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4b95cf5c | 1 | @c Copyright (C) 2009-2014 Free Software Foundation, Inc. |
11c19e16 MS |
2 | @c This is part of the GAS manual. |
3 | @c For copying conditions, see the file as.texinfo. | |
4 | @ifset GENERIC | |
5 | @page | |
6 | @node S/390-Dependent | |
7 | @chapter IBM S/390 Dependent Features | |
8 | @end ifset | |
9 | @ifclear GENERIC | |
10 | @node Machine Dependencies | |
11 | @chapter IBM S/390 Dependent Features | |
12 | @end ifclear | |
13 | ||
14 | @cindex s390 support | |
15 | ||
16 | The s390 version of @code{@value{AS}} supports two architectures modes | |
17 | and seven chip levels. The architecture modes are the Enterprise System | |
18 | Architecture (ESA) and the newer z/Architecture mode. The chip levels | |
cfc72779 | 19 | are g5, g6, z900, z990, z9-109, z9-ec, z10, z196, and zEC12. |
11c19e16 MS |
20 | |
21 | @menu | |
22 | * s390 Options:: Command-line Options. | |
23 | * s390 Characters:: Special Characters. | |
24 | * s390 Syntax:: Assembler Instruction syntax. | |
25 | * s390 Directives:: Assembler Directives. | |
26 | * s390 Floating Point:: Floating Point. | |
27 | @end menu | |
28 | ||
29 | @node s390 Options | |
30 | @section Options | |
31 | @cindex options for s390 | |
32 | @cindex s390 options | |
33 | ||
34 | The following table lists all available s390 specific options: | |
34bca508 | 35 | |
11c19e16 MS |
36 | @table @code |
37 | @cindex @samp{-m31} option, s390 | |
38 | @cindex @samp{-m64} option, s390 | |
39 | @item -m31 | -m64 | |
40 | Select 31- or 64-bit ABI implying a word size of 32- or 64-bit. | |
41 | ||
42 | These options are only available with the ELF object file format, and | |
43 | require that the necessary BFD support has been included (on a 31-bit | |
44 | platform you must add --enable-64-bit-bfd on the call to the configure | |
45 | script to enable 64-bit usage and use s390x as target platform). | |
46 | ||
47 | @cindex @samp{-mesa} option, s390 | |
48 | @cindex @samp{-mzarch} option, s390 | |
49 | @item -mesa | -mzarch | |
50 | Select the architecture mode, either the Enterprise System Architecture | |
51 | (esa) mode or the z/Architecture mode (zarch). | |
52 | ||
53 | The 64-bit instructions are only available with the z/Architecture mode. | |
54 | The combination of @samp{-m64} and @samp{-mesa} results in a warning | |
55 | message. | |
56 | ||
57 | @cindex @samp{-march=} option, s390 | |
58 | @item -march=@var{CPU} | |
59 | This option specifies the target processor. The following processor names | |
34bca508 | 60 | are recognized: |
11c19e16 MS |
61 | @code{g5}, |
62 | @code{g6}, | |
63 | @code{z900}, | |
64 | @code{z990}, | |
65 | @code{z9-109}, | |
d9aee5d7 AK |
66 | @code{z9-ec}, |
67 | @code{z10} and | |
68 | @code{z196}. | |
11c19e16 MS |
69 | Assembling an instruction that is not supported on the target processor |
70 | results in an error message. Do not specify @code{g5} or @code{g6} | |
71 | with @samp{-mzarch}. | |
72 | ||
73 | @cindex @samp{-mregnames} option, s390 | |
74 | @item -mregnames | |
75 | Allow symbolic names for registers. | |
76 | ||
77 | @cindex @samp{-mno-regnames} option, s390 | |
78 | @item -mno-regnames | |
79 | Do not allow symbolic names for registers. | |
80 | ||
81 | @cindex @samp{-mwarn-areg-zero} option, s390 | |
82 | @item -mwarn-areg-zero | |
83 | Warn whenever the operand for a base or index register has been specified | |
84 | but evaluates to zero. This can indicate the misuse of general purpose | |
85 | register 0 as an address register. | |
86 | ||
87 | @end table | |
88 | ||
89 | @node s390 Characters | |
90 | @section Special Characters | |
91 | @cindex line comment character, s390 | |
92 | @cindex s390 line comment character | |
93 | ||
94 | @samp{#} is the line comment character. | |
95 | ||
7c31ae13 NC |
96 | If a @samp{#} appears as the first character of a line then the whole |
97 | line is treated as a comment, but in this case the line could also be | |
98 | a logical line number directive (@pxref{Comments}) or a preprocessor | |
99 | control command (@pxref{Preprocessing}). | |
100 | ||
101 | @cindex line separator, s390 | |
102 | @cindex statement separator, s390 | |
103 | @cindex s390 line separator | |
104 | The @samp{;} character can be used instead of a newline to separate | |
105 | statements. | |
106 | ||
11c19e16 MS |
107 | @node s390 Syntax |
108 | @section Instruction syntax | |
109 | @cindex instruction syntax, s390 | |
110 | @cindex s390 instruction syntax | |
111 | ||
34bca508 L |
112 | The assembler syntax closely follows the syntax outlined in |
113 | Enterprise Systems Architecture/390 Principles of Operation (SA22-7201) | |
114 | and the z/Architecture Principles of Operation (SA22-7832). | |
11c19e16 MS |
115 | |
116 | Each instruction has two major parts, the instruction mnemonic | |
117 | and the instruction operands. The instruction format varies. | |
118 | ||
119 | @menu | |
120 | * s390 Register:: Register Naming | |
121 | * s390 Mnemonics:: Instruction Mnemonics | |
122 | * s390 Operands:: Instruction Operands | |
123 | * s390 Formats:: Instruction Formats | |
124 | * s390 Aliases:: Instruction Aliases | |
125 | * s390 Operand Modifier:: Instruction Operand Modifier | |
126 | * s390 Instruction Marker:: Instruction Marker | |
