies and individuals offer support for @sc{gnu} products. If | |
a4fb0134 | 8207 | you obtained @command{@value{AS}} from a support organization, we recommend you |
252b5132 RH |
8208 | contact that organization first. |
8209 | ||
8210 | You can find contact information for many support companies and | |
8211 | individuals in the file @file{etc/SERVICE} in the @sc{gnu} Emacs | |
8212 | distribution. | |
8213 | ||
ad22bfe8 | 8214 | @ifset BUGURL |
a4fb0134 | 8215 | In any event, we also recommend that you send bug reports for @command{@value{AS}} |
ad22bfe8 JM |
8216 | to @value{BUGURL}. |
8217 | @end ifset | |
252b5132 RH |
8218 | |
8219 | The fundamental principle of reporting bugs usefully is this: | |
8220 | @strong{report all the facts}. If you are not sure whether to state a | |
8221 | fact or leave it out, state it! | |
8222 | ||
8223 | Often people omit facts because they think they know what causes the problem | |
8224 | and assume that some details do not matter. Thus, you might assume that the | |
8225 | name of a symbol you use in an example does not matter. Well, probably it does | |
8226 | not, but one cannot be sure. Perhaps the bug is a stray memory reference which | |
8227 | happens to fetch from the location where that name is stored in memory; | |
8228 | perhaps, if the name were different, the contents of that location would fool | |
8229 | the assembler into doing the right thing despite the bug. Play it safe and | |
8230 | give a specific, complete example. That is the easiest thing for you to do, | |
8231 | and the most helpful. | |
8232 | ||
8233 | Keep in mind that the purpose of a bug report is to enable us to fix the bug if | |
8234 | it is new to us. Therefore, always write your bug reports on the assumption | |
8235 | that the bug has not been reported previously. | |
8236 | ||
8237 | Sometimes people give a few sketchy facts and ask, ``Does this ring a | |
c1253627 NC |
8238 | bell?'' This cannot help us fix a bug, so it is basically useless. We |
8239 | respond by asking for enough details to enable us to investigate. | |
8240 | You might as well expedite matters by sending them to begin with. | |
252b5132 RH |
8241 | |
8242 | To enable us to fix the bug, you should include all these things: | |
8243 | ||
8244 | @itemize @bullet | |
8245 | @item | |
a4fb0134 | 8246 | The version of @command{@value{AS}}. @command{@value{AS}} announces it if you start |
252b5132 RH |
8247 | it with the @samp{--version} argument. |
8248 | ||
8249 | Without this, we will not know whether there is any point in looking for | |
a4fb0134 | 8250 | the bug in the current version of @command{@value{AS}}. |
252b5132 RH |
8251 | |
8252 | @item | |
a4fb0134 | 8253 | Any patches you may have applied to the @command{@value{AS}} source. |
252b5132 RH |
8254 | |
8255 | @item | |
8256 | The type of machine you are using, and the operating system name and | |
8257 | version number. | |
8258 | ||
8259 | @item | |
a4fb0134 | 8260 | What compiler (and its version) was used to compile @command{@value{AS}}---e.g. |
252b5132 RH |
8261 | ``@code{gcc-2.7}''. |
8262 | ||
8263 | @item | |
8264 | The command arguments you gave the assembler to assemble your example and | |
8265 | observe the bug. To guarantee you will not omit something important, list them | |
8266 | all. A copy of the Makefile (or the output from make) is sufficient. | |
8267 | ||
8268 | If we were to try to guess the arguments, we would probably guess wrong | |
8269 | and then we might not encounter the bug. | |
8270 | ||
8271 | @item | |
8272 | A complete input file that will reproduce the bug. If the bug is observed when | |
8273 | the assembler is invoked via a compiler, send the assembler source, not the | |
8274 | high level language source. Most compilers will produce the assembler source | |
8275 | when run with the @samp{-S} option. If you are using @code{@value{GCC}}, use | |
8276 | the options @samp{-v --save-temps}; this will save the assembler source in a | |
8277 | file with an extension of @file{.s}, and also show you exactly how | |
a4fb0134 | 8278 | @command{@value{AS}} is being run. |
252b5132 RH |
8279 | |
8280 | @item | |
8281 | A description of what behavior you observe that you believe is | |
8282 | incorrect. For example, ``It gets a fatal signal.'' | |
8283 | ||
a4fb0134 | 8284 | Of course, if the bug is that @command{@value{AS}} gets a fatal signal, then we |
252b5132 RH |
8285 | will certainly notice it. But if the bug is incorrect output, we might not |
8286 | notice unless it is glaringly wrong. You might as well not give us a chance to | |
8287 | make a mistake. | |
8288 | ||
8289 | Even if the problem you experience is a fatal signal, you should still say so | |
8290 | explicitly. Suppose something strange is going on, such as, your copy of | |
b45619c0 | 8291 | @command{@value{AS}} is out of sync, or you have encountered a bug in the C |
252b5132 RH |
