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252b5132 1\input texinfo @c -*-Texinfo-*-
219d1afa 2@c Copyright (C) 1991-2018 Free Software Foundation, Inc.
252b5132
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3@c UPDATE!! On future updates--
4@c (1) check for new machine-dep cmdline options in
5@c md_parse_option definitions in config/tc-*.c
6@c (2) for platform-specific directives, examine md_pseudo_op
7@c in config/tc-*.c
8@c (3) for object-format specific directives, examine obj_pseudo_op
01642c12 9@c in config/obj-*.c
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10@c (4) portable directives in potable[] in read.c
11@c %**start of header
12@setfilename as.info
13@c ---config---
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14@macro gcctabopt{body}
15@code{\body\}
16@end macro
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17@c defaults, config file may override:
18@set have-stabs
19@c ---
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20@c man begin NAME
21@c ---
252b5132 22@include asconfig.texi
c428fa83 23@include bfdver.texi
252b5132 24@c ---
0285c67d 25@c man end
4a4c4a1d 26@c ---
252b5132 27@c common OR combinations of conditions
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28@ifset COFF
29@set COFF-ELF
30@end ifset
31@ifset ELF
32@set COFF-ELF
33@end ifset
252b5132 34@ifset AOUT
a8eb42a8 35@set aout
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36@end ifset
37@ifset ARM/Thumb
38@set ARM
39@end ifset
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40@ifset Blackfin
41@set Blackfin
42@end ifset
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43@ifset H8/300
44@set H8
45@end ifset
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46@ifset SH
47@set H8
48@end ifset
49@ifset HPPA
50@set abnormal-separator
51@end ifset
52@c ------------
53@ifset GENERIC
54@settitle Using @value{AS}
55@end ifset
56@ifclear GENERIC
57@settitle Using @value{AS} (@value{TARGET})
58@end ifclear
59@setchapternewpage odd
60@c %**end of header
61
62@c @smallbook
63@c @set SMALL
64@c WARE! Some of the machine-dependent sections contain tables of machine
65@c instructions. Except in multi-column format, these tables look silly.
66@c Unfortunately, Texinfo doesn't have a general-purpose multi-col format, so
67@c the multi-col format is faked within @example sections.
01642c12 68@c
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69@c Again unfortunately, the natural size that fits on a page, for these tables,
70@c is different depending on whether or not smallbook is turned on.
71@c This matters, because of order: text flow switches columns at each page
72@c break.
01642c12 73@c
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74@c The format faked in this source works reasonably well for smallbook,
75@c not well for the default large-page format. This manual expects that if you
76@c turn on @smallbook, you will also uncomment the "@set SMALL" to enable the
77@c tables in question. You can turn on one without the other at your
01642c12 78@c discretion, of course.
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79@ifinfo
80@set SMALL
81@c the insn tables look just as silly in info files regardless of smallbook,
82@c might as well show 'em anyways.
83@end ifinfo
84
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85@ifnottex
86@dircategory Software development
87@direntry
252b5132 88* As: (as). The GNU assembler.
59455fb1 89* Gas: (as). The GNU assembler.
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90@end direntry
91@end ifnottex
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92
93@finalout
94@syncodeindex ky cp
95
0e9517a9 96@copying
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97This file documents the GNU Assembler "@value{AS}".
98
0285c67d 99@c man begin COPYRIGHT
219d1afa 100Copyright @copyright{} 1991-2018 Free Software Foundation, Inc.
252b5132 101
0285c67d 102Permission is granted to copy, distribute and/or modify this document
793c5807 103under the terms of the GNU Free Documentation License, Version 1.3
0285c67d
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104or any later version published by the Free Software Foundation;
105with no Invariant Sections, with no Front-Cover Texts, and with no
106Back-Cover Texts. A copy of the license is included in the
c1253627 107section entitled ``GNU Free Documentation License''.
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108
109@c man end
0e9517a9 110@end copying
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111
112@titlepage
113@title Using @value{AS}
114@subtitle The @sc{gnu} Assembler
115@ifclear GENERIC
116@subtitle for the @value{TARGET} family
117@end ifclear
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118@ifset VERSION_PACKAGE
119@sp 1
120@subtitle @value{VERSION_PACKAGE}
121@end ifset
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122@sp 1
123@subtitle Version @value{VERSION}
124@sp 1
125@sp 13
b45619c0 126The Free Software Foundation Inc.@: thanks The Nice Computer
252b5132 127Company of Australia for loaning Dean Elsner to write the
a4fb0134 128first (Vax) version of @command{as} for Project @sc{gnu}.
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129The proprietors, management and staff of TNCCA thank FSF for
130distracting the boss while they got some work
131done.
132@sp 3
133@author Dean Elsner, Jay Fenlason & friends
134@page
135@tex
136{\parskip=0pt
137\hfill {\it Using {\tt @value{AS}}}\par
138\hfill Edited by Cygnus Support\par
139}
140%"boxit" macro for figures:
141%Modified from Knuth's ``boxit'' macro from TeXbook (answer to exercise 21.3)
142\gdef\boxit#1#2{\vbox{\hrule\hbox{\vrule\kern3pt
143 \vbox{\parindent=0pt\parskip=0pt\hsize=#1\kern3pt\strut\hfil
144#2\hfil\strut\kern3pt}\kern3pt\vrule}\hrule}}%box with visible outline
145\gdef\ibox#1#2{\hbox to #1{#2\hfil}\kern8pt}% invisible box
146@end tex
147
148@vskip 0pt plus 1filll
219d1afa 149Copyright @copyright{} 1991-2018 Free Software Foundation, Inc.
252b5132 150
cf055d54 151 Permission is granted to copy, distribute and/or modify this document
793c5807 152 under the terms of the GNU Free Documentation License, Version 1.3
cf055d54
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153 or any later version published by the Free Software Foundation;
154 with no Invariant Sections, with no Front-Cover Texts, and with no
155 Back-Cover Texts. A copy of the license is included in the
c1253627 156 section entitled ``GNU Free Documentation License''.
252b5132 157
252b5132 158@end titlepage
4ecceb71 159@contents
252b5132 160
2e64b665 161@ifnottex
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162@node Top
163@top Using @value{AS}
164
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165This file is a user guide to the @sc{gnu} assembler @command{@value{AS}}
166@ifset VERSION_PACKAGE
167@value{VERSION_PACKAGE}
168@end ifset
169version @value{VERSION}.
252b5132 170@ifclear GENERIC
a4fb0134 171This version of the file describes @command{@value{AS}} configured to generate
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172code for @value{TARGET} architectures.
173@end ifclear
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174
175This document is distributed under the terms of the GNU Free
176Documentation License. A copy of the license is included in the
c1253627 177section entitled ``GNU Free Documentation License''.
cf055d54 178
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179@menu
180* Overview:: Overview
181* Invoking:: Command-Line Options
182* Syntax:: Syntax
183* Sections:: Sections and Relocation
184* Symbols:: Symbols
185* Expressions:: Expressions
186* Pseudo Ops:: Assembler Directives
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187@ifset ELF
188* Object Attributes:: Object Attributes
189@end ifset
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190* Machine Dependencies:: Machine Dependent Features
191* Reporting Bugs:: Reporting Bugs
192* Acknowledgements:: Who Did What
cf055d54 193* GNU Free Documentation License:: GNU Free Documentation License
28c9d252 194* AS Index:: AS Index
252b5132 195@end menu
2e64b665 196@end ifnottex
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197
198@node Overview
199@chapter Overview
200@iftex
a4fb0134 201This manual is a user guide to the @sc{gnu} assembler @command{@value{AS}}.
252b5132 202@ifclear GENERIC
a4fb0134 203This version of the manual describes @command{@value{AS}} configured to generate
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204code for @value{TARGET} architectures.
205@end ifclear
206@end iftex
207
208@cindex invocation summary
209@cindex option summary
210@cindex summary of options
a4fb0134 211Here is a brief summary of how to invoke @command{@value{AS}}. For details,
96e9638b 212see @ref{Invoking,,Command-Line Options}.
252b5132 213
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214@c man title AS the portable GNU assembler.
215
a4fb0134 216@ignore
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217@c man begin SEEALSO
218gcc(1), ld(1), and the Info entries for @file{binutils} and @file{ld}.
219@c man end
a4fb0134 220@end ignore
0285c67d 221
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222@c We don't use deffn and friends for the following because they seem
223@c to be limited to one line for the header.
224@smallexample
0285c67d 225@c man begin SYNOPSIS
83f10cb2 226@value{AS} [@b{-a}[@b{cdghlns}][=@var{file}]] [@b{--alternate}] [@b{-D}]
955974c6 227 [@b{--compress-debug-sections}] [@b{--nocompress-debug-sections}]
3d6b762c 228 [@b{--debug-prefix-map} @var{old}=@var{new}]
4bdd3565 229 [@b{--defsym} @var{sym}=@var{val}] [@b{-f}] [@b{-g}] [@b{--gstabs}]
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230 [@b{--gstabs+}] [@b{--gdwarf-2}] [@b{--gdwarf-sections}]
231 [@b{--help}] [@b{-I} @var{dir}] [@b{-J}]
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232 [@b{-K}] [@b{-L}] [@b{--listing-lhs-width}=@var{NUM}]
233 [@b{--listing-lhs-width2}=@var{NUM}] [@b{--listing-rhs-width}=@var{NUM}]
d60646b9 234 [@b{--listing-cont-lines}=@var{NUM}] [@b{--keep-locals}]
2edb36e7 235 [@b{--no-pad-sections}]
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236 [@b{-o} @var{objfile}] [@b{-R}]
237 [@b{--hash-size}=@var{NUM}] [@b{--reduce-memory-overheads}]
238 [@b{--statistics}]
239 [@b{-v}] [@b{-version}] [@b{--version}]
240 [@b{-W}] [@b{--warn}] [@b{--fatal-warnings}] [@b{-w}] [@b{-x}]
241 [@b{-Z}] [@b{@@@var{FILE}}]
451133ce 242 [@b{--sectname-subst}] [@b{--size-check=[error|warning]}]
b8871f35 243 [@b{--elf-stt-common=[no|yes]}]
0df8ad28 244 [@b{--generate-missing-build-notes=[no|yes]}]
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245 [@b{--target-help}] [@var{target-options}]
246 [@b{--}|@var{files} @dots{}]
a4fb0134 247@c
6387924a 248@c man end
a4fb0134 249@c Target dependent options are listed below. Keep the list sorted.
01642c12 250@c Add an empty line for separation.
6387924a 251@c man begin TARGET
a06ea964
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252@ifset AARCH64
253
254@emph{Target AArch64 options:}
255 [@b{-EB}|@b{-EL}]
69091a2c 256 [@b{-mabi}=@var{ABI}]
a06ea964 257@end ifset
625e1353
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258@ifset ALPHA
259
260@emph{Target Alpha options:}
261 [@b{-m@var{cpu}}]
262 [@b{-mdebug} | @b{-no-mdebug}]
198f1251 263 [@b{-replace} | @b{-noreplace}]
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264 [@b{-relax}] [@b{-g}] [@b{-G@var{size}}]
265 [@b{-F}] [@b{-32addr}]
266@end ifset
252b5132 267@ifset ARC
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268
269@emph{Target ARC options:}
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270 [@b{-mcpu=@var{cpu}}]
271 [@b{-mA6}|@b{-mARC600}|@b{-mARC601}|@b{-mA7}|@b{-mARC700}|@b{-mEM}|@b{-mHS}]
272 [@b{-mcode-density}]
4670103e 273 [@b{-mrelax}]
a4fb0134 274 [@b{-EB}|@b{-EL}]
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275@end ifset
276@ifset ARM
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277
278@emph{Target ARM options:}
03b1477f 279@c Don't document the deprecated options
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280 [@b{-mcpu}=@var{processor}[+@var{extension}@dots{}]]
281 [@b{-march}=@var{architecture}[+@var{extension}@dots{}]]
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282 [@b{-mfpu}=@var{floating-point-format}]
283 [@b{-mfloat-abi}=@var{abi}]
d507cf36 284 [@b{-meabi}=@var{ver}]
03b1477f 285 [@b{-mthumb}]
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286 [@b{-EB}|@b{-EL}]
287 [@b{-mapcs-32}|@b{-mapcs-26}|@b{-mapcs-float}|
288 @b{-mapcs-reentrant}]
7f266840 289 [@b{-mthumb-interwork}] [@b{-k}]
252b5132 290@end ifset
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291@ifset Blackfin
292
293@emph{Target Blackfin options:}
294 [@b{-mcpu}=@var{processor}[-@var{sirevision}]]
295 [@b{-mfdpic}]
296 [@b{-mno-fdpic}]
297 [@b{-mnopic}]
298@end ifset
328eb32e
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299@ifset CRIS
300
301@emph{Target CRIS options:}
302 [@b{--underscore} | @b{--no-underscore}]
303 [@b{--pic}] [@b{-N}]
304 [@b{--emulation=criself} | @b{--emulation=crisaout}]
ae57792d 305 [@b{--march=v0_v10} | @b{--march=v10} | @b{--march=v32} | @b{--march=common_v10_v32}]
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306@c Deprecated -- deliberately not documented.
307@c [@b{-h}] [@b{-H}]
308@end ifset
252b5132 309@ifset D10V
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310
311@emph{Target D10V options:}
312 [@b{-O}]
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313@end ifset
314@ifset D30V
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315
316@emph{Target D30V options:}
317 [@b{-O}|@b{-n}|@b{-N}]
252b5132 318@end ifset
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319@ifset EPIPHANY
320
321@emph{Target EPIPHANY options:}
322 [@b{-mepiphany}|@b{-mepiphany16}]
323@end ifset
252b5132 324@ifset H8
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325
326@emph{Target H8/300 options:}
327 [-h-tick-hex]
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328@end ifset
329@ifset HPPA
330@c HPPA has no machine-dependent assembler options (yet).
331@end ifset
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332@ifset I80386
333
334@emph{Target i386 options:}
542385d9 335 [@b{--32}|@b{--x32}|@b{--64}] [@b{-n}]
1ef52f49 336 [@b{-march}=@var{CPU}[+@var{EXTENSION}@dots{}]] [@b{-mtune}=@var{CPU}]
252b5132 337@end ifset
587fe2b3 338@ifset IA64
a4fb0134 339
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340@emph{Target IA-64 options:}
341 [@b{-mconstant-gp}|@b{-mauto-pic}]
342 [@b{-milp32}|@b{-milp64}|@b{-mlp64}|@b{-mp64}]
343 [@b{-mle}|@b{mbe}]
8c2fda1d 344 [@b{-mtune=itanium1}|@b{-mtune=itanium2}]
970d6792 345 [@b{-munwind-check=warning}|@b{-munwind-check=error}]
91d777ee 346 [@b{-mhint.b=ok}|@b{-mhint.b=warning}|@b{-mhint.b=error}]
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347 [@b{-x}|@b{-xexplicit}] [@b{-xauto}] [@b{-xdebug}]
348@end ifset
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349@ifset IP2K
350
351@emph{Target IP2K options:}
352 [@b{-mip2022}|@b{-mip2022ext}]
353@end ifset
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354@ifset M32C
355
356@emph{Target M32C options:}
c54b5932 357 [@b{-m32c}|@b{-m16c}] [-relax] [-h-tick-hex]
49f58d10 358@end ifset
587fe2b3 359@ifset M32R
9e32ca89 360
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361@emph{Target M32R options:}
362 [@b{--m32rx}|@b{--[no-]warn-explicit-parallel-conflicts}|
587fe2b3 363 @b{--W[n]p}]
ec694b89 364@end ifset
252b5132 365@ifset M680X0
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366
367@emph{Target M680X0 options:}
368 [@b{-l}] [@b{-m68000}|@b{-m68010}|@b{-m68020}|@dots{}]
252b5132 369@end ifset
60bcf0fa 370@ifset M68HC11
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371
372@emph{Target M68HC11 options:}
6927f982 373 [@b{-m68hc11}|@b{-m68hc12}|@b{-m68hcs12}|@b{-mm9s12x}|@b{-mm9s12xg}]
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374 [@b{-mshort}|@b{-mlong}]
375 [@b{-mshort-double}|@b{-mlong-double}]
1370e33d 376 [@b{--force-long-branches}] [@b{--short-branches}]
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377 [@b{--strict-direct-mode}] [@b{--print-insn-syntax}]
378 [@b{--print-opcodes}] [@b{--generate-example}]
379@end ifset
380@ifset MCORE
381
382@emph{Target MCORE options:}
383 [@b{-jsri2bsr}] [@b{-sifilter}] [@b{-relax}]
384 [@b{-mcpu=[210|340]}]
60bcf0fa 385@end ifset
a3c62988
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386@ifset METAG
387
388@emph{Target Meta options:}
389 [@b{-mcpu=@var{cpu}}] [@b{-mfpu=@var{cpu}}] [@b{-mdsp=@var{cpu}}]
390@end ifset
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NC
391@ifset MICROBLAZE
392@emph{Target MICROBLAZE options:}
393@c MicroBlaze has no machine-dependent assembler options.
