1 \input texinfo @c -*-Texinfo-*-
2 @c Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
4 @c Free Software Foundation, Inc.
5 @c UPDATE!! On future updates--
6 @c (1) check for new machine-dep cmdline options in
7 @c md_parse_option definitions in config/tc-*.c
8 @c (2) for platform-specific directives, examine md_pseudo_op
10 @c (3) for object-format specific directives, examine obj_pseudo_op
12 @c (4) portable directives in potable[] in read.c
16 @c defaults, config file may override:
19 @include asconfig.texi
24 @c Configure for the generation of man pages
56 @c common OR combinations of conditions
76 @set abnormal-separator
80 @settitle Using @value{AS}
83 @settitle Using @value{AS} (@value{TARGET})
85 @setchapternewpage odd
90 @c WARE! Some of the machine-dependent sections contain tables of machine
91 @c instructions. Except in multi-column format, these tables look silly.
92 @c Unfortunately, Texinfo doesn't have a general-purpose multi-col format, so
93 @c the multi-col format is faked within @example sections.
95 @c Again unfortunately, the natural size that fits on a page, for these tables,
96 @c is different depending on whether or not smallbook is turned on.
97 @c This matters, because of order: text flow switches columns at each page
100 @c The format faked in this source works reasonably well for smallbook,
101 @c not well for the default large-page format. This manual expects that if you
102 @c turn on @smallbook, you will also uncomment the "@set SMALL" to enable the
103 @c tables in question. You can turn on one without the other at your
104 @c discretion, of course.
107 @c the insn tables look just as silly in info files regardless of smallbook,
108 @c might as well show 'em anyways.
114 * As: (as). The GNU assembler.
123 This file documents the GNU Assembler "@value{AS}".
125 @c man begin COPYRIGHT
126 Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001 Free Software Foundation, Inc.
128 Permission is granted to copy, distribute and/or modify this document
129 under the terms of the GNU Free Documentation License, Version 1.1
130 or any later version published by the Free Software Foundation;
131 with no Invariant Sections, with no Front-Cover Texts, and with no
132 Back-Cover Texts. A copy of the license is included in the
133 section entitled "GNU Free Documentation License".
138 Permission is granted to process this file through Tex and print the
139 results, provided the printed document carries copying permission
140 notice identical to this one except for the removal of this paragraph
141 (this paragraph not being relevant to the printed manual).
147 @title Using @value{AS}
148 @subtitle The @sc{gnu} Assembler
150 @subtitle for the @value{TARGET} family
153 @subtitle Version @value{VERSION}
156 The Free Software Foundation Inc. thanks The Nice Computer
157 Company of Australia for loaning Dean Elsner to write the
158 first (Vax) version of @code{as} for Project @sc{gnu}.
159 The proprietors, management and staff of TNCCA thank FSF for
160 distracting the boss while they got some work
163 @author Dean Elsner, Jay Fenlason & friends
167 \hfill {\it Using {\tt @value{AS}}}\par
168 \hfill Edited by Cygnus Support\par
170 %"boxit" macro for figures:
171 %Modified from Knuth's ``boxit'' macro from TeXbook (answer to exercise 21.3)
172 \gdef\boxit#1#2{\vbox{\hrule\hbox{\vrule\kern3pt
173 \vbox{\parindent=0pt\parskip=0pt\hsize=#1\kern3pt\strut\hfil
174 #2\hfil\strut\kern3pt}\kern3pt\vrule}\hrule}}%box with visible outline
175 \gdef\ibox#1#2{\hbox to #1{#2\hfil}\kern8pt}% invisible box
178 @vskip 0pt plus 1filll
179 Copyright @copyright{} 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001 Free Software Foundation, Inc.
181 Permission is granted to copy, distribute and/or modify this document
182 under the terms of the GNU Free Documentation License, Version 1.1
183 or any later version published by the Free Software Foundation;
184 with no Invariant Sections, with no Front-Cover Texts, and with no
185 Back-Cover Texts. A copy of the license is included in the
186 section entitled "GNU Free Documentation License".
192 @top Using @value{AS}
194 This file is a user guide to the @sc{gnu} assembler @code{@value{AS}} version
197 This version of the file describes @code{@value{AS}} configured to generate
198 code for @value{TARGET} architectures.
201 This document is distributed under the terms of the GNU Free
202 Documentation License. A copy of the license is included in the
203 section entitled "GNU Free Documentation License".
206 * Overview:: Overview
207 * Invoking:: Command-Line Options
209 * Sections:: Sections and Relocation
211 * Expressions:: Expressions
212 * Pseudo Ops:: Assembler Directives
213 * Machine Dependencies:: Machine Dependent Features
214 * Reporting Bugs:: Reporting Bugs
215 * Acknowledgements:: Who Did What
216 * GNU Free Documentation License:: GNU Free Documentation License
224 This manual is a user guide to the @sc{gnu} assembler @code{@value{AS}}.
226 This version of the manual describes @code{@value{AS}} configured to generate
227 code for @value{TARGET} architectures.
231 @cindex invocation summary
232 @cindex option summary
233 @cindex summary of options
234 Here is a brief summary of how to invoke @code{@value{AS}}. For details,
235 @pxref{Invoking,,Comand-Line Options}.
237 @c man title AS the portable GNU assembler.
240 gcc(1), ld(1), and the Info entries for @file{binutils} and @file{ld}.
243 @c We don't use deffn and friends for the following because they seem
244 @c to be limited to one line for the header.
246 @c man begin SYNOPSIS
247 @value{AS} [ -a[cdhlns][=file] ] [ -D ] [ --defsym @var{sym}=@var{val} ]
248 [ -f ] [ --gstabs ] [ --gdwarf2 ] [ --help ] [ -I @var{dir} ]
250 [ --listing--lhs-width=NUM ][ --listing-lhs-width2=NUM ]
251 [ --listing-rhs-width=NUM ][ --listing-cont-lines=NUM ]
252 [ --keep-locals ] [ -o @var{objfile} ] [ -R ] [ --statistics ] [ -v ]
253 [ -version ] [ --version ] [ -W ] [ --warn ] [ --fatal-warnings ]
254 [ -w ] [ -x ] [ -Z ] [ --target-help ]
256 @c am29k has no machine-dependent assembler options
263 [ -m[arm]1 | -m[arm]2 | -m[arm]250 | -m[arm]3 |
264 -m[arm]6 | -m[arm]60 | -m[arm]600 | -m[arm]610 |
265 -m[arm]620 | -m[arm]7[t][[d]m[i]][fe] | -m[arm]70 |
266 -m[arm]700 | -m[arm]710[c] | -m[arm]7100 |
267 -m[arm]7500 | -m[arm]8 | -m[arm]810 | -m[arm]9 |
268 -m[arm]920 | -m[arm]920t | -m[arm]9tdmi |
269 -mstrongarm | -mstrongarm110 | -mstrongarm1100 ]
270 [ -m[arm]v2 | -m[arm]v2a | -m[arm]v3 | -m[arm]v3m |
271 -m[arm]v4 | -m[arm]v4t | -m[arm]v5 | -[arm]v5t |
274 [ -mfpa10 | -mfpa11 | -mfpe-old | -mno-fpu ]
276 [ -mapcs-32 | -mapcs-26 | -mapcs-float |
278 [ -mthumb-interwork ] [ -moabi ] [ -k ]
287 @c Hitachi family chips have no machine-dependent assembler options
290 @c HPPA has no machine-dependent assembler options (yet).
296 [ -mpwrx | -mpwr2 | -mpwr | -m601 | -mppc | -mppc32 | -m603 | -m604 |
297 -m403 | -m405 | -mppc64 | -m620 | -mppc64bridge | -mbooke |
298 -mbooke32 | -mbooke64 ]
299 [ -mcom | -many | -maltivec ] [ -memb ]
300 [ -mregnames | -mno-regnames ]
301 [ -mrelocatable | -mrelocatable-lib ]
302 [ -mlittle | -mlittle-endian | -mbig, -mbig-endian ]
303 [ -msolaris | -mno-solaris ]
306 @c The order here is important. See c-sparc.texi.
307 [ -Av6 | -Av7 | -Av8 | -Asparclet | -Asparclite
308 -Av8plus | -Av8plusa | -Av9 | -Av9a ]
309 [ -xarch=v8plus | -xarch=v8plusa ] [ -bump ]
313 [ -mcpu=54[123589] | -mcpu=54[56]lp ] [ -mfar-mode | -mf ]
314 [ -merrors-to-file <filename> | -me <filename> ]
317 @c Z8000 has no machine-dependent assembler options
320 @c see md_parse_option in tc-i960.c
321 [ -ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB |
326 [ --m32rx | --[no-]warn-explicit-parallel-conflicts |
330 [ -l ] [ -m68000 | -m68010 | -m68020 | ... ]
333 [ -jsri2bsr ] [ -sifilter ] [ -relax ]
337 [ -m68hc11 | -m68hc12 ]
338 [ --force-long-branchs ] [ --short-branchs ]
339 [ --strict-direct-mode ] [ --print-insn-syntax ]
340 [ --print-opcodes ] [ --generate-example ]
343 [ -nocpp ] [ -EL ] [ -EB ] [ -G @var{num} ] [ -mcpu=@var{CPU} ]
344 [ -mips1 ] [ -mips2 ] [ -mips3 ] [ -mips4 ] [ -mips5 ]
345 [ -mips32 ] [ -mips64 ]
346 [ -m4650 ] [ -no-m4650 ]
347 [ --trap ] [ --break ] [ -n ]
348 [ --emulation=@var{name} ]
350 [ -- | @var{files} @dots{} ]
358 Turn on listings, in any of a variety of ways:
362 omit false conditionals
365 omit debugging directives
368 include high-level source
374 include macro expansions
377 omit forms processing
383 set the name of the listing file
386 You may combine these options; for example, use @samp{-aln} for assembly
387 listing without forms processing. The @samp{=file} option, if used, must be
388 the last one. By itself, @samp{-a} defaults to @samp{-ahls}.
391 Ignored. This option is accepted for script compatibility with calls to
394 @item --defsym @var{sym}=@var{value}
395 Define the symbol @var{sym} to be @var{value} before assembling the input file.
396 @var{value} must be an integer constant. As in C, a leading @samp{0x}
397 indicates a hexadecimal value, and a leading @samp{0} indicates an octal value.
400 ``fast''---skip whitespace and comment preprocessing (assume source is
404 Generate stabs debugging information for each assembler line. This
405 may help debugging assembler code, if the debugger can handle it.
408 Generate DWARF2 debugging information for each assembler line. This
409 may help debugging assembler code, if the debugger can handle it. Note - this
410 option is only supported by some targets, not all of them.
413 Print a summary of the command line options and exit.
416 Print a summary of all target specific options and exit.
419 Add directory @var{dir} to the search list for @code{.include} directives.
422 Don't warn about signed overflow.
425 @ifclear DIFF-TBL-KLUGE
426 This option is accepted but has no effect on the @value{TARGET} family.
428 @ifset DIFF-TBL-KLUGE
429 Issue warnings when difference tables altered for long displacements.
434 Keep (in the symbol table) local symbols. On traditional a.out systems
435 these start with @samp{L}, but different systems have different local
438 @item --listing-lhs-width=@var{number}
439 Set the maximum width, in words, of the output data column for an assembler
440 listing to @var{number}.
442 @item --listing-lhs-width2=@var{number}
443 Set the maximum width, in words, of the output data column for continuation
444 lines in an assembler listing to @var{number}.
446 @item --listing-rhs-width=@var{number}
447 Set the maximum width of an input source line, as displayed in a listing, to
450 @item --listing-cont-lines=@var{number}
451 Set the maximum number of lines printed in a listing for a single line of input
454 @item -o @var{objfile}
455 Name the object-file output from @code{@value{AS}} @var{objfile}.
458 Fold the data section into the text section.
461 Print the maximum space (in bytes) and total time (in seconds) used by
464 @item --strip-local-absolute
465 Remove local absolute symbols from the outgoing symbol table.
469 Print the @code{as} version.
472 Print the @code{as} version and exit.
476 Suppress warning messages.
478 @item --fatal-warnings
479 Treat warnings as errors.
482 Don't suppress warning messages or treat them as errors.
491 Generate an object file even after errors.
493 @item -- | @var{files} @dots{}
494 Standard input, or source files to assemble.
499 The following options are available when @value{AS} is configured for
504 This option selects the core processor variant.
506 Select either big-endian (-EB) or little-endian (-EL) output.
511 The following options are available when @value{AS} is configured for the ARM
515 @item -m[arm][1|2|3|6|7|8|9][...]
516 Specify which ARM processor variant is the target.
517 @item -m[arm]v[2|2a|3|3m|4|4t|5|5t]
518 Specify which ARM architecture variant is used by the target.
519 @item -mthumb | -mall
520 Enable or disable Thumb only instruction decoding.
521 @item -mfpa10 | -mfpa11 | -mfpe-old | -mno-fpu
522 Select which Floating Point architecture is the target.
523 @item -mapcs-32 | -mapcs-26 | -mapcs-float | -mapcs-reentrant | -moabi
524 Select which procedure calling convention is in use.
526 Select either big-endian (-EB) or little-endian (-EL) output.
527 @item -mthumb-interwork
528 Specify that the code has been generated with interworking between Thumb and
531 Specify that PIC code has been generated.
536 The following options are available when @value{AS} is configured for
539 @cindex D10V optimization
540 @cindex optimization, D10V
542 Optimize output by parallelizing instructions.
547 The following options are available when @value{AS} is configured for a D30V
550 @cindex D30V optimization
551 @cindex optimization, D30V
553 Optimize output by parallelizing instructions.
557 Warn when nops are generated.
559 @cindex D30V nops after 32-bit multiply
561 Warn when a nop after a 32-bit multiply instruction is generated.
566 The following options are available when @value{AS} is configured for the
567 Intel 80960 processor.
570 @item -ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC
571 Specify which variant of the 960 architecture is the target.
574 Add code to collect statistics about branches taken.
577 Do not alter compare-and-branch instructions for long displacements;
584 The following options are available when @value{AS} is configured for the
585 Mitsubishi M32R series.
590 Specify which processor in the M32R family is the target. The default
591 is normally the M32R, but this option changes it to the M32RX.
593 @item --warn-explicit-parallel-conflicts or --Wp
594 Produce warning messages when questionable parallel constructs are
597 @item --no-warn-explicit-parallel-conflicts or --Wnp
598 Do not produce warning messages when questionable parallel constructs are
605 The following options are available when @value{AS} is configured for the
606 Motorola 68000 series.
611 Shorten references to undefined symbols, to one word instead of two.
613 @item -m68000 | -m68008 | -m68010 | -m68020 | -m68030
614 @itemx | -m68040 | -m68060 | -m68302 | -m68331 | -m68332
615 @itemx | -m68333 | -m68340 | -mcpu32 | -m5200
616 Specify what processor in the 68000 family is the target. The default
617 is normally the 68020, but this can be changed at configuration time.
619 @item -m68881 | -m68882 | -mno-68881 | -mno-68882
620 The target machine does (or does not) have a floating-point coprocessor.
621 The default is to assume a coprocessor for 68020, 68030, and cpu32. Although
622 the basic 68000 is not compatible with the 68881, a combination of the
623 two can be specified, since it's possible to do emulation of the
624 coprocessor instructions with the main processor.
626 @item -m68851 | -mno-68851
627 The target machine does (or does not) have a memory-management
628 unit coprocessor. The default is to assume an MMU for 68020 and up.
635 For details about the PDP-11 machine dependent features options,
636 see @ref{PDP-11-Options}.
639 @item -mpic | -mno-pic
640 Generate position-independent (or position-dependent) code. The
641 default is @code{-mpic}.
644 @itemx -mall-extensions
645 Enable all instruction set extensions. This is the default.
647 @item -mno-extensions
648 Disable all instruction set extensions.
650 @item -m@var{extension} | -mno-@var{extension}
651 Enable (or disable) a particular instruction set extension.
654 Enable the instruction set extensions supported by a particular CPU, and
655 disable all other extensions.
657 @item -m@var{machine}
658 Enable the instruction set extensions supported by a particular machine
659 model, and disable all other extensions.
665 The following options are available when @value{AS} is configured for
666 a picoJava processor.
670 @cindex PJ endianness
671 @cindex endianness, PJ
672 @cindex big endian output, PJ
674 Generate ``big endian'' format output.
676 @cindex little endian output, PJ
678 Generate ``little endian'' format output.
684 The following options are available when @value{AS} is configured for the
685 Motorola 68HC11 or 68HC12 series.
689 @item -m68hc11 | -m68hc12
690 Specify what processor is the target. The default is
691 defined by the configuration option when building the assembler.
693 @item --force-long-branchs
694 Relative branches are turned into absolute ones. This concerns
695 conditional branches, unconditional branches and branches to a
698 @item -S | --short-branchs
699 Do not turn relative branchs into absolute ones
700 when the offset is out of range.
702 @item --strict-direct-mode
703 Do not turn the direct addressing mode into extended addressing mode
704 when the instruction does not support direct addressing mode.
706 @item --print-insn-syntax
707 Print the syntax of instruction in case of error.
709 @item --print-opcodes
710 print the list of instructions with syntax and then exit.
712 @item --generate-example
713 print an example of instruction for each possible instruction and then exit.
714 This option is only useful for testing @code{@value{AS}}.
720 The following options are available when @code{@value{AS}} is configured
721 for the SPARC architecture:
724 @item -Av6 | -Av7 | -Av8 | -Asparclet | -Asparclite
725 @itemx -Av8plus | -Av8plusa | -Av9 | -Av9a
726 Explicitly select a variant of the SPARC architecture.
728 @samp{-Av8plus} and @samp{-Av8plusa} select a 32 bit environment.
729 @samp{-Av9} and @samp{-Av9a} select a 64 bit environment.
731 @samp{-Av8plusa} and @samp{-Av9a} enable the SPARC V9 instruction set with
732 UltraSPARC extensions.
734 @item -xarch=v8plus | -xarch=v8plusa
735 For compatibility with the Solaris v9 assembler. These options are
736 equivalent to -Av8plus and -Av8plusa, respectively.
739 Warn when the assembler switches to another architecture.
744 The following options are available when @value{AS} is configured for the 'c54x
749 Enable extended addressing mode. All addresses and relocations will assume
750 extended addressing (usually 23 bits).
751 @item -mcpu=@var{CPU_VERSION}
752 Sets the CPU version being compiled for.
753 @item -merrors-to-file @var{FILENAME}
754 Redirect error output to a file, for broken systems which don't support such
755 behaviour in the shell.
760 The following options are available when @value{AS} is configured for
765 This option sets the largest size of an object that can be referenced
766 implicitly with the @code{gp} register. It is only accepted for targets that
767 use ECOFF format, such as a DECstation running Ultrix. The default value is 8.
769 @cindex MIPS endianness
770 @cindex endianness, MIPS
771 @cindex big endian output, MIPS
773 Generate ``big endian'' format output.
775 @cindex little endian output, MIPS
777 Generate ``little endian'' format output.
785 Generate code for a particular MIPS Instruction Set Architecture level.
786 @samp{-mips1} corresponds to the @sc{r2000} and @sc{r3000} processors,
787 @samp{-mips2} to the @sc{r6000} processor, and @samp{-mips3} to the @sc{r4000}
789 @samp{-mips5}, @samp{-mips32}, and @samp{-mips64} correspond
790 to generic @sc{MIPS V}, @sc{MIPS32}, and @sc{MIPS64} ISA
791 processors, respectively.
795 Generate code for the MIPS @sc{r4650} chip. This tells the assembler to accept
796 the @samp{mad} and @samp{madu} instruction, and to not schedule @samp{nop}
797 instructions around accesses to the @samp{HI} and @samp{LO} registers.
798 @samp{-no-m4650} turns off this option.
800 @item -mcpu=@var{CPU}
801 Generate code for a particular MIPS cpu. It is exactly equivalent to
802 @samp{-m@var{cpu}}, except that there are more value of @var{cpu}
806 @item --emulation=@var{name}
807 This option causes @code{@value{AS}} to emulate @code{@value{AS}} configured
808 for some other target, in all respects, including output format (choosing
809 between ELF and ECOFF only), handling of pseudo-opcodes which may generate
810 debugging information or store symbol table information, and default
811 endianness. The available configuration names are: @samp{mipsecoff},
812 @samp{mipself}, @samp{mipslecoff}, @samp{mipsbecoff}, @samp{mipslelf},
813 @samp{mipsbelf}. The first two do not alter the default endianness from that
814 of the primary target for which the assembler was configured; the others change
815 the default to little- or big-endian as indicated by the @samp{b} or @samp{l}
816 in the name. Using @samp{-EB} or @samp{-EL} will override the endianness
817 selection in any case.
819 This option is currently supported only when the primary target
820 @code{@value{AS}} is configured for is a MIPS ELF or ECOFF target.
821 Furthermore, the primary target or others specified with
822 @samp{--enable-targets=@dots{}} at configuration time must include support for
823 the other format, if both are to be available. For example, the Irix 5
824 configuration includes support for both.
826 Eventually, this option will support more configurations, with more
827 fine-grained control over the assembler's behavior, and will be supported for
831 @code{@value{AS}} ignores this option. It is accepted for compatibility with
839 Control how to deal with multiplication overflow and division by zero.
840 @samp{--trap} or @samp{--no-break} (which are synonyms) take a trap exception
841 (and only work for Instruction Set Architecture level 2 and higher);
842 @samp{--break} or @samp{--no-trap} (also synonyms, and the default) take a
846 When this option is used, @code{@value{AS}} will issue a warning every
847 time it generates a nop instruction from a macro.
852 The following options are available when @value{AS} is configured for
858 Enable or disable the JSRI to BSR transformation. By default this is enabled.
859 The command line option @samp{-nojsri2bsr} can be used to disable it.
863 Enable or disable the silicon filter behaviour. By default this is disabled.
864 The default can be overridden by the @samp{-sifilter} command line option.
867 Alter jump instructions for long displacements.
869 @item -mcpu=[210|340]
870 Select the cpu type on the target hardware. This controls which instructions
874 Assemble for a big endian target.
877 Assemble for a little endian target.
885 * Manual:: Structure of this Manual
886 * GNU Assembler:: The GNU Assembler
887 * Object Formats:: Object File Formats
888 * Command Line:: Command Line
889 * Input Files:: Input Files
890 * Object:: Output (Object) File
891 * Errors:: Error and Warning Messages
895 @section Structure of this Manual
897 @cindex manual, structure and purpose
898 This manual is intended to describe what you need to know to use
899 @sc{gnu} @code{@value{AS}}. We cover the syntax expected in source files, including
900 notation for symbols, constants, and expressions; the directives that
901 @code{@value{AS}} understands; and of course how to invoke @code{@value{AS}}.
904 We also cover special features in the @value{TARGET}
905 configuration of @code{@value{AS}}, including assembler directives.
908 This manual also describes some of the machine-dependent features of
909 various flavors of the assembler.
912 @cindex machine instructions (not covered)
913 On the other hand, this manual is @emph{not} intended as an introduction
914 to programming in assembly language---let alone programming in general!
915 In a similar vein, we make no attempt to introduce the machine
916 architecture; we do @emph{not} describe the instruction set, standard
917 mnemonics, registers or addressing modes that are standard to a
918 particular architecture.
920 You may want to consult the manufacturer's
921 machine architecture manual for this information.
925 For information on the H8/300 machine instruction set, see @cite{H8/300
926 Series Programming Manual} (Hitachi ADE--602--025). For the H8/300H,
927 see @cite{H8/300H Series Programming Manual} (Hitachi).
930 For information on the H8/500 machine instruction set, see @cite{H8/500
931 Series Programming Manual} (Hitachi M21T001).
934 For information on the Hitachi SH machine instruction set, see
935 @cite{SH-Microcomputer User's Manual} (Hitachi Micro Systems, Inc.).
938 For information on the Z8000 machine instruction set, see @cite{Z8000 CPU Technical Manual}
942 @c I think this is premature---doc@cygnus.com, 17jan1991
944 Throughout this manual, we assume that you are running @dfn{GNU},
945 the portable operating system from the @dfn{Free Software
946 Foundation, Inc.}. This restricts our attention to certain kinds of
947 computer (in particular, the kinds of computers that @sc{gnu} can run on);
948 once this assumption is granted examples and definitions need less
951 @code{@value{AS}} is part of a team of programs that turn a high-level
952 human-readable series of instructions into a low-level
953 computer-readable series of instructions. Different versions of
954 @code{@value{AS}} are used for different kinds of computer.
957 @c There used to be a section "Terminology" here, which defined
958 @c "contents", "byte", "word", and "long". Defining "word" to any
959 @c particular size is confusing when the .word directive may generate 16
960 @c bits on one machine and 32 bits on another; in general, for the user
961 @c version of this manual, none of these terms seem essential to define.
962 @c They were used very little even in the former draft of the manual;
963 @c this draft makes an effort to avoid them (except in names of
967 @section The GNU Assembler
969 @c man begin DESCRIPTION
971 @sc{gnu} @code{as} is really a family of assemblers.