8292 | library on your system. (This has happened!) Your copy might crash and ours |
8293 | would not. If you told us to expect a crash, then when ours fails to crash, we | |
8294 | would know that the bug was not happening for us. If you had not told us to | |
8295 | expect a crash, then we would not be able to draw any conclusion from our | |
8296 | observations. | |
8297 | ||
8298 | @item | |
a4fb0134 | 8299 | If you wish to suggest changes to the @command{@value{AS}} source, send us context |
252b5132 RH |
8300 | diffs, as generated by @code{diff} with the @samp{-u}, @samp{-c}, or @samp{-p} |
8301 | option. Always send diffs from the old file to the new file. If you even | |
a4fb0134 | 8302 | discuss something in the @command{@value{AS}} source, refer to it by context, not |
252b5132 RH |
8303 | by line number. |
8304 | ||
8305 | The line numbers in our development sources will not match those in your | |
8306 | sources. Your line numbers would convey no useful information to us. | |
8307 | @end itemize | |
8308 | ||
8309 | Here are some things that are not necessary: | |
8310 | ||
8311 | @itemize @bullet | |
8312 | @item | |
8313 | A description of the envelope of the bug. | |
8314 | ||
8315 | Often people who encounter a bug spend a lot of time investigating | |
8316 | which changes to the input file will make the bug go away and which | |
8317 | changes will not affect it. | |
8318 | ||
8319 | This is often time consuming and not very useful, because the way we | |
8320 | will find the bug is by running a single example under the debugger | |
8321 | with breakpoints, not by pure deduction from a series of examples. | |
8322 | We recommend that you save your time for something else. | |
8323 | ||
8324 | Of course, if you can find a simpler example to report @emph{instead} | |
8325 | of the original one, that is a convenience for us. Errors in the | |
8326 | output will be easier to spot, running under the debugger will take | |
8327 | less time, and so on. | |
8328 | ||
8329 | However, simplification is not vital; if you do not want to do this, | |
8330 | report the bug anyway and send us the entire test case you used. | |
8331 | ||
8332 | @item | |
8333 | A patch for the bug. | |
8334 | ||
8335 | A patch for the bug does help us if it is a good one. But do not omit | |
8336 | the necessary information, such as the test case, on the assumption that | |
8337 | a patch is all we need. We might see problems with your patch and decide | |
8338 | to fix the problem another way, or we might not understand it at all. | |
8339 | ||
a4fb0134 | 8340 | Sometimes with a program as complicated as @command{@value{AS}} it is very hard to |
252b5132 RH |
8341 | construct an example that will make the program follow a certain path through |
8342 | the code. If you do not send us the example, we will not be able to construct | |
8343 | one, so we will not be able to verify that the bug is fixed. | |
8344 | ||
8345 | And if we cannot understand what bug you are trying to fix, or why your | |
8346 | patch should be an improvement, we will not install it. A test case will | |
8347 | help us to understand. | |
8348 | ||
8349 | @item | |
8350 | A guess about what the bug is or what it depends on. | |
8351 | ||
8352 | Such guesses are usually wrong. Even we cannot guess right about such | |
8353 | things without first using the debugger to find the facts. | |
8354 | @end itemize | |
8355 | ||
8356 | @node Acknowledgements | |
8357 | @chapter Acknowledgements | |
8358 | ||
653cfe85 | 8359 | If you have contributed to GAS and your name isn't listed here, |
252b5132 | 8360 | it is not meant as a slight. We just don't know about it. Send mail to the |
01642c12 | 8361 | maintainer, and we'll correct the situation. Currently |
3bfcb652 NC |
8362 | @c (October 2012), |
8363 | the maintainer is Nick Clifton (email address @code{nickc@@redhat.com}). | |
252b5132 RH |
8364 | |
8365 | Dean Elsner wrote the original @sc{gnu} assembler for the VAX.@footnote{Any | |
8366 | more details?} | |
8367 | ||
8368 | Jay Fenlason maintained GAS for a while, adding support for GDB-specific debug | |
8369 | information and the 68k series machines, most of the preprocessing pass, and | |
8370 | extensive changes in @file{messages.c}, @file{input-file.c}, @file{write.c}. | |
8371 | ||
8372 | K. Richard Pixley maintained GAS for a while, adding various enhancements and | |
8373 | many bug fixes, including merging support for several processors, breaking GAS | |
8374 | up to handle multiple object file format back ends (including heavy rewrite, | |
8375 | testing, an integration of the coff and b.out back ends), adding configuration | |
8376 | including heavy testing and verification of cross assemblers and file splits | |
8377 | and renaming, converted GAS to strictly ANSI C including full prototypes, added | |
8378 | support for m680[34]0 and cpu32, did considerable work on i960 including a COFF | |
8379 | port (including considerable amounts of reverse engineering), a SPARC opcode | |