127 | * s390 Literal Pool Entries:: Literal Pool Entries | |
128 | @end menu | |
129 | ||
130 | @node s390 Register | |
131 | @subsection Register naming | |
132 | @cindex register naming, s390 | |
133 | @cindex s390 register naming | |
134 | ||
135 | The @code{@value{AS}} recognizes a number of predefined symbols for the | |
136 | various processor registers. A register specification in one of the | |
137 | instruction formats is an unsigned integer between 0 and 15. The specific | |
138 | instruction and the position of the register in the instruction format | |
139 | denotes the type of the register. The register symbols are prefixed with | |
140 | @samp{%}: | |
141 | ||
142 | @display | |
143 | @multitable {%rN} {the 16 general purpose registers, 0 <= N <= 15} | |
144 | @item %rN @tab the 16 general purpose registers, 0 <= N <= 15 | |
145 | @item %fN @tab the 16 floating point registers, 0 <= N <= 15 | |
146 | @item %aN @tab the 16 access registers, 0 <= N <= 15 | |
147 | @item %cN @tab the 16 control registers, 0 <= N <= 15 | |
148 | @item %lit @tab an alias for the general purpose register %r13 | |
149 | @item %sp @tab an alias for the general purpose register %r15 | |
150 | @end multitable | |
151 | @end display | |
152 | ||
153 | @node s390 Mnemonics | |
154 | @subsection Instruction Mnemonics | |
155 | @cindex instruction mnemonics, s390 | |
156 | @cindex s390 instruction mnemonics | |
157 | ||
158 | All instructions documented in the Principles of Operation are supported | |
159 | with the mnemonic and order of operands as described. | |
160 | The instruction mnemonic identifies the instruction format | |
161 | (@ref{s390 Formats}) and the specific operation code for the instruction. | |
162 | For example, the @samp{lr} mnemonic denotes the instruction format @samp{RR} | |
163 | with the operation code @samp{0x18}. | |
164 | ||
165 | The definition of the various mnemonics follows a scheme, where the first | |
166 | character usually hint at the type of the instruction: | |
167 | ||
168 | @display | |
169 | @multitable {sla, sll} {if r is the last character the instruction operates on registers} | |
170 | @item a @tab add instruction, for example @samp{al} for add logical 32-bit | |
171 | @item b @tab branch instruction, for example @samp{bc} for branch on condition | |
172 | @item c @tab compare or convert instruction, for example @samp{cr} for compare | |
173 | register 32-bit | |
174 | @item d @tab divide instruction, for example @samp{dlr} devide logical register | |
175 | 64-bit to 32-bit | |
176 | @item i @tab insert instruction, for example @samp{ic} insert character | |
177 | @item l @tab load instruction, for example @samp{ltr} load and test register | |
178 | @item mv @tab move instruction, for example @samp{mvc} move character | |
179 | @item m @tab multiply instruction, for example @samp{mh} multiply halfword | |
180 | @item n @tab and instruction, for example @samp{ni} and immediate | |
181 | @item o @tab or instruction, for example @samp{oc} or character | |
182 | @item sla, sll @tab shift left single instruction | |
183 | @item sra, srl @tab shift right single instruction | |
184 | @item st @tab store instruction, for example @samp{stm} store multiple | |
185 | @item s @tab subtract instruction, for example @samp{slr} subtract | |
186 | logical 32-bit | |
187 | @item t @tab test or translate instruction, of example @samp{tm} test under mask | |
188 | @item x @tab exclusive or instruction, for example @samp{xc} exclusive or | |
189 | character | |
190 | @end multitable | |
191 | @end display | |
192 | ||
193 | Certain characters at the end of the mnemonic may describe a property | |
194 | of the instruction: | |
195 | ||
196 | @display | |
197 | @multitable {c} {if r is the last character the instruction operates on registers} | |
198 | @item c @tab the instruction uses a 8-bit character operand | |
199 | @item f @tab the instruction extends a 32-bit operand to 64 bit | |
200 | @item g @tab the operands are treated as 64-bit values | |
201 | @item h @tab the operand uses a 16-bit halfword operand | |
202 | @item i @tab the instruction uses an immediate operand | |
203 | @item l @tab the instruction uses unsigned, logical operands | |
204 | @item m @tab the instruction uses a mask or operates on multiple values | |
205 | @item r @tab if r is the last character, the instruction operates on registers | |
206 | @item y @tab the instruction uses 20-bit displacements | |
207 | @end multitable | |
208 | @end display | |
209 | ||
210 | There are many exceptions to the scheme outlined in the above lists, in | |
211 | particular for the priviledged instructions. For non-priviledged | |
212 | instruction it works quite well, for example the instruction @samp{clgfr} | |
213 | c: compare instruction, l: unsigned operands, g: 64-bit operands, | |
214 | f: 32- to 64-bit extension, r: register operands. The instruction compares | |
215 | an 64-bit value in a register with the zero extended 32-bit value from | |
216 | a second register. | |
217 | For a complete list of all mnemonics see appendix B in the Principles | |
218 | of Operation. | |
219 | ||
220 | @node s390 Operands | |
221 | @subsection Instruction Operands | |
222 | @cindex instruction operands, s390 | |
223 | @cindex s390 instruction operands | |
224 | ||