973 This manual describes @code{@value{AS}}, a member of that family which is
974 configured for the @value{TARGET} architectures.
976 If you use (or have used) the @sc{gnu} assembler on one architecture, you
977 should find a fairly similar environment when you use it on another
978 architecture. Each version has much in common with the others,
979 including object file formats, most assembler directives (often called
980 @dfn{pseudo-ops}) and assembler syntax.@refill
982 @cindex purpose of @sc{gnu} assembler
983 @code{@value{AS}} is primarily intended to assemble the output of the
984 @sc{gnu} C compiler @code{@value{GCC}} for use by the linker
985 @code{@value{LD}}. Nevertheless, we've tried to make @code{@value{AS}}
986 assemble correctly everything that other assemblers for the same
987 machine would assemble.
989 Any exceptions are documented explicitly (@pxref{Machine Dependencies}).
992 @c This remark should appear in generic version of manual; assumption
993 @c here is that generic version sets M680x0.
994 This doesn't mean @code{@value{AS}} always uses the same syntax as another
995 assembler for the same architecture; for example, we know of several
996 incompatible versions of 680x0 assembly language syntax.
1001 Unlike older assemblers, @code{@value{AS}} is designed to assemble a source
1002 program in one pass of the source file. This has a subtle impact on the
1003 @kbd{.org} directive (@pxref{Org,,@code{.org}}).
1005 @node Object Formats
1006 @section Object File Formats
1008 @cindex object file format
1009 The @sc{gnu} assembler can be configured to produce several alternative
1010 object file formats. For the most part, this does not affect how you
1011 write assembly language programs; but directives for debugging symbols
1012 are typically different in different file formats. @xref{Symbol
1013 Attributes,,Symbol Attributes}.
1016 On the @value{TARGET}, @code{@value{AS}} is configured to produce
1017 @value{OBJ-NAME} format object files.
1019 @c The following should exhaust all configs that set MULTI-OBJ, ideally
1021 On the @value{TARGET}, @code{@value{AS}} can be configured to produce either
1022 @code{a.out} or COFF format object files.
1025 On the @value{TARGET}, @code{@value{AS}} can be configured to produce either
1026 @code{b.out} or COFF format object files.
1029 On the @value{TARGET}, @code{@value{AS}} can be configured to produce either
1030 SOM or ELF format object files.
1035 @section Command Line
1037 @cindex command line conventions
1039 After the program name @code{@value{AS}}, the command line may contain
1040 options and file names. Options may appear in any order, and may be
1041 before, after, or between file names. The order of file names is
1044 @cindex standard input, as input file
1046 @file{--} (two hyphens) by itself names the standard input file
1047 explicitly, as one of the files for @code{@value{AS}} to assemble.
1049 @cindex options, command line
1050 Except for @samp{--} any command line argument that begins with a
1051 hyphen (@samp{-}) is an option. Each option changes the behavior of
1052 @code{@value{AS}}. No option changes the way another option works. An
1053 option is a @samp{-} followed by one or more letters; the case of
1054 the letter is important. All options are optional.
1056 Some options expect exactly one file name to follow them. The file
1057 name may either immediately follow the option's letter (compatible
1058 with older assemblers) or it may be the next command argument (@sc{gnu}
1059 standard). These two command lines are equivalent:
1062 @value{AS} -o my-object-file.o mumble.s
1063 @value{AS} -omy-object-file.o mumble.s
1067 @section Input Files
1070 @cindex source program
1071 @cindex files, input
1072 We use the phrase @dfn{source program}, abbreviated @dfn{source}, to
1073 describe the program input to one run of @code{@value{AS}}. The program may
1074 be in one or more files; how the source is partitioned into files
1075 doesn't change the meaning of the source.
1077 @c I added "con" prefix to "catenation" just to prove I can overcome my
1078 @c APL training... doc@cygnus.com
1079 The source program is a concatenation of the text in all the files, in the
1082 @c man begin DESCRIPTION
1083 Each time you run @code{@value{AS}} it assembles exactly one source
1084 program. The source program is made up of one or more files.
1085 (The standard input is also a file.)
1087 You give @code{@value{AS}} a command line that has zero or more input file
1088 names. The input files are read (from left file name to right). A
1089 command line argument (in any position) that has no special meaning
1090 is taken to be an input file name.
1092 If you give @code{@value{AS}} no file names it attempts to read one input file
1093 from the @code{@value{AS}} standard input, which is normally your terminal. You
1094 may have to type @key{ctl-D} to tell @code{@value{AS}} there is no more program
1097 Use @samp{--} if you need to explicitly name the standard input file
1098 in your command line.
1100 If the source is empty, @code{@value{AS}} produces a small, empty object
1105 @subheading Filenames and Line-numbers
1107 @cindex input file linenumbers
1108 @cindex line numbers, in input files
1109 There are two ways of locating a line in the input file (or files) and
1110 either may be used in reporting error messages. One way refers to a line
1111 number in a physical file; the other refers to a line number in a
1112 ``logical'' file. @xref{Errors, ,Error and Warning Messages}.
1114 @dfn{Physical files} are those files named in the command line given
1115 to @code{@value{AS}}.
1117 @dfn{Logical files} are simply names declared explicitly by assembler
1118 directives; they bear no relation to physical files. Logical file names help
1119 error messages reflect the original source file, when @code{@value{AS}} source
1120 is itself synthesized from other files. @code{@value{AS}} understands the
1121 @samp{#} directives emitted by the @code{@value{GCC}} preprocessor. See also
1122 @ref{File,,@code{.file}}.
1125 @section Output (Object) File
1131 Every time you run @code{@value{AS}} it produces an output file, which is
1132 your assembly language program translated into numbers. This file
1133 is the object file. Its default name is
1141 @code{b.out} when @code{@value{AS}} is configured for the Intel 80960.
1143 You can give it another name by using the @code{-o} option. Conventionally,
1144 object file names end with @file{.o}. The default name is used for historical
1145 reasons: older assemblers were capable of assembling self-contained programs
1146 directly into a runnable program. (For some formats, this isn't currently
1147 possible, but it can be done for the @code{a.out} format.)
1151 The object file is meant for input to the linker @code{@value{LD}}. It contains
1152 assembled program code, information to help @code{@value{LD}} integrate
1153 the assembled program into a runnable file, and (optionally) symbolic
1154 information for the debugger.
1156 @c link above to some info file(s) like the description of a.out.
1157 @c don't forget to describe @sc{gnu} info as well as Unix lossage.
1160 @section Error and Warning Messages
1162 @c man begin DESCRIPTION
1164 @cindex error messages
1165 @cindex warning messages
1166 @cindex messages from assembler
1167 @code{@value{AS}} may write warnings and error messages to the standard error
1168 file (usually your terminal). This should not happen when a compiler
1169 runs @code{@value{AS}} automatically. Warnings report an assumption made so
1170 that @code{@value{AS}} could keep assembling a flawed program; errors report a
1171 grave problem that stops the assembly.
1175 @cindex format of warning messages
1176 Warning messages have the format
1179 file_name:@b{NNN}:Warning Message Text
1183 @cindex line numbers, in warnings/errors
1184 (where @b{NNN} is a line number). If a logical file name has been given
1185 (@pxref{File,,@code{.file}}) it is used for the filename, otherwise the name of
1186 the current input file is used. If a logical line number was given
1188 (@pxref{Line,,@code{.line}})
1192 (@pxref{Line,,@code{.line}})
1195 (@pxref{Ln,,@code{.ln}})
1198 then it is used to calculate the number printed,
1199 otherwise the actual line in the current source file is printed. The
1200 message text is intended to be self explanatory (in the grand Unix
1203 @cindex format of error messages
1204 Error messages have the format
1206 file_name:@b{NNN}:FATAL:Error Message Text
1208 The file name and line number are derived as for warning
1209 messages. The actual message text may be rather less explanatory
1210 because many of them aren't supposed to happen.
1213 @chapter Command-Line Options
1215 @cindex options, all versions of assembler
1216 This chapter describes command-line options available in @emph{all}
1217 versions of the @sc{gnu} assembler; @pxref{Machine Dependencies}, for options specific
1219 to the @value{TARGET}.
1222 to particular machine architectures.
1225 @c man begin DESCRIPTION
1227 If you are invoking @code{@value{AS}} via the @sc{gnu} C compiler (version 2),
1228 you can use the @samp{-Wa} option to pass arguments through to the assembler.
1229 The assembler arguments must be separated from each other (and the @samp{-Wa})
1230 by commas. For example:
1233 gcc -c -g -O -Wa,-alh,-L file.c
1237 This passes two options to the assembler: @samp{-alh} (emit a listing to
1238 standard output with with high-level and assembly source) and @samp{-L} (retain
1239 local symbols in the symbol table).
1241 Usually you do not need to use this @samp{-Wa} mechanism, since many compiler
1242 command-line options are automatically passed to the assembler by the compiler.
1243 (You can call the @sc{gnu} compiler driver with the @samp{-v} option to see
1244 precisely what options it passes to each compilation pass, including the
1250 * a:: -a[cdhlns] enable listings
1251 * D:: -D for compatibility
1252 * f:: -f to work faster
1253 * I:: -I for .include search path
1254 @ifclear DIFF-TBL-KLUGE
1255 * K:: -K for compatibility
1257 @ifset DIFF-TBL-KLUGE
1258 * K:: -K for difference tables
1261 * L:: -L to retain local labels
1262 * listing:: --listing-XXX to configure listing output
1263 * M:: -M or --mri to assemble in MRI compatibility mode
1264 * MD:: --MD for dependency tracking
1265 * o:: -o to name the object file
1266 * R:: -R to join data and text sections
1267 * statistics:: --statistics to see statistics about assembly
1268 * traditional-format:: --traditional-format for compatible output
1269 * v:: -v to announce version
1270 * W:: -W, --no-warn, --warn, --fatal-warnings to control warnings
1271 * Z:: -Z to make object file even after errors
1275 @section Enable Listings: @code{-a[cdhlns]}
1284 @cindex listings, enabling
1285 @cindex assembly listings, enabling
1287 These options enable listing output from the assembler. By itself,
1288 @samp{-a} requests high-level, assembly, and symbols listing.
1289 You can use other letters to select specific options for the list:
1290 @samp{-ah} requests a high-level language listing,
1291 @samp{-al} requests an output-program assembly listing, and
1292 @samp{-as} requests a symbol table listing.
1293 High-level listings require that a compiler debugging option like
1294 @samp{-g} be used, and that assembly listings (@samp{-al}) be requested
1297 Use the @samp{-ac} option to omit false conditionals from a listing. Any lines
1298 which are not assembled because of a false @code{.if} (or @code{.ifdef}, or any
1299 other conditional), or a true @code{.if} followed by an @code{.else}, will be
1300 omitted from the listing.
1302 Use the @samp{-ad} option to omit debugging directives from the
1305 Once you have specified one of these options, you can further control
1306 listing output and its appearance using the directives @code{.list},
1307 @code{.nolist}, @code{.psize}, @code{.eject}, @code{.title}, and
1309 The @samp{-an} option turns off all forms processing.
1310 If you do not request listing output with one of the @samp{-a} options, the
1311 listing-control directives have no effect.
1313 The letters after @samp{-a} may be combined into one option,
1314 @emph{e.g.}, @samp{-aln}.
1316 Note if the assembler source is coming from the standard input (eg because it
1317 is being created by @code{@value{GCC}} and the @samp{-pipe} command line switch
1318 is being used) then the listing will not contain any comments or preprocessor
1319 directives. This is because the listing code buffers input source lines from
1320 stdin only after they have been preprocessed by the assembler. This reduces
1321 memory usage and makes the code more efficient.
1327 This option has no effect whatsoever, but it is accepted to make it more
1328 likely that scripts written for other assemblers also work with
1332 @section Work Faster: @code{-f}
1335 @cindex trusted compiler
1336 @cindex faster processing (@code{-f})
1337 @samp{-f} should only be used when assembling programs written by a
1338 (trusted) compiler. @samp{-f} stops the assembler from doing whitespace
1339 and comment preprocessing on
1340 the input file(s) before assembling them. @xref{Preprocessing,
1344 @emph{Warning:} if you use @samp{-f} when the files actually need to be
1345 preprocessed (if they contain comments, for example), @code{@value{AS}} does
1350 @section @code{.include} search path: @code{-I} @var{path}
1352 @kindex -I @var{path}
1353 @cindex paths for @code{.include}
1354 @cindex search path for @code{.include}
1355 @cindex @code{include} directive search path
1356 Use this option to add a @var{path} to the list of directories
1357 @code{@value{AS}} searches for files specified in @code{.include}
1358 directives (@pxref{Include,,@code{.include}}). You may use @code{-I} as
1359 many times as necessary to include a variety of paths. The current
1360 working directory is always searched first; after that, @code{@value{AS}}
1361 searches any @samp{-I} directories in the same order as they were
1362 specified (left to right) on the command line.
1365 @section Difference Tables: @code{-K}
1368 @ifclear DIFF-TBL-KLUGE
1369 On the @value{TARGET} family, this option is allowed, but has no effect. It is
1370 permitted for compatibility with the @sc{gnu} assembler on other platforms,
1371 where it can be used to warn when the assembler alters the machine code
1372 generated for @samp{.word} directives in difference tables. The @value{TARGET}
1373 family does not have the addressing limitations that sometimes lead to this
1374 alteration on other platforms.
1377 @ifset DIFF-TBL-KLUGE
1378 @cindex difference tables, warning
1379 @cindex warning for altered difference tables
1380 @code{@value{AS}} sometimes alters the code emitted for directives of the form
1381 @samp{.word @var{sym1}-@var{sym2}}; @pxref{Word,,@code{.word}}.
1382 You can use the @samp{-K} option if you want a warning issued when this
1387 @section Include Local Labels: @code{-L}
1390 @cindex local labels, retaining in output
1391 Labels beginning with @samp{L} (upper case only) are called @dfn{local
1392 labels}. @xref{Symbol Names}. Normally you do not see such labels when
1393 debugging, because they are intended for the use of programs (like
1394 compilers) that compose assembler programs, not for your notice.
1395 Normally both @code{@value{AS}} and @code{@value{LD}} discard such labels, so you do not
1396 normally debug with them.
1398 This option tells @code{@value{AS}} to retain those @samp{L@dots{}} symbols
1399 in the object file. Usually if you do this you also tell the linker
1400 @code{@value{LD}} to preserve symbols whose names begin with @samp{L}.
1402 By default, a local label is any label beginning with @samp{L}, but each
1403 target is allowed to redefine the local label prefix.
1405 On the HPPA local labels begin with @samp{L$}.
1409 @section Configuring listing output: @code{--listing}
1411 The listing feature of the assembler can be enabled via the command line switch
1412 @samp{-a} (@pxref{a}). This feature combines the input source file(s) with a
1413 hex dump of the corresponding locations in the output object file, and displays
1414 them as a listing file. The format of this listing can be controlled by pseudo
1415 ops inside the assembler source (@pxref{List} @pxref{Title} @pxref{Sbttl}
1416 @pxref{Psize} @pxref{Eject}) and also by the following switches:
1419 @item --listing-lhs-width=@samp{number}
1420 @kindex --listing-lhs-width
1421 @cindex Width of first line disassembly output
1422 Sets the maximum width, in words, of the first line of the hex byte dump. This
1423 dump appears on the left hand side of the listing output.
1425 @item --listing-lhs-width2=@samp{number}
1426 @kindex --listing-lhs-width2
1427 @cindex Width of continuation lines of disassembly output
1428 Sets the maximum width, in words, of any further lines of the hex byte dump for
1429 a given inut source line. If this value is not specified, it defaults to being
1430 the same as the value specified for @samp{--listing-lhs-width}. If neither
1431 switch is used the default is to one.
1433 @item --listing-rhs-width=@samp{number}
1434 @kindex --listing-rhs-width
1435 @cindex Width of source line output
1436 Sets the maximum width, in characters, of the source line that is displayed
1437 alongside the hex dump. The default value for this parameter is 100. The
1438 source line is displayed on the right hand side of the listing output.
1440 @item --listing-cont-lines=@samp{number}
1441 @kindex --listing-cont-lines
1442 @cindex Maximum number of continuation lines
1443 Sets the maximum number of continuation lines of hex dump that will be
1444 displayed for a given single line of source input. The default value is 4.
1448 @section Assemble in MRI Compatibility Mode: @code{-M}
1451 @cindex MRI compatibility mode
1452 The @code{-M} or @code{--mri} option selects MRI compatibility mode. This
1453 changes the syntax and pseudo-op handling of @code{@value{AS}} to make it
1454 compatible with the @code{ASM68K} or the @code{ASM960} (depending upon the
1455 configured target) assembler from Microtec Research. The exact nature of the
1456 MRI syntax will not be documented here; see the MRI manuals for more
1457 information. Note in particular that the handling of macros and macro
1458 arguments is somewhat different. The purpose of this option is to permit
1459 assembling existing MRI assembler code using @code{@value{AS}}.
1461 The MRI compatibility is not complete. Certain operations of the MRI assembler
1462 depend upon its object file format, and can not be supported using other object
1463 file formats. Supporting these would require enhancing each object file format
1464 individually. These are:
1467 @item global symbols in common section
1469 The m68k MRI assembler supports common sections which are merged by the linker.
1470 Other object file formats do not support this. @code{@value{AS}} handles
1471 common sections by treating them as a single common symbol. It permits local
1472 symbols to be defined within a common section, but it can not support global
1473 symbols, since it has no way to describe them.
1475 @item complex relocations
1477 The MRI assemblers support relocations against a negated section address, and
1478 relocations which combine the start addresses of two or more sections. These
1479 are not support by other object file formats.
1481 @item @code{END} pseudo-op specifying start address
1483 The MRI @code{END} pseudo-op permits the specification of a start address.
1484 This is not supported by other object file formats. The start address may
1485 instead be specified using the @code{-e} option to the linker, or in a linker
1488 @item @code{IDNT}, @code{.ident} and @code{NAME} pseudo-ops
1490 The MRI @code{IDNT}, @code{.ident} and @code{NAME} pseudo-ops assign a module
1491 name to the output file. This is not supported by other object file formats.
1493 @item @code{ORG} pseudo-op
1495 The m68k MRI @code{ORG} pseudo-op begins an absolute section at a given
1496 address. This differs from the usual @code{@value{AS}} @code{.org} pseudo-op,
1497 which changes the location within the current section. Absolute sections are
1498 not supported by other object file formats. The address of a section may be
1499 assigned within a linker script.
1502 There are some other features of the MRI assembler which are not supported by
1503 @code{@value{AS}}, typically either because they are difficult or because they
1504 seem of little consequence. Some of these may be supported in future releases.
1508 @item EBCDIC strings
1510 EBCDIC strings are not supported.
1512 @item packed binary coded decimal
1514 Packed binary coded decimal is not supported. This means that the @code{DC.P}
1515 and @code{DCB.P} pseudo-ops are not supported.
1517 @item @code{FEQU} pseudo-op
1519 The m68k @code{FEQU} pseudo-op is not supported.
1521 @item @code{NOOBJ} pseudo-op
1523 The m68k @code{NOOBJ} pseudo-op is not supported.
1525 @item @code{OPT} branch control options
1527 The m68k @code{OPT} branch control options---@code{B}, @code{BRS}, @code{BRB},
1528 @code{BRL}, and @code{BRW}---are ignored. @code{@value{AS}} automatically
1529 relaxes all branches, whether forward or backward, to an appropriate size, so
1530 these options serve no purpose.
1532 @item @code{OPT} list control options
1534 The following m68k @code{OPT} list control options are ignored: @code{C},
1535 @code{CEX}, @code{CL}, @code{CRE}, @code{E}, @code{G}, @code{I}, @code{M},
1536 @code{MEX}, @code{MC}, @code{MD}, @code{X}.
1538 @item other @code{OPT} options
1540 The following m68k @code{OPT} options are ignored: @code{NEST}, @code{O},
1541 @code{OLD}, @code{OP}, @code{P}, @code{PCO}, @code{PCR}, @code{PCS}, @code{R}.
1543 @item @code{OPT} @code{D} option is default
1545 The m68k @code{OPT} @code{D} option is the default, unlike the MRI assembler.
1546 @code{OPT NOD} may be used to turn it off.
1548 @item @code{XREF} pseudo-op.
1550 The m68k @code{XREF} pseudo-op is ignored.
1552 @item @code{.debug} pseudo-op
1554 The i960 @code{.debug} pseudo-op is not supported.
1556 @item @code{.extended} pseudo-op
1558 The i960 @code{.extended} pseudo-op is not supported.
1560 @item @code{.list} pseudo-op.
1562 The various options of the i960 @code{.list} pseudo-op are not supported.
1564 @item @code{.optimize} pseudo-op
1566 The i960 @code{.optimize} pseudo-op is not supported.
1568 @item @code{.output} pseudo-op
1570 The i960 @code{.output} pseudo-op is not supported.
1572 @item @code{.setreal} pseudo-op
1574 The i960 @code{.setreal} pseudo-op is not supported.
1579 @section Dependency tracking: @code{--MD}
1582 @cindex dependency tracking
1585 @code{@value{AS}} can generate a dependency file for the file it creates. This
1586 file consists of a single rule suitable for @code{make} describing the
1587 dependencies of the main source file.
1589 The rule is written to the file named in its argument.
1591 This feature is used in the automatic updating of makefiles.
1594 @section Name the Object File: @code{-o}
1597 @cindex naming object file
1598 @cindex object file name
1599 There is always one object file output when you run @code{@value{AS}}. By
1600 default it has the name
1603 @file{a.out} (or @file{b.out}, for Intel 960 targets only).
1617 You use this option (which takes exactly one filename) to give the
1618 object file a different name.
1620 Whatever the object file is called, @code{@value{AS}} overwrites any
1621 existing file of the same name.
1624 @section Join Data and Text Sections: @code{-R}
1627 @cindex data and text sections, joining
1628 @cindex text and data sections, joining
1629 @cindex joining text and data sections
1630 @cindex merging text and data sections
1631 @code{-R} tells @code{@value{AS}} to write the object file as if all
1632 data-section data lives in the text section. This is only done at
1633 the very last moment: your binary data are the same, but data
1634 section parts are relocated differently. The data section part of
1635 your object file is zero bytes long because all its bytes are
1636 appended to the text section. (@xref{Sections,,Sections and Relocation}.)
1638 When you specify @code{-R} it would be possible to generate shorter
1639 address displacements (because we do not have to cross between text and
1640 data section). We refrain from doing this simply for compatibility with
1641 older versions of @code{@value{AS}}. In future, @code{-R} may work this way.
1644 When @code{@value{AS}} is configured for COFF output,
1645 this option is only useful if you use sections named @samp{.text} and
1650 @code{-R} is not supported for any of the HPPA targets. Using
1651 @code{-R} generates a warning from @code{@value{AS}}.
1655 @section Display Assembly Statistics: @code{--statistics}
1657 @kindex --statistics
1658 @cindex statistics, about assembly
1659 @cindex time, total for assembly
1660 @cindex space used, maximum for assembly
1661 Use @samp{--statistics} to display two statistics about the resources used by
1662 @code{@value{AS}}: the maximum amount of space allocated during the assembly
1663 (in bytes), and the total execution time taken for the assembly (in @sc{cpu}
1666 @node traditional-format
1667 @section Compatible output: @code{--traditional-format}
1669 @kindex --traditional-format
1670 For some targets, the output of @code{@value{AS}} is different in some ways
1671 from the output of some existing assembler. This switch requests
1672 @code{@value{AS}} to use the traditional format instead.
1674 For example, it disables the exception frame optimizations which
1675 @code{@value{AS}} normally does by default on @code{@value{GCC}} output.
1678 @section Announce Version: @code{-v}
1682 @cindex assembler version
1683 @cindex version of assembler
1684 You can find out what version of as is running by including the
1685 option @samp{-v} (which you can also spell as @samp{-version}) on the
1689 @section Control Warnings: @code{-W}, @code{--warn}, @code{--no-warn}, @code{--fatal-warnings}
1691 @code{@value{AS}} should never give a warning or error message when
1692 assembling compiler output. But programs written by people often
1693 cause @code{@value{AS}} to give a warning that a particular assumption was
1694 made. All such warnings are directed to the standard error file.
1697 @kindex @samp{--no-warn}
1698 @cindex suppressing warnings
1699 @cindex warnings, suppressing
1700 If you use the @code{-W} and @code{--no-warn} options, no warnings are issued.
1701 This only affects the warning messages: it does not change any particular of
1702 how @code{@value{AS}} assembles your file. Errors, which stop the assembly,
1705 @kindex @samp{--fatal-warnings}
1706 @cindex errors, caused by warnings
1707 @cindex warnings, causing error
1708 If you use the @code{--fatal-warnings} option, @code{@value{AS}} considers
1709 files that generate warnings to be in error.
1711 @kindex @samp{--warn}
1712 @cindex warnings, switching on
1713 You can switch these options off again by specifying @code{--warn}, which
1714 causes warnings to be output as usual.