394@end ifset
252b5132 395@ifset MIPS
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396
397@emph{Target MIPS options:}
78849248 398 [@b{-nocpp}] [@b{-EL}] [@b{-EB}] [@b{-O}[@var{optimization level}]]
437ee9d5 399 [@b{-g}[@var{debug level}]] [@b{-G} @var{num}] [@b{-KPIC}] [@b{-call_shared}]
0c000745 400 [@b{-non_shared}] [@b{-xgot} [@b{-mvxworks-pic}]
437ee9d5 401 [@b{-mabi}=@var{ABI}] [@b{-32}] [@b{-n32}] [@b{-64}] [@b{-mfp32}] [@b{-mgp32}]
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402 [@b{-mfp64}] [@b{-mgp64}] [@b{-mfpxx}]
403 [@b{-modd-spreg}] [@b{-mno-odd-spreg}]
437ee9d5 404 [@b{-march}=@var{CPU}] [@b{-mtune}=@var{CPU}] [@b{-mips1}] [@b{-mips2}]
af7ee8bf 405 [@b{-mips3}] [@b{-mips4}] [@b{-mips5}] [@b{-mips32}] [@b{-mips32r2}]
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406 [@b{-mips32r3}] [@b{-mips32r5}] [@b{-mips32r6}] [@b{-mips64}] [@b{-mips64r2}]
407 [@b{-mips64r3}] [@b{-mips64r5}] [@b{-mips64r6}]
437ee9d5 408 [@b{-construct-floats}] [@b{-no-construct-floats}]
8b10b0b3 409 [@b{-mignore-branch-isa}] [@b{-mno-ignore-branch-isa}]
ba92f887 410 [@b{-mnan=@var{encoding}}]
437ee9d5 411 [@b{-trap}] [@b{-no-break}] [@b{-break}] [@b{-no-trap}]
437ee9d5 412 [@b{-mips16}] [@b{-no-mips16}]
25499ac7 413 [@b{-mmips16e2}] [@b{-mno-mips16e2}]
df58fc94 414 [@b{-mmicromips}] [@b{-mno-micromips}]
e16bfa71 415 [@b{-msmartmips}] [@b{-mno-smartmips}]
1f25f5d3 416 [@b{-mips3d}] [@b{-no-mips3d}]
deec1734 417 [@b{-mdmx}] [@b{-no-mdmx}]
2ef2b9ae 418 [@b{-mdsp}] [@b{-mno-dsp}]
8b082fb1 419 [@b{-mdspr2}] [@b{-mno-dspr2}]
8f4f9071 420 [@b{-mdspr3}] [@b{-mno-dspr3}]
56d438b1 421 [@b{-mmsa}] [@b{-mno-msa}]
7d64c587 422 [@b{-mxpa}] [@b{-mno-xpa}]
ef2e4d86 423 [@b{-mmt}] [@b{-mno-mt}]
dec0624d 424 [@b{-mmcu}] [@b{-mno-mcu}]
730c3174 425 [@b{-mcrc}] [@b{-mno-crc}]
6f20c942 426 [@b{-mginv}] [@b{-mno-ginv}]
833794fc 427 [@b{-minsn32}] [@b{-mno-insn32}]
2babba43 428 [@b{-mfix7000}] [@b{-mno-fix7000}]
a8d14a88 429 [@b{-mfix-rm7000}] [@b{-mno-fix-rm7000}]
2babba43
MR
430 [@b{-mfix-vr4120}] [@b{-mno-fix-vr4120}]
431 [@b{-mfix-vr4130}] [@b{-mno-fix-vr4130}]
ecb4347a 432 [@b{-mdebug}] [@b{-no-mdebug}]
dcd410fe 433 [@b{-mpdr}] [@b{-mno-pdr}]
3c3bdf30
NC
434@end ifset
435@ifset MMIX
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436
437@emph{Target MMIX options:}
438 [@b{--fixed-special-register-names}] [@b{--globalize-symbols}]
439 [@b{--gnu-syntax}] [@b{--relax}] [@b{--no-predefined-symbols}]
440 [@b{--no-expand}] [@b{--no-merge-gregs}] [@b{-x}]
973eb340 441 [@b{--linker-allocated-gregs}]
a4fb0134 442@end ifset
36591ba1
SL
443@ifset NIOSII
444
445@emph{Target Nios II options:}
446 [@b{-relax-all}] [@b{-relax-section}] [@b{-no-relax}]
447 [@b{-EB}] [@b{-EL}]
448@end ifset
35c08157
KLC
449@ifset NDS32
450
451@emph{Target NDS32 options:}
452 [@b{-EL}] [@b{-EB}] [@b{-O}] [@b{-Os}] [@b{-mcpu=@var{cpu}}]
453 [@b{-misa=@var{isa}}] [@b{-mabi=@var{abi}}] [@b{-mall-ext}]
454 [@b{-m[no-]16-bit}] [@b{-m[no-]perf-ext}] [@b{-m[no-]perf2-ext}]
455 [@b{-m[no-]string-ext}] [@b{-m[no-]dsp-ext}] [@b{-m[no-]mac}] [@b{-m[no-]div}]
456 [@b{-m[no-]audio-isa-ext}] [@b{-m[no-]fpu-sp-ext}] [@b{-m[no-]fpu-dp-ext}]
457 [@b{-m[no-]fpu-fma}] [@b{-mfpu-freg=@var{FREG}}] [@b{-mreduced-regs}]
458 [@b{-mfull-regs}] [@b{-m[no-]dx-regs}] [@b{-mpic}] [@b{-mno-relax}]
459 [@b{-mb2bb}]
460@end ifset
a4fb0134
SC
461@ifset PDP11
462
463@emph{Target PDP11 options:}
464 [@b{-mpic}|@b{-mno-pic}] [@b{-mall}] [@b{-mno-extensions}]
465 [@b{-m}@var{extension}|@b{-mno-}@var{extension}]
01642c12 466 [@b{-m}@var{cpu}] [@b{-m}@var{machine}]
a4fb0134
SC
467@end ifset
468@ifset PJ
469
470@emph{Target picoJava options:}
471 [@b{-mb}|@b{-me}]
472@end ifset
473@ifset PPC
474
475@emph{Target PowerPC options:}
b8b738ac
AM
476 [@b{-a32}|@b{-a64}]
477 [@b{-mpwrx}|@b{-mpwr2}|@b{-mpwr}|@b{-m601}|@b{-mppc}|@b{-mppc32}|@b{-m603}|@b{-m604}|@b{-m403}|@b{-m405}|
478 @b{-m440}|@b{-m464}|@b{-m476}|@b{-m7400}|@b{-m7410}|@b{-m7450}|@b{-m7455}|@b{-m750cl}|@b{-mppc64}|
aea77599 479 @b{-m620}|@b{-me500}|@b{-e500x2}|@b{-me500mc}|@b{-me500mc64}|@b{-me5500}|@b{-me6500}|@b{-mppc64bridge}|
b36546d2 480 @b{-mbooke}|@b{-mpower4}|@b{-mpwr4}|@b{-mpower5}|@b{-mpwr5}|@b{-mpwr5x}|@b{-mpower6}|@b{-mpwr6}|
a680de9a 481 @b{-mpower7}|@b{-mpwr7}|@b{-mpower8}|@b{-mpwr8}|@b{-mpower9}|@b{-mpwr9}@b{-ma2}|
74081948 482 @b{-mcell}|@b{-mspe}|@b{-mspe2}|@b{-mtitan}|@b{-me300}|@b{-mcom}]
5817ffd1 483 [@b{-many}] [@b{-maltivec}|@b{-mvsx}|@b{-mhtm}|@b{-mvle}]
a4fb0134 484 [@b{-mregnames}|@b{-mno-regnames}]
b8b738ac
AM
485 [@b{-mrelocatable}|@b{-mrelocatable-lib}|@b{-K PIC}] [@b{-memb}]
486 [@b{-mlittle}|@b{-mlittle-endian}|@b{-le}|@b{-mbig}|@b{-mbig-endian}|@b{-be}]
a4fb0134 487 [@b{-msolaris}|@b{-mno-solaris}]
b8b738ac 488 [@b{-nops=@var{count}}]
a4fb0134 489@end ifset
93f11b16
DD
490@ifset PRU
491
492@emph{Target PRU options:}
493 [@b{-link-relax}]
494 [@b{-mnolink-relax}]
495 [@b{-mno-warn-regname-label}]
496@end ifset
b57e49f7
JW
497@ifset RISCV
498
499@emph{Target RISC-V options:}
500 [@b{-fpic}|@b{-fPIC}|@b{-fno-pic}]
501 [@b{-march}=@var{ISA}]
502 [@b{-mabi}=@var{ABI}]
503@end ifset
856ea05c
KP
504@ifset RL78
505
506@emph{Target RL78 options:}
507 [@b{-mg10}]
508 [@b{-m32bit-doubles}|@b{-m64bit-doubles}]
509@end ifset
c7927a3c
NC
510@ifset RX
511
512@emph{Target RX options:}
513 [@b{-mlittle-endian}|@b{-mbig-endian}]
c7927a3c 514 [@b{-m32bit-doubles}|@b{-m64bit-doubles}]
708e2187
NC
515 [@b{-muse-conventional-section-names}]
516 [@b{-msmall-data-limit}]
517 [@b{-mpid}]
518 [@b{-mrelax}]
519 [@b{-mint-register=@var{number}}]
520 [@b{-mgcc-abi}|@b{-mrx-abi}]
c7927a3c 521@end ifset
11c19e16
MS
522@ifset S390
523
524@emph{Target s390 options:}
525 [@b{-m31}|@b{-m64}] [@b{-mesa}|@b{-mzarch}] [@b{-march}=@var{CPU}]
526 [@b{-mregnames}|@b{-mno-regnames}]
527 [@b{-mwarn-areg-zero}]
528@end ifset
c3b7224a
NC
529@ifset SCORE
530
531@emph{Target SCORE options:}
532 [@b{-EB}][@b{-EL}][@b{-FIXDD}][@b{-NWARN}]
533 [@b{-SCORE5}][@b{-SCORE5U}][@b{-SCORE7}][@b{-SCORE3}]
534 [@b{-march=score7}][@b{-march=score3}]
535 [@b{-USE_R1}][@b{-KPIC}][@b{-O0}][@b{-G} @var{num}][@b{-V}]
536@end ifset
a4fb0134
SC
537@ifset SPARC
538
539@emph{Target SPARC options:}
540@c The order here is important. See c-sparc.texi.
46a2d504
JM
541 [@b{-Av6}|@b{-Av7}|@b{-Av8}|@b{-Aleon}|@b{-Asparclet}|@b{-Asparclite}
542 @b{-Av8plus}|@b{-Av8plusa}|@b{-Av8plusb}|@b{-Av8plusc}|@b{-Av8plusd}
543 @b{-Av8plusv}|@b{-Av8plusm}|@b{-Av9}|@b{-Av9a}|@b{-Av9b}|@b{-Av9c}
544 @b{-Av9d}|@b{-Av9e}|@b{-Av9v}|@b{-Av9m}|@b{-Asparc}|@b{-Asparcvis}
545 @b{-Asparcvis2}|@b{-Asparcfmaf}|@b{-Asparcima}|@b{-Asparcvis3}
546 @b{-Asparcvisr}|@b{-Asparc5}]
547 [@b{-xarch=v8plus}|@b{-xarch=v8plusa}]|@b{-xarch=v8plusb}|@b{-xarch=v8plusc}
548 @b{-xarch=v8plusd}|@b{-xarch=v8plusv}|@b{-xarch=v8plusm}|@b{-xarch=v9}
549 @b{-xarch=v9a}|@b{-xarch=v9b}|@b{-xarch=v9c}|@b{-xarch=v9d}|@b{-xarch=v9e}
550 @b{-xarch=v9v}|@b{-xarch=v9m}|@b{-xarch=sparc}|@b{-xarch=sparcvis}
551 @b{-xarch=sparcvis2}|@b{-xarch=sparcfmaf}|@b{-xarch=sparcima}
552 @b{-xarch=sparcvis3}|@b{-xarch=sparcvisr}|@b{-xarch=sparc5}
553 @b{-bump}]
a4fb0134 554 [@b{-32}|@b{-64}]
46a2d504 555 [@b{--enforce-aligned-data}][@b{--dcti-couples-detect}]
a4fb0134
SC
556@end ifset
557@ifset TIC54X
558
559@emph{Target TIC54X options:}
01642c12 560 [@b{-mcpu=54[123589]}|@b{-mcpu=54[56]lp}] [@b{-mfar-mode}|@b{-mf}]
a4fb0134
SC
561 [@b{-merrors-to-file} @var{<filename>}|@b{-me} @var{<filename>}]
562@end ifset
40b36596
JM
563@ifset TIC6X
564
565@emph{Target TIC6X options:}
98d23bef
BS
566 [@b{-march=@var{arch}}] [@b{-mbig-endian}|@b{-mlittle-endian}]
567 [@b{-mdsbt}|@b{-mno-dsbt}] [@b{-mpid=no}|@b{-mpid=near}|@b{-mpid=far}]
568 [@b{-mpic}|@b{-mno-pic}]
40b36596 569@end ifset
aa137e4d
NC
570@ifset TILEGX
571
572@emph{Target TILE-Gx options:}
fb6cedde 573 [@b{-m32}|@b{-m64}][@b{-EB}][@b{-EL}]
aa137e4d
NC
574@end ifset
575@ifset TILEPRO
576@c TILEPro has no machine-dependent assembler options
577@end ifset
b6605ddd 578@ifset VISIUM
40b36596 579
b6605ddd
EB
580@emph{Target Visium options:}
581 [@b{-mtune=@var{arch}}]
582@end ifset
2d8b84ae
SA
583@ifset XTENSA
584
585@emph{Target Xtensa options:}
b46824bd
MF
586 [@b{--[no-]text-section-literals}] [@b{--[no-]auto-litpools}]
587 [@b{--[no-]absolute-literals}]
2d8b84ae
SA
588 [@b{--[no-]target-align}] [@b{--[no-]longcalls}]
589 [@b{--[no-]transform}]
590 [@b{--rename-section} @var{oldname}=@var{newname}]
a82c7d90 591 [@b{--[no-]trampolines}]
2d8b84ae 592@end ifset
3c9b82ba
NC
593@ifset Z80
594
595@emph{Target Z80 options:}
596 [@b{-z80}] [@b{-r800}]
597 [@b{ -ignore-undocumented-instructions}] [@b{-Wnud}]
598 [@b{ -ignore-unportable-instructions}] [@b{-Wnup}]
599 [@b{ -warn-undocumented-instructions}] [@b{-Wud}]
600 [@b{ -warn-unportable-instructions}] [@b{-Wup}]
601 [@b{ -forbid-undocumented-instructions}] [@b{-Fud}]
602 [@b{ -forbid-unportable-instructions}] [@b{-Fup}]
603@end ifset
a4fb0134 604@ifset Z8000
b6605ddd 605
a4fb0134 606@c Z8000 has no machine-dependent assembler options
252b5132 607@end ifset
e0001a05 608
0285c67d 609@c man end
252b5132
RH
610@end smallexample
611
0285c67d
NC
612@c man begin OPTIONS
613
a4fb0134 614@table @gcctabopt
38fc1cb1 615@include at-file.texi
a0b7da79 616
83f10cb2 617@item -a[cdghlmns]
252b5132
RH
618Turn on listings, in any of a variety of ways:
619
a4fb0134 620@table @gcctabopt
252b5132
RH
621@item -ac
622omit false conditionals
623
624@item -ad
625omit debugging directives
626
83f10cb2
NC
627@item -ag
628include general information, like @value{AS} version and options passed
629
252b5132
RH
630@item -ah
631include high-level source
632
633@item -al
634include assembly
635
636@item -am
637include macro expansions
638
639@item -an
640omit forms processing
641
642@item -as
643include symbols
644
645@item =file
646set the name of the listing file
647@end table
648
649You may combine these options; for example, use @samp{-aln} for assembly
650listing without forms processing. The @samp{=file} option, if used, must be
651the last one. By itself, @samp{-a} defaults to @samp{-ahls}.