225 | Instruction operands can be grouped into three classes, operands located | |
226 | in registers, immediate operands, and operands in storage. | |
227 | ||
228 | A register operand can be located in general, floating-point, access, | |
229 | or control register. The register is identified by a four-bit field. | |
230 | The field containing the register operand is called the R field. | |
231 | ||
232 | Immediate operands are contained within the instruction and can have | |
233 | 8, 16 or 32 bits. The field containing the immediate operand is called | |
234 | the I field. Dependent on the instruction the I field is either signed | |
235 | or unsigned. | |
236 | ||
237 | A storage operand consists of an address and a length. The address of a | |
238 | storage operands can be specified in any of these ways: | |
239 | ||
240 | @itemize | |
241 | @item The content of a single general R | |
242 | @item The sum of the content of a general register called the base | |
243 | register B plus the content of a displacement field D | |
244 | @item The sum of the contents of two general registers called the | |
245 | index register X and the base register B plus the content of a | |
246 | displacement field | |
247 | @item The sum of the current instruction address and a 32-bit signed | |
248 | immediate field multiplied by two. | |
249 | @end itemize | |
250 | ||
251 | The length of a storage operand can be: | |
252 | ||
253 | @itemize | |
254 | @item Implied by the instruction | |
255 | @item Specified by a bitmask | |
256 | @item Specified by a four-bit or eight-bit length field L | |
257 | @item Specified by the content of a general register | |
258 | @end itemize | |
259 | ||
260 | The notation for storage operand addresses formed from multiple fields is | |
261 | as follows: | |
262 | ||
263 | @table @code | |
264 | @item Dn(Bn) | |
265 | the address for operand number n is formed from the content of general | |
266 | register Bn called the base register and the displacement field Dn. | |
267 | @item Dn(Xn,Bn) | |
268 | the address for operand number n is formed from the content of general | |
269 | register Xn called the index register, general register Bn called the | |
270 | base register and the displacement field Dn. | |
271 | @item Dn(Ln,Bn) | |
272 | the address for operand number n is formed from the content of general | |
273 | regiser Bn called the base register and the displacement field Dn. | |
274 | The length of the operand n is specified by the field Ln. | |
275 | @end table | |
276 | ||
277 | The base registers Bn and the index registers Xn of a storage operand can | |
278 | be skipped. If Bn and Xn are skipped, a zero will be stored to the operand | |
279 | field. The notation changes as follows: | |
280 | ||
281 | @display | |
282 | @multitable @columnfractions 0.30 0.30 | |
283 | @headitem full notation @tab short notation | |
284 | @item Dn(0,Bn) @tab Dn(Bn) | |
285 | @item Dn(0,0) @tab Dn | |
286 | @item Dn(0) @tab Dn | |
287 | @item Dn(Ln,0) @tab Dn(Ln) | |
288 | @end multitable | |
289 | @end display | |
290 | ||
291 | ||
292 | @node s390 Formats | |
293 | @subsection Instruction Formats | |
294 | @cindex instruction formats, s390 | |
295 | @cindex s390 instruction formats | |
296 | ||
297 | The Principles of Operation manuals lists 26 instruction formats where | |
298 | some of the formats have multiple variants. For the @samp{.insn} | |
34bca508 | 299 | pseudo directive the assembler recognizes some of the formats. |
11c19e16 MS |
300 | Typically, the most general variant of the instruction format is used |
301 | by the @samp{.insn} directive. | |
302 | ||
303 | The following table lists the abbreviations used in the table of | |
304 | instruction formats: | |
305 | ||
306 | @display | |
307 | @multitable {OpCode / OpCd} {Displacement lower 12 bits for operand x.} | |
308 | @item OpCode / OpCd @tab Part of the op code. | |
309 | @item Bx @tab Base register number for operand x. | |
310 | @item Dx @tab Displacement for operand x. | |
311 | @item DLx @tab Displacement lower 12 bits for operand x. | |
312 | @item DHx @tab Displacement higher 8-bits for operand x. | |
313 | @item Rx @tab Register number for operand x. | |
314 | @item Xx @tab Index register number for operand x. | |
315 | @item Ix @tab Signed immediate for operand x. | |
316 | @item Ux @tab Unsigned immediate for operand x. | |
317 | @end multitable | |
318 | @end display | |
319 | ||
320 | An instruction is two, four, or six bytes in length and must be aligned | |
321 | on a 2 byte boundary. The first two bits of the instruction specify the | |
322 | length of the instruction, 00 indicates a two byte instruction, 01 and 10 | |
323 | indicates a four byte instruction, and 11 indicates a six byte instruction. | |
324 | ||
325 | The following table lists the s390 instruction formats that are available | |
326 | with the @samp{.insn} pseudo directive: | |
327 | ||
328 | @table @code | |
329 | @item E format | |
330 | @verbatim | |
331 | +-------------+ | |
332 | | OpCode | | |
333 | +-------------+ | |
334 | 0 15 | |
335 | @end verbatim | |
336 | ||
337 | @item RI format: <insn> R1,I2 | |
338 | @verbatim | |
339 | +--------+----+----+------------------+ | |
340 | | OpCode | R1 |OpCd| I2 | | |
341 | +--------+----+----+------------------+ | |
342 | 0 8 12 16 31 | |