1717 @section Generate Object File in Spite of Errors: @code{-Z}
1718 @cindex object file, after errors
1719 @cindex errors, continuing after
1720 After an error message, @code{@value{AS}} normally produces no output. If for
1721 some reason you are interested in object file output even after
1722 @code{@value{AS}} gives an error message on your program, use the @samp{-Z}
1723 option. If there are any errors, @code{@value{AS}} continues anyways, and
1724 writes an object file after a final warning message of the form @samp{@var{n}
1725 errors, @var{m} warnings, generating bad object file.}
1730 @cindex machine-independent syntax
1731 @cindex syntax, machine-independent
1732 This chapter describes the machine-independent syntax allowed in a
1733 source file. @code{@value{AS}} syntax is similar to what many other
1734 assemblers use; it is inspired by the BSD 4.2
1739 assembler, except that @code{@value{AS}} does not assemble Vax bit-fields.
1743 * Preprocessing:: Preprocessing
1744 * Whitespace:: Whitespace
1745 * Comments:: Comments
1746 * Symbol Intro:: Symbols
1747 * Statements:: Statements
1748 * Constants:: Constants
1752 @section Preprocessing
1754 @cindex preprocessing
1755 The @code{@value{AS}} internal preprocessor:
1757 @cindex whitespace, removed by preprocessor
1759 adjusts and removes extra whitespace. It leaves one space or tab before
1760 the keywords on a line, and turns any other whitespace on the line into
1763 @cindex comments, removed by preprocessor
1765 removes all comments, replacing them with a single space, or an
1766 appropriate number of newlines.
1768 @cindex constants, converted by preprocessor
1770 converts character constants into the appropriate numeric values.
1773 It does not do macro processing, include file handling, or
1774 anything else you may get from your C compiler's preprocessor. You can
1775 do include file processing with the @code{.include} directive
1776 (@pxref{Include,,@code{.include}}). You can use the @sc{gnu} C compiler driver
1777 to get other ``CPP'' style preprocessing, by giving the input file a
1778 @samp{.S} suffix. @xref{Overall Options,, Options Controlling the Kind of
1779 Output, gcc.info, Using GNU CC}.
1781 Excess whitespace, comments, and character constants
1782 cannot be used in the portions of the input text that are not
1785 @cindex turning preprocessing on and off
1786 @cindex preprocessing, turning on and off
1789 If the first line of an input file is @code{#NO_APP} or if you use the
1790 @samp{-f} option, whitespace and comments are not removed from the input file.
1791 Within an input file, you can ask for whitespace and comment removal in
1792 specific portions of the by putting a line that says @code{#APP} before the
1793 text that may contain whitespace or comments, and putting a line that says
1794 @code{#NO_APP} after this text. This feature is mainly intend to support
1795 @code{asm} statements in compilers whose output is otherwise free of comments
1802 @dfn{Whitespace} is one or more blanks or tabs, in any order.
1803 Whitespace is used to separate symbols, and to make programs neater for
1804 people to read. Unless within character constants
1805 (@pxref{Characters,,Character Constants}), any whitespace means the same
1806 as exactly one space.
1812 There are two ways of rendering comments to @code{@value{AS}}. In both
1813 cases the comment is equivalent to one space.
1815 Anything from @samp{/*} through the next @samp{*/} is a comment.
1816 This means you may not nest these comments.
1820 The only way to include a newline ('\n') in a comment
1821 is to use this sort of comment.
1824 /* This sort of comment does not nest. */
1827 @cindex line comment character
1828 Anything from the @dfn{line comment} character to the next newline
1829 is considered a comment and is ignored. The line comment character is
1831 @samp{;} for the AMD 29K family;
1834 @samp{;} on the ARC;
1837 @samp{@@} on the ARM;
1840 @samp{;} for the H8/300 family;
1843 @samp{!} for the H8/500 family;
1846 @samp{;} for the HPPA;
1849 @samp{#} on the i386 and x86-64;
1852 @samp{#} on the i960;
1855 @samp{;} for the PDP-11;
1858 @samp{;} for picoJava;
1861 @samp{;} for Motorola PowerPC;
1864 @samp{!} for the Hitachi SH;
1867 @samp{!} on the SPARC;
1870 @samp{#} on the m32r;
1873 @samp{|} on the 680x0;
1876 @samp{#} on the 68HC11 and 68HC12;
1879 @samp{;} on the M880x0;
1882 @samp{#} on the Vax;
1885 @samp{!} for the Z8000;
1888 @samp{#} on the V850;
1890 see @ref{Machine Dependencies}. @refill
1891 @c FIXME What about i860?
1894 On some machines there are two different line comment characters. One
1895 character only begins a comment if it is the first non-whitespace character on
1896 a line, while the other always begins a comment.
1900 The V850 assembler also supports a double dash as starting a comment that
1901 extends to the end of the line.
1907 @cindex lines starting with @code{#}
1908 @cindex logical line numbers
1909 To be compatible with past assemblers, lines that begin with @samp{#} have a
1910 special interpretation. Following the @samp{#} should be an absolute
1911 expression (@pxref{Expressions}): the logical line number of the @emph{next}
1912 line. Then a string (@pxref{Strings,, Strings}) is allowed: if present it is a
1913 new logical file name. The rest of the line, if any, should be whitespace.
1915 If the first non-whitespace characters on the line are not numeric,
1916 the line is ignored. (Just like a comment.)
1919 # This is an ordinary comment.
1920 # 42-6 "new_file_name" # New logical file name
1921 # This is logical line # 36.
1923 This feature is deprecated, and may disappear from future versions
1924 of @code{@value{AS}}.
1929 @cindex characters used in symbols
1930 @ifclear SPECIAL-SYMS
1931 A @dfn{symbol} is one or more characters chosen from the set of all
1932 letters (both upper and lower case), digits and the three characters
1938 A @dfn{symbol} is one or more characters chosen from the set of all
1939 letters (both upper and lower case), digits and the three characters
1940 @samp{._$}. (Save that, on the H8/300 only, you may not use @samp{$} in
1946 On most machines, you can also use @code{$} in symbol names; exceptions
1947 are noted in @ref{Machine Dependencies}.
1949 No symbol may begin with a digit. Case is significant.
1950 There is no length limit: all characters are significant. Symbols are
1951 delimited by characters not in that set, or by the beginning of a file
1952 (since the source program must end with a newline, the end of a file is
1953 not a possible symbol delimiter). @xref{Symbols}.
1954 @cindex length of symbols
1959 @cindex statements, structure of
1960 @cindex line separator character
1961 @cindex statement separator character
1963 @ifclear abnormal-separator
1964 A @dfn{statement} ends at a newline character (@samp{\n}) or at a
1965 semicolon (@samp{;}). The newline or semicolon is considered part of
1966 the preceding statement. Newlines and semicolons within character
1967 constants are an exception: they do not end statements.
1969 @ifset abnormal-separator
1971 A @dfn{statement} ends at a newline character (@samp{\n}) or an ``at''
1972 sign (@samp{@@}). The newline or at sign is considered part of the
1973 preceding statement. Newlines and at signs within character constants
1974 are an exception: they do not end statements.
1977 A @dfn{statement} ends at a newline character (@samp{\n}) or an exclamation
1978 point (@samp{!}). The newline or exclamation point is considered part of the
1979 preceding statement. Newlines and exclamation points within character
1980 constants are an exception: they do not end statements.
1983 A @dfn{statement} ends at a newline character (@samp{\n}); or (for the
1984 H8/300) a dollar sign (@samp{$}); or (for the
1987 (@samp{;}). The newline or separator character is considered part of
1988 the preceding statement. Newlines and separators within character
1989 constants are an exception: they do not end statements.
1994 A @dfn{statement} ends at a newline character (@samp{\n}) or line
1995 separator character. (The line separator is usually @samp{;}, unless
1996 this conflicts with the comment character; @pxref{Machine Dependencies}.) The
1997 newline or separator character is considered part of the preceding
1998 statement. Newlines and separators within character constants are an
1999 exception: they do not end statements.
2002 @cindex newline, required at file end
2003 @cindex EOF, newline must precede
2004 It is an error to end any statement with end-of-file: the last
2005 character of any input file should be a newline.@refill
2007 An empty statement is allowed, and may include whitespace. It is ignored.
2009 @cindex instructions and directives
2010 @cindex directives and instructions
2011 @c "key symbol" is not used elsewhere in the document; seems pedantic to
2012 @c @defn{} it in that case, as was done previously... doc@cygnus.com,
2014 A statement begins with zero or more labels, optionally followed by a
2015 key symbol which determines what kind of statement it is. The key
2016 symbol determines the syntax of the rest of the statement. If the
2017 symbol begins with a dot @samp{.} then the statement is an assembler
2018 directive: typically valid for any computer. If the symbol begins with
2019 a letter the statement is an assembly language @dfn{instruction}: it
2020 assembles into a machine language instruction.
2022 Different versions of @code{@value{AS}} for different computers
2023 recognize different instructions. In fact, the same symbol may
2024 represent a different instruction in a different computer's assembly
2028 @cindex @code{:} (label)
2029 @cindex label (@code{:})
2030 A label is a symbol immediately followed by a colon (@code{:}).
2031 Whitespace before a label or after a colon is permitted, but you may not
2032 have whitespace between a label's symbol and its colon. @xref{Labels}.
2035 For HPPA targets, labels need not be immediately followed by a colon, but
2036 the definition of a label must begin in column zero. This also implies that
2037 only one label may be defined on each line.
2041 label: .directive followed by something
2042 another_label: # This is an empty statement.
2043 instruction operand_1, operand_2, @dots{}
2050 A constant is a number, written so that its value is known by
2051 inspection, without knowing any context. Like this:
2054 .byte 74, 0112, 092, 0x4A, 0X4a, 'J, '\J # All the same value.
2055 .ascii "Ring the bell\7" # A string constant.
2056 .octa 0x123456789abcdef0123456789ABCDEF0 # A bignum.
2057 .float 0f-314159265358979323846264338327\
2058 95028841971.693993751E-40 # - pi, a flonum.
2063 * Characters:: Character Constants
2064 * Numbers:: Number Constants
2068 @subsection Character Constants
2070 @cindex character constants
2071 @cindex constants, character
2072 There are two kinds of character constants. A @dfn{character} stands
2073 for one character in one byte and its value may be used in
2074 numeric expressions. String constants (properly called string
2075 @emph{literals}) are potentially many bytes and their values may not be
2076 used in arithmetic expressions.
2080 * Chars:: Characters
2084 @subsubsection Strings
2086 @cindex string constants
2087 @cindex constants, string
2088 A @dfn{string} is written between double-quotes. It may contain
2089 double-quotes or null characters. The way to get special characters
2090 into a string is to @dfn{escape} these characters: precede them with
2091 a backslash @samp{\} character. For example @samp{\\} represents
2092 one backslash: the first @code{\} is an escape which tells
2093 @code{@value{AS}} to interpret the second character literally as a backslash
2094 (which prevents @code{@value{AS}} from recognizing the second @code{\} as an
2095 escape character). The complete list of escapes follows.
2097 @cindex escape codes, character
2098 @cindex character escape codes
2101 @c Mnemonic for ACKnowledge; for ASCII this is octal code 007.
2103 @cindex @code{\b} (backspace character)
2104 @cindex backspace (@code{\b})
2106 Mnemonic for backspace; for ASCII this is octal code 010.
2109 @c Mnemonic for EOText; for ASCII this is octal code 004.
2111 @cindex @code{\f} (formfeed character)
2112 @cindex formfeed (@code{\f})
2114 Mnemonic for FormFeed; for ASCII this is octal code 014.
2116 @cindex @code{\n} (newline character)
2117 @cindex newline (@code{\n})
2119 Mnemonic for newline; for ASCII this is octal code 012.
2122 @c Mnemonic for prefix; for ASCII this is octal code 033, usually known as @code{escape}.
2124 @cindex @code{\r} (carriage return character)
2125 @cindex carriage return (@code{\r})
2127 Mnemonic for carriage-Return; for ASCII this is octal code 015.
2130 @c Mnemonic for space; for ASCII this is octal code 040. Included for compliance with
2131 @c other assemblers.
2133 @cindex @code{\t} (tab)
2134 @cindex tab (@code{\t})
2136 Mnemonic for horizontal Tab; for ASCII this is octal code 011.
2139 @c Mnemonic for Vertical tab; for ASCII this is octal code 013.
2140 @c @item \x @var{digit} @var{digit} @var{digit}
2141 @c A hexadecimal character code. The numeric code is 3 hexadecimal digits.
2143 @cindex @code{\@var{ddd}} (octal character code)
2144 @cindex octal character code (@code{\@var{ddd}})
2145 @item \ @var{digit} @var{digit} @var{digit}
2146 An octal character code. The numeric code is 3 octal digits.
2147 For compatibility with other Unix systems, 8 and 9 are accepted as digits:
2148 for example, @code{\008} has the value 010, and @code{\009} the value 011.
2150 @cindex @code{\@var{xd...}} (hex character code)
2151 @cindex hex character code (@code{\@var{xd...}})
2152 @item \@code{x} @var{hex-digits...}
2153 A hex character code. All trailing hex digits are combined. Either upper or
2154 lower case @code{x} works.
2156 @cindex @code{\\} (@samp{\} character)
2157 @cindex backslash (@code{\\})
2159 Represents one @samp{\} character.
2162 @c Represents one @samp{'} (accent acute) character.
2163 @c This is needed in single character literals
2164 @c (@xref{Characters,,Character Constants}.) to represent
2167 @cindex @code{\"} (doublequote character)
2168 @cindex doublequote (@code{\"})
2170 Represents one @samp{"} character. Needed in strings to represent
2171 this character, because an unescaped @samp{"} would end the string.
2173 @item \ @var{anything-else}
2174 Any other character when escaped by @kbd{\} gives a warning, but
2175 assembles as if the @samp{\} was not present. The idea is that if
2176 you used an escape sequence you clearly didn't want the literal
2177 interpretation of the following character. However @code{@value{AS}} has no
2178 other interpretation, so @code{@value{AS}} knows it is giving you the wrong
2179 code and warns you of the fact.
2182 Which characters are escapable, and what those escapes represent,
2183 varies widely among assemblers. The current set is what we think
2184 the BSD 4.2 assembler recognizes, and is a subset of what most C
2185 compilers recognize. If you are in doubt, do not use an escape
2189 @subsubsection Characters
2191 @cindex single character constant
2192 @cindex character, single
2193 @cindex constant, single character
2194 A single character may be written as a single quote immediately
2195 followed by that character. The same escapes apply to characters as
2196 to strings. So if you want to write the character backslash, you
2197 must write @kbd{'\\} where the first @code{\} escapes the second
2198 @code{\}. As you can see, the quote is an acute accent, not a
2199 grave accent. A newline
2201 @ifclear abnormal-separator
2202 (or semicolon @samp{;})
2204 @ifset abnormal-separator
2206 (or at sign @samp{@@})
2209 (or dollar sign @samp{$}, for the H8/300; or semicolon @samp{;} for the
2215 immediately following an acute accent is taken as a literal character
2216 and does not count as the end of a statement. The value of a character
2217 constant in a numeric expression is the machine's byte-wide code for
2218 that character. @code{@value{AS}} assumes your character code is ASCII:
2219 @kbd{'A} means 65, @kbd{'B} means 66, and so on. @refill
2222 @subsection Number Constants
2224 @cindex constants, number
2225 @cindex number constants
2226 @code{@value{AS}} distinguishes three kinds of numbers according to how they
2227 are stored in the target machine. @emph{Integers} are numbers that
2228 would fit into an @code{int} in the C language. @emph{Bignums} are
2229 integers, but they are stored in more than 32 bits. @emph{Flonums}
2230 are floating point numbers, described below.
2233 * Integers:: Integers
2238 * Bit Fields:: Bit Fields
2244 @subsubsection Integers
2246 @cindex constants, integer
2248 @cindex binary integers
2249 @cindex integers, binary
2250 A binary integer is @samp{0b} or @samp{0B} followed by zero or more of
2251 the binary digits @samp{01}.
2253 @cindex octal integers
2254 @cindex integers, octal
2255 An octal integer is @samp{0} followed by zero or more of the octal
2256 digits (@samp{01234567}).
2258 @cindex decimal integers
2259 @cindex integers, decimal
2260 A decimal integer starts with a non-zero digit followed by zero or
2261 more digits (@samp{0123456789}).
2263 @cindex hexadecimal integers
2264 @cindex integers, hexadecimal
2265 A hexadecimal integer is @samp{0x} or @samp{0X} followed by one or
2266 more hexadecimal digits chosen from @samp{0123456789abcdefABCDEF}.
2268 Integers have the usual values. To denote a negative integer, use
2269 the prefix operator @samp{-} discussed under expressions
2270 (@pxref{Prefix Ops,,Prefix Operators}).
2273 @subsubsection Bignums
2276 @cindex constants, bignum
2277 A @dfn{bignum} has the same syntax and semantics as an integer
2278 except that the number (or its negative) takes more than 32 bits to
2279 represent in binary. The distinction is made because in some places
2280 integers are permitted while bignums are not.
2283 @subsubsection Flonums
2285 @cindex floating point numbers
2286 @cindex constants, floating point
2288 @cindex precision, floating point
2289 A @dfn{flonum} represents a floating point number. The translation is
2290 indirect: a decimal floating point number from the text is converted by
2291 @code{@value{AS}} to a generic binary floating point number of more than
2292 sufficient precision. This generic floating point number is converted
2293 to a particular computer's floating point format (or formats) by a
2294 portion of @code{@value{AS}} specialized to that computer.
2296 A flonum is written by writing (in order)
2301 (@samp{0} is optional on the HPPA.)
2305 A letter, to tell @code{@value{AS}} the rest of the number is a flonum.
2307 @kbd{e} is recommended. Case is not important.
2309 @c FIXME: verify if flonum syntax really this vague for most cases
2310 (Any otherwise illegal letter works here, but that might be changed. Vax BSD
2311 4.2 assembler seems to allow any of @samp{defghDEFGH}.)
2314 On the H8/300, H8/500,
2316 and AMD 29K architectures, the letter must be
2317 one of the letters @samp{DFPRSX} (in upper or lower case).
2319 On the ARC, the letter must be one of the letters @samp{DFRS}
2320 (in upper or lower case).
2322 On the Intel 960 architecture, the letter must be
2323 one of the letters @samp{DFT} (in upper or lower case).
2325 On the HPPA architecture, the letter must be @samp{E} (upper case only).
2329 One of the letters @samp{DFPRSX} (in upper or lower case).
2332 One of the letters @samp{DFRS} (in upper or lower case).
2335 One of the letters @samp{DFPRSX} (in upper or lower case).
2338 The letter @samp{E} (upper case only).
2341 One of the letters @samp{DFT} (in upper or lower case).
2346 An optional sign: either @samp{+} or @samp{-}.
2349 An optional @dfn{integer part}: zero or more decimal digits.
2352 An optional @dfn{fractional part}: @samp{.} followed by zero
2353 or more decimal digits.
2356 An optional exponent, consisting of:
2360 An @samp{E} or @samp{e}.
2361 @c I can't find a config where "EXP_CHARS" is other than 'eE', but in
2362 @c principle this can perfectly well be different on different targets.
2364 Optional sign: either @samp{+} or @samp{-}.
2366 One or more decimal digits.
2371 At least one of the integer part or the fractional part must be
2372 present. The floating point number has the usual base-10 value.
2374 @code{@value{AS}} does all processing using integers. Flonums are computed
2375 independently of any floating point hardware in the computer running
2380 @c Bit fields are written as a general facility but are also controlled
2381 @c by a conditional-compilation flag---which is as of now (21mar91)
2382 @c turned on only by the i960 config of GAS.
2384 @subsubsection Bit Fields
2387 @cindex constants, bit field
2388 You can also define numeric constants as @dfn{bit fields}.
2389 specify two numbers separated by a colon---
2391 @var{mask}:@var{value}
2394 @code{@value{AS}} applies a bitwise @sc{and} between @var{mask} and
2397 The resulting number is then packed
2399 @c this conditional paren in case bit fields turned on elsewhere than 960
2400 (in host-dependent byte order)
2402 into a field whose width depends on which assembler directive has the
2403 bit-field as its argument. Overflow (a result from the bitwise and
2404 requiring more binary digits to represent) is not an error; instead,
2405 more constants are generated, of the specified width, beginning with the
2406 least significant digits.@refill
2408 The directives @code{.byte}, @code{.hword}, @code{.int}, @code{.long},
2409 @code{.short}, and @code{.word} accept bit-field arguments.
2414 @chapter Sections and Relocation
2419 * Secs Background:: Background
2420 * Ld Sections:: Linker Sections
2421 * As Sections:: Assembler Internal Sections
2422 * Sub-Sections:: Sub-Sections
2426 @node Secs Background
2429 Roughly, a section is a range of addresses, with no gaps; all data
2430 ``in'' those addresses is treated the same for some particular purpose.
2431 For example there may be a ``read only'' section.
2433 @cindex linker, and assembler
2434 @cindex assembler, and linker
2435 The linker @code{@value{LD}} reads many object files (partial programs) and
2436 combines their contents to form a runnable program. When @code{@value{AS}}
2437 emits an object file, the partial program is assumed to start at address 0.
2438 @code{@value{LD}} assigns the final addresses for the partial program, so that
2439 different partial programs do not overlap. This is actually an
2440 oversimplification, but it suffices to explain how @code{@value{AS}} uses
2443 @code{@value{LD}} moves blocks of bytes of your program to their run-time
2444 addresses. These blocks slide to their run-time addresses as rigid
2445 units; their length does not change and neither does the order of bytes
2446 within them. Such a rigid unit is called a @emph{section}. Assigning
2447 run-time addresses to sections is called @dfn{relocation}. It includes
2448 the task of adjusting mentions of object-file addresses so they refer to
2449 the proper run-time addresses.
2451 For the H8/300 and H8/500,
2452 and for the Hitachi SH,
2453 @code{@value{AS}} pads sections if needed to
2454 ensure they end on a word (sixteen bit) boundary.
2457 @cindex standard assembler sections
2458 An object file written by @code{@value{AS}} has at least three sections, any
2459 of which may be empty. These are named @dfn{text}, @dfn{data} and
2464 When it generates COFF output,
2466 @code{@value{AS}} can also generate whatever other named sections you specify
2467 using the @samp{.section} directive (@pxref{Section,,@code{.section}}).
2468 If you do not use any directives that place output in the @samp{.text}
2469 or @samp{.data} sections, these sections still exist, but are empty.
2474 When @code{@value{AS}} generates SOM or ELF output for the HPPA,
2476 @code{@value{AS}} can also generate whatever other named sections you
2477 specify using the @samp{.space} and @samp{.subspace} directives. See
2478 @cite{HP9000 Series 800 Assembly Language Reference Manual}
2479 (HP 92432-90001) for details on the @samp{.space} and @samp{.subspace}
2480 assembler directives.
2483 Additionally, @code{@value{AS}} uses different names for the standard
2484 text, data, and bss sections when generating SOM output. Program text
2485 is placed into the @samp{$CODE$} section, data into @samp{$DATA$}, and
2486 BSS into @samp{$BSS$}.
2490 Within the object file, the text section starts at address @code{0}, the
2491 data section follows, and the bss section follows the data section.
2494 When generating either SOM or ELF output files on the HPPA, the text
2495 section starts at address @code{0}, the data section at address
2496 @code{0x4000000}, and the bss section follows the data section.
2499 To let @code{@value{LD}} know which data changes when the sections are
2500 relocated, and how to change that data, @code{@value{AS}} also writes to the
2501 object file details of the relocation needed. To perform relocation
2502 @code{@value{LD}} must know, each time an address in the object
2506 Where in the object file is the beginning of this reference to
2509 How long (in bytes) is this reference?
2511 Which section does the address refer to? What is the numeric value of
2513 (@var{address}) @minus{} (@var{start-address of section})?
2516 Is the reference to an address ``Program-Counter relative''?
2519 @cindex addresses, format of
2520 @cindex section-relative addressing
2521 In fact, every address @code{@value{AS}} ever uses is expressed as
2523 (@var{section}) + (@var{offset into section})
2526 Further, most expressions @code{@value{AS}} computes have this section-relative
2529 (For some object formats, such as SOM for the HPPA, some expressions are
2530 symbol-relative instead.)
2533 In this manual we use the notation @{@var{secname} @var{N}@} to mean ``offset
2534 @var{N} into section @var{secname}.''
2536 Apart from text, data and bss sections you need to know about the
2537 @dfn{absolute} section. When @code{@value{LD}} mixes partial programs,
2538 addresses in the absolute section remain unchanged. For example, address
2539 @code{@{absolute 0@}} is ``relocated'' to run-time address 0 by
2540 @code{@value{LD}}. Although the linker never arranges two partial programs'
2541 data sections with overlapping addresses after linking, @emph{by definition}
2542 their absolute sections must overlap. Address @code{@{absolute@ 239@}} in one
2543 part of a program is always the same address when the program is running as
2544 address @code{@{absolute@ 239@}} in any other part of the program.
2546 The idea of sections is extended to the @dfn{undefined} section. Any
2547 address whose section is unknown at assembly time is by definition
2548 rendered @{undefined @var{U}@}---where @var{U} is filled in later.