652
caa32fe5 653@item --alternate
96e9638b
BW
654Begin in alternate macro mode.
655@ifclear man
656@xref{Altmacro,,@code{.altmacro}}.
657@end ifclear
caa32fe5 658
955974c6 659@item --compress-debug-sections
19a7fe52
L
660Compress DWARF debug sections using zlib with SHF_COMPRESSED from the
661ELF ABI. The resulting object file may not be compatible with older
662linkers and object file utilities. Note if compression would make a
663given section @emph{larger} then it is not compressed.
955974c6 664
151411f8
L
665@ifset ELF
666@cindex @samp{--compress-debug-sections=} option
667@item --compress-debug-sections=none
668@itemx --compress-debug-sections=zlib
669@itemx --compress-debug-sections=zlib-gnu
670@itemx --compress-debug-sections=zlib-gabi
671These options control how DWARF debug sections are compressed.
672@option{--compress-debug-sections=none} is equivalent to
673@option{--nocompress-debug-sections}.
674@option{--compress-debug-sections=zlib} and
19a7fe52 675@option{--compress-debug-sections=zlib-gabi} are equivalent to
151411f8 676@option{--compress-debug-sections}.
19a7fe52
L
677@option{--compress-debug-sections=zlib-gnu} compresses DWARF debug
678sections using zlib. The debug sections are renamed to begin with
679@samp{.zdebug}. Note if compression would make a given section
680@emph{larger} then it is not compressed nor renamed.
681
151411f8
L
682@end ifset
683
955974c6 684@item --nocompress-debug-sections
e12fe555
NC
685Do not compress DWARF debug sections. This is usually the default for all
686targets except the x86/x86_64, but a configure time option can be used to
687override this.
955974c6 688
252b5132
RH
689@item -D
690Ignored. This option is accepted for script compatibility with calls to
691other assemblers.
692
3d6b762c
JM
693@item --debug-prefix-map @var{old}=@var{new}
694When assembling files in directory @file{@var{old}}, record debugging
695information describing them as in @file{@var{new}} instead.
696
252b5132
RH
697@item --defsym @var{sym}=@var{value}
698Define the symbol @var{sym} to be @var{value} before assembling the input file.
699@var{value} must be an integer constant. As in C, a leading @samp{0x}
bf083c64
NC
700indicates a hexadecimal value, and a leading @samp{0} indicates an octal
701value. The value of the symbol can be overridden inside a source file via the
702use of a @code{.set} pseudo-op.
252b5132
RH
703
704@item -f
705``fast''---skip whitespace and comment preprocessing (assume source is
706compiler output).
707
329e276d
NC
708@item -g
709@itemx --gen-debug
710Generate debugging information for each assembler source line using whichever
711debug format is preferred by the target. This currently means either STABS,
712ECOFF or DWARF2.
713
252b5132
RH
714@item --gstabs
715Generate stabs debugging information for each assembler line. This
716may help debugging assembler code, if the debugger can handle it.
717
05da4302
NC
718@item --gstabs+
719Generate stabs debugging information for each assembler line, with GNU
720extensions that probably only gdb can handle, and that could make other
721debuggers crash or refuse to read your program. This
722may help debugging assembler code. Currently the only GNU extension is
723the location of the current working directory at assembling time.
724
329e276d 725@item --gdwarf-2
cdf82bcf 726Generate DWARF2 debugging information for each assembler line. This
c1253627 727may help debugging assembler code, if the debugger can handle it. Note---this
85a39694 728option is only supported by some targets, not all of them.
cdf82bcf 729
b40bf0a2
NC
730@item --gdwarf-sections
731Instead of creating a .debug_line section, create a series of
732.debug_line.@var{foo} sections where @var{foo} is the name of the
733corresponding code section. For example a code section called @var{.text.func}
734will have its dwarf line number information placed into a section called
735@var{.debug_line.text.func}. If the code section is just called @var{.text}
736then debug line section will still be called just @var{.debug_line} without any
737suffix.
738
b8871f35 739@ifset ELF
21be61f5
L
740@item --size-check=error
741@itemx --size-check=warning
742Issue an error or warning for invalid ELF .size directive.
743
b8871f35
L
744@item --elf-stt-common=no
745@itemx --elf-stt-common=yes
746These options control whether the ELF assembler should generate common
747symbols with the @code{STT_COMMON} type. The default can be controlled
748by a configure option @option{--enable-elf-stt-common}.
0df8ad28
NC
749
750@item --generate-missing-build-notes=yes
751@itemx --generate-missing-build-notes=no
752These options control whether the ELF assembler should generate GNU Build
753attribute notes if none are present in the input sources.
754The default can be controlled by the @option{--enable-generate-build-notes}
755configure option.
756
b8871f35
L
757@end ifset
758
252b5132
RH
759@item --help
760Print a summary of the command line options and exit.
761
ea20a7da
CC
762@item --target-help
763Print a summary of all target specific options and exit.
764
252b5132
RH
765@item -I @var{dir}
766Add directory @var{dir} to the search list for @code{.include} directives.
767
768@item -J
769Don't warn about signed overflow.
770
771@item -K
772@ifclear DIFF-TBL-KLUGE
773This option is accepted but has no effect on the @value{TARGET} family.
774@end ifclear
775@ifset DIFF-TBL-KLUGE
776Issue warnings when difference tables altered for long displacements.
777@end ifset
778
779@item -L
780@itemx --keep-locals
ba83aca1
BW
781Keep (in the symbol table) local symbols. These symbols start with
782system-specific local label prefixes, typically @samp{.L} for ELF systems
783or @samp{L} for traditional a.out systems.
784@ifclear man
785@xref{Symbol Names}.
786@end ifclear
252b5132 787
c3a27914
NC
788@item --listing-lhs-width=@var{number}
789Set the maximum width, in words, of the output data column for an assembler
790listing to @var{number}.
791
792@item --listing-lhs-width2=@var{number}
793Set the maximum width, in words, of the output data column for continuation
794lines in an assembler listing to @var{number}.
795
796@item --listing-rhs-width=@var{number}
797Set the maximum width of an input source line, as displayed in a listing, to
798@var{number} bytes.
799
800@item --listing-cont-lines=@var{number}
801Set the maximum number of lines printed in a listing for a single line of input
802to @var{number} + 1.
803
2edb36e7
NC
804@item --no-pad-sections
805Stop the assembler for padding the ends of output sections to the alignment
806of that section. The default is to pad the sections, but this can waste space
807which might be needed on targets which have tight memory constraints.
808
252b5132 809@item -o @var{objfile}
a4fb0134 810Name the object-file output from @command{@value{AS}} @var{objfile}.
252b5132
RH
811
812@item -R
813Fold the data section into the text section.
814
d60646b9 815@item --hash-size=@var{number}
4bdd3565
NC
816Set the default size of GAS's hash tables to a prime number close to
817@var{number}. Increasing this value can reduce the length of time it takes the
818assembler to perform its tasks, at the expense of increasing the assembler's
819memory requirements. Similarly reducing this value can reduce the memory
820requirements at the expense of speed.
821
822@item --reduce-memory-overheads
823This option reduces GAS's memory requirements, at the expense of making the
824assembly processes slower. Currently this switch is a synonym for
825@samp{--hash-size=4051}, but in the future it may have other effects as well.
826
451133ce
NP
827@ifset ELF
828@item --sectname-subst
829Honor substitution sequences in section names.
830@ifclear man
831@xref{Section Name Substitutions,,@code{.section @var{name}}}.
832@end ifclear
833@end ifset
834
252b5132
RH
835@item --statistics
836Print the maximum space (in bytes) and total time (in seconds) used by
837assembly.
838
839@item --strip-local-absolute
840Remove local absolute symbols from the outgoing symbol table.
841
842@item -v
843@itemx -version
a4fb0134 844Print the @command{as} version.
252b5132
RH
845
846@item --version
a4fb0134 847Print the @command{as} version and exit.
252b5132
RH
848
849@item -W
2bdd6cf5 850@itemx --no-warn
252b5132
RH
851Suppress warning messages.
852
2bdd6cf5
GK
853@item --fatal-warnings
854Treat warnings as errors.
855
856@item --warn
857Don't suppress warning messages or treat them as errors.
858
252b5132
RH
859@item -w
860Ignored.
861
862@item -x
863Ignored.
864
865@item -Z
866Generate an object file even after errors.
867
868@item -- | @var{files} @dots{}
869Standard input, or source files to assemble.
870
871@end table
2a633939
JM
872@c man end
873
a06ea964
NC
874@ifset AARCH64
875
876@ifclear man
877@xref{AArch64 Options}, for the options available when @value{AS} is configured
878for the 64-bit mode of the ARM Architecture (AArch64).
879@end ifclear
880
881@ifset man
882@c man begin OPTIONS
883The following options are available when @value{AS} is configured for the
88464-bit mode of the ARM Architecture (AArch64).
885@c man end
886@c man begin INCLUDE
887@include c-aarch64.texi
888@c ended inside the included file
889@end ifset
890
891@end ifset
892
2a633939
JM
893@ifset ALPHA
894
895@ifclear man
896@xref{Alpha Options}, for the options available when @value{AS} is configured
897for an Alpha processor.
898@end ifclear
899
900@ifset man
901@c man begin OPTIONS
902The following options are available when @value{AS} is configured for an Alpha
903processor.
904@c man end
905@c man begin INCLUDE
906@include c-alpha.texi
907@c ended inside the included file
908@end ifset
909
910@end ifset
252b5132 911
2a633939 912@c man begin OPTIONS
252b5132 913@ifset ARC
886a2506
NC
914The following options are available when @value{AS} is configured for an ARC
915processor.
252b5132 916
a4fb0134 917@table @gcctabopt
886a2506 918@item -mcpu=@var{cpu}
0d2bcfaf
NC
919This option selects the core processor variant.
920@item -EB | -EL
921Select either big-endian (-EB) or little-endian (-EL) output.
886a2506
NC
922@item -mcode-density
923Enable Code Density extenssion instructions.
252b5132
RH
924@end table
925@end ifset
926
927@ifset ARM
928The following options are available when @value{AS} is configured for the ARM
929processor family.
930
a4fb0134 931@table @gcctabopt
92081f48 932@item -mcpu=@var{processor}[+@var{extension}@dots{}]
cdf82bcf 933Specify which ARM processor variant is the target.
92081f48 934@item -march=@var{architecture}[+@var{extension}@dots{}]
cdf82bcf 935Specify which ARM architecture variant is used by the target.
03b1477f 936@item -mfpu=@var{floating-point-format}
a349d9dd 937Select which Floating Point architecture is the target.
33a392fb
PB
938@item -mfloat-abi=@var{abi}
939Select which floating point ABI is in use.
03b1477f
RE
940@item -mthumb
941Enable Thumb only instruction decoding.
7f266840 942@item -mapcs-32 | -mapcs-26 | -mapcs-float | -mapcs-reentrant
252b5132
RH
943Select which procedure calling convention is in use.
944@item -EB | -EL
945Select either big-endian (-EB) or little-endian (-EL) output.
cdf82bcf
NC
946@item -mthumb-interwork
947Specify that the code has been generated with interworking between Thumb and
948ARM code in mind.
2e6976a8
DG
949@item -mccs
950Turns on CodeComposer Studio assembly syntax compatibility mode.
cdf82bcf
NC
951@item -k
952Specify that PIC code has been generated.
252b5132
RH
953@end table
954@end ifset
635fb38d 955@c man end
252b5132 956
9982501a 957@ifset Blackfin
8611b8fd
MF
958
959@ifclear man
960@xref{Blackfin Options}, for the options available when @value{AS} is
961configured for the Blackfin processor family.
962@end ifclear
963
964@ifset man
965@c man begin OPTIONS
9982501a
JZ
966The following options are available when @value{AS} is configured for
967the Blackfin processor family.
8611b8fd
MF
968@c man end
969@c man begin INCLUDE
970@include c-bfin.texi
971@c ended inside the included file
972@end ifset
9982501a 973
9982501a
JZ
974@end ifset
975
635fb38d 976@c man begin OPTIONS
328eb32e
HPN
977@ifset CRIS
978See the info pages for documentation of the CRIS-specific options.
979@end ifset
980
252b5132
RH
981@ifset D10V
982The following options are available when @value{AS} is configured for
983a D10V processor.
a4fb0134 984@table @gcctabopt
252b5132
RH
985@cindex D10V optimization
986@cindex optimization, D10V
987@item -O
988Optimize output by parallelizing instructions.
989@end table
990@end ifset
991
992@ifset D30V
993The following options are available when @value{AS} is configured for a D30V
994processor.
a4fb0134 995@table @gcctabopt
252b5132
RH
996@cindex D30V optimization
997@cindex optimization, D30V
998@item -O
999Optimize output by parallelizing instructions.
1000
1001@cindex D30V nops
1002@item -n
1003Warn when nops are generated.
1004
1005@cindex D30V nops after 32-bit multiply
1006@item -N
1007Warn when a nop after a 32-bit multiply instruction is generated.
1008@end table
1009@end ifset
731caf76
L
1010@c man end
1011
cfb8c092
NC
1012@ifset EPIPHANY
1013The following options are available when @value{AS} is configured for the
1014Adapteva EPIPHANY series.
1015
56b13185
JR
1016@ifclear man
1017@xref{Epiphany Options}, for the options available when @value{AS} is
1018configured for an Epiphany processor.
1019@end ifclear
cfb8c092 1020
56b13185
JR
1021@ifset man
1022@c man begin OPTIONS
1023The following options are available when @value{AS} is configured for
1024an Epiphany processor.
1025@c man end
1026@c man begin INCLUDE
1027@include c-epiphany.texi
0c76cae8
AM
1028@c ended inside the included file
1029@end ifset
1030
1031@end ifset
1032
1033@ifset H8300
1034
1035@ifclear man
1036@xref{H8/300 Options}, for the options available when @value{AS} is configured
1037for an H8/300 processor.
1038@end ifclear
1039
1040@ifset man
1041@c man begin OPTIONS
1042The following options are available when @value{AS} is configured for an H8/300
1043processor.
1044@c man end
1045@c man begin INCLUDE
1046@include c-h8300.texi
56b13185
JR
1047@c ended inside the included file
1048@end ifset
cfb8c092 1049
cfb8c092
NC
1050@end ifset
1051
731caf76 1052@ifset I80386
252b5132 1053
731caf76
L
1054@ifclear man
1055@xref{i386-Options}, for the options available when @value{AS} is
1056configured for an i386 processor.
1057@end ifclear
1058
1059@ifset man
1060@c man begin OPTIONS
1061The following options are available when @value{AS} is configured for
1062an i386 processor.
1063@c man end
1064@c man begin INCLUDE
1065@include c-i386.texi
1066@c ended inside the included file
1067@end ifset
1068
1069@end ifset
1070
1071@c man begin OPTIONS
a40cbfa3
NC
1072@ifset IP2K
1073The following options are available when @value{AS} is configured for the
ec88d317 1074Ubicom IP2K series.
a40cbfa3
NC
1075
1076@table @gcctabopt
1077
1078@item -mip2022ext
1079Specifies that the extended IP2022 instructions are allowed.
1080
1081@item -mip2022
8dfa0188 1082Restores the default behaviour, which restricts the permitted instructions to
a40cbfa3
NC
1083just the basic IP2022 ones.
1084
1085@end table
1086@end ifset
1087
49f58d10
JB
1088@ifset M32C
1089The following options are available when @value{AS} is configured for the
1090Renesas M32C and M16C processors.
1091
1092@table @gcctabopt
1093
1094@item -m32c
1095Assemble M32C instructions.
1096
1097@item -m16c
1098Assemble M16C instructions (the default).