343 | @end verbatim | |
344 | ||
345 | @item RIE format: <insn> R1,R3,I2 | |
346 | @verbatim | |
347 | +--------+----+----+------------------+--------+--------+ | |
348 | | OpCode | R1 | R3 | I2 |////////| OpCode | | |
349 | +--------+----+----+------------------+--------+--------+ | |
350 | 0 8 12 16 32 40 47 | |
351 | @end verbatim | |
352 | ||
353 | @item RIL format: <insn> R1,I2 | |
354 | @verbatim | |
355 | +--------+----+----+------------------------------------+ | |
356 | | OpCode | R1 |OpCd| I2 | | |
357 | +--------+----+----+------------------------------------+ | |
358 | 0 8 12 16 47 | |
359 | @end verbatim | |
360 | ||
361 | @item RILU format: <insn> R1,U2 | |
362 | @verbatim | |
363 | +--------+----+----+------------------------------------+ | |
364 | | OpCode | R1 |OpCd| U2 | | |
365 | +--------+----+----+------------------------------------+ | |
366 | 0 8 12 16 47 | |
367 | @end verbatim | |
368 | ||
369 | @item RIS format: <insn> R1,I2,M3,D4(B4) | |
370 | @verbatim | |
371 | +--------+----+----+----+-------------+--------+--------+ | |
372 | | OpCode | R1 | M3 | B4 | D4 | I2 | Opcode | | |
373 | +--------+----+----+----+-------------+--------+--------+ | |
374 | 0 8 12 16 20 32 36 47 | |
375 | @end verbatim | |
376 | ||
377 | @item RR format: <insn> R1,R2 | |
378 | @verbatim | |
379 | +--------+----+----+ | |
380 | | OpCode | R1 | R2 | | |
381 | +--------+----+----+ | |
34bca508 | 382 | 0 8 12 15 |
11c19e16 MS |
383 | @end verbatim |
384 | ||
385 | @item RRE format: <insn> R1,R2 | |
386 | @verbatim | |
387 | +------------------+--------+----+----+ | |
388 | | OpCode |////////| R1 | R2 | | |
389 | +------------------+--------+----+----+ | |
390 | 0 16 24 28 31 | |
391 | @end verbatim | |
392 | ||
393 | @item RRF format: <insn> R1,R2,R3,M4 | |
394 | @verbatim | |
395 | +------------------+----+----+----+----+ | |
396 | | OpCode | R3 | M4 | R1 | R2 | | |
397 | +------------------+----+----+----+----+ | |
398 | 0 16 20 24 28 31 | |
399 | @end verbatim | |
400 | ||
401 | @item RRS format: <insn> R1,R2,M3,D4(B4) | |
402 | @verbatim | |
403 | +--------+----+----+----+-------------+----+----+--------+ | |
404 | | OpCode | R1 | R3 | B4 | D4 | M3 |////| OpCode | | |
405 | +--------+----+----+----+-------------+----+----+--------+ | |
406 | 0 8 12 16 20 32 36 40 47 | |
407 | @end verbatim | |
408 | ||
409 | @item RS format: <insn> R1,R3,D2(B2) | |
410 | @verbatim | |
411 | +--------+----+----+----+-------------+ | |
412 | | OpCode | R1 | R3 | B2 | D2 | | |
413 | +--------+----+----+----+-------------+ | |
414 | 0 8 12 16 20 31 | |
415 | @end verbatim | |
416 | ||
417 | @item RSE format: <insn> R1,R3,D2(B2) | |
418 | @verbatim | |
419 | +--------+----+----+----+-------------+--------+--------+ | |
420 | | OpCode | R1 | R3 | B2 | D2 |////////| OpCode | | |
421 | +--------+----+----+----+-------------+--------+--------+ | |
422 | 0 8 12 16 20 32 40 47 | |
423 | @end verbatim | |
424 | ||
425 | @item RSI format: <insn> R1,R3,I2 | |
426 | @verbatim | |
427 | +--------+----+----+------------------------------------+ | |
428 | | OpCode | R1 | R3 | I2 | | |
429 | +--------+----+----+------------------------------------+ | |
430 | 0 8 12 16 47 | |
431 | @end verbatim | |
432 | ||
433 | @item RSY format: <insn> R1,R3,D2(B2) | |
434 | @verbatim | |
435 | +--------+----+----+----+-------------+--------+--------+ | |
436 | | OpCode | R1 | R3 | B2 | DL2 | DH2 | OpCode | | |
437 | +--------+----+----+----+-------------+--------+--------+ | |
438 | 0 8 12 16 20 32 40 47 | |
439 | @end verbatim | |
440 | ||
441 | @item RX format: <insn> R1,D2(X2,B2) | |
442 | @verbatim | |
443 | +--------+----+----+----+-------------+ | |
444 | | OpCode | R1 | X2 | B2 | D2 | | |
445 | +--------+----+----+----+-------------+ | |
446 | 0 8 12 16 20 31 | |
447 | @end verbatim | |
448 | ||
449 | @item RXE format: <insn> R1,D2(X2,B2) | |
450 | @verbatim | |
451 | +--------+----+----+----+-------------+--------+--------+ | |
452 | | OpCode | R1 | X2 | B2 | D2 |////////| OpCode | | |
453 | +--------+----+----+----+-------------+--------+--------+ | |
454 | 0 8 12 16 20 32 40 47 | |
455 | @end verbatim | |
456 | ||
457 | @item RXF format: <insn> R1,R3,D2(X2,B2) | |
458 | @verbatim | |
459 | +--------+----+----+----+-------------+----+---+--------+ | |
460 | | OpCode | R3 | X2 | B2 | D2 | R1 |///| OpCode | | |
461 | +--------+----+----+----+-------------+----+---+--------+ | |
462 | 0 8 12 16 20 32 36 40 47 | |
463 | @end verbatim | |
464 | ||
465 | @item RXY format: <insn> R1,D2(X2,B2) | |
466 | @verbatim | |
467 | +--------+----+----+----+-------------+--------+--------+ | |
468 | | OpCode | R1 | X2 | B2 | DL2 | DH2 | OpCode | | |
469 | +--------+----+----+----+-------------+--------+--------+ | |
470 | 0 8 12 16 20 32 36 40 47 | |
471 | @end verbatim | |
472 | ||
473 | @item S format: <insn> D2(B2) | |
474 | @verbatim | |
475 | +------------------+----+-------------+ | |
476 | | OpCode | B2 | D2 | | |
477 | +------------------+----+-------------+ | |
478 | 0 16 20 31 | |
479 | @end verbatim | |
480 | ||
481 | @item SI format: <insn> D1(B1),I2 | |
482 | @verbatim | |
483 | +--------+---------+----+-------------+ | |
484 | | OpCode | I2 | B1 | D1 | | |
485 | +--------+---------+----+-------------+ | |
486 | 0 8 16 20 31 | |
487 | @end verbatim | |
488 | ||