2549 Since numbers are always defined, the only way to generate an undefined
2550 address is to mention an undefined symbol. A reference to a named
2551 common block would be such a symbol: its value is unknown at assembly
2552 time so it has section @emph{undefined}.
2554 By analogy the word @emph{section} is used to describe groups of sections in
2555 the linked program. @code{@value{LD}} puts all partial programs' text
2556 sections in contiguous addresses in the linked program. It is
2557 customary to refer to the @emph{text section} of a program, meaning all
2558 the addresses of all partial programs' text sections. Likewise for
2559 data and bss sections.
2561 Some sections are manipulated by @code{@value{LD}}; others are invented for
2562 use of @code{@value{AS}} and have no meaning except during assembly.
2565 @section Linker Sections
2566 @code{@value{LD}} deals with just four kinds of sections, summarized below.
2571 @cindex named sections
2572 @cindex sections, named
2573 @item named sections
2576 @cindex text section
2577 @cindex data section
2581 These sections hold your program. @code{@value{AS}} and @code{@value{LD}} treat them as
2582 separate but equal sections. Anything you can say of one section is
2585 When the program is running, however, it is
2586 customary for the text section to be unalterable. The
2587 text section is often shared among processes: it contains
2588 instructions, constants and the like. The data section of a running
2589 program is usually alterable: for example, C variables would be stored
2590 in the data section.
2595 This section contains zeroed bytes when your program begins running. It
2596 is used to hold uninitialized variables or common storage. The length of
2597 each partial program's bss section is important, but because it starts
2598 out containing zeroed bytes there is no need to store explicit zero
2599 bytes in the object file. The bss section was invented to eliminate
2600 those explicit zeros from object files.
2602 @cindex absolute section
2603 @item absolute section
2604 Address 0 of this section is always ``relocated'' to runtime address 0.
2605 This is useful if you want to refer to an address that @code{@value{LD}} must
2606 not change when relocating. In this sense we speak of absolute
2607 addresses being ``unrelocatable'': they do not change during relocation.
2609 @cindex undefined section
2610 @item undefined section
2611 This ``section'' is a catch-all for address references to objects not in
2612 the preceding sections.
2613 @c FIXME: ref to some other doc on obj-file formats could go here.
2616 @cindex relocation example
2617 An idealized example of three relocatable sections follows.
2619 The example uses the traditional section names @samp{.text} and @samp{.data}.
2621 Memory addresses are on the horizontal axis.
2625 @c END TEXI2ROFF-KILL
2628 partial program # 1: |ttttt|dddd|00|
2635 partial program # 2: |TTT|DDD|000|
2638 +--+---+-----+--+----+---+-----+~~
2639 linked program: | |TTT|ttttt| |dddd|DDD|00000|
2640 +--+---+-----+--+----+---+-----+~~
2642 addresses: 0 @dots{}
2649 \line{\it Partial program \#1: \hfil}
2650 \line{\ibox{2.5cm}{\tt text}\ibox{2cm}{\tt data}\ibox{1cm}{\tt bss}\hfil}
2651 \line{\boxit{2.5cm}{\tt ttttt}\boxit{2cm}{\tt dddd}\boxit{1cm}{\tt 00}\hfil}
2653 \line{\it Partial program \#2: \hfil}
2654 \line{\ibox{1cm}{\tt text}\ibox{1.5cm}{\tt data}\ibox{1cm}{\tt bss}\hfil}
2655 \line{\boxit{1cm}{\tt TTT}\boxit{1.5cm}{\tt DDDD}\boxit{1cm}{\tt 000}\hfil}
2657 \line{\it linked program: \hfil}
2658 \line{\ibox{.5cm}{}\ibox{1cm}{\tt text}\ibox{2.5cm}{}\ibox{.75cm}{}\ibox{2cm}{\tt data}\ibox{1.5cm}{}\ibox{2cm}{\tt bss}\hfil}
2659 \line{\boxit{.5cm}{}\boxit{1cm}{\tt TTT}\boxit{2.5cm}{\tt
2660 ttttt}\boxit{.75cm}{}\boxit{2cm}{\tt dddd}\boxit{1.5cm}{\tt
2661 DDDD}\boxit{2cm}{\tt 00000}\ \dots\hfil}
2663 \line{\it addresses: \hfil}
2667 @c END TEXI2ROFF-KILL
2670 @section Assembler Internal Sections
2672 @cindex internal assembler sections
2673 @cindex sections in messages, internal
2674 These sections are meant only for the internal use of @code{@value{AS}}. They
2675 have no meaning at run-time. You do not really need to know about these
2676 sections for most purposes; but they can be mentioned in @code{@value{AS}}
2677 warning messages, so it might be helpful to have an idea of their
2678 meanings to @code{@value{AS}}. These sections are used to permit the
2679 value of every expression in your assembly language program to be a
2680 section-relative address.
2683 @cindex assembler internal logic error
2684 @item ASSEMBLER-INTERNAL-LOGIC-ERROR!
2685 An internal assembler logic error has been found. This means there is a
2686 bug in the assembler.
2688 @cindex expr (internal section)
2690 The assembler stores complex expression internally as combinations of
2691 symbols. When it needs to represent an expression as a symbol, it puts
2692 it in the expr section.
2694 @c FIXME item transfer[t] vector preload
2695 @c FIXME item transfer[t] vector postload
2696 @c FIXME item register
2700 @section Sub-Sections
2702 @cindex numbered subsections
2703 @cindex grouping data
2709 fall into two sections: text and data.
2711 You may have separate groups of
2713 data in named sections
2717 data in named sections
2723 that you want to end up near to each other in the object file, even though they
2724 are not contiguous in the assembler source. @code{@value{AS}} allows you to
2725 use @dfn{subsections} for this purpose. Within each section, there can be
2726 numbered subsections with values from 0 to 8192. Objects assembled into the
2727 same subsection go into the object file together with other objects in the same
2728 subsection. For example, a compiler might want to store constants in the text
2729 section, but might not want to have them interspersed with the program being
2730 assembled. In this case, the compiler could issue a @samp{.text 0} before each
2731 section of code being output, and a @samp{.text 1} before each group of
2732 constants being output.
2734 Subsections are optional. If you do not use subsections, everything
2735 goes in subsection number zero.
2738 Each subsection is zero-padded up to a multiple of four bytes.
2739 (Subsections may be padded a different amount on different flavors
2740 of @code{@value{AS}}.)
2744 On the H8/300 and H8/500 platforms, each subsection is zero-padded to a word
2745 boundary (two bytes).
2746 The same is true on the Hitachi SH.
2749 @c FIXME section padding (alignment)?
2750 @c Rich Pixley says padding here depends on target obj code format; that
2751 @c doesn't seem particularly useful to say without further elaboration,
2752 @c so for now I say nothing about it. If this is a generic BFD issue,
2753 @c these paragraphs might need to vanish from this manual, and be
2754 @c discussed in BFD chapter of binutils (or some such).
2757 On the AMD 29K family, no particular padding is added to section or
2758 subsection sizes; @value{AS} forces no alignment on this platform.
2762 Subsections appear in your object file in numeric order, lowest numbered
2763 to highest. (All this to be compatible with other people's assemblers.)
2764 The object file contains no representation of subsections; @code{@value{LD}} and
2765 other programs that manipulate object files see no trace of them.
2766 They just see all your text subsections as a text section, and all your
2767 data subsections as a data section.
2769 To specify which subsection you want subsequent statements assembled
2770 into, use a numeric argument to specify it, in a @samp{.text
2771 @var{expression}} or a @samp{.data @var{expression}} statement.
2774 When generating COFF output, you
2779 can also use an extra subsection
2780 argument with arbitrary named sections: @samp{.section @var{name},
2783 @var{Expression} should be an absolute expression.
2784 (@xref{Expressions}.) If you just say @samp{.text} then @samp{.text 0}
2785 is assumed. Likewise @samp{.data} means @samp{.data 0}. Assembly
2786 begins in @code{text 0}. For instance:
2788 .text 0 # The default subsection is text 0 anyway.
2789 .ascii "This lives in the first text subsection. *"
2791 .ascii "But this lives in the second text subsection."
2793 .ascii "This lives in the data section,"
2794 .ascii "in the first data subsection."
2796 .ascii "This lives in the first text section,"
2797 .ascii "immediately following the asterisk (*)."
2800 Each section has a @dfn{location counter} incremented by one for every byte
2801 assembled into that section. Because subsections are merely a convenience
2802 restricted to @code{@value{AS}} there is no concept of a subsection location
2803 counter. There is no way to directly manipulate a location counter---but the
2804 @code{.align} directive changes it, and any label definition captures its
2805 current value. The location counter of the section where statements are being
2806 assembled is said to be the @dfn{active} location counter.
2809 @section bss Section
2812 @cindex common variable storage
2813 The bss section is used for local common variable storage.
2814 You may allocate address space in the bss section, but you may
2815 not dictate data to load into it before your program executes. When
2816 your program starts running, all the contents of the bss
2817 section are zeroed bytes.
2819 The @code{.lcomm} pseudo-op defines a symbol in the bss section; see
2820 @ref{Lcomm,,@code{.lcomm}}.
2822 The @code{.comm} pseudo-op may be used to declare a common symbol, which is
2823 another form of uninitialized symbol; see @xref{Comm,,@code{.comm}}.
2826 When assembling for a target which supports multiple sections, such as ELF or
2827 COFF, you may switch into the @code{.bss} section and define symbols as usual;
2828 see @ref{Section,,@code{.section}}. You may only assemble zero values into the
2829 section. Typically the section will only contain symbol definitions and
2830 @code{.skip} directives (@pxref{Skip,,@code{.skip}}).
2837 Symbols are a central concept: the programmer uses symbols to name
2838 things, the linker uses symbols to link, and the debugger uses symbols
2842 @cindex debuggers, and symbol order
2843 @emph{Warning:} @code{@value{AS}} does not place symbols in the object file in
2844 the same order they were declared. This may break some debuggers.
2849 * Setting Symbols:: Giving Symbols Other Values
2850 * Symbol Names:: Symbol Names
2851 * Dot:: The Special Dot Symbol
2852 * Symbol Attributes:: Symbol Attributes
2859 A @dfn{label} is written as a symbol immediately followed by a colon
2860 @samp{:}. The symbol then represents the current value of the
2861 active location counter, and is, for example, a suitable instruction
2862 operand. You are warned if you use the same symbol to represent two
2863 different locations: the first definition overrides any other
2867 On the HPPA, the usual form for a label need not be immediately followed by a
2868 colon, but instead must start in column zero. Only one label may be defined on
2869 a single line. To work around this, the HPPA version of @code{@value{AS}} also
2870 provides a special directive @code{.label} for defining labels more flexibly.
2873 @node Setting Symbols
2874 @section Giving Symbols Other Values
2876 @cindex assigning values to symbols
2877 @cindex symbol values, assigning
2878 A symbol can be given an arbitrary value by writing a symbol, followed
2879 by an equals sign @samp{=}, followed by an expression
2880 (@pxref{Expressions}). This is equivalent to using the @code{.set}
2881 directive. @xref{Set,,@code{.set}}.
2884 @section Symbol Names
2886 @cindex symbol names
2887 @cindex names, symbol
2888 @ifclear SPECIAL-SYMS
2889 Symbol names begin with a letter or with one of @samp{._}. On most
2890 machines, you can also use @code{$} in symbol names; exceptions are
2891 noted in @ref{Machine Dependencies}. That character may be followed by any
2892 string of digits, letters, dollar signs (unless otherwise noted in
2893 @ref{Machine Dependencies}), and underscores.
2896 For the AMD 29K family, @samp{?} is also allowed in the
2897 body of a symbol name, though not at its beginning.
2902 Symbol names begin with a letter or with one of @samp{._}. On the
2904 H8/500, you can also use @code{$} in symbol names. That character may
2905 be followed by any string of digits, letters, dollar signs (save on the
2906 H8/300), and underscores.
2910 Case of letters is significant: @code{foo} is a different symbol name
2913 Each symbol has exactly one name. Each name in an assembly language program
2914 refers to exactly one symbol. You may use that symbol name any number of times
2917 @subheading Local Symbol Names
2919 @cindex local symbol names
2920 @cindex symbol names, local
2921 @cindex temporary symbol names
2922 @cindex symbol names, temporary
2923 Local symbols help compilers and programmers use names temporarily.
2924 They create symbols which are guaranteed to be unique over the entire scope of
2925 the input source code and which can be referred to by a simple notation.
2926 To define a local symbol, write a label of the form @samp{@b{N}:} (where @b{N}
2927 represents any positive integer). To refer to the most recent previous
2928 definition of that symbol write @samp{@b{N}b}, using the same number as when
2929 you defined the label. To refer to the next definition of a local label, write
2930 @samp{@b{N}f}--- The @samp{b} stands for``backwards'' and the @samp{f} stands
2933 There is no restriction on how you can use these labels, and you can reuse them
2934 too. So that it is possible to repeatedly define the same local label (using
2935 the same number @samp{@b{N}}), although you can only refer to the most recently
2936 defined local label of that number (for a backwards reference) or the next
2937 definition of a specific local label for a forward reference. It is also worth
2938 noting that the first 10 local labels (@samp{@b{0:}}@dots{}@samp{@b{9:}}) are
2939 implemented in a slightly more efficient manner than the others.
2950 Which is the equivalent of:
2953 label_1: branch label_3
2954 label_2: branch label_1
2955 label_3: branch label_4
2956 label_4: branch label_3
2959 Local symbol names are only a notational device. They are immediately
2960 transformed into more conventional symbol names before the assembler uses them.
2961 The symbol names stored in the symbol table, appearing in error messages and
2962 optionally emitted to the object file. The names are constructed using these
2967 All local labels begin with @samp{L}. Normally both @code{@value{AS}} and
2968 @code{@value{LD}} forget symbols that start with @samp{L}. These labels are
2969 used for symbols you are never intended to see. If you use the
2970 @samp{-L} option then @code{@value{AS}} retains these symbols in the
2971 object file. If you also instruct @code{@value{LD}} to retain these symbols,
2972 you may use them in debugging.
2975 This is the number that was used in the local label definition. So if the
2976 label is written @samp{55:} then the number is @samp{55}.
2979 This unusual character is included so you do not accidentally invent a symbol
2980 of the same name. The character has ASCII value of @samp{\002} (control-B).
2982 @item @emph{ordinal number}
2983 This is a serial number to keep the labels distinct. The first definition of
2984 @samp{0:} gets the number @samp{1}. The 15th definition of @samp{0:} gets the
2985 number @samp{15}, and so on. Likewise the first definition of @samp{1:} gets
2986 the number @samp{1} and its 15th defintion gets @samp{15} as well.
2989 So for example, the first @code{1:} is named @code{L1@kbd{C-B}1}, the 44th
2990 @code{3:} is named @code{L3@kbd{C-B}44}.
2992 @subheading Dollar Local Labels
2993 @cindex dollar local symbols
2995 @code{@value{AS}} also supports an even more local form of local labels called
2996 dollar labels. These labels go out of scope (ie they become undefined) as soon
2997 as a non-local label is defined. Thus they remain valid for only a small
2998 region of the input source code. Normal local labels, by contrast, remain in
2999 scope for the entire file, or until they are redefined by another occurrence of
3000 the same local label.
3002 Dollar labels are defined in exactly the same way as ordinary local labels,
3003 except that instead of being terminated by a colon, they are terminated by a
3004 dollar sign. eg @samp{@b{55$}}.
3006 They can also be distinguished from ordinary local labels by their transformed
3007 name which uses ASCII character @samp{\001} (control-A) as the magic character
3008 to distinguish them from ordinary labels. Thus the 5th defintion of @samp{6$}
3009 is named @samp{L6@kbd{C-A}5}.
3012 @section The Special Dot Symbol
3014 @cindex dot (symbol)
3015 @cindex @code{.} (symbol)
3016 @cindex current address
3017 @cindex location counter
3018 The special symbol @samp{.} refers to the current address that
3019 @code{@value{AS}} is assembling into. Thus, the expression @samp{melvin:
3020 .long .} defines @code{melvin} to contain its own address.
3021 Assigning a value to @code{.} is treated the same as a @code{.org}
3022 directive. Thus, the expression @samp{.=.+4} is the same as saying
3023 @ifclear no-space-dir
3032 @node Symbol Attributes
3033 @section Symbol Attributes
3035 @cindex symbol attributes
3036 @cindex attributes, symbol
3037 Every symbol has, as well as its name, the attributes ``Value'' and
3038 ``Type''. Depending on output format, symbols can also have auxiliary
3041 The detailed definitions are in @file{a.out.h}.
3044 If you use a symbol without defining it, @code{@value{AS}} assumes zero for
3045 all these attributes, and probably won't warn you. This makes the
3046 symbol an externally defined symbol, which is generally what you
3050 * Symbol Value:: Value
3051 * Symbol Type:: Type
3054 * a.out Symbols:: Symbol Attributes: @code{a.out}
3058 * a.out Symbols:: Symbol Attributes: @code{a.out}
3061 * a.out Symbols:: Symbol Attributes: @code{a.out}, @code{b.out}
3066 * COFF Symbols:: Symbol Attributes for COFF
3069 * SOM Symbols:: Symbol Attributes for SOM
3076 @cindex value of a symbol
3077 @cindex symbol value
3078 The value of a symbol is (usually) 32 bits. For a symbol which labels a
3079 location in the text, data, bss or absolute sections the value is the
3080 number of addresses from the start of that section to the label.
3081 Naturally for text, data and bss sections the value of a symbol changes
3082 as @code{@value{LD}} changes section base addresses during linking. Absolute
3083 symbols' values do not change during linking: that is why they are
3086 The value of an undefined symbol is treated in a special way. If it is
3087 0 then the symbol is not defined in this assembler source file, and
3088 @code{@value{LD}} tries to determine its value from other files linked into the
3089 same program. You make this kind of symbol simply by mentioning a symbol
3090 name without defining it. A non-zero value represents a @code{.comm}
3091 common declaration. The value is how much common storage to reserve, in
3092 bytes (addresses). The symbol refers to the first address of the
3098 @cindex type of a symbol
3100 The type attribute of a symbol contains relocation (section)
3101 information, any flag settings indicating that a symbol is external, and
3102 (optionally), other information for linkers and debuggers. The exact
3103 format depends on the object-code output format in use.
3108 @c The following avoids a "widow" subsection title. @group would be
3109 @c better if it were available outside examples.
3112 @subsection Symbol Attributes: @code{a.out}, @code{b.out}
3114 @cindex @code{b.out} symbol attributes
3115 @cindex symbol attributes, @code{b.out}
3116 These symbol attributes appear only when @code{@value{AS}} is configured for
3117 one of the Berkeley-descended object output formats---@code{a.out} or
3123 @subsection Symbol Attributes: @code{a.out}
3125 @cindex @code{a.out} symbol attributes
3126 @cindex symbol attributes, @code{a.out}
3132 @subsection Symbol Attributes: @code{a.out}
3134 @cindex @code{a.out} symbol attributes
3135 @cindex symbol attributes, @code{a.out}
3139 * Symbol Desc:: Descriptor
3140 * Symbol Other:: Other
3144 @subsubsection Descriptor
3146 @cindex descriptor, of @code{a.out} symbol
3147 This is an arbitrary 16-bit value. You may establish a symbol's
3148 descriptor value by using a @code{.desc} statement
3149 (@pxref{Desc,,@code{.desc}}). A descriptor value means nothing to
3153 @subsubsection Other
3155 @cindex other attribute, of @code{a.out} symbol
3156 This is an arbitrary 8-bit value. It means nothing to @code{@value{AS}}.
3161 @subsection Symbol Attributes for COFF
3163 @cindex COFF symbol attributes
3164 @cindex symbol attributes, COFF
3166 The COFF format supports a multitude of auxiliary symbol attributes;
3167 like the primary symbol attributes, they are set between @code{.def} and
3168 @code{.endef} directives.
3170 @subsubsection Primary Attributes
3172 @cindex primary attributes, COFF symbols
3173 The symbol name is set with @code{.def}; the value and type,
3174 respectively, with @code{.val} and @code{.type}.
3176 @subsubsection Auxiliary Attributes
3178 @cindex auxiliary attributes, COFF symbols
3179 The @code{@value{AS}} directives @code{.dim}, @code{.line}, @code{.scl},
3180 @code{.size}, and @code{.tag} can generate auxiliary symbol table
3181 information for COFF.
3186 @subsection Symbol Attributes for SOM
3188 @cindex SOM symbol attributes
3189 @cindex symbol attributes, SOM
3191 The SOM format for the HPPA supports a multitude of symbol attributes set with
3192 the @code{.EXPORT} and @code{.IMPORT} directives.
3194 The attributes are described in @cite{HP9000 Series 800 Assembly
3195 Language Reference Manual} (HP 92432-90001) under the @code{IMPORT} and
3196 @code{EXPORT} assembler directive documentation.
3200 @chapter Expressions
3204 @cindex numeric values
3205 An @dfn{expression} specifies an address or numeric value.
3206 Whitespace may precede and/or follow an expression.
3208 The result of an expression must be an absolute number, or else an offset into
3209 a particular section. If an expression is not absolute, and there is not
3210 enough information when @code{@value{AS}} sees the expression to know its
3211 section, a second pass over the source program might be necessary to interpret
3212 the expression---but the second pass is currently not implemented.
3213 @code{@value{AS}} aborts with an error message in this situation.
3216 * Empty Exprs:: Empty Expressions
3217 * Integer Exprs:: Integer Expressions
3221 @section Empty Expressions
3223 @cindex empty expressions
3224 @cindex expressions, empty
3225 An empty expression has no value: it is just whitespace or null.
3226 Wherever an absolute expression is required, you may omit the
3227 expression, and @code{@value{AS}} assumes a value of (absolute) 0. This
3228 is compatible with other assemblers.
3231 @section Integer Expressions
3233 @cindex integer expressions
3234 @cindex expressions, integer
3235 An @dfn{integer expression} is one or more @emph{arguments} delimited
3236 by @emph{operators}.
3239 * Arguments:: Arguments
3240 * Operators:: Operators
3241 * Prefix Ops:: Prefix Operators
3242 * Infix Ops:: Infix Operators
3246 @subsection Arguments
3248 @cindex expression arguments
3249 @cindex arguments in expressions
3250 @cindex operands in expressions
3251 @cindex arithmetic operands
3252 @dfn{Arguments} are symbols, numbers or subexpressions. In other
3253 contexts arguments are sometimes called ``arithmetic operands''. In
3254 this manual, to avoid confusing them with the ``instruction operands'' of
3255 the machine language, we use the term ``argument'' to refer to parts of
3256 expressions only, reserving the word ``operand'' to refer only to machine
3257 instruction operands.
3259 Symbols are evaluated to yield @{@var{section} @var{NNN}@} where
3260 @var{section} is one of text, data, bss, absolute,
3261 or undefined. @var{NNN} is a signed, 2's complement 32 bit
3264 Numbers are usually integers.
3266 A number can be a flonum or bignum. In this case, you are warned
3267 that only the low order 32 bits are used, and @code{@value{AS}} pretends
3268 these 32 bits are an integer. You may write integer-manipulating
3269 instructions that act on exotic constants, compatible with other
3272 @cindex subexpressions
3273 Subexpressions are a left parenthesis @samp{(} followed by an integer
3274 expression, followed by a right parenthesis @samp{)}; or a prefix
3275 operator followed by an argument.
3278 @subsection Operators
3280 @cindex operators, in expressions
3281 @cindex arithmetic functions
3282 @cindex functions, in expressions
3283 @dfn{Operators} are arithmetic functions, like @code{+} or @code{%}. Prefix
3284 operators are followed by an argument. Infix operators appear
3285 between their arguments. Operators may be preceded and/or followed by
3289 @subsection Prefix Operator
3291 @cindex prefix operators
3292 @code{@value{AS}} has the following @dfn{prefix operators}. They each take
3293 one argument, which must be absolute.
3295 @c the tex/end tex stuff surrounding this small table is meant to make
3296 @c it align, on the printed page, with the similar table in the next
3297 @c section (which is inside an enumerate).
3299 \global\advance\leftskip by \itemindent
3304 @dfn{Negation}. Two's complement negation.
3306 @dfn{Complementation}. Bitwise not.
3310 \global\advance\leftskip by -\itemindent
3314 @subsection Infix Operators
3316 @cindex infix operators
3317 @cindex operators, permitted arguments
3318 @dfn{Infix operators} take two arguments, one on either side. Operators
3319 have precedence, but operations with equal precedence are performed left
3320 to right. Apart from @code{+} or @code{-}, both arguments must be
3321 absolute, and the result is absolute.
3324 @cindex operator precedence
3325 @cindex precedence of operators
3332 @dfn{Multiplication}.
3335 @dfn{Division}. Truncation is the same as the C operator @samp{/}
3342 @dfn{Shift Left}. Same as the C operator @samp{<<}.
3346 @dfn{Shift Right}. Same as the C operator @samp{>>}.
3350 Intermediate precedence
3355 @dfn{Bitwise Inclusive Or}.
3361 @dfn{Bitwise Exclusive Or}.