1099
c54b5932
DD
1100@item -relax
1101Enable support for link-time relaxations.
1102
1103@item -h-tick-hex
1104Support H'00 style hex constants in addition to 0x00 style.
1105
49f58d10
JB
1106@end table
1107@end ifset
1108
ec694b89
NC
1109@ifset M32R
1110The following options are available when @value{AS} is configured for the
26597c86 1111Renesas M32R (formerly Mitsubishi M32R) series.
ec694b89 1112
a4fb0134 1113@table @gcctabopt
ec694b89
NC
1114
1115@item --m32rx
1116Specify which processor in the M32R family is the target. The default
1117is normally the M32R, but this option changes it to the M32RX.
1118
1119@item --warn-explicit-parallel-conflicts or --Wp
1120Produce warning messages when questionable parallel constructs are
01642c12 1121encountered.
ec694b89
NC
1122
1123@item --no-warn-explicit-parallel-conflicts or --Wnp
01642c12
RM
1124Do not produce warning messages when questionable parallel constructs are
1125encountered.
ec694b89
NC
1126
1127@end table
1128@end ifset
252b5132
RH
1129
1130@ifset M680X0
1131The following options are available when @value{AS} is configured for the
1132Motorola 68000 series.
1133
a4fb0134 1134@table @gcctabopt
252b5132
RH
1135
1136@item -l
1137Shorten references to undefined symbols, to one word instead of two.
1138
0285c67d
NC
1139@item -m68000 | -m68008 | -m68010 | -m68020 | -m68030
1140@itemx | -m68040 | -m68060 | -m68302 | -m68331 | -m68332
1141@itemx | -m68333 | -m68340 | -mcpu32 | -m5200
252b5132
RH
1142Specify what processor in the 68000 family is the target. The default
1143is normally the 68020, but this can be changed at configuration time.
1144
1145@item -m68881 | -m68882 | -mno-68881 | -mno-68882
1146The target machine does (or does not) have a floating-point coprocessor.
1147The default is to assume a coprocessor for 68020, 68030, and cpu32. Although
1148the basic 68000 is not compatible with the 68881, a combination of the
1149two can be specified, since it's possible to do emulation of the
1150coprocessor instructions with the main processor.
1151
1152@item -m68851 | -mno-68851
1153The target machine does (or does not) have a memory-management
1154unit coprocessor. The default is to assume an MMU for 68020 and up.
1155
1156@end table
1157@end ifset
1158
36591ba1
SL
1159@ifset NIOSII
1160
1161@ifclear man
1162@xref{Nios II Options}, for the options available when @value{AS} is configured
1163for an Altera Nios II processor.
1164@end ifclear
1165
1166@ifset man
1167@c man begin OPTIONS
1168The following options are available when @value{AS} is configured for an
1169Altera Nios II processor.
1170@c man end
1171@c man begin INCLUDE
1172@include c-nios2.texi
1173@c ended inside the included file
1174@end ifset
1175@end ifset
1176
e135f41b
NC
1177@ifset PDP11
1178
1179For details about the PDP-11 machine dependent features options,
1180see @ref{PDP-11-Options}.
1181
a4fb0134 1182@table @gcctabopt
e135f41b
NC
1183@item -mpic | -mno-pic
1184Generate position-independent (or position-dependent) code. The
a4fb0134 1185default is @option{-mpic}.
e135f41b
NC
1186
1187@item -mall
1188@itemx -mall-extensions
1189Enable all instruction set extensions. This is the default.
1190
1191@item -mno-extensions
1192Disable all instruction set extensions.
1193
1194@item -m@var{extension} | -mno-@var{extension}
1195Enable (or disable) a particular instruction set extension.
1196
1197@item -m@var{cpu}
1198Enable the instruction set extensions supported by a particular CPU, and
1199disable all other extensions.
1200
1201@item -m@var{machine}
1202Enable the instruction set extensions supported by a particular machine
1203model, and disable all other extensions.
1204@end table
1205
1206@end ifset
1207
041dd5a9
ILT
1208@ifset PJ
1209The following options are available when @value{AS} is configured for
1210a picoJava processor.
1211
a4fb0134 1212@table @gcctabopt
041dd5a9
ILT
1213
1214@cindex PJ endianness
1215@cindex endianness, PJ
1216@cindex big endian output, PJ
1217@item -mb
1218Generate ``big endian'' format output.
1219
1220@cindex little endian output, PJ
1221@item -ml
1222Generate ``little endian'' format output.
1223
1224@end table
1225@end ifset
1226
93f11b16
DD
1227@ifset PRU
1228
1229@ifclear man
1230@xref{PRU Options}, for the options available when @value{AS} is configured
1231for a PRU processor.
1232@end ifclear
1233
1234@ifset man
1235@c man begin OPTIONS
1236The following options are available when @value{AS} is configured for a
1237PRU processor.
1238@c man end
1239@c man begin INCLUDE
1240@include c-pru.texi
1241@c ended inside the included file
1242@end ifset
1243@end ifset
1244
60bcf0fa
NC
1245@ifset M68HC11
1246The following options are available when @value{AS} is configured for the
1247Motorola 68HC11 or 68HC12 series.
1248
a4fb0134 1249@table @gcctabopt
60bcf0fa 1250
6927f982 1251@item -m68hc11 | -m68hc12 | -m68hcs12 | -mm9s12x | -mm9s12xg
60bcf0fa
NC
1252Specify what processor is the target. The default is
1253defined by the configuration option when building the assembler.
1254
6927f982
NC
1255@item --xgate-ramoffset
1256Instruct the linker to offset RAM addresses from S12X address space into
1257XGATE address space.
1258
2f904664
SC
1259@item -mshort
1260Specify to use the 16-bit integer ABI.
1261
1262@item -mlong
01642c12 1263Specify to use the 32-bit integer ABI.
2f904664
SC
1264
1265@item -mshort-double
01642c12 1266Specify to use the 32-bit double ABI.
2f904664
SC
1267
1268@item -mlong-double
01642c12 1269Specify to use the 64-bit double ABI.
2f904664 1270
1370e33d 1271@item --force-long-branches
60bcf0fa
NC
1272Relative branches are turned into absolute ones. This concerns
1273conditional branches, unconditional branches and branches to a
1274sub routine.
1275
1370e33d
NC
1276@item -S | --short-branches
1277Do not turn relative branches into absolute ones
60bcf0fa
NC
1278when the offset is out of range.
1279
1280@item --strict-direct-mode
1281Do not turn the direct addressing mode into extended addressing mode
1282when the instruction does not support direct addressing mode.
1283
1284@item --print-insn-syntax
1285Print the syntax of instruction in case of error.
1286
1287@item --print-opcodes
6927f982 1288Print the list of instructions with syntax and then exit.
60bcf0fa
NC
1289
1290@item --generate-example
6927f982 1291Print an example of instruction for each possible instruction and then exit.
a4fb0134 1292This option is only useful for testing @command{@value{AS}}.
60bcf0fa
NC
1293
1294@end table
1295@end ifset
1296
252b5132 1297@ifset SPARC
a4fb0134 1298The following options are available when @command{@value{AS}} is configured
252b5132
RH
1299for the SPARC architecture:
1300
a4fb0134 1301@table @gcctabopt
252b5132
RH
1302@item -Av6 | -Av7 | -Av8 | -Asparclet | -Asparclite
1303@itemx -Av8plus | -Av8plusa | -Av9 | -Av9a
1304Explicitly select a variant of the SPARC architecture.
1305
1306@samp{-Av8plus} and @samp{-Av8plusa} select a 32 bit environment.
1307@samp{-Av9} and @samp{-Av9a} select a 64 bit environment.
1308
1309@samp{-Av8plusa} and @samp{-Av9a} enable the SPARC V9 instruction set with
1310UltraSPARC extensions.
1311
1312@item -xarch=v8plus | -xarch=v8plusa
1313For compatibility with the Solaris v9 assembler. These options are
1314equivalent to -Av8plus and -Av8plusa, respectively.
1315
1316@item -bump
1317Warn when the assembler switches to another architecture.
1318@end table
1319@end ifset
1320
39bec121
TW
1321@ifset TIC54X
1322The following options are available when @value{AS} is configured for the 'c54x
01642c12 1323architecture.
39bec121 1324
a4fb0134 1325@table @gcctabopt
39bec121
TW
1326@item -mfar-mode
1327Enable extended addressing mode. All addresses and relocations will assume
1328extended addressing (usually 23 bits).
1329@item -mcpu=@var{CPU_VERSION}
1330Sets the CPU version being compiled for.
1331@item -merrors-to-file @var{FILENAME}
1332Redirect error output to a file, for broken systems which don't support such
1333behaviour in the shell.
1334@end table
1335@end ifset
1336
252b5132 1337@ifset MIPS
73201331 1338@c man begin OPTIONS
252b5132 1339The following options are available when @value{AS} is configured for
98508b2a 1340a MIPS processor.
252b5132 1341
a4fb0134 1342@table @gcctabopt
252b5132
RH
1343@item -G @var{num}
1344This option sets the largest size of an object that can be referenced
1345implicitly with the @code{gp} register. It is only accepted for targets that
1346use ECOFF format, such as a DECstation running Ultrix. The default value is 8.
1347
1348@cindex MIPS endianness
1349@cindex endianness, MIPS
1350@cindex big endian output, MIPS
1351@item -EB
1352Generate ``big endian'' format output.
1353
1354@cindex little endian output, MIPS
1355@item -EL
1356Generate ``little endian'' format output.
1357
1358@cindex MIPS ISA
1359@item -mips1
1360@itemx -mips2
1361@itemx -mips3
e7af610e 1362@itemx -mips4
437ee9d5 1363@itemx -mips5
e7af610e 1364@itemx -mips32
af7ee8bf 1365@itemx -mips32r2
ae52f483
AB
1366@itemx -mips32r3
1367@itemx -mips32r5
7361da2c 1368@itemx -mips32r6
4058e45f 1369@itemx -mips64
5f74bc13 1370@itemx -mips64r2
ae52f483
AB
1371@itemx -mips64r3
1372@itemx -mips64r5
7361da2c 1373@itemx -mips64r6
98508b2a 1374Generate code for a particular MIPS Instruction Set Architecture level.
437ee9d5
TS
1375@samp{-mips1} is an alias for @samp{-march=r3000}, @samp{-mips2} is an
1376alias for @samp{-march=r6000}, @samp{-mips3} is an alias for
1377@samp{-march=r4000} and @samp{-mips4} is an alias for @samp{-march=r8000}.
ae52f483 1378@samp{-mips5}, @samp{-mips32}, @samp{-mips32r2}, @samp{-mips32r3},
7361da2c
AB
1379@samp{-mips32r5}, @samp{-mips32r6}, @samp{-mips64}, @samp{-mips64r2},
1380@samp{-mips64r3}, @samp{-mips64r5}, and @samp{-mips64r6} correspond to generic
1381MIPS V, MIPS32, MIPS32 Release 2, MIPS32 Release 3, MIPS32 Release 5, MIPS32
1382Release 6, MIPS64, MIPS64 Release 2, MIPS64 Release 3, MIPS64 Release 5, and
1383MIPS64 Release 6 ISA processors, respectively.
437ee9d5 1384
98508b2a
RS
1385@item -march=@var{cpu}
1386Generate code for a particular MIPS CPU.
437ee9d5
TS
1387
1388@item -mtune=@var{cpu}
98508b2a 1389Schedule and tune for a particular MIPS CPU.
437ee9d5
TS
1390
1391@item -mfix7000
1392@itemx -mno-fix7000
1393Cause nops to be inserted if the read of the destination register
1394of an mfhi or mflo instruction occurs in the following two instructions.
1395
a8d14a88
CM
1396@item -mfix-rm7000
1397@itemx -mno-fix-rm7000
1398Cause nops to be inserted if a dmult or dmultu instruction is
1399followed by a load instruction.
1400
ecb4347a
DJ
1401@item -mdebug
1402@itemx -no-mdebug
1403Cause stabs-style debugging output to go into an ECOFF-style .mdebug
1404section instead of the standard ELF .stabs sections.
1405
dcd410fe
RO
1406@item -mpdr
1407@itemx -mno-pdr
1408Control generation of @code{.pdr} sections.
1409
437ee9d5
TS
1410@item -mgp32
1411@itemx -mfp32
1412The register sizes are normally inferred from the ISA and ABI, but these
1413flags force a certain group of registers to be treated as 32 bits wide at
1414all times. @samp{-mgp32} controls the size of general-purpose registers
1415and @samp{-mfp32} controls the size of floating-point registers.
1416
351cdf24
MF
1417@item -mgp64
1418@itemx -mfp64
1419The register sizes are normally inferred from the ISA and ABI, but these
1420flags force a certain group of registers to be treated as 64 bits wide at
1421all times. @samp{-mgp64} controls the size of general-purpose registers
1422and @samp{-mfp64} controls the size of floating-point registers.
1423
1424@item -mfpxx
1425The register sizes are normally inferred from the ISA and ABI, but using
1426this flag in combination with @samp{-mabi=32} enables an ABI variant
1427which will operate correctly with floating-point registers which are
142832 or 64 bits wide.
1429
1430@item -modd-spreg
1431@itemx -mno-odd-spreg
1432Enable use of floating-point operations on odd-numbered single-precision
1433registers when supported by the ISA. @samp{-mfpxx} implies
1434@samp{-mno-odd-spreg}, otherwise the default is @samp{-modd-spreg}.
1435
437ee9d5
TS
1436@item -mips16
1437@itemx -no-mips16
1438Generate code for the MIPS 16 processor. This is equivalent to putting
32035f51 1439@code{.module mips16} at the start of the assembly file. @samp{-no-mips16}
437ee9d5 1440turns off this option.
252b5132 1441
25499ac7
MR
1442@item -mmips16e2
1443@itemx -mno-mips16e2
1444Enable the use of MIPS16e2 instructions in MIPS16 mode. This is equivalent
1445to putting @code{.module mips16e2} at the start of the assembly file.
1446@samp{-mno-mips16e2} turns off this option.
1447
df58fc94
RS
1448@item -mmicromips
1449@itemx -mno-micromips
1450Generate code for the microMIPS processor. This is equivalent to putting
32035f51
MR
1451@code{.module micromips} at the start of the assembly file.
1452@samp{-mno-micromips} turns off this option. This is equivalent to putting
1453@code{.module nomicromips} at the start of the assembly file.
df58fc94 1454
e16bfa71
TS
1455@item -msmartmips
1456@itemx -mno-smartmips
32035f51
MR
1457Enables the SmartMIPS extension to the MIPS32 instruction set. This is
1458equivalent to putting @code{.module smartmips} at the start of the assembly
1459file. @samp{-mno-smartmips} turns off this option.
e16bfa71 1460
1f25f5d3
CD
1461@item -mips3d
1462@itemx -no-mips3d
1463Generate code for the MIPS-3D Application Specific Extension.
1464This tells the assembler to accept MIPS-3D instructions.
1465@samp{-no-mips3d} turns off this option.
1466
deec1734
CD
1467@item -mdmx
1468@itemx -no-mdmx
1469Generate code for the MDMX Application Specific Extension.
1470This tells the assembler to accept MDMX instructions.
1471@samp{-no-mdmx} turns off this option.
1472
2ef2b9ae
CF
1473@item -mdsp
1474@itemx -mno-dsp
8b082fb1
TS
1475Generate code for the DSP Release 1 Application Specific Extension.
1476This tells the assembler to accept DSP Release 1 instructions.
2ef2b9ae
CF
1477@samp{-mno-dsp} turns off this option.
1478
8b082fb1
TS
1479@item -mdspr2
1480@itemx -mno-dspr2
1481Generate code for the DSP Release 2 Application Specific Extension.
8f4f9071 1482This option implies @samp{-mdsp}.
8b082fb1
TS
1483This tells the assembler to accept DSP Release 2 instructions.
1484@samp{-mno-dspr2} turns off this option.
1485
8f4f9071
MF
1486@item -mdspr3
1487@itemx -mno-dspr3
1488Generate code for the DSP Release 3 Application Specific Extension.
1489This option implies @samp{-mdsp} and @samp{-mdspr2}.
1490This tells the assembler to accept DSP Release 3 instructions.
1491@samp{-mno-dspr3} turns off this option.