489 | @item SIY format: <insn> D1(B1),U2 | |
490 | @verbatim | |
491 | +--------+---------+----+-------------+--------+--------+ | |
492 | | OpCode | I2 | B1 | DL1 | DH1 | OpCode | | |
493 | +--------+---------+----+-------------+--------+--------+ | |
494 | 0 8 16 20 32 36 40 47 | |
495 | @end verbatim | |
496 | ||
497 | @item SIL format: <insn> D1(B1),I2 | |
498 | @verbatim | |
499 | +------------------+----+-------------+-----------------+ | |
500 | | OpCode | B1 | D1 | I2 | | |
501 | +------------------+----+-------------+-----------------+ | |
502 | 0 16 20 32 47 | |
503 | @end verbatim | |
504 | ||
505 | @item SS format: <insn> D1(R1,B1),D2(B3),R3 | |
506 | @verbatim | |
507 | +--------+----+----+----+-------------+----+------------+ | |
508 | | OpCode | R1 | R3 | B1 | D1 | B2 | D2 | | |
509 | +--------+----+----+----+-------------+----+------------+ | |
510 | 0 8 12 16 20 32 36 47 | |
511 | @end verbatim | |
512 | ||
513 | @item SSE format: <insn> D1(B1),D2(B2) | |
514 | @verbatim | |
515 | +------------------+----+-------------+----+------------+ | |
516 | | OpCode | B1 | D1 | B2 | D2 | | |
517 | +------------------+----+-------------+----+------------+ | |
518 | 0 8 12 16 20 32 36 47 | |
519 | @end verbatim | |
520 | ||
521 | @item SSF format: <insn> D1(B1),D2(B2),R3 | |
522 | @verbatim | |
523 | +--------+----+----+----+-------------+----+------------+ | |
524 | | OpCode | R3 |OpCd| B1 | D1 | B2 | D2 | | |
525 | +--------+----+----+----+-------------+----+------------+ | |
526 | 0 8 12 16 20 32 36 47 | |
527 | @end verbatim | |
528 | ||
529 | @end table | |
530 | ||
531 | For the complete list of all instruction format variants see the | |
532 | Principles of Operation manuals. | |
533 | ||
534 | @node s390 Aliases | |
535 | @subsection Instruction Aliases | |
536 | @cindex instruction aliases, s390 | |
537 | @cindex s390 instruction aliases | |
538 | ||
539 | A specific bit pattern can have multiple mnemonics, for example | |
540 | the bit pattern @samp{0xa7000000} has the mnemonics @samp{tmh} and | |
541 | @samp{tmlh}. In addition, there are a number of mnemonics recognized by | |
542 | @code{@value{AS}} that are not present in the Principles of Operation. | |
543 | These are the short forms of the branch instructions, where the condition | |
544 | code mask operand is encoded in the mnemonic. This is relevant for the | |
545 | branch instructions, the compare and branch instructions, and the | |
546 | compare and trap instructions. | |
547 | ||
548 | For the branch instructions there are 20 condition code strings that can | |
549 | be used as part of the mnemonic in place of a mask operand in the instruction | |
550 | format: | |
551 | ||
552 | @display | |
553 | @multitable @columnfractions .30 .30 | |
554 | @headitem instruction @tab short form | |
555 | @item bcr M1,R2 @tab b<m>r R2 | |
556 | @item bc M1,D2(X2,B2) @tab b<m> D2(X2,B2) | |
557 | @item brc M1,I2 @tab j<m> I2 | |
558 | @item brcl M1,I2 @tab jg<m> I2 | |
559 | @end multitable | |
560 | @end display | |
561 | ||
562 | In the mnemonic for a branch instruction the condition code string <m> | |
563 | can be any of the following: | |
564 | ||
565 | @display | |
566 | @multitable {nle} {jump on not zero / if not zeros} | |
567 | @item o @tab jump on overflow / if ones | |
568 | @item h @tab jump on A high | |
569 | @item p @tab jump on plus | |
570 | @item nle @tab jump on not low or equal | |
571 | @item l @tab jump on A low | |
572 | @item m @tab jump on minus | |
573 | @item nhe @tab jump on not high or equal | |
574 | @item lh @tab jump on low or high | |
575 | @item ne @tab jump on A not equal B | |
576 | @item nz @tab jump on not zero / if not zeros | |
577 | @item e @tab jump on A equal B | |
578 | @item z @tab jump on zero / if zeroes | |
579 | @item nlh @tab jump on not low or high | |
580 | @item he @tab jump on high or equal | |
581 | @item nl @tab jump on A not low | |
582 | @item nm @tab jump on not minus / if not mixed | |
583 | @item le @tab jump on low or equal | |
584 | @item nh @tab jump on A not high | |
585 | @item np @tab jump on not plus | |
586 | @item no @tab jump on not overflow / if not ones | |
587 | @end multitable | |
588 | @end display | |
589 | ||
590 | For the compare and branch, and compare and trap instructions there | |
591 | are 12 condition code strings that can be used as part of the mnemonic in | |
592 | place of a mask operand in the instruction format: | |
593 | ||
594 | @display | |
595 | @multitable @columnfractions .40 .40 | |
596 | @headitem instruction @tab short form | |
597 | @item crb R1,R2,M3,D4(B4) @tab crb<m> R1,R2,D4(B4) | |
598 | @item cgrb R1,R2,M3,D4(B4) @tab cgrb<m> R1,R2,D4(B4) | |
599 | @item crj R1,R2,M3,I4 @tab crj<m> R1,R2,I4 | |
600 | @item cgrj R1,R2,M3,I4 @tab cgrj<m> R1,R2,I4 | |
601 | @item cib R1,I2,M3,D4(B4) @tab cib<m> R1,I2,D4(B4) | |
602 | @item cgib R1,I2,M3,D4(B4) @tab cgib<m> R1,I2,D4(B4) | |
603 | @item cij R1,I2,M3,I4 @tab cij<m> R1,I2,I4 | |
604 | @item cgij R1,I2,M3,I4 @tab cgij<m> R1,I2,I4 | |
605 | @item crt R1,R2,M3 @tab crt<m> R1,R2 | |
606 | @item cgrt R1,R2,M3 @tab cgrt<m> R1,R2 | |
607 | @item cit R1,I2,M3 @tab cit<m> R1,I2 | |
608 | @item cgit R1,I2,M3 @tab cgit<m> R1,I2 | |
609 | @item clrb R1,R2,M3,D4(B4) @tab clrb<m> R1,R2,D4(B4) | |
610 | @item clgrb R1,R2,M3,D4(B4) @tab clgrb<m> R1,R2,D4(B4) | |