8380 | file rewrite, DECstation, rs6000, and hp300hpux host ports, updated ``know'' | |
8381 | assertions and made them work, much other reorganization, cleanup, and lint. | |
8382 | ||
8383 | Ken Raeburn wrote the high-level BFD interface code to replace most of the code | |
8384 | in format-specific I/O modules. | |
8385 | ||
8386 | The original VMS support was contributed by David L. Kashtan. Eric Youngdale | |
8387 | has done much work with it since. | |
8388 | ||
8389 | The Intel 80386 machine description was written by Eliot Dresselhaus. | |
8390 | ||
8391 | Minh Tran-Le at IntelliCorp contributed some AIX 386 support. | |
8392 | ||
8393 | The Motorola 88k machine description was contributed by Devon Bowen of Buffalo | |
8394 | University and Torbjorn Granlund of the Swedish Institute of Computer Science. | |
8395 | ||
8396 | Keith Knowles at the Open Software Foundation wrote the original MIPS back end | |
8397 | (@file{tc-mips.c}, @file{tc-mips.h}), and contributed Rose format support | |
8398 | (which hasn't been merged in yet). Ralph Campbell worked with the MIPS code to | |
8399 | support a.out format. | |
8400 | ||
7be1c489 AM |
8401 | Support for the Zilog Z8k and Renesas H8/300 processors (tc-z8k, |
8402 | tc-h8300), and IEEE 695 object file format (obj-ieee), was written by | |
252b5132 RH |
8403 | Steve Chamberlain of Cygnus Support. Steve also modified the COFF back end to |
8404 | use BFD for some low-level operations, for use with the H8/300 and AMD 29k | |
8405 | targets. | |
8406 | ||
8407 | John Gilmore built the AMD 29000 support, added @code{.include} support, and | |
8408 | simplified the configuration of which versions accept which directives. He | |
8409 | updated the 68k machine description so that Motorola's opcodes always produced | |
c1253627 | 8410 | fixed-size instructions (e.g., @code{jsr}), while synthetic instructions |
252b5132 RH |
8411 | remained shrinkable (@code{jbsr}). John fixed many bugs, including true tested |
8412 | cross-compilation support, and one bug in relaxation that took a week and | |
8413 | required the proverbial one-bit fix. | |
8414 | ||
8415 | Ian Lance Taylor of Cygnus Support merged the Motorola and MIT syntax for the | |
8416 | 68k, completed support for some COFF targets (68k, i386 SVR3, and SCO Unix), | |
8417 | added support for MIPS ECOFF and ELF targets, wrote the initial RS/6000 and | |
8418 | PowerPC assembler, and made a few other minor patches. | |
8419 | ||
653cfe85 | 8420 | Steve Chamberlain made GAS able to generate listings. |
252b5132 RH |
8421 | |
8422 | Hewlett-Packard contributed support for the HP9000/300. | |
8423 | ||
8424 | Jeff Law wrote GAS and BFD support for the native HPPA object format (SOM) | |
8425 | along with a fairly extensive HPPA testsuite (for both SOM and ELF object | |
8426 | formats). This work was supported by both the Center for Software Science at | |
8427 | the University of Utah and Cygnus Support. | |
8428 | ||
8429 | Support for ELF format files has been worked on by Mark Eichin of Cygnus | |
8430 | Support (original, incomplete implementation for SPARC), Pete Hoogenboom and | |
8431 | Jeff Law at the University of Utah (HPPA mainly), Michael Meissner of the Open | |
8432 | Software Foundation (i386 mainly), and Ken Raeburn of Cygnus Support (sparc, | |
8433 | and some initial 64-bit support). | |
8434 | ||
c1253627 | 8435 | Linas Vepstas added GAS support for the ESA/390 ``IBM 370'' architecture. |
5b93d8bb | 8436 | |
252b5132 RH |
8437 | Richard Henderson rewrote the Alpha assembler. Klaus Kaempf wrote GAS and BFD |
8438 | support for openVMS/Alpha. | |
8439 | ||
39bec121 TW |
8440 | Timothy Wall, Michael Hayes, and Greg Smart contributed to the various tic* |
8441 | flavors. | |
8442 | ||
e0001a05 | 8443 | David Heine, Sterling Augustine, Bob Wilson and John Ruttenberg from Tensilica, |
b45619c0 | 8444 | Inc.@: added support for Xtensa processors. |
e0001a05 | 8445 | |
252b5132 RH |
8446 | Several engineers at Cygnus Support have also provided many small bug fixes and |
8447 | configuration enhancements. | |
8448 | ||
84e94c90 NC |
8449 | Jon Beniston added support for the Lattice Mico32 architecture. |
8450 | ||
252b5132 RH |
8451 | Many others have contributed large or small bugfixes and enhancements. If |
8452 | you have contributed significant work and are not mentioned on this list, and | |
8453 | want to be, let us know. Some of the history has been lost; we are not | |
8454 | intentionally leaving anyone out. | |
8455 | ||
793c5807 NC |
8456 | @node GNU Free Documentation License |
8457 | @appendix GNU Free Documentation License | |
c1253627 | 8458 | @include fdl.texi |
cf055d54 | 8459 | |
370b66a1 CD |
8460 | @node AS Index |
8461 | @unnumbered AS Index | |
252b5132 RH |
8462 | |
8463 | @printindex cp | |
8464 | ||
252b5132 RH |
8465 | @bye |
8466 | @c Local Variables: | |
8467 | @c fill-column: 79 | |
8468 | @c End: |