1492
56d438b1
CF
1493@item -mmsa
1494@itemx -mno-msa
1495Generate code for the MIPS SIMD Architecture Extension.
1496This tells the assembler to accept MSA instructions.
1497@samp{-mno-msa} turns off this option.
1498
7d64c587
AB
1499@item -mxpa
1500@itemx -mno-xpa
1501Generate code for the MIPS eXtended Physical Address (XPA) Extension.
1502This tells the assembler to accept XPA instructions.
1503@samp{-mno-xpa} turns off this option.
1504
ef2e4d86
CF
1505@item -mmt
1506@itemx -mno-mt
1507Generate code for the MT Application Specific Extension.
1508This tells the assembler to accept MT instructions.
1509@samp{-mno-mt} turns off this option.
1510
dec0624d
MR
1511@item -mmcu
1512@itemx -mno-mcu
1513Generate code for the MCU Application Specific Extension.
1514This tells the assembler to accept MCU instructions.
1515@samp{-mno-mcu} turns off this option.
1516
730c3174
SE
1517@item -mcrc
1518@itemx -mno-crc
1519Generate code for the MIPS cyclic redundancy check (CRC) Application
1520Specific Extension. This tells the assembler to accept CRC instructions.
1521@samp{-mno-crc} turns off this option.
1522
6f20c942
FS
1523@item -mginv
1524@itemx -mno-ginv
1525Generate code for the Global INValidate (GINV) Application Specific
1526Extension. This tells the assembler to accept GINV instructions.
1527@samp{-mno-ginv} turns off this option.
1528
833794fc
MR
1529@item -minsn32
1530@itemx -mno-insn32
1531Only use 32-bit instruction encodings when generating code for the
1532microMIPS processor. This option inhibits the use of any 16-bit
1533instructions. This is equivalent to putting @code{.set insn32} at
1534the start of the assembly file. @samp{-mno-insn32} turns off this
1535option. This is equivalent to putting @code{.set noinsn32} at the
1536start of the assembly file. By default @samp{-mno-insn32} is
1537selected, allowing all instructions to be used.
1538
437ee9d5
TS
1539@item --construct-floats
1540@itemx --no-construct-floats
1541The @samp{--no-construct-floats} option disables the construction of
1542double width floating point constants by loading the two halves of the
1543value into the two single width floating point registers that make up
1544the double width register. By default @samp{--construct-floats} is
1545selected, allowing construction of these floating point constants.
252b5132 1546
3bf0dbfb
MR
1547@item --relax-branch
1548@itemx --no-relax-branch
1549The @samp{--relax-branch} option enables the relaxation of out-of-range
1550branches. By default @samp{--no-relax-branch} is selected, causing any
1551out-of-range branches to produce an error.
1552
8b10b0b3
MR
1553@item -mignore-branch-isa
1554@itemx -mno-ignore-branch-isa
1555Ignore branch checks for invalid transitions between ISA modes. The
1556semantics of branches does not provide for an ISA mode switch, so in
1557most cases the ISA mode a branch has been encoded for has to be the
1558same as the ISA mode of the branch's target label. Therefore GAS has
1559checks implemented that verify in branch assembly that the two ISA
1560modes match. @samp{-mignore-branch-isa} disables these checks. By
1561default @samp{-mno-ignore-branch-isa} is selected, causing any invalid
1562branch requiring a transition between ISA modes to produce an error.
1563
ba92f887
MR
1564@item -mnan=@var{encoding}
1565Select between the IEEE 754-2008 (@option{-mnan=2008}) or the legacy
1566(@option{-mnan=legacy}) NaN encoding format. The latter is the default.
1567
252b5132
RH
1568@cindex emulation
1569@item --emulation=@var{name}
e8044f35
RS
1570This option was formerly used to switch between ELF and ECOFF output
1571on targets like IRIX 5 that supported both. MIPS ECOFF support was
1572removed in GAS 2.24, so the option now serves little purpose.
1573It is retained for backwards compatibility.
1574
1575The available configuration names are: @samp{mipself}, @samp{mipslelf} and
1576@samp{mipsbelf}. Choosing @samp{mipself} now has no effect, since the output
1577is always ELF. @samp{mipslelf} and @samp{mipsbelf} select little- and
1578big-endian output respectively, but @samp{-EL} and @samp{-EB} are now the
1579preferred options instead.
252b5132
RH
1580
1581@item -nocpp
a4fb0134 1582@command{@value{AS}} ignores this option. It is accepted for compatibility with
252b5132
RH
1583the native tools.
1584
252b5132
RH
1585@item --trap
1586@itemx --no-trap
1587@itemx --break
1588@itemx --no-break
1589Control how to deal with multiplication overflow and division by zero.
1590@samp{--trap} or @samp{--no-break} (which are synonyms) take a trap exception
1591(and only work for Instruction Set Architecture level 2 and higher);
1592@samp{--break} or @samp{--no-trap} (also synonyms, and the default) take a
1593break exception.
63486801
L
1594
1595@item -n
a4fb0134 1596When this option is used, @command{@value{AS}} will issue a warning every
63486801 1597time it generates a nop instruction from a macro.
252b5132 1598@end table
73201331 1599@c man end
252b5132
RH
1600@end ifset
1601
1602@ifset MCORE
1603The following options are available when @value{AS} is configured for
1604an MCore processor.
1605
a4fb0134 1606@table @gcctabopt
252b5132
RH
1607@item -jsri2bsr
1608@itemx -nojsri2bsr
1609Enable or disable the JSRI to BSR transformation. By default this is enabled.
1610The command line option @samp{-nojsri2bsr} can be used to disable it.
1611
1612@item -sifilter
1613@itemx -nosifilter
1614Enable or disable the silicon filter behaviour. By default this is disabled.
a349d9dd 1615The default can be overridden by the @samp{-sifilter} command line option.
252b5132
RH
1616
1617@item -relax
1618Alter jump instructions for long displacements.
1619
ec694b89
NC
1620@item -mcpu=[210|340]
1621Select the cpu type on the target hardware. This controls which instructions
1622can be assembled.
1623
1624@item -EB
1625Assemble for a big endian target.
1626
1627@item -EL
1628Assemble for a little endian target.
252b5132
RH
1629
1630@end table
1631@end ifset
a3c62988 1632@c man end
252b5132 1633
a3c62988
NC
1634@ifset METAG
1635
1636@ifclear man
1637@xref{Meta Options}, for the options available when @value{AS} is configured
1638for a Meta processor.
1639@end ifclear
1640
1641@ifset man
1642@c man begin OPTIONS
1643The following options are available when @value{AS} is configured for a
1644Meta processor.
1645@c man end
1646@c man begin INCLUDE
1647@include c-metag.texi
1648@c ended inside the included file
1649@end ifset
1650
1651@end ifset
1652
1653@c man begin OPTIONS
3c3bdf30
NC
1654@ifset MMIX
1655See the info pages for documentation of the MMIX-specific options.
1656@end ifset
1657
35c08157
KLC
1658@ifset NDS32
1659
1660@ifclear man
1661@xref{NDS32 Options}, for the options available when @value{AS} is configured
1662for a NDS32 processor.
1663@end ifclear
1664@c ended inside the included file
1665@end ifset
1666
1667@ifset man
1668@c man begin OPTIONS
1669The following options are available when @value{AS} is configured for a
1670NDS32 processor.
1671@c man end
1672@c man begin INCLUDE
1673@include c-nds32.texi
1674@c ended inside the included file
1675@end ifset
1676
635fb38d 1677@c man end
b8b738ac
AM
1678@ifset PPC
1679
1680@ifclear man
1681@xref{PowerPC-Opts}, for the options available when @value{AS} is configured
1682for a PowerPC processor.
1683@end ifclear
1684
1685@ifset man
1686@c man begin OPTIONS
1687The following options are available when @value{AS} is configured for a
1688PowerPC processor.
1689@c man end
1690@c man begin INCLUDE
1691@include c-ppc.texi
1692@c ended inside the included file
1693@end ifset
1694
1695@end ifset
1696
e23eba97
NC
1697@ifset RISCV
1698
1699@ifclear man
b57e49f7 1700@xref{RISC-V-Options}, for the options available when @value{AS} is configured
e23eba97
NC
1701for a RISC-V processor.
1702@end ifclear
1703
1704@ifset man
1705@c man begin OPTIONS
1706The following options are available when @value{AS} is configured for a
b57e49f7 1707RISC-V processor.
e23eba97
NC
1708@c man end
1709@c man begin INCLUDE
1710@include c-riscv.texi
1711@c ended inside the included file
1712@end ifset
1713
1714@end ifset
1715
635fb38d 1716@c man begin OPTIONS
046d31c2
NC
1717@ifset RX
1718See the info pages for documentation of the RX-specific options.
1719@end ifset
1720
11c19e16
MS
1721@ifset S390
1722The following options are available when @value{AS} is configured for the s390
1723processor family.
1724
1725@table @gcctabopt
1726@item -m31
1727@itemx -m64
1728Select the word size, either 31/32 bits or 64 bits.
1729@item -mesa
1730@item -mzarch
1731Select the architecture mode, either the Enterprise System
1732Architecture (esa) or the z/Architecture mode (zarch).
1733@item -march=@var{processor}
952c3f51
AK
1734Specify which s390 processor variant is the target, @samp{g5} (or
1735@samp{arch3}), @samp{g6}, @samp{z900} (or @samp{arch5}), @samp{z990} (or
1736@samp{arch6}), @samp{z9-109}, @samp{z9-ec} (or @samp{arch7}), @samp{z10} (or
1737@samp{arch8}), @samp{z196} (or @samp{arch9}), @samp{zEC12} (or @samp{arch10}),
47826cdb 1738@samp{z13} (or @samp{arch11}), or @samp{z14} (or @samp{arch12}).
11c19e16
MS
1739@item -mregnames
1740@itemx -mno-regnames
1741Allow or disallow symbolic names for registers.
1742@item -mwarn-areg-zero
1743Warn whenever the operand for a base or index register has been specified
1744but evaluates to zero.
1745@end table
1746@end ifset
2a633939 1747@c man end
11c19e16 1748
40b36596 1749@ifset TIC6X
2a633939
JM
1750
1751@ifclear man
1752@xref{TIC6X Options}, for the options available when @value{AS} is configured
1753for a TMS320C6000 processor.
1754@end ifclear
1755
1756@ifset man
1757@c man begin OPTIONS
40b36596
JM
1758The following options are available when @value{AS} is configured for a
1759TMS320C6000 processor.
2a633939
JM
1760@c man end
1761@c man begin INCLUDE
1762@include c-tic6x.texi
1763@c ended inside the included file
1764@end ifset
40b36596
JM
1765
1766@end ifset
1767
aa137e4d
NC
1768@ifset TILEGX
1769
1770@ifclear man
1771@xref{TILE-Gx Options}, for the options available when @value{AS} is configured
1772for a TILE-Gx processor.
1773@end ifclear
1774
1775@ifset man
1776@c man begin OPTIONS
1777The following options are available when @value{AS} is configured for a TILE-Gx
1778processor.
1779@c man end
1780@c man begin INCLUDE
1781@include c-tilegx.texi
1782@c ended inside the included file
1783@end ifset
1784
1785@end ifset
1786
b6605ddd
EB
1787@ifset VISIUM
1788
1789@ifclear man
1790@xref{Visium Options}, for the options available when @value{AS} is configured
1791for a Visium processor.
1792@end ifclear
1793
1794@ifset man
1795@c man begin OPTIONS
1796The following option is available when @value{AS} is configured for a Visium
1797processor.
1798@c man end
1799@c man begin INCLUDE
1800@include c-visium.texi
1801@c ended inside the included file
1802@end ifset
1803
1804@end ifset
1805
e0001a05 1806@ifset XTENSA
e0001a05 1807
2d8b84ae
SA
1808@ifclear man
1809@xref{Xtensa Options}, for the options available when @value{AS} is configured
1810for an Xtensa processor.
1811@end ifclear
1812
1813@ifset man
1814@c man begin OPTIONS
1815The following options are available when @value{AS} is configured for an
1816Xtensa processor.
1817@c man end
1818@c man begin INCLUDE
1819@include c-xtensa.texi
1820@c ended inside the included file
e0001a05
NC
1821@end ifset
1822
2d8b84ae
SA
1823@end ifset
1824
1825@c man begin OPTIONS
1826
3c9b82ba
NC
1827@ifset Z80
1828The following options are available when @value{AS} is configured for
1829a Z80 family processor.
1830@table @gcctabopt
1831@item -z80
1832Assemble for Z80 processor.
1833@item -r800
1834Assemble for R800 processor.
01642c12 1835@item -ignore-undocumented-instructions
3c9b82ba
NC
1836@itemx -Wnud
1837Assemble undocumented Z80 instructions that also work on R800 without warning.
01642c12 1838@item -ignore-unportable-instructions
3c9b82ba
NC
1839@itemx -Wnup
1840Assemble all undocumented Z80 instructions without warning.
01642c12 1841@item -warn-undocumented-instructions
3c9b82ba
NC
1842@itemx -Wud
1843Issue a warning for undocumented Z80 instructions that also work on R800.
01642c12 1844@item -warn-unportable-instructions
3c9b82ba 1845@itemx -Wup
01642c12
RM
1846Issue a warning for undocumented Z80 instructions that do not work on R800.
1847@item -forbid-undocumented-instructions
3c9b82ba
NC
1848@itemx -Fud
1849Treat all undocumented instructions as errors.
01642c12 1850@item -forbid-unportable-instructions
3c9b82ba 1851@itemx -Fup
b45619c0 1852Treat undocumented Z80 instructions that do not work on R800 as errors.
3c9b82ba
NC
1853@end table
1854@end ifset
1855
0285c67d
NC
1856@c man end
1857
252b5132
RH
1858@menu
1859* Manual:: Structure of this Manual
1860* GNU Assembler:: The GNU Assembler
1861* Object Formats:: Object File Formats
1862* Command Line:: Command Line
1863* Input Files:: Input Files
1864* Object:: Output (Object) File
1865* Errors:: Error and Warning Messages
1866@end menu
1867
1868@node Manual
1869@section Structure of this Manual
1870
1871@cindex manual, structure and purpose
1872This manual is intended to describe what you need to know to use
a4fb0134 1873@sc{gnu} @command{@value{AS}}. We cover the syntax expected in source files, including
252b5132 1874notation for symbols, constants, and expressions; the directives that
a4fb0134 1875@command{@value{AS}} understands; and of course how to invoke @command{@value{AS}}.
252b5132
RH
1876
1877@ifclear GENERIC
1878We also cover special features in the @value{TARGET}
a4fb0134 1879configuration of @command{@value{AS}}, including assembler directives.
252b5132
RH
1880@end ifclear
1881@ifset GENERIC
1882This manual also describes some of the machine-dependent features of
1883various flavors of the assembler.
1884@end ifset
1885
1886@cindex machine instructions (not covered)
1887On the other hand, this manual is @emph{not} intended as an introduction
1888to programming in assembly language---let alone programming in general!
1889In a similar vein, we make no attempt to introduce the machine
1890architecture; we do @emph{not} describe the instruction set, standard
1891mnemonics, registers or addressing modes that are standard to a
1892particular architecture.
1893@ifset GENERIC
1894You may want to consult the manufacturer's
1895machine architecture manual for this information.
1896@end ifset
1897@ifclear GENERIC
1898@ifset H8/300
1899For information on the H8/300 machine instruction set, see @cite{H8/300
c2dcd04e
NC
1900Series Programming Manual}. For the H8/300H, see @cite{H8/300H Series
1901Programming Manual} (Renesas).
252b5132 1902@end ifset
252b5132 1903@ifset SH
ef230218
JR
1904For information on the Renesas (formerly Hitachi) / SuperH SH machine instruction set,
1905see @cite{SH-Microcomputer User's Manual} (Renesas) or
1906@cite{SH-4 32-bit CPU Core Architecture} (SuperH) and
1907@cite{SuperH (SH) 64-Bit RISC Series} (SuperH).