611 | @item clrj R1,R2,M3,I4 @tab clrj<m> R1,R2,I4 | |
612 | @item clgrj R1,R2,M3,I4 @tab clgrj<m> R1,R2,I4 | |
613 | @item clib R1,I2,M3,D4(B4) @tab clib<m> R1,I2,D4(B4) | |
614 | @item clgib R1,I2,M3,D4(B4) @tab clgib<m> R1,I2,D4(B4) | |
615 | @item clij R1,I2,M3,I4 @tab clij<m> R1,I2,I4 | |
616 | @item clgij R1,I2,M3,I4 @tab clgij<m> R1,I2,I4 | |
617 | @item clrt R1,R2,M3 @tab clrt<m> R1,R2 | |
618 | @item clgrt R1,R2,M3 @tab clgrt<m> R1,R2 | |
619 | @item clfit R1,I2,M3 @tab clfit<m> R1,I2 | |
620 | @item clgit R1,I2,M3 @tab clgit<m> R1,I2 | |
621 | @end multitable | |
622 | @end display | |
623 | ||
624 | In the mnemonic for a compare and branch and compare and trap instruction | |
625 | the condition code string <m> can be any of the following: | |
626 | ||
627 | @display | |
628 | @multitable {nle} {jump on not zero / if not zeros} | |
629 | @item h @tab jump on A high | |
630 | @item nle @tab jump on not low or equal | |
631 | @item l @tab jump on A low | |
632 | @item nhe @tab jump on not high or equal | |
633 | @item ne @tab jump on A not equal B | |
634 | @item lh @tab jump on low or high | |
635 | @item e @tab jump on A equal B | |
636 | @item nlh @tab jump on not low or high | |
637 | @item nl @tab jump on A not low | |
638 | @item he @tab jump on high or equal | |
639 | @item nh @tab jump on A not high | |
640 | @item le @tab jump on low or equal | |
641 | @end multitable | |
642 | @end display | |
643 | ||
644 | @node s390 Operand Modifier | |
645 | @subsection Instruction Operand Modifier | |
646 | @cindex instruction operand modifier, s390 | |
647 | @cindex s390 instruction operand modifier | |
648 | ||
649 | If a symbol modifier is attached to a symbol in an expression for an | |
650 | instruction operand field, the symbol term is replaced with a reference | |
651 | to an object in the global offset table (GOT) or the procedure linkage | |
652 | table (PLT). The following expressions are allowed: | |
653 | @samp{symbol@@modifier + constant}, | |
654 | @samp{symbol@@modifier + label + constant}, and | |
655 | @samp{symbol@@modifier - label + constant}. | |
656 | The term @samp{symbol} is the symbol that will be entered into the GOT or | |
657 | PLT, @samp{label} is a local label, and @samp{constant} is an arbitrary | |
658 | expression that the assembler can evaluate to a constant value. | |
659 | ||
660 | The term @samp{(symbol + constant1)@@modifier +/- label + constant2} | |
661 | is also accepted but a warning message is printed and the term is | |
662 | converted to @samp{symbol@@modifier +/- label + constant1 + constant2}. | |
663 | ||
664 | @table @code | |
665 | @item @@got | |
666 | @itemx @@got12 | |
667 | The @@got modifier can be used for displacement fields, 16-bit immediate | |
668 | fields and 32-bit pc-relative immediate fields. The @@got12 modifier is | |
669 | synonym to @@got. The symbol is added to the GOT. For displacement | |
670 | fields and 16-bit immediate fields the symbol term is replaced with | |
671 | the offset from the start of the GOT to the GOT slot for the symbol. | |
672 | For a 32-bit pc-relative field the pc-relative offset to the GOT | |
673 | slot from the current instruction address is used. | |
674 | @item @@gotent | |
675 | The @@gotent modifier can be used for 32-bit pc-relative immediate fields. | |
676 | The symbol is added to the GOT and the symbol term is replaced with | |
677 | the pc-relative offset from the current instruction to the GOT slot for the | |
678 | symbol. | |
679 | @item @@gotoff | |
680 | The @@gotoff modifier can be used for 16-bit immediate fields. The symbol | |
34bca508 | 681 | term is replaced with the offset from the start of the GOT to the |
11c19e16 MS |
682 | address of the symbol. |
683 | @item @@gotplt | |
684 | The @@gotplt modifier can be used for displacement fields, 16-bit immediate | |
685 | fields, and 32-bit pc-relative immediate fields. A procedure linkage | |
686 | table entry is generated for the symbol and a jump slot for the symbol | |
687 | is added to the GOT. For displacement fields and 16-bit immediate | |
688 | fields the symbol term is replaced with the offset from the start of the | |
689 | GOT to the jump slot for the symbol. For a 32-bit pc-relative field | |
690 | the pc-relative offset to the jump slot from the current instruction | |
691 | address is used. | |
692 | @item @@plt | |
693 | The @@plt modifier can be used for 16-bit and 32-bit pc-relative immediate | |
694 | fields. A procedure linkage table entry is generated for the symbol. | |
695 | The symbol term is replaced with the relative offset from the current | |
696 | instruction to the PLT entry for the symbol. | |
697 | @item @@pltoff | |
698 | The @@pltoff modifier can be used for 16-bit immediate fields. The symbol | |
699 | term is replaced with the offset from the start of the PLT to the address | |
700 | of the symbol. | |
701 | @item @@gotntpoff | |
702 | The @@gotntpoff modifier can be used for displacement fields. The symbol | |
703 | is added to the static TLS block and the negated offset to the symbol | |
704 | in the static TLS block is added to the GOT. The symbol term is replaced | |
34bca508 | 705 | with the offset to the GOT slot from the start of the GOT. |
11c19e16 MS |
706 | @item @@indntpoff |