3364 @dfn{Bitwise Or Not}.
3371 @cindex addition, permitted arguments
3372 @cindex plus, permitted arguments
3373 @cindex arguments for addition
3375 @dfn{Addition}. If either argument is absolute, the result has the section of
3376 the other argument. You may not add together arguments from different
3379 @cindex subtraction, permitted arguments
3380 @cindex minus, permitted arguments
3381 @cindex arguments for subtraction
3383 @dfn{Subtraction}. If the right argument is absolute, the
3384 result has the section of the left argument.
3385 If both arguments are in the same section, the result is absolute.
3386 You may not subtract arguments from different sections.
3387 @c FIXME is there still something useful to say about undefined - undefined ?
3389 @cindex comparison expressions
3390 @cindex expressions, comparison
3394 @dfn{Is Not Equal To}
3398 @dfn{Is Greater Than}
3400 @dfn{Is Greater Than Or Equal To}
3402 @dfn{Is Less Than Or Equal To}
3404 The comparison operators can be used as infix operators. A true results has a
3405 value of -1 whereas a false result has a value of 0. Note, these operators
3406 perform signed comparisons.
3409 @item Lowest Precedence
3418 These two logical operations can be used to combine the results of sub
3419 expressions. Note, unlike the comparison operators a true result returns a
3420 value of 1 but a false results does still return 0. Also note that the logical
3421 or operator has a slightly lower precedence than logical and.
3426 In short, it's only meaningful to add or subtract the @emph{offsets} in an
3427 address; you can only have a defined section in one of the two arguments.
3430 @chapter Assembler Directives
3432 @cindex directives, machine independent
3433 @cindex pseudo-ops, machine independent
3434 @cindex machine independent directives
3435 All assembler directives have names that begin with a period (@samp{.}).
3436 The rest of the name is letters, usually in lower case.
3438 This chapter discusses directives that are available regardless of the
3439 target machine configuration for the @sc{gnu} assembler.
3441 Some machine configurations provide additional directives.
3442 @xref{Machine Dependencies}.
3445 @ifset machine-directives
3446 @xref{Machine Dependencies} for additional directives.
3451 * Abort:: @code{.abort}
3453 * ABORT:: @code{.ABORT}
3456 * Align:: @code{.align @var{abs-expr} , @var{abs-expr}}
3457 * Ascii:: @code{.ascii "@var{string}"}@dots{}
3458 * Asciz:: @code{.asciz "@var{string}"}@dots{}
3459 * Balign:: @code{.balign @var{abs-expr} , @var{abs-expr}}
3460 * Byte:: @code{.byte @var{expressions}}
3461 * Comm:: @code{.comm @var{symbol} , @var{length} }
3462 * Data:: @code{.data @var{subsection}}
3464 * Def:: @code{.def @var{name}}
3467 * Desc:: @code{.desc @var{symbol}, @var{abs-expression}}
3473 * Double:: @code{.double @var{flonums}}
3474 * Eject:: @code{.eject}
3475 * Else:: @code{.else}
3476 * Elseif:: @code{.elseif}
3479 * Endef:: @code{.endef}
3482 * Endfunc:: @code{.endfunc}
3483 * Endif:: @code{.endif}
3484 * Equ:: @code{.equ @var{symbol}, @var{expression}}
3485 * Equiv:: @code{.equiv @var{symbol}, @var{expression}}
3487 * Exitm:: @code{.exitm}
3488 * Extern:: @code{.extern}
3489 * Fail:: @code{.fail}
3490 @ifclear no-file-dir
3491 * File:: @code{.file @var{string}}
3494 * Fill:: @code{.fill @var{repeat} , @var{size} , @var{value}}
3495 * Float:: @code{.float @var{flonums}}
3496 * Func:: @code{.func}
3497 * Global:: @code{.global @var{symbol}}, @code{.globl @var{symbol}}
3499 * Hidden:: @code{.hidden @var{names}}
3502 * hword:: @code{.hword @var{expressions}}
3503 * Ident:: @code{.ident}
3504 * If:: @code{.if @var{absolute expression}}
3505 * Incbin:: @code{.incbin "@var{file}"[,@var{skip}[,@var{count}]]}
3506 * Include:: @code{.include "@var{file}"}
3507 * Int:: @code{.int @var{expressions}}
3509 * Internal:: @code{.internal @var{names}}
3512 * Irp:: @code{.irp @var{symbol},@var{values}}@dots{}
3513 * Irpc:: @code{.irpc @var{symbol},@var{values}}@dots{}
3514 * Lcomm:: @code{.lcomm @var{symbol} , @var{length}}
3515 * Lflags:: @code{.lflags}
3516 @ifclear no-line-dir
3517 * Line:: @code{.line @var{line-number}}
3520 * Ln:: @code{.ln @var{line-number}}
3521 * Linkonce:: @code{.linkonce [@var{type}]}
3522 * List:: @code{.list}
3523 * Long:: @code{.long @var{expressions}}
3525 * Lsym:: @code{.lsym @var{symbol}, @var{expression}}
3528 * Macro:: @code{.macro @var{name} @var{args}}@dots{}
3529 * MRI:: @code{.mri @var{val}}
3530 * Nolist:: @code{.nolist}
3531 * Octa:: @code{.octa @var{bignums}}
3532 * Org:: @code{.org @var{new-lc} , @var{fill}}
3533 * P2align:: @code{.p2align @var{abs-expr} , @var{abs-expr}}
3535 * PopSection:: @code{.popsection}
3536 * Previous:: @code{.previous}
3539 * Print:: @code{.print @var{string}}
3541 * Protected:: @code{.protected @var{names}}
3544 * Psize:: @code{.psize @var{lines}, @var{columns}}
3545 * Purgem:: @code{.purgem @var{name}}
3547 * PushSection:: @code{.pushsection @var{name}}
3550 * Quad:: @code{.quad @var{bignums}}
3551 * Rept:: @code{.rept @var{count}}
3552 * Sbttl:: @code{.sbttl "@var{subheading}"}
3554 * Scl:: @code{.scl @var{class}}
3555 * Section:: @code{.section @var{name}, @var{subsection}}
3558 * Set:: @code{.set @var{symbol}, @var{expression}}
3559 * Short:: @code{.short @var{expressions}}
3560 * Single:: @code{.single @var{flonums}}
3561 * Size:: @code{.size [@var{name} , @var{expression}]}
3562 * Skip:: @code{.skip @var{size} , @var{fill}}
3563 * Sleb128:: @code{.sleb128 @var{expressions}}
3564 * Space:: @code{.space @var{size} , @var{fill}}
3566 * Stab:: @code{.stabd, .stabn, .stabs}
3569 * String:: @code{.string "@var{str}"}
3570 * Struct:: @code{.struct @var{expression}}
3572 * SubSection:: @code{.subsection}
3573 * Symver:: @code{.symver @var{name},@var{name2@@nodename}}
3577 * Tag:: @code{.tag @var{structname}}
3580 * Text:: @code{.text @var{subsection}}
3581 * Title:: @code{.title "@var{heading}"}
3582 * Type:: @code{.type <@var{int} | @var{name} , @var{type description}>}
3583 * Uleb128:: @code{.uleb128 @var{expressions}}
3585 * Val:: @code{.val @var{addr}}
3589 * Version:: @code{.version "@var{string}"}
3590 * VTableEntry:: @code{.vtable_entry @var{table}, @var{offset}}
3591 * VTableInherit:: @code{.vtable_inherit @var{child}, @var{parent}}
3592 * Weak:: @code{.weak @var{names}}
3595 * Word:: @code{.word @var{expressions}}
3596 * Deprecated:: Deprecated Directives
3600 @section @code{.abort}
3602 @cindex @code{abort} directive
3603 @cindex stopping the assembly
3604 This directive stops the assembly immediately. It is for
3605 compatibility with other assemblers. The original idea was that the
3606 assembly language source would be piped into the assembler. If the sender
3607 of the source quit, it could use this directive tells @code{@value{AS}} to
3608 quit also. One day @code{.abort} will not be supported.
3612 @section @code{.ABORT}
3614 @cindex @code{ABORT} directive
3615 When producing COFF output, @code{@value{AS}} accepts this directive as a
3616 synonym for @samp{.abort}.
3619 When producing @code{b.out} output, @code{@value{AS}} accepts this directive,
3625 @section @code{.align @var{abs-expr}, @var{abs-expr}, @var{abs-expr}}
3627 @cindex padding the location counter
3628 @cindex @code{align} directive
3629 Pad the location counter (in the current subsection) to a particular storage
3630 boundary. The first expression (which must be absolute) is the alignment
3631 required, as described below.
3633 The second expression (also absolute) gives the fill value to be stored in the
3634 padding bytes. It (and the comma) may be omitted. If it is omitted, the
3635 padding bytes are normally zero. However, on some systems, if the section is
3636 marked as containing code and the fill value is omitted, the space is filled
3637 with no-op instructions.
3639 The third expression is also absolute, and is also optional. If it is present,
3640 it is the maximum number of bytes that should be skipped by this alignment
3641 directive. If doing the alignment would require skipping more bytes than the
3642 specified maximum, then the alignment is not done at all. You can omit the
3643 fill value (the second argument) entirely by simply using two commas after the
3644 required alignment; this can be useful if you want the alignment to be filled
3645 with no-op instructions when appropriate.
3647 The way the required alignment is specified varies from system to system.
3648 For the a29k, hppa, m68k, m88k, w65, sparc, and Hitachi SH, and i386 using ELF
3650 the first expression is the
3651 alignment request in bytes. For example @samp{.align 8} advances
3652 the location counter until it is a multiple of 8. If the location counter
3653 is already a multiple of 8, no change is needed.
3655 For other systems, including the i386 using a.out format, and the arm and
3656 strongarm, it is the
3657 number of low-order zero bits the location counter must have after
3658 advancement. For example @samp{.align 3} advances the location
3659 counter until it a multiple of 8. If the location counter is already a
3660 multiple of 8, no change is needed.
3662 This inconsistency is due to the different behaviors of the various
3663 native assemblers for these systems which GAS must emulate.
3664 GAS also provides @code{.balign} and @code{.p2align} directives,
3665 described later, which have a consistent behavior across all
3666 architectures (but are specific to GAS).
3669 @section @code{.ascii "@var{string}"}@dots{}
3671 @cindex @code{ascii} directive
3672 @cindex string literals
3673 @code{.ascii} expects zero or more string literals (@pxref{Strings})
3674 separated by commas. It assembles each string (with no automatic
3675 trailing zero byte) into consecutive addresses.
3678 @section @code{.asciz "@var{string}"}@dots{}
3680 @cindex @code{asciz} directive
3681 @cindex zero-terminated strings
3682 @cindex null-terminated strings
3683 @code{.asciz} is just like @code{.ascii}, but each string is followed by
3684 a zero byte. The ``z'' in @samp{.asciz} stands for ``zero''.
3687 @section @code{.balign[wl] @var{abs-expr}, @var{abs-expr}, @var{abs-expr}}
3689 @cindex padding the location counter given number of bytes
3690 @cindex @code{balign} directive
3691 Pad the location counter (in the current subsection) to a particular
3692 storage boundary. The first expression (which must be absolute) is the
3693 alignment request in bytes. For example @samp{.balign 8} advances
3694 the location counter until it is a multiple of 8. If the location counter
3695 is already a multiple of 8, no change is needed.
3697 The second expression (also absolute) gives the fill value to be stored in the
3698 padding bytes. It (and the comma) may be omitted. If it is omitted, the
3699 padding bytes are normally zero. However, on some systems, if the section is
3700 marked as containing code and the fill value is omitted, the space is filled
3701 with no-op instructions.
3703 The third expression is also absolute, and is also optional. If it is present,
3704 it is the maximum number of bytes that should be skipped by this alignment
3705 directive. If doing the alignment would require skipping more bytes than the
3706 specified maximum, then the alignment is not done at all. You can omit the
3707 fill value (the second argument) entirely by simply using two commas after the
3708 required alignment; this can be useful if you want the alignment to be filled
3709 with no-op instructions when appropriate.
3711 @cindex @code{balignw} directive
3712 @cindex @code{balignl} directive
3713 The @code{.balignw} and @code{.balignl} directives are variants of the
3714 @code{.balign} directive. The @code{.balignw} directive treats the fill
3715 pattern as a two byte word value. The @code{.balignl} directives treats the
3716 fill pattern as a four byte longword value. For example, @code{.balignw
3717 4,0x368d} will align to a multiple of 4. If it skips two bytes, they will be
3718 filled in with the value 0x368d (the exact placement of the bytes depends upon
3719 the endianness of the processor). If it skips 1 or 3 bytes, the fill value is
3723 @section @code{.byte @var{expressions}}
3725 @cindex @code{byte} directive
3726 @cindex integers, one byte
3727 @code{.byte} expects zero or more expressions, separated by commas.
3728 Each expression is assembled into the next byte.
3731 @section @code{.comm @var{symbol} , @var{length} }
3733 @cindex @code{comm} directive
3734 @cindex symbol, common
3735 @code{.comm} declares a common symbol named @var{symbol}. When linking, a
3736 common symbol in one object file may be merged with a defined or common symbol
3737 of the same name in another object file. If @code{@value{LD}} does not see a
3738 definition for the symbol--just one or more common symbols--then it will
3739 allocate @var{length} bytes of uninitialized memory. @var{length} must be an
3740 absolute expression. If @code{@value{LD}} sees multiple common symbols with
3741 the same name, and they do not all have the same size, it will allocate space
3742 using the largest size.
3745 When using ELF, the @code{.comm} directive takes an optional third argument.
3746 This is the desired alignment of the symbol, specified as a byte boundary (for
3747 example, an alignment of 16 means that the least significant 4 bits of the
3748 address should be zero). The alignment must be an absolute expression, and it
3749 must be a power of two. If @code{@value{LD}} allocates uninitialized memory
3750 for the common symbol, it will use the alignment when placing the symbol. If
3751 no alignment is specified, @code{@value{AS}} will set the alignment to the
3752 largest power of two less than or equal to the size of the symbol, up to a
3757 The syntax for @code{.comm} differs slightly on the HPPA. The syntax is
3758 @samp{@var{symbol} .comm, @var{length}}; @var{symbol} is optional.
3762 @section @code{.data @var{subsection}}
3764 @cindex @code{data} directive
3765 @code{.data} tells @code{@value{AS}} to assemble the following statements onto the
3766 end of the data subsection numbered @var{subsection} (which is an
3767 absolute expression). If @var{subsection} is omitted, it defaults
3772 @section @code{.def @var{name}}
3774 @cindex @code{def} directive
3775 @cindex COFF symbols, debugging
3776 @cindex debugging COFF symbols
3777 Begin defining debugging information for a symbol @var{name}; the
3778 definition extends until the @code{.endef} directive is encountered.
3781 This directive is only observed when @code{@value{AS}} is configured for COFF
3782 format output; when producing @code{b.out}, @samp{.def} is recognized,
3789 @section @code{.desc @var{symbol}, @var{abs-expression}}
3791 @cindex @code{desc} directive
3792 @cindex COFF symbol descriptor
3793 @cindex symbol descriptor, COFF
3794 This directive sets the descriptor of the symbol (@pxref{Symbol Attributes})
3795 to the low 16 bits of an absolute expression.
3798 The @samp{.desc} directive is not available when @code{@value{AS}} is
3799 configured for COFF output; it is only for @code{a.out} or @code{b.out}
3800 object format. For the sake of compatibility, @code{@value{AS}} accepts
3801 it, but produces no output, when configured for COFF.
3807 @section @code{.dim}
3809 @cindex @code{dim} directive
3810 @cindex COFF auxiliary symbol information
3811 @cindex auxiliary symbol information, COFF
3812 This directive is generated by compilers to include auxiliary debugging
3813 information in the symbol table. It is only permitted inside
3814 @code{.def}/@code{.endef} pairs.
3817 @samp{.dim} is only meaningful when generating COFF format output; when
3818 @code{@value{AS}} is generating @code{b.out}, it accepts this directive but
3824 @section @code{.double @var{flonums}}
3826 @cindex @code{double} directive
3827 @cindex floating point numbers (double)
3828 @code{.double} expects zero or more flonums, separated by commas. It
3829 assembles floating point numbers.
3831 The exact kind of floating point numbers emitted depends on how
3832 @code{@value{AS}} is configured. @xref{Machine Dependencies}.
3836 On the @value{TARGET} family @samp{.double} emits 64-bit floating-point numbers
3837 in @sc{ieee} format.
3842 @section @code{.eject}
3844 @cindex @code{eject} directive
3845 @cindex new page, in listings
3846 @cindex page, in listings
3847 @cindex listing control: new page
3848 Force a page break at this point, when generating assembly listings.
3851 @section @code{.else}
3853 @cindex @code{else} directive
3854 @code{.else} is part of the @code{@value{AS}} support for conditional
3855 assembly; @pxref{If,,@code{.if}}. It marks the beginning of a section
3856 of code to be assembled if the condition for the preceding @code{.if}
3860 @section @code{.elseif}
3862 @cindex @code{elseif} directive
3863 @code{.elseif} is part of the @code{@value{AS}} support for conditional
3864 assembly; @pxref{If,,@code{.if}}. It is shorthand for beginning a new
3865 @code{.if} block that would otherwise fill the entire @code{.else} section.
3868 @section @code{.end}
3870 @cindex @code{end} directive
3871 @code{.end} marks the end of the assembly file. @code{@value{AS}} does not
3872 process anything in the file past the @code{.end} directive.
3876 @section @code{.endef}
3878 @cindex @code{endef} directive
3879 This directive flags the end of a symbol definition begun with
3883 @samp{.endef} is only meaningful when generating COFF format output; if
3884 @code{@value{AS}} is configured to generate @code{b.out}, it accepts this
3885 directive but ignores it.
3890 @section @code{.endfunc}
3891 @cindex @code{endfunc} directive
3892 @code{.endfunc} marks the end of a function specified with @code{.func}.
3895 @section @code{.endif}
3897 @cindex @code{endif} directive
3898 @code{.endif} is part of the @code{@value{AS}} support for conditional assembly;
3899 it marks the end of a block of code that is only assembled
3900 conditionally. @xref{If,,@code{.if}}.
3903 @section @code{.equ @var{symbol}, @var{expression}}
3905 @cindex @code{equ} directive
3906 @cindex assigning values to symbols
3907 @cindex symbols, assigning values to
3908 This directive sets the value of @var{symbol} to @var{expression}.
3909 It is synonymous with @samp{.set}; @pxref{Set,,@code{.set}}.
3912 The syntax for @code{equ} on the HPPA is
3913 @samp{@var{symbol} .equ @var{expression}}.
3917 @section @code{.equiv @var{symbol}, @var{expression}}
3918 @cindex @code{equiv} directive
3919 The @code{.equiv} directive is like @code{.equ} and @code{.set}, except that
3920 the assembler will signal an error if @var{symbol} is already defined.
3922 Except for the contents of the error message, this is roughly equivalent to
3931 @section @code{.err}
3932 @cindex @code{err} directive
3933 If @code{@value{AS}} assembles a @code{.err} directive, it will print an error
3934 message and, unless the @code{-Z} option was used, it will not generate an
3935 object file. This can be used to signal error an conditionally compiled code.
3938 @section @code{.exitm}
3939 Exit early from the current macro definition. @xref{Macro}.
3942 @section @code{.extern}
3944 @cindex @code{extern} directive
3945 @code{.extern} is accepted in the source program---for compatibility
3946 with other assemblers---but it is ignored. @code{@value{AS}} treats
3947 all undefined symbols as external.
3950 @section @code{.fail @var{expression}}
3952 @cindex @code{fail} directive
3953 Generates an error or a warning. If the value of the @var{expression} is 500
3954 or more, @code{@value{AS}} will print a warning message. If the value is less
3955 than 500, @code{@value{AS}} will print an error message. The message will
3956 include the value of @var{expression}. This can occasionally be useful inside
3957 complex nested macros or conditional assembly.
3959 @ifclear no-file-dir
3961 @section @code{.file @var{string}}
3963 @cindex @code{file} directive
3964 @cindex logical file name
3965 @cindex file name, logical
3966 @code{.file} tells @code{@value{AS}} that we are about to start a new logical
3967 file. @var{string} is the new file name. In general, the filename is
3968 recognized whether or not it is surrounded by quotes @samp{"}; but if you wish
3969 to specify an empty file name, you must give the quotes--@code{""}. This
3970 statement may go away in future: it is only recognized to be compatible with
3971 old @code{@value{AS}} programs.
3973 In some configurations of @code{@value{AS}}, @code{.file} has already been
3974 removed to avoid conflicts with other assemblers. @xref{Machine Dependencies}.
3979 @section @code{.fill @var{repeat} , @var{size} , @var{value}}
3981 @cindex @code{fill} directive
3982 @cindex writing patterns in memory
3983 @cindex patterns, writing in memory
3984 @var{repeat}, @var{size} and @var{value} are absolute expressions.
3985 This emits @var{repeat} copies of @var{size} bytes. @var{Repeat}
3986 may be zero or more. @var{Size} may be zero or more, but if it is
3987 more than 8, then it is deemed to have the value 8, compatible with
3988 other people's assemblers. The contents of each @var{repeat} bytes
3989 is taken from an 8-byte number. The highest order 4 bytes are
3990 zero. The lowest order 4 bytes are @var{value} rendered in the
3991 byte-order of an integer on the computer @code{@value{AS}} is assembling for.
3992 Each @var{size} bytes in a repetition is taken from the lowest order
3993 @var{size} bytes of this number. Again, this bizarre behavior is
3994 compatible with other people's assemblers.
3996 @var{size} and @var{value} are optional.
3997 If the second comma and @var{value} are absent, @var{value} is
3998 assumed zero. If the first comma and following tokens are absent,
3999 @var{size} is assumed to be 1.
4002 @section @code{.float @var{flonums}}
4004 @cindex floating point numbers (single)
4005 @cindex @code{float} directive
4006 This directive assembles zero or more flonums, separated by commas. It
4007 has the same effect as @code{.single}.
4009 The exact kind of floating point numbers emitted depends on how
4010 @code{@value{AS}} is configured.
4011 @xref{Machine Dependencies}.
4015 On the @value{TARGET} family, @code{.float} emits 32-bit floating point numbers
4016 in @sc{ieee} format.
4021 @section @code{.func @var{name}[,@var{label}]}
4022 @cindex @code{func} directive
4023 @code{.func} emits debugging information to denote function @var{name}, and
4024 is ignored unless the file is assembled with debugging enabled.
4025 Only @samp{--gstabs} is currently supported.
4026 @var{label} is the entry point of the function and if omitted @var{name}
4027 prepended with the @samp{leading char} is used.
4028 @samp{leading char} is usually @code{_} or nothing, depending on the target.
4029 All functions are currently defined to have @code{void} return type.
4030 The function must be terminated with @code{.endfunc}.
4033 @section @code{.global @var{symbol}}, @code{.globl @var{symbol}}
4035 @cindex @code{global} directive
4036 @cindex symbol, making visible to linker
4037 @code{.global} makes the symbol visible to @code{@value{LD}}. If you define
4038 @var{symbol} in your partial program, its value is made available to
4039 other partial programs that are linked with it. Otherwise,
4040 @var{symbol} takes its attributes from a symbol of the same name
4041 from another file linked into the same program.
4043 Both spellings (@samp{.globl} and @samp{.global}) are accepted, for
4044 compatibility with other assemblers.
4047 On the HPPA, @code{.global} is not always enough to make it accessible to other
4048 partial programs. You may need the HPPA-only @code{.EXPORT} directive as well.
4049 @xref{HPPA Directives,, HPPA Assembler Directives}.
4054 @section @code{.hidden @var{names}}
4056 @cindex @code{.hidden} directive
4058 This one of the ELF visibility directives. The other two are
4059 @code{.internal} (@pxref{Internal,,@code{.internal}}) and
4060 @code{.protected} (@pxref{Protected,,@code{.protected}}).
4062 This directive overrides the named symbols default visibility (which is set by
4063 their binding: local, global or weak). The directive sets the visibility to
4064 @code{hidden} which means that the symbols are not visible to other components.
4065 Such symbols are always considered to be @code{protected} as well.
4069 @section @code{.hword @var{expressions}}
4071 @cindex @code{hword} directive
4072 @cindex integers, 16-bit
4073 @cindex numbers, 16-bit
4074 @cindex sixteen bit integers
4075 This expects zero or more @var{expressions}, and emits
4076 a 16 bit number for each.
4079 This directive is a synonym for @samp{.short}; depending on the target
4080 architecture, it may also be a synonym for @samp{.word}.
4084 This directive is a synonym for @samp{.short}.
4087 This directive is a synonym for both @samp{.short} and @samp{.word}.
4092 @section @code{.ident}
4094 @cindex @code{ident} directive
4095 This directive is used by some assemblers to place tags in object files.
4096 @code{@value{AS}} simply accepts the directive for source-file
4097 compatibility with such assemblers, but does not actually emit anything
4101 @section @code{.if @var{absolute expression}}
4103 @cindex conditional assembly
4104 @cindex @code{if} directive
4105 @code{.if} marks the beginning of a section of code which is only
4106 considered part of the source program being assembled if the argument
4107 (which must be an @var{absolute expression}) is non-zero. The end of
4108 the conditional section of code must be marked by @code{.endif}
4109 (@pxref{Endif,,@code{.endif}}); optionally, you may include code for the
4110 alternative condition, flagged by @code{.else} (@pxref{Else,,@code{.else}}).