252b5132
RH
1908@end ifset
1909@ifset Z8000
1910For information on the Z8000 machine instruction set, see @cite{Z8000 CPU Technical Manual}
1911@end ifset
1912@end ifclear
1913
1914@c I think this is premature---doc@cygnus.com, 17jan1991
1915@ignore
1916Throughout this manual, we assume that you are running @dfn{GNU},
1917the portable operating system from the @dfn{Free Software
1918Foundation, Inc.}. This restricts our attention to certain kinds of
1919computer (in particular, the kinds of computers that @sc{gnu} can run on);
1920once this assumption is granted examples and definitions need less
1921qualification.
1922
a4fb0134 1923@command{@value{AS}} is part of a team of programs that turn a high-level
252b5132
RH
1924human-readable series of instructions into a low-level
1925computer-readable series of instructions. Different versions of
a4fb0134 1926@command{@value{AS}} are used for different kinds of computer.
252b5132
RH
1927@end ignore
1928
1929@c There used to be a section "Terminology" here, which defined
1930@c "contents", "byte", "word", and "long". Defining "word" to any
1931@c particular size is confusing when the .word directive may generate 16
1932@c bits on one machine and 32 bits on another; in general, for the user
1933@c version of this manual, none of these terms seem essential to define.
1934@c They were used very little even in the former draft of the manual;
1935@c this draft makes an effort to avoid them (except in names of
1936@c directives).
1937
1938@node GNU Assembler
1939@section The GNU Assembler
1940
0285c67d
NC
1941@c man begin DESCRIPTION
1942
a4fb0134 1943@sc{gnu} @command{as} is really a family of assemblers.
252b5132 1944@ifclear GENERIC
a4fb0134 1945This manual describes @command{@value{AS}}, a member of that family which is
252b5132
RH
1946configured for the @value{TARGET} architectures.
1947@end ifclear
1948If you use (or have used) the @sc{gnu} assembler on one architecture, you
1949should find a fairly similar environment when you use it on another
1950architecture. Each version has much in common with the others,
1951including object file formats, most assembler directives (often called
1952@dfn{pseudo-ops}) and assembler syntax.@refill
1953
1954@cindex purpose of @sc{gnu} assembler
a4fb0134 1955@command{@value{AS}} is primarily intended to assemble the output of the
252b5132 1956@sc{gnu} C compiler @code{@value{GCC}} for use by the linker
a4fb0134 1957@code{@value{LD}}. Nevertheless, we've tried to make @command{@value{AS}}
252b5132
RH
1958assemble correctly everything that other assemblers for the same
1959machine would assemble.
1960@ifset VAX
1961Any exceptions are documented explicitly (@pxref{Machine Dependencies}).
1962@end ifset
1963@ifset M680X0
1964@c This remark should appear in generic version of manual; assumption
1965@c here is that generic version sets M680x0.
a4fb0134 1966This doesn't mean @command{@value{AS}} always uses the same syntax as another
252b5132
RH
1967assembler for the same architecture; for example, we know of several
1968incompatible versions of 680x0 assembly language syntax.
1969@end ifset
1970
0285c67d
NC
1971@c man end
1972
a4fb0134 1973Unlike older assemblers, @command{@value{AS}} is designed to assemble a source
252b5132
RH
1974program in one pass of the source file. This has a subtle impact on the
1975@kbd{.org} directive (@pxref{Org,,@code{.org}}).
1976
1977@node Object Formats
1978@section Object File Formats
1979
1980@cindex object file format
1981The @sc{gnu} assembler can be configured to produce several alternative
1982object file formats. For the most part, this does not affect how you
1983write assembly language programs; but directives for debugging symbols
1984are typically different in different file formats. @xref{Symbol
1985Attributes,,Symbol Attributes}.
1986@ifclear GENERIC
1987@ifclear MULTI-OBJ
c1253627 1988For the @value{TARGET} target, @command{@value{AS}} is configured to produce
252b5132
RH
1989@value{OBJ-NAME} format object files.
1990@end ifclear
1991@c The following should exhaust all configs that set MULTI-OBJ, ideally
252b5132 1992@ifset HPPA
a4fb0134 1993On the @value{TARGET}, @command{@value{AS}} can be configured to produce either
252b5132
RH
1994SOM or ELF format object files.
1995@end ifset
1996@end ifclear
1997
1998@node Command Line
1999@section Command Line
2000
2001@cindex command line conventions
0285c67d 2002
a4fb0134 2003After the program name @command{@value{AS}}, the command line may contain
252b5132
RH
2004options and file names. Options may appear in any order, and may be
2005before, after, or between file names. The order of file names is
2006significant.
2007
2008@cindex standard input, as input file
2009@kindex --
2010@file{--} (two hyphens) by itself names the standard input file
a4fb0134 2011explicitly, as one of the files for @command{@value{AS}} to assemble.
252b5132
RH
2012
2013@cindex options, command line
2014Except for @samp{--} any command line argument that begins with a
2015hyphen (@samp{-}) is an option. Each option changes the behavior of
a4fb0134 2016@command{@value{AS}}. No option changes the way another option works. An
252b5132
RH
2017option is a @samp{-} followed by one or more letters; the case of
2018the letter is important. All options are optional.
2019
2020Some options expect exactly one file name to follow them. The file
2021name may either immediately follow the option's letter (compatible
2022with older assemblers) or it may be the next command argument (@sc{gnu}
2023standard). These two command lines are equivalent:
2024
2025@smallexample
2026@value{AS} -o my-object-file.o mumble.s
2027@value{AS} -omy-object-file.o mumble.s
2028@end smallexample
2029
2030@node Input Files
2031@section Input Files
2032
2033@cindex input
2034@cindex source program
2035@cindex files, input
2036We use the phrase @dfn{source program}, abbreviated @dfn{source}, to
a4fb0134 2037describe the program input to one run of @command{@value{AS}}. The program may
252b5132
RH
2038be in one or more files; how the source is partitioned into files
2039doesn't change the meaning of the source.
2040
2041@c I added "con" prefix to "catenation" just to prove I can overcome my
2042@c APL training... doc@cygnus.com
2043The source program is a concatenation of the text in all the files, in the
2044order specified.
2045
0285c67d 2046@c man begin DESCRIPTION
a4fb0134 2047Each time you run @command{@value{AS}} it assembles exactly one source
252b5132
RH
2048program. The source program is made up of one or more files.
2049(The standard input is also a file.)
2050
a4fb0134 2051You give @command{@value{AS}} a command line that has zero or more input file
252b5132
RH
2052names. The input files are read (from left file name to right). A
2053command line argument (in any position) that has no special meaning
2054is taken to be an input file name.
2055
a4fb0134
SC
2056If you give @command{@value{AS}} no file names it attempts to read one input file
2057from the @command{@value{AS}} standard input, which is normally your terminal. You
2058may have to type @key{ctl-D} to tell @command{@value{AS}} there is no more program
252b5132
RH
2059to assemble.
2060
2061Use @samp{--} if you need to explicitly name the standard input file
2062in your command line.
2063
a4fb0134 2064If the source is empty, @command{@value{AS}} produces a small, empty object
252b5132
RH
2065file.
2066
0285c67d
NC
2067@c man end
2068
252b5132
RH
2069@subheading Filenames and Line-numbers
2070
2071@cindex input file linenumbers
2072@cindex line numbers, in input files
2073There are two ways of locating a line in the input file (or files) and
2074either may be used in reporting error messages. One way refers to a line
2075number in a physical file; the other refers to a line number in a
2076``logical'' file. @xref{Errors, ,Error and Warning Messages}.
2077
2078@dfn{Physical files} are those files named in the command line given
a4fb0134 2079to @command{@value{AS}}.
252b5132
RH
2080
2081@dfn{Logical files} are simply names declared explicitly by assembler
2082directives; they bear no relation to physical files. Logical file names help
a4fb0134
SC
2083error messages reflect the original source file, when @command{@value{AS}} source
2084is itself synthesized from other files. @command{@value{AS}} understands the
252b5132
RH
2085@samp{#} directives emitted by the @code{@value{GCC}} preprocessor. See also
2086@ref{File,,@code{.file}}.
2087
2088@node Object
2089@section Output (Object) File
2090
2091@cindex object file
2092@cindex output file
2093@kindex a.out
2094@kindex .o
a4fb0134 2095Every time you run @command{@value{AS}} it produces an output file, which is
252b5132 2096your assembly language program translated into numbers. This file
a8eb42a8 2097is the object file. Its default name is @code{a.out}.
a4fb0134 2098You can give it another name by using the @option{-o} option. Conventionally,
252b5132
RH
2099object file names end with @file{.o}. The default name is used for historical
2100reasons: older assemblers were capable of assembling self-contained programs
2101directly into a runnable program. (For some formats, this isn't currently
2102possible, but it can be done for the @code{a.out} format.)
2103
2104@cindex linker
2105@kindex ld
2106The object file is meant for input to the linker @code{@value{LD}}. It contains
2107assembled program code, information to help @code{@value{LD}} integrate
2108the assembled program into a runnable file, and (optionally) symbolic
2109information for the debugger.
2110
2111@c link above to some info file(s) like the description of a.out.
2112@c don't forget to describe @sc{gnu} info as well as Unix lossage.
2113
2114@node Errors
2115@section Error and Warning Messages
2116
0285c67d
NC
2117@c man begin DESCRIPTION
2118
a349d9dd 2119@cindex error messages
252b5132
RH
2120@cindex warning messages
2121@cindex messages from assembler
a4fb0134 2122@command{@value{AS}} may write warnings and error messages to the standard error
252b5132 2123file (usually your terminal). This should not happen when a compiler
a4fb0134
SC
2124runs @command{@value{AS}} automatically. Warnings report an assumption made so
2125that @command{@value{AS}} could keep assembling a flawed program; errors report a
252b5132
RH
2126grave problem that stops the assembly.
2127
0285c67d
NC
2128@c man end
2129
252b5132
RH
2130@cindex format of warning messages
2131Warning messages have the format
2132
2133@smallexample
2134file_name:@b{NNN}:Warning Message Text
2135@end smallexample
2136
2137@noindent
72e0b254
NC
2138@cindex file names and line numbers, in warnings/errors
2139(where @b{NNN} is a line number). If both a logical file name
2140(@pxref{File,,@code{.file}}) and a logical line number
252b5132
RH
2141@ifset GENERIC
2142(@pxref{Line,,@code{.line}})
2143@end ifset
72e0b254
NC
2144have been given then they will be used, otherwise the file name and line number
2145in the current assembler source file will be used. The message text is
2146intended to be self explanatory (in the grand Unix tradition).
2147
2148Note the file name must be set via the logical version of the @code{.file}
2149directive, not the DWARF2 version of the @code{.file} directive. For example:
2150
2151@smallexample
2152 .file 2 "bar.c"
2153 error_assembler_source
2154 .file "foo.c"
2155 .line 30
2156 error_c_source
2157@end smallexample
2158
2159produces this output:
2160
2161@smallexample
2162 Assembler messages:
2163 asm.s:2: Error: no such instruction: `error_assembler_source'
2164 foo.c:31: Error: no such instruction: `error_c_source'
2165@end smallexample
252b5132
RH
2166
2167@cindex format of error messages
2168Error messages have the format
72e0b254 2169
252b5132
RH
2170@smallexample
2171file_name:@b{NNN}:FATAL:Error Message Text
2172@end smallexample
72e0b254 2173
252b5132
RH
2174The file name and line number are derived as for warning
2175messages. The actual message text may be rather less explanatory
2176because many of them aren't supposed to happen.
2177
2178@node Invoking
2179@chapter Command-Line Options
2180
2181@cindex options, all versions of assembler
2182This chapter describes command-line options available in @emph{all}
96e9638b
BW
2183versions of the @sc{gnu} assembler; see @ref{Machine Dependencies},
2184for options specific
252b5132 2185@ifclear GENERIC
c1253627 2186to the @value{TARGET} target.
252b5132
RH
2187@end ifclear
2188@ifset GENERIC
2189to particular machine architectures.
2190@end ifset
2191
0285c67d
NC
2192@c man begin DESCRIPTION
2193
c1253627 2194If you are invoking @command{@value{AS}} via the @sc{gnu} C compiler,
252b5132
RH
2195you can use the @samp{-Wa} option to pass arguments through to the assembler.
2196The assembler arguments must be separated from each other (and the @samp{-Wa})
2197by commas. For example:
2198
2199@smallexample
2200gcc -c -g -O -Wa,-alh,-L file.c
2201@end smallexample
2202
2203@noindent
2204This passes two options to the assembler: @samp{-alh} (emit a listing to
5f5e16be 2205standard output with high-level and assembly source) and @samp{-L} (retain
252b5132
RH
2206local symbols in the symbol table).
2207
2208Usually you do not need to use this @samp{-Wa} mechanism, since many compiler
2209command-line options are automatically passed to the assembler by the compiler.
2210(You can call the @sc{gnu} compiler driver with the @samp{-v} option to see
2211precisely what options it passes to each compilation pass, including the
2212assembler.)
2213
0285c67d
NC
2214@c man end
2215
252b5132 2216@menu
83f10cb2 2217* a:: -a[cdghlns] enable listings
caa32fe5 2218* alternate:: --alternate enable alternate macro syntax
252b5132
RH
2219* D:: -D for compatibility
2220* f:: -f to work faster
2221* I:: -I for .include search path
2222@ifclear DIFF-TBL-KLUGE
2223* K:: -K for compatibility
2224@end ifclear
2225@ifset DIFF-TBL-KLUGE
2226* K:: -K for difference tables
2227@end ifset
2228
ba83aca1 2229* L:: -L to retain local symbols
c3a27914 2230* listing:: --listing-XXX to configure listing output
252b5132
RH
2231* M:: -M or --mri to assemble in MRI compatibility mode
2232* MD:: --MD for dependency tracking
2edb36e7 2233* no-pad-sections:: --no-pad-sections to stop section padding
252b5132
RH
2234* o:: -o to name the object file
2235* R:: -R to join data and text sections
2236* statistics:: --statistics to see statistics about assembly
2237* traditional-format:: --traditional-format for compatible output
2238* v:: -v to announce version
2bdd6cf5 2239* W:: -W, --no-warn, --warn, --fatal-warnings to control warnings
252b5132
RH
2240* Z:: -Z to make object file even after errors
2241@end menu
2242
2243@node a
83f10cb2 2244@section Enable Listings: @option{-a[cdghlns]}
252b5132
RH
2245
2246@kindex -a
2247@kindex -ac
2248@kindex -ad
83f10cb2 2249@kindex -ag
252b5132
RH
2250@kindex -ah
2251@kindex -al
2252@kindex -an
2253@kindex -as
2254@cindex listings, enabling
2255@cindex assembly listings, enabling
2256
2257These options enable listing output from the assembler. By itself,
2258@samp{-a} requests high-level, assembly, and symbols listing.
2259You can use other letters to select specific options for the list:
2260@samp{-ah} requests a high-level language listing,
2261@samp{-al} requests an output-program assembly listing, and
2262@samp{-as} requests a symbol table listing.
2263High-level listings require that a compiler debugging option like
2264@samp{-g} be used, and that assembly listings (@samp{-al}) be requested
2265also.
2266
83f10cb2
NC
2267Use the @samp{-ag} option to print a first section with general assembly
2268information, like @value{AS} version, switches passed, or time stamp.
2269
252b5132
RH
2270Use the @samp{-ac} option to omit false conditionals from a listing. Any lines
2271which are not assembled because of a false @code{.if} (or @code{.ifdef}, or any
2272other conditional), or a true @code{.if} followed by an @code{.else}, will be
2273omitted from the listing.
2274
2275Use the @samp{-ad} option to omit debugging directives from the
2276listing.
2277
2278Once you have specified one of these options, you can further control
2279listing output and its appearance using the directives @code{.list},
2280@code{.nolist}, @code{.psize}, @code{.eject}, @code{.title}, and
2281@code{.sbttl}.
2282The @samp{-an} option turns off all forms processing.
2283If you do not request listing output with one of the @samp{-a} options, the
2284listing-control directives have no effect.
2285
2286The letters after @samp{-a} may be combined into one option,
2287@emph{e.g.}, @samp{-aln}.
2288
96e9638b
BW
2289Note if the assembler source is coming from the standard input (e.g.,
2290because it
c3a27914
NC
2291is being created by @code{@value{GCC}} and the @samp{-pipe} command line switch
2292is being used) then the listing will not contain any comments or preprocessor
2293directives. This is because the listing code buffers input source lines from
2294stdin only after they have been preprocessed by the assembler. This reduces
2295memory usage and makes the code more efficient.