707 | The @@indntpoff modifier can be used for 32-bit pc-relative immediate | |
708 | fields. The symbol is added to the static TLS block and the negated offset | |
709 | to the symbol in the static TLS block is added to the GOT. The symbol term | |
710 | is replaced with the pc-relative offset to the GOT slot from the current | |
711 | instruction address. | |
712 | @end table | |
713 | ||
714 | For more information about the thread local storage modifiers | |
715 | @samp{gotntpoff} and @samp{indntpoff} see the ELF extension documentation | |
716 | @samp{ELF Handling For Thread-Local Storage}. | |
717 | ||
718 | @node s390 Instruction Marker | |
719 | @subsection Instruction Marker | |
720 | @cindex instruction marker, s390 | |
721 | @cindex s390 instruction marker | |
722 | ||
723 | The thread local storage instruction markers are used by the linker to | |
724 | perform code optimization. | |
725 | ||
726 | @table @code | |
727 | @item :tls_load | |
728 | The :tls_load marker is used to flag the load instruction in the initial | |
729 | exec TLS model that retrieves the offset from the thread pointer to a | |
34bca508 | 730 | thread local storage variable from the GOT. |
11c19e16 MS |
731 | @item :tls_gdcall |
732 | The :tls_gdcall marker is used to flag the branch-and-save instruction to | |
733 | the __tls_get_offset function in the global dynamic TLS model. | |
734 | @item :tls_ldcall | |
735 | The :tls_ldcall marker is used to flag the branch-and-save instruction to | |
736 | the __tls_get_offset function in the local dynamic TLS model. | |
737 | @end table | |
738 | ||
739 | For more information about the thread local storage instruction marker | |
740 | and the linker optimizations see the ELF extension documentation | |
741 | @samp{ELF Handling For Thread-Local Storage}. | |
742 | ||
743 | @node s390 Literal Pool Entries | |
744 | @subsection Literal Pool Entries | |
745 | @cindex literal pool entries, s390 | |
746 | @cindex s390 literal pool entries | |
747 | ||
748 | A literal pool is a collection of values. To access the values a pointer | |
749 | to the literal pool is loaded to a register, the literal pool register. | |
750 | Usually, register %r13 is used as the literal pool register | |
751 | (@ref{s390 Register}). Literal pool entries are created by adding the | |
752 | suffix :lit1, :lit2, :lit4, or :lit8 to the end of an expression for an | |
753 | instruction operand. The expression is added to the literal pool and the | |
754 | operand is replaced with the offset to the literal in the literal pool. | |
755 | ||
756 | @table @code | |
757 | @item :lit1 | |
758 | The literal pool entry is created as an 8-bit value. An operand modifier | |
759 | must not be used for the original expression. | |
760 | @item :lit2 | |
761 | The literal pool entry is created as a 16 bit value. The operand modifier | |
762 | @@got may be used in the original expression. The term @samp{x@@got:lit2} | |
763 | will put the got offset for the global symbol x to the literal pool as | |
764 | 16 bit value. | |
765 | @item :lit4 | |
766 | The literal pool entry is created as a 32-bit value. The operand modifier | |
767 | @@got and @@plt may be used in the original expression. The term | |
768 | @samp{x@@got:lit4} will put the got offset for the global symbol x to the | |
769 | literal pool as a 32-bit value. The term @samp{x@@plt:lit4} will put the | |
770 | plt offset for the global symbol x to the literal pool as a 32-bit value. | |
771 | @item :lit8 | |
772 | The literal pool entry is created as a 64-bit value. The operand modifier | |
773 | @@got and @@plt may be used in the original expression. The term | |
774 | @samp{x@@got:lit8} will put the got offset for the global symbol x to the | |
775 | literal pool as a 64-bit value. The term @samp{x@@plt:lit8} will put the | |
776 | plt offset for the global symbol x to the literal pool as a 64-bit value. | |
777 | @end table | |
778 | ||
779 | The assembler directive @samp{.ltorg} is used to emit all literal pool | |
780 | entries to the current position. | |
781 | ||
782 | @node s390 Directives | |
783 | @section Assembler Directives | |
784 | ||
34bca508 | 785 | @code{@value{AS}} for s390 supports all of the standard ELF |
11c19e16 MS |
786 | assembler directives as outlined in the main part of this document. |
787 | Some directives have been extended and there are some additional | |
788 | directives, which are only available for the s390 @code{@value{AS}}. | |
789 | ||
790 | @table @code | |
791 | @cindex @code{.insn} directive, s390 | |
792 | @item .insn | |
793 | This directive permits the numeric representation of an instructions | |
794 | and makes the assembler insert the operands according to one of the | |
795 | instructions formats for @samp{.insn} (@ref{s390 Formats}). | |
796 | For example, the instruction @samp{l %r1,24(%r15)} could be written as | |
797 | @samp{.insn rx,0x58000000,%r1,24(%r15)}. | |
798 | @cindex @code{.short} directive, s390 | |
799 | @cindex @code{.long} directive, s390 | |
800 | @cindex @code{.quad} directive, s390 | |
801 | @item .short | |
802 | @itemx .long | |
803 | @itemx .quad | |
804 | This directive places one or more 16-bit (.short), 32-bit (.long), or | |
805 | 64-bit (.quad) values into the current section. If an ELF or TLS modifier | |
34bca508 | 806 | is used only the following expressions are allowed: |