4111 If you have several conditions to check, @code{.elseif} may be used to avoid
4112 nesting blocks if/else within each subsequent @code{.else} block.
4114 The following variants of @code{.if} are also supported:
4116 @cindex @code{ifdef} directive
4117 @item .ifdef @var{symbol}
4118 Assembles the following section of code if the specified @var{symbol}
4121 @cindex @code{ifc} directive
4122 @item .ifc @var{string1},@var{string2}
4123 Assembles the following section of code if the two strings are the same. The
4124 strings may be optionally quoted with single quotes. If they are not quoted,
4125 the first string stops at the first comma, and the second string stops at the
4126 end of the line. Strings which contain whitespace should be quoted. The
4127 string comparison is case sensitive.
4129 @cindex @code{ifeq} directive
4130 @item .ifeq @var{absolute expression}
4131 Assembles the following section of code if the argument is zero.
4133 @cindex @code{ifeqs} directive
4134 @item .ifeqs @var{string1},@var{string2}
4135 Another form of @code{.ifc}. The strings must be quoted using double quotes.
4137 @cindex @code{ifge} directive
4138 @item .ifge @var{absolute expression}
4139 Assembles the following section of code if the argument is greater than or
4142 @cindex @code{ifgt} directive
4143 @item .ifgt @var{absolute expression}
4144 Assembles the following section of code if the argument is greater than zero.
4146 @cindex @code{ifle} directive
4147 @item .ifle @var{absolute expression}
4148 Assembles the following section of code if the argument is less than or equal
4151 @cindex @code{iflt} directive
4152 @item .iflt @var{absolute expression}
4153 Assembles the following section of code if the argument is less than zero.
4155 @cindex @code{ifnc} directive
4156 @item .ifnc @var{string1},@var{string2}.
4157 Like @code{.ifc}, but the sense of the test is reversed: this assembles the
4158 following section of code if the two strings are not the same.
4160 @cindex @code{ifndef} directive
4161 @cindex @code{ifnotdef} directive
4162 @item .ifndef @var{symbol}
4163 @itemx .ifnotdef @var{symbol}
4164 Assembles the following section of code if the specified @var{symbol}
4165 has not been defined. Both spelling variants are equivalent.
4167 @cindex @code{ifne} directive
4168 @item .ifne @var{absolute expression}
4169 Assembles the following section of code if the argument is not equal to zero
4170 (in other words, this is equivalent to @code{.if}).
4172 @cindex @code{ifnes} directive
4173 @item .ifnes @var{string1},@var{string2}
4174 Like @code{.ifeqs}, but the sense of the test is reversed: this assembles the
4175 following section of code if the two strings are not the same.
4179 @section @code{.incbin "@var{file}"[,@var{skip}[,@var{count}]]}
4181 @cindex @code{incbin} directive
4182 @cindex binary files, including
4183 The @code{incbin} directive includes @var{file} verbatim at the current
4184 location. You can control the search paths used with the @samp{-I} command-line
4185 option (@pxref{Invoking,,Command-Line Options}). Quotation marks are required
4188 The @var{skip} argument skips a number of bytes from the start of the
4189 @var{file}. The @var{count} argument indicates the maximum number of bytes to
4190 read. Note that the data is not aligned in any way, so it is the user's
4191 responsibility to make sure that proper alignment is provided both before and
4192 after the @code{incbin} directive.
4195 @section @code{.include "@var{file}"}
4197 @cindex @code{include} directive
4198 @cindex supporting files, including
4199 @cindex files, including
4200 This directive provides a way to include supporting files at specified
4201 points in your source program. The code from @var{file} is assembled as
4202 if it followed the point of the @code{.include}; when the end of the
4203 included file is reached, assembly of the original file continues. You
4204 can control the search paths used with the @samp{-I} command-line option
4205 (@pxref{Invoking,,Command-Line Options}). Quotation marks are required
4209 @section @code{.int @var{expressions}}
4211 @cindex @code{int} directive
4212 @cindex integers, 32-bit
4213 Expect zero or more @var{expressions}, of any section, separated by commas.
4214 For each expression, emit a number that, at run time, is the value of that
4215 expression. The byte order and bit size of the number depends on what kind
4216 of target the assembly is for.
4220 On the H8/500 and most forms of the H8/300, @code{.int} emits 16-bit
4221 integers. On the H8/300H and the Hitachi SH, however, @code{.int} emits
4228 @section @code{.internal @var{names}}
4230 @cindex @code{.internal} directive
4232 This one of the ELF visibility directives. The other two are
4233 @code{.hidden} (@pxref{Hidden,,@code{.hidden}}) and
4234 @code{.protected} (@pxref{Protected,,@code{.protected}}).
4236 This directive overrides the named symbols default visibility (which is set by
4237 their binding: local, global or weak). The directive sets the visibility to
4238 @code{internal} which means that the symbols are considered to be @code{hidden}
4239 (ie not visible to other components), and that some extra, processor specific
4240 processing must also be performed upon the symbols as well.
4244 @section @code{.irp @var{symbol},@var{values}}@dots{}
4246 @cindex @code{irp} directive
4247 Evaluate a sequence of statements assigning different values to @var{symbol}.
4248 The sequence of statements starts at the @code{.irp} directive, and is
4249 terminated by an @code{.endr} directive. For each @var{value}, @var{symbol} is
4250 set to @var{value}, and the sequence of statements is assembled. If no
4251 @var{value} is listed, the sequence of statements is assembled once, with
4252 @var{symbol} set to the null string. To refer to @var{symbol} within the
4253 sequence of statements, use @var{\symbol}.
4255 For example, assembling
4263 is equivalent to assembling
4272 @section @code{.irpc @var{symbol},@var{values}}@dots{}
4274 @cindex @code{irpc} directive
4275 Evaluate a sequence of statements assigning different values to @var{symbol}.
4276 The sequence of statements starts at the @code{.irpc} directive, and is
4277 terminated by an @code{.endr} directive. For each character in @var{value},
4278 @var{symbol} is set to the character, and the sequence of statements is
4279 assembled. If no @var{value} is listed, the sequence of statements is
4280 assembled once, with @var{symbol} set to the null string. To refer to
4281 @var{symbol} within the sequence of statements, use @var{\symbol}.
4283 For example, assembling
4291 is equivalent to assembling
4300 @section @code{.lcomm @var{symbol} , @var{length}}
4302 @cindex @code{lcomm} directive
4303 @cindex local common symbols
4304 @cindex symbols, local common
4305 Reserve @var{length} (an absolute expression) bytes for a local common
4306 denoted by @var{symbol}. The section and value of @var{symbol} are
4307 those of the new local common. The addresses are allocated in the bss
4308 section, so that at run-time the bytes start off zeroed. @var{Symbol}
4309 is not declared global (@pxref{Global,,@code{.global}}), so is normally
4310 not visible to @code{@value{LD}}.
4313 Some targets permit a third argument to be used with @code{.lcomm}. This
4314 argument specifies the desired alignment of the symbol in the bss section.
4318 The syntax for @code{.lcomm} differs slightly on the HPPA. The syntax is
4319 @samp{@var{symbol} .lcomm, @var{length}}; @var{symbol} is optional.
4323 @section @code{.lflags}
4325 @cindex @code{lflags} directive (ignored)
4326 @code{@value{AS}} accepts this directive, for compatibility with other
4327 assemblers, but ignores it.
4329 @ifclear no-line-dir
4331 @section @code{.line @var{line-number}}
4333 @cindex @code{line} directive
4337 @section @code{.ln @var{line-number}}
4339 @cindex @code{ln} directive
4341 @cindex logical line number
4343 Change the logical line number. @var{line-number} must be an absolute
4344 expression. The next line has that logical line number. Therefore any other
4345 statements on the current line (after a statement separator character) are
4346 reported as on logical line number @var{line-number} @minus{} 1. One day
4347 @code{@value{AS}} will no longer support this directive: it is recognized only
4348 for compatibility with existing assembler programs.
4352 @emph{Warning:} In the AMD29K configuration of @value{AS}, this command is
4353 not available; use the synonym @code{.ln} in that context.
4358 @ifclear no-line-dir
4359 Even though this is a directive associated with the @code{a.out} or
4360 @code{b.out} object-code formats, @code{@value{AS}} still recognizes it
4361 when producing COFF output, and treats @samp{.line} as though it
4362 were the COFF @samp{.ln} @emph{if} it is found outside a
4363 @code{.def}/@code{.endef} pair.
4365 Inside a @code{.def}, @samp{.line} is, instead, one of the directives
4366 used by compilers to generate auxiliary symbol information for
4371 @section @code{.linkonce [@var{type}]}
4373 @cindex @code{linkonce} directive
4374 @cindex common sections
4375 Mark the current section so that the linker only includes a single copy of it.
4376 This may be used to include the same section in several different object files,
4377 but ensure that the linker will only include it once in the final output file.
4378 The @code{.linkonce} pseudo-op must be used for each instance of the section.
4379 Duplicate sections are detected based on the section name, so it should be
4382 This directive is only supported by a few object file formats; as of this
4383 writing, the only object file format which supports it is the Portable
4384 Executable format used on Windows NT.
4386 The @var{type} argument is optional. If specified, it must be one of the
4387 following strings. For example:
4391 Not all types may be supported on all object file formats.
4395 Silently discard duplicate sections. This is the default.
4398 Warn if there are duplicate sections, but still keep only one copy.
4401 Warn if any of the duplicates have different sizes.
4404 Warn if any of the duplicates do not have exactly the same contents.
4408 @section @code{.ln @var{line-number}}
4410 @cindex @code{ln} directive
4411 @ifclear no-line-dir
4412 @samp{.ln} is a synonym for @samp{.line}.
4415 Tell @code{@value{AS}} to change the logical line number. @var{line-number}
4416 must be an absolute expression. The next line has that logical
4417 line number, so any other statements on the current line (after a
4418 statement separator character @code{;}) are reported as on logical
4419 line number @var{line-number} @minus{} 1.
4422 This directive is accepted, but ignored, when @code{@value{AS}} is
4423 configured for @code{b.out}; its effect is only associated with COFF
4429 @section @code{.mri @var{val}}
4431 @cindex @code{mri} directive
4432 @cindex MRI mode, temporarily
4433 If @var{val} is non-zero, this tells @code{@value{AS}} to enter MRI mode. If
4434 @var{val} is zero, this tells @code{@value{AS}} to exit MRI mode. This change
4435 affects code assembled until the next @code{.mri} directive, or until the end
4436 of the file. @xref{M, MRI mode, MRI mode}.
4439 @section @code{.list}
4441 @cindex @code{list} directive
4442 @cindex listing control, turning on
4443 Control (in conjunction with the @code{.nolist} directive) whether or
4444 not assembly listings are generated. These two directives maintain an
4445 internal counter (which is zero initially). @code{.list} increments the
4446 counter, and @code{.nolist} decrements it. Assembly listings are
4447 generated whenever the counter is greater than zero.
4449 By default, listings are disabled. When you enable them (with the
4450 @samp{-a} command line option; @pxref{Invoking,,Command-Line Options}),
4451 the initial value of the listing counter is one.
4454 @section @code{.long @var{expressions}}
4456 @cindex @code{long} directive
4457 @code{.long} is the same as @samp{.int}, @pxref{Int,,@code{.int}}.
4460 @c no one seems to know what this is for or whether this description is
4461 @c what it really ought to do
4463 @section @code{.lsym @var{symbol}, @var{expression}}
4465 @cindex @code{lsym} directive
4466 @cindex symbol, not referenced in assembly
4467 @code{.lsym} creates a new symbol named @var{symbol}, but does not put it in
4468 the hash table, ensuring it cannot be referenced by name during the
4469 rest of the assembly. This sets the attributes of the symbol to be
4470 the same as the expression value:
4472 @var{other} = @var{descriptor} = 0
4473 @var{type} = @r{(section of @var{expression})}
4474 @var{value} = @var{expression}
4477 The new symbol is not flagged as external.
4481 @section @code{.macro}
4484 The commands @code{.macro} and @code{.endm} allow you to define macros that
4485 generate assembly output. For example, this definition specifies a macro
4486 @code{sum} that puts a sequence of numbers into memory:
4489 .macro sum from=0, to=5
4498 With that definition, @samp{SUM 0,5} is equivalent to this assembly input:
4510 @item .macro @var{macname}
4511 @itemx .macro @var{macname} @var{macargs} @dots{}
4512 @cindex @code{macro} directive
4513 Begin the definition of a macro called @var{macname}. If your macro
4514 definition requires arguments, specify their names after the macro name,
4515 separated by commas or spaces. You can supply a default value for any
4516 macro argument by following the name with @samp{=@var{deflt}}. For
4517 example, these are all valid @code{.macro} statements:
4521 Begin the definition of a macro called @code{comm}, which takes no
4524 @item .macro plus1 p, p1
4525 @itemx .macro plus1 p p1
4526 Either statement begins the definition of a macro called @code{plus1},
4527 which takes two arguments; within the macro definition, write
4528 @samp{\p} or @samp{\p1} to evaluate the arguments.
4530 @item .macro reserve_str p1=0 p2
4531 Begin the definition of a macro called @code{reserve_str}, with two
4532 arguments. The first argument has a default value, but not the second.
4533 After the definition is complete, you can call the macro either as
4534 @samp{reserve_str @var{a},@var{b}} (with @samp{\p1} evaluating to
4535 @var{a} and @samp{\p2} evaluating to @var{b}), or as @samp{reserve_str
4536 ,@var{b}} (with @samp{\p1} evaluating as the default, in this case
4537 @samp{0}, and @samp{\p2} evaluating to @var{b}).
4540 When you call a macro, you can specify the argument values either by
4541 position, or by keyword. For example, @samp{sum 9,17} is equivalent to
4542 @samp{sum to=17, from=9}.
4545 @cindex @code{endm} directive
4546 Mark the end of a macro definition.
4549 @cindex @code{exitm} directive
4550 Exit early from the current macro definition.
4552 @cindex number of macros executed
4553 @cindex macros, count executed
4555 @code{@value{AS}} maintains a counter of how many macros it has
4556 executed in this pseudo-variable; you can copy that number to your
4557 output with @samp{\@@}, but @emph{only within a macro definition}.
4560 @item LOCAL @var{name} [ , @dots{} ]
4561 @emph{Warning: @code{LOCAL} is only available if you select ``alternate
4562 macro syntax'' with @samp{-a} or @samp{--alternate}.} @xref{Alternate,,
4563 Alternate macro syntax}.
4565 Generate a string replacement for each of the @var{name} arguments, and
4566 replace any instances of @var{name} in each macro expansion. The
4567 replacement string is unique in the assembly, and different for each
4568 separate macro expansion. @code{LOCAL} allows you to write macros that
4569 define symbols, without fear of conflict between separate macro expansions.
4574 @section @code{.nolist}
4576 @cindex @code{nolist} directive
4577 @cindex listing control, turning off
4578 Control (in conjunction with the @code{.list} directive) whether or
4579 not assembly listings are generated. These two directives maintain an
4580 internal counter (which is zero initially). @code{.list} increments the
4581 counter, and @code{.nolist} decrements it. Assembly listings are
4582 generated whenever the counter is greater than zero.
4585 @section @code{.octa @var{bignums}}
4587 @c FIXME: double size emitted for "octa" on i960, others? Or warn?
4588 @cindex @code{octa} directive
4589 @cindex integer, 16-byte
4590 @cindex sixteen byte integer
4591 This directive expects zero or more bignums, separated by commas. For each
4592 bignum, it emits a 16-byte integer.
4594 The term ``octa'' comes from contexts in which a ``word'' is two bytes;
4595 hence @emph{octa}-word for 16 bytes.
4598 @section @code{.org @var{new-lc} , @var{fill}}
4600 @cindex @code{org} directive
4601 @cindex location counter, advancing
4602 @cindex advancing location counter
4603 @cindex current address, advancing
4604 Advance the location counter of the current section to
4605 @var{new-lc}. @var{new-lc} is either an absolute expression or an
4606 expression with the same section as the current subsection. That is,
4607 you can't use @code{.org} to cross sections: if @var{new-lc} has the
4608 wrong section, the @code{.org} directive is ignored. To be compatible
4609 with former assemblers, if the section of @var{new-lc} is absolute,
4610 @code{@value{AS}} issues a warning, then pretends the section of @var{new-lc}
4611 is the same as the current subsection.
4613 @code{.org} may only increase the location counter, or leave it
4614 unchanged; you cannot use @code{.org} to move the location counter
4617 @c double negative used below "not undefined" because this is a specific
4618 @c reference to "undefined" (as SEG_UNKNOWN is called in this manual)
4619 @c section. doc@cygnus.com 18feb91
4620 Because @code{@value{AS}} tries to assemble programs in one pass, @var{new-lc}
4621 may not be undefined. If you really detest this restriction we eagerly await
4622 a chance to share your improved assembler.
4624 Beware that the origin is relative to the start of the section, not
4625 to the start of the subsection. This is compatible with other
4626 people's assemblers.
4628 When the location counter (of the current subsection) is advanced, the
4629 intervening bytes are filled with @var{fill} which should be an
4630 absolute expression. If the comma and @var{fill} are omitted,
4631 @var{fill} defaults to zero.
4634 @section @code{.p2align[wl] @var{abs-expr}, @var{abs-expr}, @var{abs-expr}}
4636 @cindex padding the location counter given a power of two
4637 @cindex @code{p2align} directive
4638 Pad the location counter (in the current subsection) to a particular
4639 storage boundary. The first expression (which must be absolute) is the
4640 number of low-order zero bits the location counter must have after
4641 advancement. For example @samp{.p2align 3} advances the location
4642 counter until it a multiple of 8. If the location counter is already a
4643 multiple of 8, no change is needed.
4645 The second expression (also absolute) gives the fill value to be stored in the
4646 padding bytes. It (and the comma) may be omitted. If it is omitted, the
4647 padding bytes are normally zero. However, on some systems, if the section is
4648 marked as containing code and the fill value is omitted, the space is filled
4649 with no-op instructions.
4651 The third expression is also absolute, and is also optional. If it is present,
4652 it is the maximum number of bytes that should be skipped by this alignment
4653 directive. If doing the alignment would require skipping more bytes than the
4654 specified maximum, then the alignment is not done at all. You can omit the
4655 fill value (the second argument) entirely by simply using two commas after the
4656 required alignment; this can be useful if you want the alignment to be filled
4657 with no-op instructions when appropriate.
4659 @cindex @code{p2alignw} directive
4660 @cindex @code{p2alignl} directive
4661 The @code{.p2alignw} and @code{.p2alignl} directives are variants of the
4662 @code{.p2align} directive. The @code{.p2alignw} directive treats the fill
4663 pattern as a two byte word value. The @code{.p2alignl} directives treats the
4664 fill pattern as a four byte longword value. For example, @code{.p2alignw
4665 2,0x368d} will align to a multiple of 4. If it skips two bytes, they will be
4666 filled in with the value 0x368d (the exact placement of the bytes depends upon
4667 the endianness of the processor). If it skips 1 or 3 bytes, the fill value is
4672 @section @code{.previous}
4674 @cindex @code{.previous} directive
4675 @cindex Section Stack
4676 This is one of the ELF section stack manipulation directives. The others are
4677 @code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}),
4678 @code{.pushsection} (@pxref{PushSection}), and @code{.popsection}
4679 (@pxref{PopSection}).
4681 This directive swaps the current section (and subsection) with most recently
4682 referenced section (and subsection) prior to this one. Multiple
4683 @code{.previous} directives in a row will flip between two sections (and their
4686 In terms of the section stack, this directive swaps the current section with
4687 the top section on the section stack.
4692 @section @code{.popsection}
4694 @cindex @code{.popsection} directive
4695 @cindex Section Stack
4696 This is one of the ELF section stack manipulation directives. The others are
4697 @code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}),
4698 @code{.pushsection} (@pxref{PushSection}), and @code{.previous}
4701 This directive replaces the current section (and subsection) with the top
4702 section (and subsection) on the section stack. This section is popped off the
4707 @section @code{.print @var{string}}
4709 @cindex @code{print} directive
4710 @code{@value{AS}} will print @var{string} on the standard output during
4711 assembly. You must put @var{string} in double quotes.
4715 @section @code{.protected @var{names}}
4717 @cindex @code{.protected} directive
4719 This one of the ELF visibility directives. The other two are
4720 @code{.hidden} (@pxref{Hidden}) and @code{.internal} (@pxref{Internal}).
4722 This directive overrides the named symbols default visibility (which is set by
4723 their binding: local, global or weak). The directive sets the visibility to
4724 @code{protected} which means that any references to the symbols from within the
4725 components that defines them must be resolved to the definition in that
4726 component, even if a definition in another component would normally preempt
4731 @section @code{.psize @var{lines} , @var{columns}}
4733 @cindex @code{psize} directive
4734 @cindex listing control: paper size
4735 @cindex paper size, for listings
4736 Use this directive to declare the number of lines---and, optionally, the
4737 number of columns---to use for each page, when generating listings.
4739 If you do not use @code{.psize}, listings use a default line-count
4740 of 60. You may omit the comma and @var{columns} specification; the
4741 default width is 200 columns.
4743 @code{@value{AS}} generates formfeeds whenever the specified number of
4744 lines is exceeded (or whenever you explicitly request one, using
4747 If you specify @var{lines} as @code{0}, no formfeeds are generated save
4748 those explicitly specified with @code{.eject}.
4751 @section @code{.purgem @var{name}}
4753 @cindex @code{purgem} directive
4754 Undefine the macro @var{name}, so that later uses of the string will not be
4755 expanded. @xref{Macro}.
4759 @section @code{.pushsection @var{name} , @var{subsection}}
4761 @cindex @code{.pushsection} directive
4762 @cindex Section Stack
4763 This is one of the ELF section stack manipulation directives. The others are
4764 @code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}),
4765 @code{.popsection} (@pxref{PopSection}), and @code{.previous}
4768 This directive is a synonym for @code{.section}. It pushes the current section
4769 (and subsection) onto the top of the section stack, and then replaces the
4770 current section and subsection with @code{name} and @code{subsection}.
4774 @section @code{.quad @var{bignums}}
4776 @cindex @code{quad} directive
4777 @code{.quad} expects zero or more bignums, separated by commas. For
4778 each bignum, it emits
4780 an 8-byte integer. If the bignum won't fit in 8 bytes, it prints a
4781 warning message; and just takes the lowest order 8 bytes of the bignum.
4782 @cindex eight-byte integer
4783 @cindex integer, 8-byte
4785 The term ``quad'' comes from contexts in which a ``word'' is two bytes;
4786 hence @emph{quad}-word for 8 bytes.
4789 a 16-byte integer. If the bignum won't fit in 16 bytes, it prints a
4790 warning message; and just takes the lowest order 16 bytes of the bignum.
4791 @cindex sixteen-byte integer
4792 @cindex integer, 16-byte
4796 @section @code{.rept @var{count}}
4798 @cindex @code{rept} directive
4799 Repeat the sequence of lines between the @code{.rept} directive and the next
4800 @code{.endr} directive @var{count} times.
4802 For example, assembling
4810 is equivalent to assembling
4819 @section @code{.sbttl "@var{subheading}"}
4821 @cindex @code{sbttl} directive
4822 @cindex subtitles for listings
4823 @cindex listing control: subtitle
4824 Use @var{subheading} as the title (third line, immediately after the
4825 title line) when generating assembly listings.
4827 This directive affects subsequent pages, as well as the current page if
4828 it appears within ten lines of the top of a page.
4832 @section @code{.scl @var{class}}
4834 @cindex @code{scl} directive
4835 @cindex symbol storage class (COFF)
4836 @cindex COFF symbol storage class
4837 Set the storage-class value for a symbol. This directive may only be
4838 used inside a @code{.def}/@code{.endef} pair. Storage class may flag
4839 whether a symbol is static or external, or it may record further
4840 symbolic debugging information.
4843 The @samp{.scl} directive is primarily associated with COFF output; when
4844 configured to generate @code{b.out} output format, @code{@value{AS}}
4845 accepts this directive but ignores it.
4850 @section @code{.section @var{name}} (COFF version)
4852 @cindex @code{section} directive
4853 @cindex named section
4854 Use the @code{.section} directive to assemble the following code into a section
4857 This directive is only supported for targets that actually support arbitrarily
4858 named sections; on @code{a.out} targets, for example, it is not accepted, even
4859 with a standard @code{a.out} section name.