2296
caa32fe5
NC
2297@node alternate
2298@section @option{--alternate}
2299
2300@kindex --alternate
2301Begin in alternate macro mode, see @ref{Altmacro,,@code{.altmacro}}.
2302
252b5132 2303@node D
a4fb0134 2304@section @option{-D}
252b5132
RH
2305
2306@kindex -D
2307This option has no effect whatsoever, but it is accepted to make it more
2308likely that scripts written for other assemblers also work with
a4fb0134 2309@command{@value{AS}}.
252b5132
RH
2310
2311@node f
a4fb0134 2312@section Work Faster: @option{-f}
252b5132
RH
2313
2314@kindex -f
2315@cindex trusted compiler
a4fb0134 2316@cindex faster processing (@option{-f})
252b5132
RH
2317@samp{-f} should only be used when assembling programs written by a
2318(trusted) compiler. @samp{-f} stops the assembler from doing whitespace
2319and comment preprocessing on
2320the input file(s) before assembling them. @xref{Preprocessing,
2321,Preprocessing}.
2322
2323@quotation
2324@emph{Warning:} if you use @samp{-f} when the files actually need to be
a4fb0134 2325preprocessed (if they contain comments, for example), @command{@value{AS}} does
252b5132
RH
2326not work correctly.
2327@end quotation
2328
2329@node I
c1253627 2330@section @code{.include} Search Path: @option{-I} @var{path}
252b5132
RH
2331
2332@kindex -I @var{path}
2333@cindex paths for @code{.include}
2334@cindex search path for @code{.include}
2335@cindex @code{include} directive search path
2336Use this option to add a @var{path} to the list of directories
a4fb0134
SC
2337@command{@value{AS}} searches for files specified in @code{.include}
2338directives (@pxref{Include,,@code{.include}}). You may use @option{-I} as
252b5132 2339many times as necessary to include a variety of paths. The current
a4fb0134 2340working directory is always searched first; after that, @command{@value{AS}}
252b5132
RH
2341searches any @samp{-I} directories in the same order as they were
2342specified (left to right) on the command line.
2343
2344@node K
a4fb0134 2345@section Difference Tables: @option{-K}
252b5132
RH
2346
2347@kindex -K
2348@ifclear DIFF-TBL-KLUGE
2349On the @value{TARGET} family, this option is allowed, but has no effect. It is
2350permitted for compatibility with the @sc{gnu} assembler on other platforms,
2351where it can be used to warn when the assembler alters the machine code
2352generated for @samp{.word} directives in difference tables. The @value{TARGET}
2353family does not have the addressing limitations that sometimes lead to this
2354alteration on other platforms.
2355@end ifclear
2356
2357@ifset DIFF-TBL-KLUGE
2358@cindex difference tables, warning
2359@cindex warning for altered difference tables
96e9638b
BW
2360@command{@value{AS}} sometimes alters the code emitted for directives of the
2361form @samp{.word @var{sym1}-@var{sym2}}. @xref{Word,,@code{.word}}.
252b5132
RH
2362You can use the @samp{-K} option if you want a warning issued when this
2363is done.
2364@end ifset
2365
2366@node L
ba83aca1 2367@section Include Local Symbols: @option{-L}
252b5132
RH
2368
2369@kindex -L
ba83aca1
BW
2370@cindex local symbols, retaining in output
2371Symbols beginning with system-specific local label prefixes, typically
2372@samp{.L} for ELF systems or @samp{L} for traditional a.out systems, are
2373called @dfn{local symbols}. @xref{Symbol Names}. Normally you do not see
2374such symbols when debugging, because they are intended for the use of
2375programs (like compilers) that compose assembler programs, not for your
2376notice. Normally both @command{@value{AS}} and @code{@value{LD}} discard
2377such symbols, so you do not normally debug with them.
2378
2379This option tells @command{@value{AS}} to retain those local symbols
252b5132 2380in the object file. Usually if you do this you also tell the linker
ba83aca1 2381@code{@value{LD}} to preserve those symbols.
252b5132 2382
c3a27914 2383@node listing
a4fb0134 2384@section Configuring listing output: @option{--listing}
c3a27914
NC
2385
2386The listing feature of the assembler can be enabled via the command line switch
2387@samp{-a} (@pxref{a}). This feature combines the input source file(s) with a
2388hex dump of the corresponding locations in the output object file, and displays
96e9638b
BW
2389them as a listing file. The format of this listing can be controlled by
2390directives inside the assembler source (i.e., @code{.list} (@pxref{List}),
2391@code{.title} (@pxref{Title}), @code{.sbttl} (@pxref{Sbttl}),
2392@code{.psize} (@pxref{Psize}), and
2393@code{.eject} (@pxref{Eject}) and also by the following switches:
c3a27914 2394
a4fb0134 2395@table @gcctabopt
c3a27914
NC
2396@item --listing-lhs-width=@samp{number}
2397@kindex --listing-lhs-width
2398@cindex Width of first line disassembly output
2399Sets the maximum width, in words, of the first line of the hex byte dump. This
2400dump appears on the left hand side of the listing output.
2401
2402@item --listing-lhs-width2=@samp{number}
2403@kindex --listing-lhs-width2
2404@cindex Width of continuation lines of disassembly output
2405Sets the maximum width, in words, of any further lines of the hex byte dump for
8dfa0188 2406a given input source line. If this value is not specified, it defaults to being
c3a27914
NC
2407the same as the value specified for @samp{--listing-lhs-width}. If neither
2408switch is used the default is to one.
2409
2410@item --listing-rhs-width=@samp{number}
2411@kindex --listing-rhs-width
2412@cindex Width of source line output
2413Sets the maximum width, in characters, of the source line that is displayed
2414alongside the hex dump. The default value for this parameter is 100. The
2415source line is displayed on the right hand side of the listing output.
2416
2417@item --listing-cont-lines=@samp{number}
2418@kindex --listing-cont-lines
2419@cindex Maximum number of continuation lines
2420Sets the maximum number of continuation lines of hex dump that will be
2421displayed for a given single line of source input. The default value is 4.
2422@end table
2423
252b5132 2424@node M
a4fb0134 2425@section Assemble in MRI Compatibility Mode: @option{-M}
252b5132
RH
2426
2427@kindex -M
2428@cindex MRI compatibility mode
a4fb0134
SC
2429The @option{-M} or @option{--mri} option selects MRI compatibility mode. This
2430changes the syntax and pseudo-op handling of @command{@value{AS}} to make it
a8eb42a8
AM
2431compatible with the @code{ASM68K} assembler from Microtec Research.
2432The exact nature of the
252b5132
RH
2433MRI syntax will not be documented here; see the MRI manuals for more
2434information. Note in particular that the handling of macros and macro
2435arguments is somewhat different. The purpose of this option is to permit
a4fb0134 2436assembling existing MRI assembler code using @command{@value{AS}}.
252b5132
RH
2437
2438The MRI compatibility is not complete. Certain operations of the MRI assembler
2439depend upon its object file format, and can not be supported using other object
2440file formats. Supporting these would require enhancing each object file format
2441individually. These are:
2442
2443@itemize @bullet
2444@item global symbols in common section
2445
2446The m68k MRI assembler supports common sections which are merged by the linker.
a4fb0134 2447Other object file formats do not support this. @command{@value{AS}} handles
252b5132
RH
2448common sections by treating them as a single common symbol. It permits local
2449symbols to be defined within a common section, but it can not support global
2450symbols, since it has no way to describe them.
2451
2452@item complex relocations
2453
2454The MRI assemblers support relocations against a negated section address, and
2455relocations which combine the start addresses of two or more sections. These
2456are not support by other object file formats.
2457
2458@item @code{END} pseudo-op specifying start address
2459
2460The MRI @code{END} pseudo-op permits the specification of a start address.
2461This is not supported by other object file formats. The start address may
a4fb0134 2462instead be specified using the @option{-e} option to the linker, or in a linker
252b5132
RH
2463script.
2464
2465@item @code{IDNT}, @code{.ident} and @code{NAME} pseudo-ops
2466
2467The MRI @code{IDNT}, @code{.ident} and @code{NAME} pseudo-ops assign a module
2468name to the output file. This is not supported by other object file formats.
2469
2470@item @code{ORG} pseudo-op
2471
2472The m68k MRI @code{ORG} pseudo-op begins an absolute section at a given
a4fb0134 2473address. This differs from the usual @command{@value{AS}} @code{.org} pseudo-op,
252b5132
RH
2474which changes the location within the current section. Absolute sections are
2475not supported by other object file formats. The address of a section may be
2476assigned within a linker script.
2477@end itemize
2478
2479There are some other features of the MRI assembler which are not supported by
a4fb0134 2480@command{@value{AS}}, typically either because they are difficult or because they
252b5132
RH
2481seem of little consequence. Some of these may be supported in future releases.
2482
2483@itemize @bullet
2484
2485@item EBCDIC strings
2486
2487EBCDIC strings are not supported.
2488
2489@item packed binary coded decimal
2490
2491Packed binary coded decimal is not supported. This means that the @code{DC.P}
2492and @code{DCB.P} pseudo-ops are not supported.
2493
2494@item @code{FEQU} pseudo-op
2495
2496The m68k @code{FEQU} pseudo-op is not supported.
2497
2498@item @code{NOOBJ} pseudo-op
2499
2500The m68k @code{NOOBJ} pseudo-op is not supported.
2501
2502@item @code{OPT} branch control options
2503
2504The m68k @code{OPT} branch control options---@code{B}, @code{BRS}, @code{BRB},
a4fb0134 2505@code{BRL}, and @code{BRW}---are ignored. @command{@value{AS}} automatically
252b5132
RH
2506relaxes all branches, whether forward or backward, to an appropriate size, so
2507these options serve no purpose.
2508
2509@item @code{OPT} list control options
2510
2511The following m68k @code{OPT} list control options are ignored: @code{C},
2512@code{CEX}, @code{CL}, @code{CRE}, @code{E}, @code{G}, @code{I}, @code{M},
2513@code{MEX}, @code{MC}, @code{MD}, @code{X}.
2514
2515@item other @code{OPT} options
2516
2517The following m68k @code{OPT} options are ignored: @code{NEST}, @code{O},
2518@code{OLD}, @code{OP}, @code{P}, @code{PCO}, @code{PCR}, @code{PCS}, @code{R}.
2519
2520@item @code{OPT} @code{D} option is default
2521
2522The m68k @code{OPT} @code{D} option is the default, unlike the MRI assembler.
2523@code{OPT NOD} may be used to turn it off.
2524
2525@item @code{XREF} pseudo-op.
2526
2527The m68k @code{XREF} pseudo-op is ignored.
2528
252b5132
RH
2529@end itemize
2530
2531@node MD
c1253627 2532@section Dependency Tracking: @option{--MD}
252b5132
RH
2533
2534@kindex --MD
2535@cindex dependency tracking
2536@cindex make rules
2537
a4fb0134 2538@command{@value{AS}} can generate a dependency file for the file it creates. This
252b5132
RH
2539file consists of a single rule suitable for @code{make} describing the
2540dependencies of the main source file.
2541
2542The rule is written to the file named in its argument.
2543
2544This feature is used in the automatic updating of makefiles.
2545
2edb36e7
NC
2546@node no-pad-sections
2547@section Output Section Padding
2548@kindex --no-pad-sections
2549@cindex output section padding
2550Normally the assembler will pad the end of each output section up to its
2551alignment boundary. But this can waste space, which can be significant on
2552memory constrained targets. So the @option{--no-pad-sections} option will
2553disable this behaviour.
2554
252b5132 2555@node o
a4fb0134 2556@section Name the Object File: @option{-o}
252b5132
RH
2557
2558@kindex -o
2559@cindex naming object file
2560@cindex object file name
a4fb0134 2561There is always one object file output when you run @command{@value{AS}}. By
a8eb42a8 2562default it has the name @file{a.out}.
252b5132
RH
2563You use this option (which takes exactly one filename) to give the
2564object file a different name.
2565
a4fb0134 2566Whatever the object file is called, @command{@value{AS}} overwrites any
252b5132
RH
2567existing file of the same name.
2568
2569@node R
a4fb0134 2570@section Join Data and Text Sections: @option{-R}
252b5132
RH
2571
2572@kindex -R
2573@cindex data and text sections, joining
2574@cindex text and data sections, joining
2575@cindex joining text and data sections
2576@cindex merging text and data sections
a4fb0134 2577@option{-R} tells @command{@value{AS}} to write the object file as if all
252b5132
RH
2578data-section data lives in the text section. This is only done at
2579the very last moment: your binary data are the same, but data
2580section parts are relocated differently. The data section part of
2581your object file is zero bytes long because all its bytes are
2582appended to the text section. (@xref{Sections,,Sections and Relocation}.)
2583
a4fb0134 2584When you specify @option{-R} it would be possible to generate shorter
252b5132
RH
2585address displacements (because we do not have to cross between text and
2586data section). We refrain from doing this simply for compatibility with
a4fb0134 2587older versions of @command{@value{AS}}. In future, @option{-R} may work this way.
252b5132 2588
c1253627
NC
2589@ifset COFF-ELF
2590When @command{@value{AS}} is configured for COFF or ELF output,
252b5132
RH
2591this option is only useful if you use sections named @samp{.text} and
2592@samp{.data}.
2593@end ifset
2594
2595@ifset HPPA
a4fb0134
SC
2596@option{-R} is not supported for any of the HPPA targets. Using
2597@option{-R} generates a warning from @command{@value{AS}}.
252b5132
RH
2598@end ifset
2599
2600@node statistics
a4fb0134 2601@section Display Assembly Statistics: @option{--statistics}
252b5132
RH
2602
2603@kindex --statistics
2604@cindex statistics, about assembly
2605@cindex time, total for assembly
2606@cindex space used, maximum for assembly
2607Use @samp{--statistics} to display two statistics about the resources used by
a4fb0134 2608@command{@value{AS}}: the maximum amount of space allocated during the assembly
252b5132
RH
2609(in bytes), and the total execution time taken for the assembly (in @sc{cpu}
2610seconds).
2611
2612@node traditional-format
c1253627 2613@section Compatible Output: @option{--traditional-format}
252b5132
RH
2614
2615@kindex --traditional-format
a4fb0134 2616For some targets, the output of @command{@value{AS}} is different in some ways
252b5132 2617from the output of some existing assembler. This switch requests
a4fb0134 2618@command{@value{AS}} to use the traditional format instead.
252b5132
RH
2619
2620For example, it disables the exception frame optimizations which
a4fb0134 2621@command{@value{AS}} normally does by default on @code{@value{GCC}} output.
252b5132
RH
2622
2623@node v
a4fb0134 2624@section Announce Version: @option{-v}
252b5132
RH
2625
2626@kindex -v
2627@kindex -version
2628@cindex assembler version
2629@cindex version of assembler
2630You can find out what version of as is running by including the
2631option @samp{-v} (which you can also spell as @samp{-version}) on the
2632command line.
2633
2634@node W
a4fb0134 2635@section Control Warnings: @option{-W}, @option{--warn}, @option{--no-warn}, @option{--fatal-warnings}
252b5132 2636
a4fb0134 2637@command{@value{AS}} should never give a warning or error message when
252b5132 2638assembling compiler output. But programs written by people often
a4fb0134 2639cause @command{@value{AS}} to give a warning that a particular assumption was
252b5132 2640made. All such warnings are directed to the standard error file.
2bdd6cf5 2641
c1253627
NC
2642@kindex -W
2643@kindex --no-warn
2bdd6cf5
GK
2644@cindex suppressing warnings
2645@cindex warnings, suppressing
a4fb0134 2646If you use the @option{-W} and @option{--no-warn} options, no warnings are issued.
2bdd6cf5 2647This only affects the warning messages: it does not change any particular of
a4fb0134 2648how @command{@value{AS}} assembles your file. Errors, which stop the assembly,
2bdd6cf5
GK
2649are still reported.
2650
c1253627 2651@kindex --fatal-warnings
2bdd6cf5
GK
2652@cindex errors, caused by warnings
2653@cindex warnings, causing error
a4fb0134 2654If you use the @option{--fatal-warnings} option, @command{@value{AS}} considers
2bdd6cf5
GK
2655files that generate warnings to be in error.