11c19e16 MS |
807 | @samp{symbol@@modifier + constant}, |
808 | @samp{symbol@@modifier + label + constant}, and | |
809 | @samp{symbol@@modifier - label + constant}. | |
810 | The following modifiers are available: | |
811 | @table @code | |
812 | @item @@got | |
813 | @itemx @@got12 | |
814 | The @@got modifier can be used for .short, .long and .quad. The @@got12 | |
815 | modifier is synonym to @@got. The symbol is added to the GOT. The symbol | |
816 | term is replaced with offset from the start of the GOT to the GOT slot for | |
817 | the symbol. | |
818 | @item @@gotoff | |
819 | The @@gotoff modifier can be used for .short, .long and .quad. The symbol | |
820 | term is replaced with the offset from the start of the GOT to the address | |
821 | of the symbol. | |
822 | @item @@gotplt | |
823 | The @@gotplt modifier can be used for .long and .quad. A procedure linkage | |
824 | table entry is generated for the symbol and a jump slot for the symbol | |
825 | is added to the GOT. The symbol term is replaced with the offset from the | |
826 | start of the GOT to the jump slot for the symbol. | |
827 | @item @@plt | |
828 | The @@plt modifier can be used for .long and .quad. A procedure linkage | |
829 | table entry us generated for the symbol. The symbol term is replaced with | |
830 | the address of the PLT entry for the symbol. | |
831 | @item @@pltoff | |
832 | The @@pltoff modifier can be used for .short, .long and .quad. The symbol | |
833 | term is replaced with the offset from the start of the PLT to the address | |
834 | of the symbol. | |
835 | @item @@tlsgd | |
836 | @itemx @@tlsldm | |
837 | The @@tlsgd and @@tlsldm modifier can be used for .long and .quad. A | |
838 | tls_index structure for the symbol is added to the GOT. The symbol term is | |
839 | replaced with the offset from the start of the GOT to the tls_index structure. | |
840 | @item @@gotntpoff | |
841 | @itemx @@indntpoff | |
842 | The @@gotntpoff and @@indntpoff modifier can be used for .long and .quad. | |
843 | The symbol is added to the static TLS block and the negated offset to the | |
844 | symbol in the static TLS block is added to the GOT. For @@gotntpoff the | |
845 | symbol term is replaced with the offset from the start of the GOT to the | |
846 | GOT slot, for @@indntpoff the symbol term is replaced with the address | |
847 | of the GOT slot. | |
848 | @item @@dtpoff | |
849 | The @@dtpoff modifier can be used for .long and .quad. The symbol term | |
850 | is replaced with the offset of the symbol relative to the start of the | |
851 | TLS block it is contained in. | |
852 | @item @@ntpoff | |
853 | The @@ntpoff modifier can be used for .long and .quad. The symbol term | |
854 | is replaced with the offset of the symbol relative to the TCB pointer. | |
855 | @end table | |
856 | ||
857 | For more information about the thread local storage modifiers see the | |
858 | ELF extension documentation @samp{ELF Handling For Thread-Local Storage}. | |
859 | ||
860 | @cindex @code{.ltorg} directive, s390 | |
861 | @item .ltorg | |
862 | This directive causes the current contents of the literal pool to be | |
863 | dumped to the current location (@ref{s390 Literal Pool Entries}). | |
902cc293 AK |
864 | |
865 | @cindex @code{.machine} directive, s390 | |
866 | @item .machine string | |
867 | This directive allows you to change the machine for which code is | |
868 | generated. @code{string} may be any of the @code{-march=} selection | |
869 | options (without the -march=), @code{push}, or @code{pop}. | |
870 | @code{.machine push} saves the currently selected cpu, which may be | |
871 | restored with @code{.machine pop}. Be aware that the cpu string has | |
872 | to be put into double quotes in case it contains characters not | |
873 | appropriate for identifiers. So you have to write @code{"z9-109"} | |
874 | instead of just @code{z9-109}. | |
1dd53816 AK |
875 | |
876 | @cindex @code{.machinemode} directive, s390 | |
877 | @item .machinemode string | |
878 | This directive allows to change the architecture mode for which code | |
879 | is being generated. @code{string} may be @code{esa}, @code{zarch}, | |
880 | @code{zarch_nohighgprs}, @code{push}, or @code{pop}. | |
881 | @code{.machinemode zarch_nohighgprs} can be used to prevent the | |
882 | @code{highgprs} flag from being set in the ELF header of the output | |
883 | file. This is useful in situations where the code is gated with a | |
884 | runtime check which makes sure that the code is only executed on | |
885 | kernels providing the @code{highgprs} feature. | |
886 | @code{.machinemode push} saves the currently selected mode, which may | |
887 | be restored with @code{.machinemode pop}. | |
11c19e16 MS |
888 | @end table |
889 | ||
890 | @node s390 Floating Point | |
891 | @section Floating Point | |
892 | @cindex floating point, s390 | |
893 | @cindex s390 floating point | |
894 | ||
895 | The assembler recognizes both the @sc{ieee} floating-point instruction and | |
896 | the hexadecimal floating-point instructions. The floating-point constructors | |
897 | @samp{.float}, @samp{.single}, and @samp{.double} always emit the | |
898 | @sc{ieee} format. To assemble hexadecimal floating-point constants the | |
899 | @samp{.long} and @samp{.quad} directives must be used. |