4861 For COFF targets, the @code{.section} directive is used in one of the following
4865 .section @var{name}[, "@var{flags}"]
4866 .section @var{name}[, @var{subsegment}]
4869 If the optional argument is quoted, it is taken as flags to use for the
4870 section. Each flag is a single character. The following flags are recognized:
4873 bss section (uninitialized data)
4875 section is not loaded
4885 shared section (meaningful for PE targets)
4888 If no flags are specified, the default flags depend upon the section name. If
4889 the section name is not recognized, the default will be for the section to be
4890 loaded and writable. Note the @code{n} and @code{w} flags remove attributes
4891 from the section, rather than adding them, so if they are used on their own it
4892 will be as if no flags had been specified at all.
4894 If the optional argument to the @code{.section} directive is not quoted, it is
4895 taken as a subsegment number (@pxref{Sub-Sections}).
4898 @section @code{.section @var{name}} (ELF version)
4900 @cindex @code{section} directive
4901 @cindex named section
4903 @cindex Section Stack
4904 This is one of the ELF section stack manipulation directives. The others are
4905 @code{.subsection} (@pxref{SubSection}), @code{.pushsection}
4906 (@pxref{PushSection}), @code{.popsection} (@pxref{PopSection}), and
4907 @code{.previous} (@pxref{Previous}).
4910 For ELF targets, the @code{.section} directive is used like this:
4913 .section @var{name} [, "@var{flags}"[, @@@var{type}[, @@@var{entsize}]]]
4916 The optional @var{flags} argument is a quoted string which may contain any
4917 combination of the following characters:
4920 section is allocatable
4924 section is executable
4926 section is mergeable
4928 section contains zero terminated strings
4931 The optional @var{type} argument may contain one of the following constants:
4934 section contains data
4936 section does not contain data (i.e., section only occupies space)
4939 If @var{flags} contains @code{M} flag, @var{type} argument must be specified
4940 as well as @var{entsize} argument. Sections with @code{M} flag but not
4941 @code{S} flag must contain fixed size constants, each @var{entsize} octets
4942 long. Sections with both @code{M} and @code{S} must contain zero terminated
4943 strings where each character is @var{entsize} bytes long. The linker may remove
4944 duplicates within sections with the same name, same entity size and same flags.
4946 If no flags are specified, the default flags depend upon the section name. If
4947 the section name is not recognized, the default will be for the section to have
4948 none of the above flags: it will not be allocated in memory, nor writable, nor
4949 executable. The section will contain data.
4951 For ELF targets, the assembler supports another type of @code{.section}
4952 directive for compatibility with the Solaris assembler:
4955 .section "@var{name}"[, @var{flags}...]
4958 Note that the section name is quoted. There may be a sequence of comma
4962 section is allocatable
4966 section is executable
4969 This directive replaces the current section and subsection. The replaced
4970 section and subsection are pushed onto the section stack. See the contents of
4971 the gas testsuite directory @code{gas/testsuite/gas/elf} for some examples of
4972 how this directive and the other section stack directives work.
4975 @section @code{.set @var{symbol}, @var{expression}}
4977 @cindex @code{set} directive
4978 @cindex symbol value, setting
4979 Set the value of @var{symbol} to @var{expression}. This
4980 changes @var{symbol}'s value and type to conform to
4981 @var{expression}. If @var{symbol} was flagged as external, it remains
4982 flagged (@pxref{Symbol Attributes}).
4984 You may @code{.set} a symbol many times in the same assembly.
4986 If you @code{.set} a global symbol, the value stored in the object
4987 file is the last value stored into it.
4990 The syntax for @code{set} on the HPPA is
4991 @samp{@var{symbol} .set @var{expression}}.
4995 @section @code{.short @var{expressions}}
4997 @cindex @code{short} directive
4999 @code{.short} is normally the same as @samp{.word}.
5000 @xref{Word,,@code{.word}}.
5002 In some configurations, however, @code{.short} and @code{.word} generate
5003 numbers of different lengths; @pxref{Machine Dependencies}.
5007 @code{.short} is the same as @samp{.word}. @xref{Word,,@code{.word}}.
5010 This expects zero or more @var{expressions}, and emits
5011 a 16 bit number for each.
5016 @section @code{.single @var{flonums}}
5018 @cindex @code{single} directive
5019 @cindex floating point numbers (single)
5020 This directive assembles zero or more flonums, separated by commas. It
5021 has the same effect as @code{.float}.
5023 The exact kind of floating point numbers emitted depends on how
5024 @code{@value{AS}} is configured. @xref{Machine Dependencies}.
5028 On the @value{TARGET} family, @code{.single} emits 32-bit floating point
5029 numbers in @sc{ieee} format.
5034 @section @code{.size} (COFF version)
5036 @cindex @code{size} directive
5037 This directive is generated by compilers to include auxiliary debugging
5038 information in the symbol table. It is only permitted inside
5039 @code{.def}/@code{.endef} pairs.
5042 @samp{.size} is only meaningful when generating COFF format output; when
5043 @code{@value{AS}} is generating @code{b.out}, it accepts this directive but
5047 @section @code{.size @var{name} , @var{expression}} (ELF version)
5048 @cindex @code{size} directive
5050 This directive is used to set the size associated with a symbol @var{name}.
5051 The size in bytes is computed from @var{expression} which can make use of label
5052 arithmetic. This directive is typically used to set the size of function
5056 @section @code{.sleb128 @var{expressions}}
5058 @cindex @code{sleb128} directive
5059 @var{sleb128} stands for ``signed little endian base 128.'' This is a
5060 compact, variable length representation of numbers used by the DWARF
5061 symbolic debugging format. @xref{Uleb128,@code{.uleb128}}.
5063 @ifclear no-space-dir
5065 @section @code{.skip @var{size} , @var{fill}}
5067 @cindex @code{skip} directive
5068 @cindex filling memory
5069 This directive emits @var{size} bytes, each of value @var{fill}. Both
5070 @var{size} and @var{fill} are absolute expressions. If the comma and
5071 @var{fill} are omitted, @var{fill} is assumed to be zero. This is the same as
5075 @section @code{.space @var{size} , @var{fill}}
5077 @cindex @code{space} directive
5078 @cindex filling memory
5079 This directive emits @var{size} bytes, each of value @var{fill}. Both
5080 @var{size} and @var{fill} are absolute expressions. If the comma
5081 and @var{fill} are omitted, @var{fill} is assumed to be zero. This is the same
5086 @emph{Warning:} @code{.space} has a completely different meaning for HPPA
5087 targets; use @code{.block} as a substitute. See @cite{HP9000 Series 800
5088 Assembly Language Reference Manual} (HP 92432-90001) for the meaning of the
5089 @code{.space} directive. @xref{HPPA Directives,,HPPA Assembler Directives},
5098 @section @code{.space}
5099 @cindex @code{space} directive
5101 On the AMD 29K, this directive is ignored; it is accepted for
5102 compatibility with other AMD 29K assemblers.
5105 @emph{Warning:} In most versions of the @sc{gnu} assembler, the directive
5106 @code{.space} has the effect of @code{.block} @xref{Machine Dependencies}.
5112 @section @code{.stabd, .stabn, .stabs}
5114 @cindex symbolic debuggers, information for
5115 @cindex @code{stab@var{x}} directives
5116 There are three directives that begin @samp{.stab}.
5117 All emit symbols (@pxref{Symbols}), for use by symbolic debuggers.
5118 The symbols are not entered in the @code{@value{AS}} hash table: they
5119 cannot be referenced elsewhere in the source file.
5120 Up to five fields are required:
5124 This is the symbol's name. It may contain any character except
5125 @samp{\000}, so is more general than ordinary symbol names. Some
5126 debuggers used to code arbitrarily complex structures into symbol names
5130 An absolute expression. The symbol's type is set to the low 8 bits of
5131 this expression. Any bit pattern is permitted, but @code{@value{LD}}
5132 and debuggers choke on silly bit patterns.
5135 An absolute expression. The symbol's ``other'' attribute is set to the
5136 low 8 bits of this expression.
5139 An absolute expression. The symbol's descriptor is set to the low 16
5140 bits of this expression.
5143 An absolute expression which becomes the symbol's value.
5146 If a warning is detected while reading a @code{.stabd}, @code{.stabn},
5147 or @code{.stabs} statement, the symbol has probably already been created;
5148 you get a half-formed symbol in your object file. This is
5149 compatible with earlier assemblers!
5152 @cindex @code{stabd} directive
5153 @item .stabd @var{type} , @var{other} , @var{desc}
5155 The ``name'' of the symbol generated is not even an empty string.
5156 It is a null pointer, for compatibility. Older assemblers used a
5157 null pointer so they didn't waste space in object files with empty
5160 The symbol's value is set to the location counter,
5161 relocatably. When your program is linked, the value of this symbol
5162 is the address of the location counter when the @code{.stabd} was
5165 @cindex @code{stabn} directive
5166 @item .stabn @var{type} , @var{other} , @var{desc} , @var{value}
5167 The name of the symbol is set to the empty string @code{""}.
5169 @cindex @code{stabs} directive
5170 @item .stabs @var{string} , @var{type} , @var{other} , @var{desc} , @var{value}
5171 All five fields are specified.
5177 @section @code{.string} "@var{str}"
5179 @cindex string, copying to object file
5180 @cindex @code{string} directive
5182 Copy the characters in @var{str} to the object file. You may specify more than
5183 one string to copy, separated by commas. Unless otherwise specified for a
5184 particular machine, the assembler marks the end of each string with a 0 byte.
5185 You can use any of the escape sequences described in @ref{Strings,,Strings}.
5188 @section @code{.struct @var{expression}}
5190 @cindex @code{struct} directive
5191 Switch to the absolute section, and set the section offset to @var{expression},
5192 which must be an absolute expression. You might use this as follows:
5201 This would define the symbol @code{field1} to have the value 0, the symbol
5202 @code{field2} to have the value 4, and the symbol @code{field3} to have the
5203 value 8. Assembly would be left in the absolute section, and you would need to
5204 use a @code{.section} directive of some sort to change to some other section
5205 before further assembly.
5209 @section @code{.subsection @var{name}}
5211 @cindex @code{.subsection} directive
5212 @cindex Section Stack
5213 This is one of the ELF section stack manipulation directives. The others are
5214 @code{.section} (@pxref{Section}), @code{.pushsection} (@pxref{PushSection}),
5215 @code{.popsection} (@pxref{PopSection}), and @code{.previous}
5218 This directive replaces the current subsection with @code{name}. The current
5219 section is not changed. The replaced subsection is put onto the section stack
5220 in place of the then current top of stack subsection.
5225 @section @code{.symver}
5226 @cindex @code{symver} directive
5227 @cindex symbol versioning
5228 @cindex versions of symbols
5229 Use the @code{.symver} directive to bind symbols to specific version nodes
5230 within a source file. This is only supported on ELF platforms, and is
5231 typically used when assembling files to be linked into a shared library.
5232 There are cases where it may make sense to use this in objects to be bound
5233 into an application itself so as to override a versioned symbol from a
5236 For ELF targets, the @code{.symver} directive can be used like this:
5238 .symver @var{name}, @var{name2@@nodename}
5240 If the symbol @var{name} is defined within the file
5241 being assembled, the @code{.symver} directive effectively creates a symbol
5242 alias with the name @var{name2@@nodename}, and in fact the main reason that we
5243 just don't try and create a regular alias is that the @var{@@} character isn't
5244 permitted in symbol names. The @var{name2} part of the name is the actual name
5245 of the symbol by which it will be externally referenced. The name @var{name}
5246 itself is merely a name of convenience that is used so that it is possible to
5247 have definitions for multiple versions of a function within a single source
5248 file, and so that the compiler can unambiguously know which version of a
5249 function is being mentioned. The @var{nodename} portion of the alias should be
5250 the name of a node specified in the version script supplied to the linker when
5251 building a shared library. If you are attempting to override a versioned
5252 symbol from a shared library, then @var{nodename} should correspond to the
5253 nodename of the symbol you are trying to override.
5255 If the symbol @var{name} is not defined within the file being assembled, all
5256 references to @var{name} will be changed to @var{name2@@nodename}. If no
5257 reference to @var{name} is made, @var{name2@@nodename} will be removed from the
5260 Another usage of the @code{.symver} directive is:
5262 .symver @var{name}, @var{name2@@@@nodename}
5264 In this case, the symbol @var{name} must exist and be defined within
5265 the file being assembled. It is similar to @var{name2@@nodename}. The
5266 difference is @var{name2@@@@nodename} will also be used to resolve
5267 references to @var{name2} by the linker.
5269 The third usage of the @code{.symver} directive is:
5271 .symver @var{name}, @var{name2@@@@@@nodename}
5273 When @var{name} is not defined within the
5274 file being assembled, it is treated as @var{name2@@nodename}. When
5275 @var{name} is defined within the file being assembled, the symbol
5276 name, @var{name}, will be changed to @var{name2@@@@nodename}.
5281 @section @code{.tag @var{structname}}
5283 @cindex COFF structure debugging
5284 @cindex structure debugging, COFF
5285 @cindex @code{tag} directive
5286 This directive is generated by compilers to include auxiliary debugging
5287 information in the symbol table. It is only permitted inside
5288 @code{.def}/@code{.endef} pairs. Tags are used to link structure
5289 definitions in the symbol table with instances of those structures.
5292 @samp{.tag} is only used when generating COFF format output; when
5293 @code{@value{AS}} is generating @code{b.out}, it accepts this directive but
5299 @section @code{.text @var{subsection}}
5301 @cindex @code{text} directive
5302 Tells @code{@value{AS}} to assemble the following statements onto the end of
5303 the text subsection numbered @var{subsection}, which is an absolute
5304 expression. If @var{subsection} is omitted, subsection number zero
5308 @section @code{.title "@var{heading}"}
5310 @cindex @code{title} directive
5311 @cindex listing control: title line
5312 Use @var{heading} as the title (second line, immediately after the
5313 source file name and pagenumber) when generating assembly listings.
5315 This directive affects subsequent pages, as well as the current page if
5316 it appears within ten lines of the top of a page.
5319 @section @code{.type @var{int}} (COFF version)
5321 @cindex COFF symbol type
5322 @cindex symbol type, COFF
5323 @cindex @code{type} directive
5324 This directive, permitted only within @code{.def}/@code{.endef} pairs,
5325 records the integer @var{int} as the type attribute of a symbol table entry.
5328 @samp{.type} is associated only with COFF format output; when
5329 @code{@value{AS}} is configured for @code{b.out} output, it accepts this
5330 directive but ignores it.
5333 @section @code{.type @var{name} , @var{type description}} (ELF version)
5335 @cindex ELF symbol type
5336 @cindex symbol type, ELF
5337 @cindex @code{type} directive
5338 This directive is used to set the type of symbol @var{name} to be either a
5339 function symbol or an object symbol. There are five different syntaxes
5340 supported for the @var{type description} field, in order to provide
5341 compatibility with various other assemblers. The syntaxes supported are:
5344 .type <name>,#function
5345 .type <name>,#object
5347 .type <name>,@@function
5348 .type <name>,@@object
5350 .type <name>,%function
5351 .type <name>,%object
5353 .type <name>,"function"
5354 .type <name>,"object"
5356 .type <name> STT_FUNCTION
5357 .type <name> STT_OBJECT
5361 @section @code{.uleb128 @var{expressions}}
5363 @cindex @code{uleb128} directive
5364 @var{uleb128} stands for ``unsigned little endian base 128.'' This is a
5365 compact, variable length representation of numbers used by the DWARF
5366 symbolic debugging format. @xref{Sleb128,@code{.sleb128}}.
5370 @section @code{.val @var{addr}}
5372 @cindex @code{val} directive
5373 @cindex COFF value attribute
5374 @cindex value attribute, COFF
5375 This directive, permitted only within @code{.def}/@code{.endef} pairs,
5376 records the address @var{addr} as the value attribute of a symbol table
5380 @samp{.val} is used only for COFF output; when @code{@value{AS}} is
5381 configured for @code{b.out}, it accepts this directive but ignores it.
5387 @section @code{.version "@var{string}"}
5389 @cindex @code{.version}
5390 This directive creates a @code{.note} section and places into it an ELF
5391 formatted note of type NT_VERSION. The note's name is set to @code{string}.
5396 @section @code{.vtable_entry @var{table}, @var{offset}}
5398 @cindex @code{.vtable_entry}
5399 This directive finds or creates a symbol @code{table} and creates a
5400 @code{VTABLE_ENTRY} relocation for it with an addend of @code{offset}.
5403 @section @code{.vtable_inherit @var{child}, @var{parent}}
5405 @cindex @code{.vtable_inherit}
5406 This directive finds the symbol @code{child} and finds or creates the symbol
5407 @code{parent} and then creates a @code{VTABLE_INHERIT} relocation for the
5408 parent whose addend is the value of the child symbol. As a special case the
5409 parent name of @code{0} is treated as refering the @code{*ABS*} section.
5414 @section @code{.weak @var{names}}
5416 @cindex @code{.weak}
5417 This directive sets the weak attribute on the comma separated list of symbol
5418 @code{names}. If the symbols do not already exist, they will be created.
5422 @section @code{.word @var{expressions}}
5424 @cindex @code{word} directive
5425 This directive expects zero or more @var{expressions}, of any section,
5426 separated by commas.
5429 For each expression, @code{@value{AS}} emits a 32-bit number.
5432 For each expression, @code{@value{AS}} emits a 16-bit number.
5437 The size of the number emitted, and its byte order,
5438 depend on what target computer the assembly is for.
5441 @c on amd29k, i960, sparc the "special treatment to support compilers" doesn't
5442 @c happen---32-bit addressability, period; no long/short jumps.
5443 @ifset DIFF-TBL-KLUGE
5444 @cindex difference tables altered
5445 @cindex altered difference tables
5447 @emph{Warning: Special Treatment to support Compilers}
5451 Machines with a 32-bit address space, but that do less than 32-bit
5452 addressing, require the following special treatment. If the machine of
5453 interest to you does 32-bit addressing (or doesn't require it;
5454 @pxref{Machine Dependencies}), you can ignore this issue.
5457 In order to assemble compiler output into something that works,
5458 @code{@value{AS}} occasionally does strange things to @samp{.word} directives.
5459 Directives of the form @samp{.word sym1-sym2} are often emitted by
5460 compilers as part of jump tables. Therefore, when @code{@value{AS}} assembles a
5461 directive of the form @samp{.word sym1-sym2}, and the difference between
5462 @code{sym1} and @code{sym2} does not fit in 16 bits, @code{@value{AS}}
5463 creates a @dfn{secondary jump table}, immediately before the next label.
5464 This secondary jump table is preceded by a short-jump to the
5465 first byte after the secondary table. This short-jump prevents the flow
5466 of control from accidentally falling into the new table. Inside the
5467 table is a long-jump to @code{sym2}. The original @samp{.word}
5468 contains @code{sym1} minus the address of the long-jump to
5471 If there were several occurrences of @samp{.word sym1-sym2} before the
5472 secondary jump table, all of them are adjusted. If there was a
5473 @samp{.word sym3-sym4}, that also did not fit in sixteen bits, a
5474 long-jump to @code{sym4} is included in the secondary jump table,
5475 and the @code{.word} directives are adjusted to contain @code{sym3}
5476 minus the address of the long-jump to @code{sym4}; and so on, for as many
5477 entries in the original jump table as necessary.
5480 @emph{This feature may be disabled by compiling @code{@value{AS}} with the
5481 @samp{-DWORKING_DOT_WORD} option.} This feature is likely to confuse
5482 assembly language programmers.
5485 @c end DIFF-TBL-KLUGE
5488 @section Deprecated Directives
5490 @cindex deprecated directives
5491 @cindex obsolescent directives
5492 One day these directives won't work.
5493 They are included for compatibility with older assemblers.
5500 @node Machine Dependencies
5501 @chapter Machine Dependent Features
5503 @cindex machine dependencies
5504 The machine instruction sets are (almost by definition) different on
5505 each machine where @code{@value{AS}} runs. Floating point representations
5506 vary as well, and @code{@value{AS}} often supports a few additional
5507 directives or command-line options for compatibility with other
5508 assemblers on a particular platform. Finally, some versions of
5509 @code{@value{AS}} support special pseudo-instructions for branch
5512 This chapter discusses most of these differences, though it does not
5513 include details on any machine's instruction set. For details on that
5514 subject, see the hardware manufacturer's manual.
5518 * AMD29K-Dependent:: AMD 29K Dependent Features
5521 * ARC-Dependent:: ARC Dependent Features
5524 * ARM-Dependent:: ARM Dependent Features
5527 * D10V-Dependent:: D10V Dependent Features
5530 * D30V-Dependent:: D30V Dependent Features
5533 * H8/300-Dependent:: Hitachi H8/300 Dependent Features
5536 * H8/500-Dependent:: Hitachi H8/500 Dependent Features
5539 * HPPA-Dependent:: HPPA Dependent Features
5542 * ESA/390-Dependent:: IBM ESA/390 Dependent Features
5545 * i386-Dependent:: Intel 80386 and AMD x86-64 Dependent Features
5548 * i860-Dependent:: Intel 80860 Dependent Features
5551 * i960-Dependent:: Intel 80960 Dependent Features
5554 * M32R-Dependent:: M32R Dependent Features
5557 * M68K-Dependent:: M680x0 Dependent Features
5560 * M68HC11-Dependent:: M68HC11 and 68HC12 Dependent Features
5563 * M88K-Dependent:: M880x0 Dependent Features
5566 * MIPS-Dependent:: MIPS Dependent Features
5569 * SH-Dependent:: Hitachi SH Dependent Features
5572 * PDP-11-Dependent:: PDP-11 Dependent Features
5575 * PJ-Dependent:: picoJava Dependent Features
5578 * PPC-Dependent:: PowerPC Dependent Features
5581 * Sparc-Dependent:: SPARC Dependent Features
5584 * TIC54X-Dependent:: TI TMS320C54x Dependent Features
5587 * V850-Dependent:: V850 Dependent Features
5590 * Z8000-Dependent:: Z8000 Dependent Features
5593 * Vax-Dependent:: VAX Dependent Features
5600 @c The following major nodes are *sections* in the GENERIC version, *chapters*
5601 @c in single-cpu versions. This is mainly achieved by @lowersections. There is a
5602 @c peculiarity: to preserve cross-references, there must be a node called
5603 @c "Machine Dependencies". Hence the conditional nodenames in each
5604 @c major node below. Node defaulting in makeinfo requires adjacency of
5605 @c node and sectioning commands; hence the repetition of @chapter BLAH
5606 @c in both conditional blocks.
5613 @include c-a29k.texi
5622 @node Machine Dependencies
5623 @chapter Machine Dependent Features
5625 The machine instruction sets are different on each Hitachi chip family,
5626 and there are also some syntax differences among the families. This
5627 chapter describes the specific @code{@value{AS}} features for each
5631 * H8/300-Dependent:: Hitachi H8/300 Dependent Features
5632 * H8/500-Dependent:: Hitachi H8/500 Dependent Features
5633 * SH-Dependent:: Hitachi SH Dependent Features
5640 @include c-d10v.texi
5644 @include c-d30v.texi
5648 @include c-h8300.texi
5652 @include c-h8500.texi
5656 @include c-hppa.texi
5660 @include c-i370.texi
5664 @include c-i386.texi
5668 @include c-i860.texi
5672 @include c-i960.texi
5676 @include c-m32r.texi
5680 @include c-m68k.texi
5684 @include c-m68hc11.texi
5688 @include c-m88k.texi
5692 @include c-mips.texi
5696 @include c-ns32k.texi
5700 @include c-pdp11.texi
5716 @include c-sparc.texi
5720 @include c-tic54x.texi
5732 @include c-v850.texi
5736 @c reverse effect of @down at top of generic Machine-Dep chapter
5740 @node Reporting Bugs
5741 @chapter Reporting Bugs
5742 @cindex bugs in assembler
5743 @cindex reporting bugs in assembler
5745 Your bug reports play an essential role in making @code{@value{AS}} reliable.
5747 Reporting a bug may help you by bringing a solution to your problem, or it may
5748 not. But in any case the principal function of a bug report is to help the
5749 entire community by making the next version of @code{@value{AS}} work better.
5750 Bug reports are your contribution to the maintenance of @code{@value{AS}}.
5752 In order for a bug report to serve its purpose, you must include the
5753 information that enables us to fix the bug.
5756 * Bug Criteria:: Have you found a bug?
5757 * Bug Reporting:: How to report bugs
5761 @section Have you found a bug?
5762 @cindex bug criteria
5764 If you are not sure whether you have found a bug, here are some guidelines:
5767 @cindex fatal signal
5768 @cindex assembler crash
5769 @cindex crash of assembler
5771 If the assembler gets a fatal signal, for any input whatever, that is a
5772 @code{@value{AS}} bug. Reliable assemblers never crash.
5774 @cindex error on valid input
5776 If @code{@value{AS}} produces an error message for valid input, that is a bug.
5778 @cindex invalid input
5780 If @code{@value{AS}} does not produce an error message for invalid input, that
5781 is a bug. However, you should note that your idea of ``invalid input'' might
5782 be our idea of ``an extension'' or ``support for traditional practice''.
5785 If you are an experienced user of assemblers, your suggestions for improvement
5786 of @code{@value{AS}} are welcome in any case.
5790 @section How to report bugs
5792 @cindex assembler bugs, reporting
5794 A number of companies and individuals offer support for @sc{gnu} products. If
5795 you obtained @code{@value{AS}} from a support organization, we recommend you
5796 contact that organization first.
5798 You can find contact information for many support companies and
5799 individuals in the file @file{etc/SERVICE} in the @sc{gnu} Emacs
5802 In any event, we also recommend that you send bug reports for @code{@value{AS}}
5803 to @samp{bug-binutils@@gnu.org}.
5805 The fundamental principle of reporting bugs usefully is this:
5806 @strong{report all the facts}. If you are not sure whether to state a
5807 fact or leave it out, state it!
5809 Often people omit facts because they think they know what causes the problem
5810 and assume that some details do not matter. Thus, you might assume that the
5811 name of a symbol you use in an example does not matter. Well, probably it does
5812 not, but one cannot be sure. Perhaps the bug is a stray memory reference which
5813 happens to fetch from the location where that name is stored in memory;
5814 perhaps, if the name were different, the contents of that location would fool
5815 the assembler into doing the right thing despite the bug. Play it safe and
5816 give a specific, complete example. That is the easiest thing for you to do,
5817 and the most helpful.
5819 Keep in mind that the purpose of a bug report is to enable us to fix the bug if
5820 it is new to us. Therefore, always write your bug reports on the assumption
5821 that the bug has not been reported previously.
5823 Sometimes people give a few sketchy facts and ask, ``Does this ring a
5824 bell?'' Those bug reports are useless, and we urge everyone to
5825 @emph{refuse to respond to them} except to chide the sender to report
5828 To enable us to fix the bug, you should include all these things:
5832 The version of @code{@value{AS}}. @code{@value{AS}} announces it if you start
5833 it with the @samp{--version} argument.
5835 Without this, we will not know whether there is any point in looking for
5836 the bug in the current version of @code{@value{AS}}.
5839 Any patches you may have applied to the @code{@value{AS}} source.
5842 The type of machine you are using, and the operating system name and
5846 What compiler (and its version) was used to compile @code{@value{AS}}---e.g.
5850 The command arguments you gave the assembler to assemble your example and
5851 observe the bug. To guarantee you will not omit something important, list them
5852 all. A copy of the Makefile (or the output from make) is sufficient.
5854 If we were to try to guess the arguments, we would probably guess wrong
5855 and then we might not encounter the bug.
5858 A complete input file that will reproduce the bug. If the bug is observed when
5859 the assembler is invoked via a compiler, send the assembler source, not the
5860 high level language source. Most compilers will produce the assembler source
5861 when run with the @samp{-S} option. If you are using @code{@value{GCC}}, use
5862 the options @samp{-v --save-temps}; this will save the assembler source in a
5863 file with an extension of @file{.s}, and also show you exactly how
5864 @code{@value{AS}} is being run.
5867 A description of what behavior you observe that you believe is
5868 incorrect. For example, ``It gets a fatal signal.''
5870 Of course, if the bug is that @code{@value{AS}} gets a fatal signal, then we
5871 will certainly notice it. But if the bug is incorrect output, we might not
5872 notice unless it is glaringly wrong. You might as well not give us a chance to
5875 Even if the problem you experience is a fatal signal, you should still say so
5876 explicitly. Suppose something strange is going on, such as, your copy of
5877 @code{@value{AS}} is out of synch, or you have encountered a bug in the C
5878 library on your system. (This has happened!) Your copy might crash and ours
5879 would not. If you told us to expect a crash, then when ours fails to crash, we
5880 would know that the bug was not happening for us. If you had not told us to
5881 expect a crash, then we would not be able to draw any conclusion from our
5885 If you wish to suggest changes to the @code{@value{AS}} source, send us context
5886 diffs, as generated by @code{diff} with the @samp{-u}, @samp{-c}, or @samp{-p}
5887 option. Always send diffs from the old file to the new file. If you even
5888 discuss something in the @code{@value{AS}} source, refer to it by context, not
5891 The line numbers in our development sources will not match those in your
5892 sources. Your line numbers would convey no useful information to us.
5895 Here are some things that are not necessary:
5899 A description of the envelope of the bug.
5901 Often people who encounter a bug spend a lot of time investigating
5902 which changes to the input file will make the bug go away and which
5903 changes will not affect it.
5905 This is often time consuming and not very useful, because the way we
5906 will find the bug is by running a single example under the debugger
5907 with breakpoints, not by pure deduction from a series of examples.
5908 We recommend that you save your time for something else.
5910 Of course, if you can find a simpler example to report @emph{instead}
5911 of the original one, that is a convenience for us. Errors in the
5912 output will be easier to spot, running under the debugger will take
5913 less time, and so on.
5915 However, simplification is not vital; if you do not want to do this,
5916 report the bug anyway and send us the entire test case you used.
5919 A patch for the bug.
5921 A patch for the bug does help us if it is a good one. But do not omit
5922 the necessary information, such as the test case, on the assumption that
5923 a patch is all we need. We might see problems with your patch and decide
5924 to fix the problem another way, or we might not understand it at all.
5926 Sometimes with a program as complicated as @code{@value{AS}} it is very hard to
5927 construct an example that will make the program follow a certain path through
5928 the code. If you do not send us the example, we will not be able to construct
5929 one, so we will not be able to verify that the bug is fixed.
5931 And if we cannot understand what bug you are trying to fix, or why your
5932 patch should be an improvement, we will not install it. A test case will
5933 help us to understand.
5936 A guess about what the bug is or what it depends on.
5938 Such guesses are usually wrong. Even we cannot guess right about such
5939 things without first using the debugger to find the facts.
5942 @node Acknowledgements
5943 @chapter Acknowledgements
5945 If you have contributed to @code{@value{AS}} and your name isn't listed here,
5946 it is not meant as a slight. We just don't know about it. Send mail to the
5947 maintainer, and we'll correct the situation. Currently
5949 the maintainer is Ken Raeburn (email address @code{raeburn@@cygnus.com}).
5951 Dean Elsner wrote the original @sc{gnu} assembler for the VAX.@footnote{Any
5954 Jay Fenlason maintained GAS for a while, adding support for GDB-specific debug
5955 information and the 68k series machines, most of the preprocessing pass, and
5956 extensive changes in @file{messages.c}, @file{input-file.c}, @file{write.c}.
5958 K. Richard Pixley maintained GAS for a while, adding various enhancements and
5959 many bug fixes, including merging support for several processors, breaking GAS
5960 up to handle multiple object file format back ends (including heavy rewrite,
5961 testing, an integration of the coff and b.out back ends), adding configuration
5962 including heavy testing and verification of cross assemblers and file splits
5963 and renaming, converted GAS to strictly ANSI C including full prototypes, added
5964 support for m680[34]0 and cpu32, did considerable work on i960 including a COFF
5965 port (including considerable amounts of reverse engineering), a SPARC opcode
5966 file rewrite, DECstation, rs6000, and hp300hpux host ports, updated ``know''
5967 assertions and made them work, much other reorganization, cleanup, and lint.
5969 Ken Raeburn wrote the high-level BFD interface code to replace most of the code
5970 in format-specific I/O modules.
5972 The original VMS support was contributed by David L. Kashtan. Eric Youngdale
5973 has done much work with it since.
5975 The Intel 80386 machine description was written by Eliot Dresselhaus.
5977 Minh Tran-Le at IntelliCorp contributed some AIX 386 support.
5979 The Motorola 88k machine description was contributed by Devon Bowen of Buffalo
5980 University and Torbjorn Granlund of the Swedish Institute of Computer Science.
5982 Keith Knowles at the Open Software Foundation wrote the original MIPS back end
5983 (@file{tc-mips.c}, @file{tc-mips.h}), and contributed Rose format support
5984 (which hasn't been merged in yet). Ralph Campbell worked with the MIPS code to
5985 support a.out format.
5987 Support for the Zilog Z8k and Hitachi H8/300 and H8/500 processors (tc-z8k,
5988 tc-h8300, tc-h8500), and IEEE 695 object file format (obj-ieee), was written by
5989 Steve Chamberlain of Cygnus Support. Steve also modified the COFF back end to
5990 use BFD for some low-level operations, for use with the H8/300 and AMD 29k
5993 John Gilmore built the AMD 29000 support, added @code{.include} support, and
5994 simplified the configuration of which versions accept which directives. He
5995 updated the 68k machine description so that Motorola's opcodes always produced
5996 fixed-size instructions (e.g. @code{jsr}), while synthetic instructions
5997 remained shrinkable (@code{jbsr}). John fixed many bugs, including true tested
5998 cross-compilation support, and one bug in relaxation that took a week and
5999 required the proverbial one-bit fix.
6001 Ian Lance Taylor of Cygnus Support merged the Motorola and MIT syntax for the
6002 68k, completed support for some COFF targets (68k, i386 SVR3, and SCO Unix),
6003 added support for MIPS ECOFF and ELF targets, wrote the initial RS/6000 and
6004 PowerPC assembler, and made a few other minor patches.
6006 Steve Chamberlain made @code{@value{AS}} able to generate listings.
6008 Hewlett-Packard contributed support for the HP9000/300.
6010 Jeff Law wrote GAS and BFD support for the native HPPA object format (SOM)
6011 along with a fairly extensive HPPA testsuite (for both SOM and ELF object
6012 formats). This work was supported by both the Center for Software Science at
6013 the University of Utah and Cygnus Support.
6015 Support for ELF format files has been worked on by Mark Eichin of Cygnus
6016 Support (original, incomplete implementation for SPARC), Pete Hoogenboom and
6017 Jeff Law at the University of Utah (HPPA mainly), Michael Meissner of the Open
6018 Software Foundation (i386 mainly), and Ken Raeburn of Cygnus Support (sparc,
6019 and some initial 64-bit support).
6021 Linas Vepstas added GAS support for the ESA/390 "IBM 370" architecture.
6023 Richard Henderson rewrote the Alpha assembler. Klaus Kaempf wrote GAS and BFD
6024 support for openVMS/Alpha.
6026 Timothy Wall, Michael Hayes, and Greg Smart contributed to the various tic*
6029 Several engineers at Cygnus Support have also provided many small bug fixes and
6030 configuration enhancements.
6032 Many others have contributed large or small bugfixes and enhancements. If
6033 you have contributed significant work and are not mentioned on this list, and
6034 want to be, let us know. Some of the history has been lost; we are not
6035 intentionally leaving anyone out.
6037 @node GNU Free Documentation License
6038 @chapter GNU Free Documentation License
6040 GNU Free Documentation License
6042 Version 1.1, March 2000
6044 Copyright (C) 2000 Free Software Foundation, Inc.
6045 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
6047 Everyone is permitted to copy and distribute verbatim copies
6048 of this license document, but changing it is not allowed.
6053 The purpose of this License is to make a manual, textbook, or other
6054 written document "free" in the sense of freedom: to assure everyone
6055 the effective freedom to copy and redistribute it, with or without
6056 modifying it, either commercially or noncommercially. Secondarily,
6057 this License preserves for the author and publisher a way to get
6058 credit for their work, while not being considered responsible for
6059 modifications made by others.
6061 This License is a kind of "copyleft", which means that derivative
6062 works of the document must themselves be free in the same sense. It
6063 complements the GNU General Public License, which is a copyleft
6064 license designed for free software.
6066 We have designed this License in order to use it for manuals for free
6067 software, because free software needs free documentation: a free
6068 program should come with manuals providing the same freedoms that the
6069 software does. But this License is not limited to software manuals;
6070 it can be used for any textual work, regardless of subject matter or
6071 whether it is published as a printed book. We recommend this License
6072 principally for works whose purpose is instruction or reference.
6075 1. APPLICABILITY AND DEFINITIONS
6077 This License applies to any manual or other work that contains a
6078 notice placed by the copyright holder saying it can be distributed
6079 under the terms of this License. The "Document", below, refers to any
6080 such manual or work. Any member of the public is a licensee, and is
6083 A "Modified Version" of the Document means any work containing the
6084 Document or a portion of it, either copied verbatim, or with
6085 modifications and/or translated into another language.
6087 A "Secondary Section" is a named appendix or a front-matter section of
6088 the Document that deals exclusively with the relationship of the
6089 publishers or authors of the Document to the Document's overall subject
6090 (or to related matters) and contains nothing that could fall directly
6091 within that overall subject. (For example, if the Document is in part a
6092 textbook of mathematics, a Secondary Section may not explain any
6093 mathematics.) The relationship could be a matter of historical
6094 connection with the subject or with related matters, or of legal,
6095 commercial, philosophical, ethical or political position regarding
6098 The "Invariant Sections" are certain Secondary Sections whose titles
6099 are designated, as being those of Invariant Sections, in the notice
6100 that says that the Document is released under this License.
6102 The "Cover Texts" are certain short passages of text that are listed,
6103 as Front-Cover Texts or Back-Cover Texts, in the notice that says that
6104 the Document is released under this License.
6106 A "Transparent" copy of the Document means a machine-readable copy,
6107 represented in a format whose specification is available to the
6108 general public, whose contents can be viewed and edited directly and
6109 straightforwardly with generic text editors or (for images composed of
6110 pixels) generic paint programs or (for drawings) some widely available
6111 drawing editor, and that is suitable for input to text formatters or
6112 for automatic translation to a variety of formats suitable for input
6113 to text formatters. A copy made in an otherwise Transparent file
6114 format whose markup has been designed to thwart or discourage
6115 subsequent modification by readers is not Transparent. A copy that is
6116 not "Transparent" is called "Opaque".
6118 Examples of suitable formats for Transparent copies include plain
6119 ASCII without markup, Texinfo input format, LaTeX input format, SGML
6120 or XML using a publicly available DTD, and standard-conforming simple
6121 HTML designed for human modification. Opaque formats include
6122 PostScript, PDF, proprietary formats that can be read and edited only
6123 by proprietary word processors, SGML or XML for which the DTD and/or
6124 processing tools are not generally available, and the
6125 machine-generated HTML produced by some word processors for output
6128 The "Title Page" means, for a printed book, the title page itself,
6129 plus such following pages as are needed to hold, legibly, the material
6130 this License requires to appear in the title page. For works in
6131 formats which do not have any title page as such, "Title Page" means
6132 the text near the most prominent appearance of the work's title,
6133 preceding the beginning of the body of the text.
6138 You may copy and distribute the Document in any medium, either
6139 commercially or noncommercially, provided that this License, the
6140 copyright notices, and the license notice saying this License applies
6141 to the Document are reproduced in all copies, and that you add no other
6142 conditions whatsoever to those of this License. You may not use
6143 technical measures to obstruct or control the reading or further
6144 copying of the copies you make or distribute. However, you may accept
6145 compensation in exchange for copies. If you distribute a large enough
6146 number of copies you must also follow the conditions in section 3.
6148 You may also lend copies, under the same conditions stated above, and
6149 you may publicly display copies.
6152 3. COPYING IN QUANTITY
6154 If you publish printed copies of the Document numbering more than 100,
6155 and the Document's license notice requires Cover Texts, you must enclose
6156 the copies in covers that carry, clearly and legibly, all these Cover
6157 Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on
6158 the back cover. Both covers must also clearly and legibly identify
6159 you as the publisher of these copies. The front cover must present
6160 the full title with all words of the title equally prominent and
6161 visible. You may add other material on the covers in addition.
6162 Copying with changes limited to the covers, as long as they preserve
6163 the title of the Document and satisfy these conditions, can be treated
6164 as verbatim copying in other respects.
6166 If the required texts for either cover are too voluminous to fit
6167 legibly, you should put the first ones listed (as many as fit
6168 reasonably) on the actual cover, and continue the rest onto adjacent
6171 If you publish or distribute Opaque copies of the Document numbering
6172 more than 100, you must either include a machine-readable Transparent
6173 copy along with each Opaque copy, or state in or with each Opaque copy
6174 a publicly-accessible computer-network location containing a complete
6175 Transparent copy of the Document, free of added material, which the
6176 general network-using public has access to download anonymously at no
6177 charge using public-standard network protocols. If you use the latter
6178 option, you must take reasonably prudent steps, when you begin
6179 distribution of Opaque copies in quantity, to ensure that this
6180 Transparent copy will remain thus accessible at the stated location
6181 until at least one year after the last time you distribute an Opaque
6182 copy (directly or through your agents or retailers) of that edition to
6185 It is requested, but not required, that you contact the authors of the
6186 Document well before redistributing any large number of copies, to give
6187 them a chance to provide you with an updated version of the Document.
6192 You may copy and distribute a Modified Version of the Document under
6193 the conditions of sections 2 and 3 above, provided that you release
6194 the Modified Version under precisely this License, with the Modified
6195 Version filling the role of the Document, thus licensing distribution
6196 and modification of the Modified Version to whoever possesses a copy
6197 of it. In addition, you must do these things in the Modified Version:
6199 A. Use in the Title Page (and on the covers, if any) a title distinct
6200 from that of the Document, and from those of previous versions
6201 (which should, if there were any, be listed in the History section
6202 of the Document). You may use the same title as a previous version
6203 if the original publisher of that version gives permission.
6204 B. List on the Title Page, as authors, one or more persons or entities
6205 responsible for authorship of the modifications in the Modified
6206 Version, together with at least five of the principal authors of the
6207 Document (all of its principal authors, if it has less than five).
6208 C. State on the Title page the name of the publisher of the
6209 Modified Version, as the publisher.
6210 D. Preserve all the copyright notices of the Document.
6211 E. Add an appropriate copyright notice for your modifications
6212 adjacent to the other copyright notices.
6213 F. Include, immediately after the copyright notices, a license notice
6214 giving the public permission to use the Modified Version under the
6215 terms of this License, in the form shown in the Addendum below.
6216 G. Preserve in that license notice the full lists of Invariant Sections
6217 and required Cover Texts given in the Document's license notice.
6218 H. Include an unaltered copy of this License.
6219 I. Preserve the section entitled "History", and its title, and add to
6220 it an item stating at least the title, year, new authors, and
6221 publisher of the Modified Version as given on the Title Page. If
6222 there is no section entitled "History" in the Document, create one
6223 stating the title, year, authors, and publisher of the Document as
6224 given on its Title Page, then add an item describing the Modified
6225 Version as stated in the previous sentence.
6226 J. Preserve the network location, if any, given in the Document for
6227 public access to a Transparent copy of the Document, and likewise
6228 the network locations given in the Document for previous versions
6229 it was based on. These may be placed in the "History" section.
6230 You may omit a network location for a work that was published at
6231 least four years before the Document itself, or if the original
6232 publisher of the version it refers to gives permission.
6233 K. In any section entitled "Acknowledgements" or "Dedications",
6234 preserve the section's title, and preserve in the section all the
6235 substance and tone of each of the contributor acknowledgements
6236 and/or dedications given therein.
6237 L. Preserve all the Invariant Sections of the Document,
6238 unaltered in their text and in their titles. Section numbers
6239 or the equivalent are not considered part of the section titles.
6240 M. Delete any section entitled "Endorsements". Such a section
6241 may not be included in the Modified Version.
6242 N. Do not retitle any existing section as "Endorsements"
6243 or to conflict in title with any Invariant Section.
6245 If the Modified Version includes new front-matter sections or
6246 appendices that qualify as Secondary Sections and contain no material
6247 copied from the Document, you may at your option designate some or all
6248 of these sections as invariant. To do this, add their titles to the
6249 list of Invariant Sections in the Modified Version's license notice.
6250 These titles must be distinct from any other section titles.
6252 You may add a section entitled "Endorsements", provided it contains
6253 nothing but endorsements of your Modified Version by various
6254 parties--for example, statements of peer review or that the text has
6255 been approved by an organization as the authoritative definition of a
6258 You may add a passage of up to five words as a Front-Cover Text, and a
6259 passage of up to 25 words as a Back-Cover Text, to the end of the list
6260 of Cover Texts in the Modified Version. Only one passage of
6261 Front-Cover Text and one of Back-Cover Text may be added by (or
6262 through arrangements made by) any one entity. If the Document already
6263 includes a cover text for the same cover, previously added by you or
6264 by arrangement made by the same entity you are acting on behalf of,
6265 you may not add another; but you may replace the old one, on explicit
6266 permission from the previous publisher that added the old one.
6268 The author(s) and publisher(s) of the Document do not by this License
6269 give permission to use their names for publicity for or to assert or
6270 imply endorsement of any Modified Version.
6273 5. COMBINING DOCUMENTS
6275 You may combine the Document with other documents released under this
6276 License, under the terms defined in section 4 above for modified
6277 versions, provided that you include in the combination all of the
6278 Invariant Sections of all of the original documents, unmodified, and
6279 list them all as Invariant Sections of your combined work in its
6282 The combined work need only contain one copy of this License, and
6283 multiple identical Invariant Sections may be replaced with a single
6284 copy. If there are multiple Invariant Sections with the same name but
6285 different contents, make the title of each such section unique by
6286 adding at the end of it, in parentheses, the name of the original
6287 author or publisher of that section if known, or else a unique number.
6288 Make the same adjustment to the section titles in the list of
6289 Invariant Sections in the license notice of the combined work.
6291 In the combination, you must combine any sections entitled "History"
6292 in the various original documents, forming one section entitled
6293 "History"; likewise combine any sections entitled "Acknowledgements",
6294 and any sections entitled "Dedications". You must delete all sections
6295 entitled "Endorsements."
6298 6. COLLECTIONS OF DOCUMENTS
6300 You may make a collection consisting of the Document and other documents
6301 released under this License, and replace the individual copies of this
6302 License in the various documents with a single copy that is included in
6303 the collection, provided that you follow the rules of this License for
6304 verbatim copying of each of the documents in all other respects.
6306 You may extract a single document from such a collection, and distribute
6307 it individually under this License, provided you insert a copy of this
6308 License into the extracted document, and follow this License in all
6309 other respects regarding verbatim copying of that document.
6312 7. AGGREGATION WITH INDEPENDENT WORKS
6314 A compilation of the Document or its derivatives with other separate
6315 and independent documents or works, in or on a volume of a storage or
6316 distribution medium, does not as a whole count as a Modified Version
6317 of the Document, provided no compilation copyright is claimed for the
6318 compilation. Such a compilation is called an "aggregate", and this
6319 License does not apply to the other self-contained works thus compiled
6320 with the Document, on account of their being thus compiled, if they
6321 are not themselves derivative works of the Document.
6323 If the Cover Text requirement of section 3 is applicable to these
6324 copies of the Document, then if the Document is less than one quarter
6325 of the entire aggregate, the Document's Cover Texts may be placed on
6326 covers that surround only the Document within the aggregate.
6327 Otherwise they must appear on covers around the whole aggregate.
6332 Translation is considered a kind of modification, so you may
6333 distribute translations of the Document under the terms of section 4.
6334 Replacing Invariant Sections with translations requires special
6335 permission from their copyright holders, but you may include
6336 translations of some or all Invariant Sections in addition to the
6337 original versions of these Invariant Sections. You may include a
6338 translation of this License provided that you also include the
6339 original English version of this License. In case of a disagreement
6340 between the translation and the original English version of this
6341 License, the original English version will prevail.
6346 You may not copy, modify, sublicense, or distribute the Document except
6347 as expressly provided for under this License. Any other attempt to
6348 copy, modify, sublicense or distribute the Document is void, and will
6349 automatically terminate your rights under this License. However,
6350 parties who have received copies, or rights, from you under this
6351 License will not have their licenses terminated so long as such
6352 parties remain in full compliance.
6355 10. FUTURE REVISIONS OF THIS LICENSE
6357 The Free Software Foundation may publish new, revised versions
6358 of the GNU Free Documentation License from time to time. Such new
6359 versions will be similar in spirit to the present version, but may
6360 differ in detail to address new problems or concerns. See
6361 http://www.gnu.org/copyleft/.
6363 Each version of the License is given a distinguishing version number.
6364 If the Document specifies that a particular numbered version of this
6365 License "or any later version" applies to it, you have the option of
6366 following the terms and conditions either of that specified version or
6367 of any later version that has been published (not as a draft) by the
6368 Free Software Foundation. If the Document does not specify a version
6369 number of this License, you may choose any version ever published (not
6370 as a draft) by the Free Software Foundation.
6373 ADDENDUM: How to use this License for your documents
6375 To use this License in a document you have written, include a copy of
6376 the License in the document and put the following copyright and
6377 license notices just after the title page:
6380 Copyright (c) YEAR YOUR NAME.
6381 Permission is granted to copy, distribute and/or modify this document
6382 under the terms of the GNU Free Documentation License, Version 1.1
6383 or any later version published by the Free Software Foundation;
6384 with the Invariant Sections being LIST THEIR TITLES, with the
6385 Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.
6386 A copy of the license is included in the section entitled "GNU
6387 Free Documentation License".
6390 If you have no Invariant Sections, write "with no Invariant Sections"
6391 instead of saying which ones are invariant. If you have no
6392 Front-Cover Texts, write "no Front-Cover Texts" instead of
6393 "Front-Cover Texts being LIST"; likewise for Back-Cover Texts.
6395 If your document contains nontrivial examples of program code, we
6396 recommend releasing these examples in parallel under your choice of
6397 free software license, such as the GNU General Public License,
6398 to permit their use in free software.
projects / deliverable / binutils-gdb.git / blob