2656
c1253627 2657@kindex --warn
2bdd6cf5 2658@cindex warnings, switching on
a4fb0134 2659You can switch these options off again by specifying @option{--warn}, which
2bdd6cf5 2660causes warnings to be output as usual.
252b5132
RH
2661
2662@node Z
a4fb0134 2663@section Generate Object File in Spite of Errors: @option{-Z}
252b5132
RH
2664@cindex object file, after errors
2665@cindex errors, continuing after
a4fb0134 2666After an error message, @command{@value{AS}} normally produces no output. If for
252b5132 2667some reason you are interested in object file output even after
a4fb0134
SC
2668@command{@value{AS}} gives an error message on your program, use the @samp{-Z}
2669option. If there are any errors, @command{@value{AS}} continues anyways, and
252b5132
RH
2670writes an object file after a final warning message of the form @samp{@var{n}
2671errors, @var{m} warnings, generating bad object file.}
2672
2673@node Syntax
2674@chapter Syntax
2675
2676@cindex machine-independent syntax
2677@cindex syntax, machine-independent
2678This chapter describes the machine-independent syntax allowed in a
a4fb0134 2679source file. @command{@value{AS}} syntax is similar to what many other
252b5132
RH
2680assemblers use; it is inspired by the BSD 4.2
2681@ifclear VAX
2682assembler.
2683@end ifclear
2684@ifset VAX
a4fb0134 2685assembler, except that @command{@value{AS}} does not assemble Vax bit-fields.
252b5132
RH
2686@end ifset
2687
2688@menu
7c31ae13 2689* Preprocessing:: Preprocessing
252b5132
RH
2690* Whitespace:: Whitespace
2691* Comments:: Comments
2692* Symbol Intro:: Symbols
2693* Statements:: Statements
2694* Constants:: Constants
2695@end menu
2696
2697@node Preprocessing
2698@section Preprocessing
2699
2700@cindex preprocessing
a4fb0134 2701The @command{@value{AS}} internal preprocessor:
252b5132
RH
2702@itemize @bullet
2703@cindex whitespace, removed by preprocessor
2704@item
2705adjusts and removes extra whitespace. It leaves one space or tab before
2706the keywords on a line, and turns any other whitespace on the line into
2707a single space.
2708
2709@cindex comments, removed by preprocessor
2710@item
2711removes all comments, replacing them with a single space, or an
2712appropriate number of newlines.
2713
2714@cindex constants, converted by preprocessor
2715@item
2716converts character constants into the appropriate numeric values.
2717@end itemize
2718
2719It does not do macro processing, include file handling, or
2720anything else you may get from your C compiler's preprocessor. You can
2721do include file processing with the @code{.include} directive
2722(@pxref{Include,,@code{.include}}). You can use the @sc{gnu} C compiler driver
c1253627 2723to get other ``CPP'' style preprocessing by giving the input file a
96e9638b 2724@samp{.S} suffix. @xref{Overall Options, ,Options Controlling the Kind of
2edb36e7 2725Output, gcc info, Using GNU CC}.
252b5132
RH
2726
2727Excess whitespace, comments, and character constants
2728cannot be used in the portions of the input text that are not
2729preprocessed.
2730
2731@cindex turning preprocessing on and off
2732@cindex preprocessing, turning on and off
2733@kindex #NO_APP
2734@kindex #APP
2735If the first line of an input file is @code{#NO_APP} or if you use the
2736@samp{-f} option, whitespace and comments are not removed from the input file.
2737Within an input file, you can ask for whitespace and comment removal in
2738specific portions of the by putting a line that says @code{#APP} before the
2739text that may contain whitespace or comments, and putting a line that says
2740@code{#NO_APP} after this text. This feature is mainly intend to support
2741@code{asm} statements in compilers whose output is otherwise free of comments
2742and whitespace.
2743
2744@node Whitespace
2745@section Whitespace
2746
2747@cindex whitespace
2748@dfn{Whitespace} is one or more blanks or tabs, in any order.
2749Whitespace is used to separate symbols, and to make programs neater for
2750people to read. Unless within character constants
2751(@pxref{Characters,,Character Constants}), any whitespace means the same
2752as exactly one space.
2753
2754@node Comments
2755@section Comments
2756
2757@cindex comments
a4fb0134 2758There are two ways of rendering comments to @command{@value{AS}}. In both
252b5132
RH
2759cases the comment is equivalent to one space.
2760
2761Anything from @samp{/*} through the next @samp{*/} is a comment.
2762This means you may not nest these comments.
2763
2764@smallexample
2765/*
2766 The only way to include a newline ('\n') in a comment
2767 is to use this sort of comment.
2768*/
2769
2770/* This sort of comment does not nest. */
2771@end smallexample
2772
2773@cindex line comment character
7c31ae13
NC
2774Anything from a @dfn{line comment} character up to the next newline is
2775considered a comment and is ignored. The line comment character is target
2776specific, and some targets multiple comment characters. Some targets also have
2777line comment characters that only work if they are the first character on a
2778line. Some targets use a sequence of two characters to introduce a line
2779comment. Some targets can also change their line comment characters depending
2780upon command line options that have been used. For more details see the
2781@emph{Syntax} section in the documentation for individual targets.
2782
2783If the line comment character is the hash sign (@samp{#}) then it still has the
2784special ability to enable and disable preprocessing (@pxref{Preprocessing}) and
2785to specify logical line numbers:
252b5132
RH
2786
2787@kindex #
2788@cindex lines starting with @code{#}
2789@cindex logical line numbers
2790To be compatible with past assemblers, lines that begin with @samp{#} have a
2791special interpretation. Following the @samp{#} should be an absolute
2792expression (@pxref{Expressions}): the logical line number of the @emph{next}
96e9638b 2793line. Then a string (@pxref{Strings, ,Strings}) is allowed: if present it is a
252b5132
RH
2794new logical file name. The rest of the line, if any, should be whitespace.
2795
2796If the first non-whitespace characters on the line are not numeric,
2797the line is ignored. (Just like a comment.)
2798
2799@smallexample
2800 # This is an ordinary comment.
2801# 42-6 "new_file_name" # New logical file name
2802 # This is logical line # 36.
2803@end smallexample
2804This feature is deprecated, and may disappear from future versions
a4fb0134 2805of @command{@value{AS}}.
252b5132
RH
2806
2807@node Symbol Intro
2808@section Symbols
2809
2810@cindex characters used in symbols
2811@ifclear SPECIAL-SYMS
2812A @dfn{symbol} is one or more characters chosen from the set of all
2813letters (both upper and lower case), digits and the three characters
2814@samp{_.$}.
2815@end ifclear
2816@ifset SPECIAL-SYMS
2817@ifclear GENERIC
2818@ifset H8
2819A @dfn{symbol} is one or more characters chosen from the set of all
2820letters (both upper and lower case), digits and the three characters
2821@samp{._$}. (Save that, on the H8/300 only, you may not use @samp{$} in
2822symbol names.)
2823@end ifset
2824@end ifclear
2825@end ifset
2826@ifset GENERIC
2827On most machines, you can also use @code{$} in symbol names; exceptions
2828are noted in @ref{Machine Dependencies}.
2829@end ifset
2830No symbol may begin with a digit. Case is significant.
d02603dc 2831There is no length limit; all characters are significant. Multibyte characters
7bfd842d
NC
2832are supported. Symbols are delimited by characters not in that set, or by the
2833beginning of a file (since the source program must end with a newline, the end
2834of a file is not a possible symbol delimiter). @xref{Symbols}.
d02603dc
NC
2835
2836Symbol names may also be enclosed in double quote @code{"} characters. In such
2837cases any characters are allowed, except for the NUL character. If a double
2838quote character is to be included in the symbol name it must be preceeded by a
2839backslash @code{\} character.
252b5132
RH
2840@cindex length of symbols
2841
2842@node Statements
2843@section Statements
2844
2845@cindex statements, structure of
2846@cindex line separator character
2847@cindex statement separator character
7c31ae13
NC
2848
2849A @dfn{statement} ends at a newline character (@samp{\n}) or a
2850@dfn{line separator character}. The line separator character is target
2851specific and described in the @emph{Syntax} section of each
2852target's documentation. Not all targets support a line separator character.
2853The newline or line separator character is considered to be part of the
2854preceding statement. Newlines and separators within character constants are an
252b5132 2855exception: they do not end statements.
252b5132
RH
2856
2857@cindex newline, required at file end
2858@cindex EOF, newline must precede
2859It is an error to end any statement with end-of-file: the last
2860character of any input file should be a newline.@refill
2861
2862An empty statement is allowed, and may include whitespace. It is ignored.
2863
2864@cindex instructions and directives
2865@cindex directives and instructions
2866@c "key symbol" is not used elsewhere in the document; seems pedantic to
2867@c @defn{} it in that case, as was done previously... doc@cygnus.com,
2868@c 13feb91.
2869A statement begins with zero or more labels, optionally followed by a
2870key symbol which determines what kind of statement it is. The key
2871symbol determines the syntax of the rest of the statement. If the
2872symbol begins with a dot @samp{.} then the statement is an assembler
2873directive: typically valid for any computer. If the symbol begins with
2874a letter the statement is an assembly language @dfn{instruction}: it
2875assembles into a machine language instruction.
2876@ifset GENERIC
a4fb0134 2877Different versions of @command{@value{AS}} for different computers
252b5132
RH
2878recognize different instructions. In fact, the same symbol may
2879represent a different instruction in a different computer's assembly
2880language.@refill
2881@end ifset
2882
2883@cindex @code{:} (label)
2884@cindex label (@code{:})
2885A label is a symbol immediately followed by a colon (@code{:}).
2886Whitespace before a label or after a colon is permitted, but you may not
2887have whitespace between a label's symbol and its colon. @xref{Labels}.
2888
2889@ifset HPPA
01642c12 2890For HPPA targets, labels need not be immediately followed by a colon, but
252b5132
RH
2891the definition of a label must begin in column zero. This also implies that
2892only one label may be defined on each line.
2893@end ifset
2894
2895@smallexample
2896label: .directive followed by something
2897another_label: # This is an empty statement.
2898 instruction operand_1, operand_2, @dots{}
2899@end smallexample
2900
2901@node Constants
2902@section Constants
2903
2904@cindex constants
2905A constant is a number, written so that its value is known by
2906inspection, without knowing any context. Like this:
2907@smallexample
2908@group
2909.byte 74, 0112, 092, 0x4A, 0X4a, 'J, '\J # All the same value.
2910.ascii "Ring the bell\7" # A string constant.
2911.octa 0x123456789abcdef0123456789ABCDEF0 # A bignum.
2912.float 0f-314159265358979323846264338327\
291395028841971.693993751E-40 # - pi, a flonum.
2914@end group
2915@end smallexample
2916
2917@menu
2918* Characters:: Character Constants
2919* Numbers:: Number Constants
2920@end menu
2921
2922@node Characters
2923@subsection Character Constants
2924
2925@cindex character constants
2926@cindex constants, character
2927There are two kinds of character constants. A @dfn{character} stands
2928for one character in one byte and its value may be used in
2929numeric expressions. String constants (properly called string
2930@emph{literals}) are potentially many bytes and their values may not be
2931used in arithmetic expressions.
2932
2933@menu
2934* Strings:: Strings
2935* Chars:: Characters
2936@end menu
2937
2938@node Strings
2939@subsubsection Strings
2940
2941@cindex string constants
2942@cindex constants, string
2943A @dfn{string} is written between double-quotes. It may contain
2944double-quotes or null characters. The way to get special characters
2945into a string is to @dfn{escape} these characters: precede them with
2946a backslash @samp{\} character. For example @samp{\\} represents
2947one backslash: the first @code{\} is an escape which tells
a4fb0134
SC
2948@command{@value{AS}} to interpret the second character literally as a backslash
2949(which prevents @command{@value{AS}} from recognizing the second @code{\} as an
252b5132
RH
2950escape character). The complete list of escapes follows.
2951
2952@cindex escape codes, character
2953@cindex character escape codes
361fa3a4
NC
2954@c NOTE: Cindex entries must not start with a backlash character.
2955@c NOTE: This confuses the pdf2texi script when it is creating the
2956@c NOTE: index based upon the first character and so it generates:
2957@c NOTE: \initial {\\}
2958@c NOTE: which then results in the error message:
2959@c NOTE: Argument of \\ has an extra }.
2960@c NOTE: So in the index entries below a space character has been
2961@c NOTE: prepended to avoid this problem.
252b5132
RH
2962@table @kbd
2963@c @item \a
2964@c Mnemonic for ACKnowledge; for ASCII this is octal code 007.
2965@c
361fa3a4 2966@cindex @code{ \b} (backspace character)
252b5132
RH
2967@cindex backspace (@code{\b})
2968@item \b
2969Mnemonic for backspace; for ASCII this is octal code 010.
2970
2971@c @item \e
2972@c Mnemonic for EOText; for ASCII this is octal code 004.
2973@c
361fa3a4 2974@cindex @code{ \f} (formfeed character)
252b5132 2975@cindex formfeed (@code{\f})
361fa3a4 2976@item backslash-f
252b5132
RH
2977Mnemonic for FormFeed; for ASCII this is octal code 014.
2978
361fa3a4 2979@cindex @code{ \n} (newline character)
252b5132
RH
2980@cindex newline (@code{\n})
2981@item \n
2982Mnemonic for newline; for ASCII this is octal code 012.
2983
2984@c @item \p
2985@c Mnemonic for prefix; for ASCII this is octal code 033, usually known as @code{escape}.
2986@c
361fa3a4
NC
2987@cindex @code{ \r} (carriage return character)
2988@cindex carriage return (@code{backslash-r})
252b5132
RH
2989@item \r
2990Mnemonic for carriage-Return; for ASCII this is octal code 015.
2991
2992@c @item \s
2993@c Mnemonic for space; for ASCII this is octal code 040. Included for compliance with
2994@c other assemblers.
2995@c
361fa3a4 2996@cindex @code{ \t} (tab)
252b5132
RH
2997@cindex tab (@code{\t})
2998@item \t
2999Mnemonic for horizontal Tab; for ASCII this is octal code 011.
3000
3001@c @item \v
3002@c Mnemonic for Vertical tab; for ASCII this is octal code 013.
3003@c @item \x @var{digit} @var{digit} @var{digit}
3004@c A hexadecimal character code. The numeric code is 3 hexadecimal digits.
3005@c
361fa3a4 3006@cindex @code{ \@var{ddd}} (octal character code)
252b5132
RH
3007@cindex octal character code (@code{\@var{ddd}})
3008@item \ @var{digit} @var{digit} @var{digit}
3009An octal character code. The numeric code is 3 octal digits.
3010For compatibility with other Unix systems, 8 and 9 are accepted as digits:
3011for example, @code{\008} has the value 010, and @code{\009} the value 011.
3012
361fa3a4 3013@cindex @code{ \@var{xd...}} (hex character code)
252b5132
RH
3014@cindex hex character code (@code{\@var{xd...}})
3015@item \@code{x} @var{hex-digits...}
3016A hex character code. All trailing hex digits are combined. Either upper or
3017lower case @code{x} works.
3018
361fa3a4 3019@cindex @code{ \\} (@samp{\} character)
252b5132
RH
3020@cindex backslash (@code{\\})
3021@item \\
3022Represents one @samp{\} character.
3023
3024@c @item \'
3025@c Represents one @samp{'} (accent acute) character.
3026@c This is needed in single character literals
3027@c (@xref{Characters,,Character Constants}.) to represent
3028@c a @samp{'}.
3029@c
361fa3a4 3030@cindex @code{ \"} (doublequote character)
252b5132
RH
3031@cindex doublequote (@code{\"})
3032@item \"
3033Represents one @samp{"} character. Needed in strings to represent
3034this character, because an unescaped @samp{"} would end the string.
3035
3036@item \ @var{anything-else}
3037Any other character when escaped by @kbd{\} gives a warning, but
3038assembles as if the @samp{\} was not present. The idea is that if
3039you used an escape sequence you clearly didn't want the literal
a4fb0134
SC
3040interpretation of the following character. However @command{@value{AS}} has no
3041other interpretation, so @command{@value{AS}} knows it is giving you the wrong
252b5132
RH
3042code and warns you of the fact.
3043@end table
3044
3045Which characters are escapable, and what those escapes represent,
3046varies widely among assemblers. The current set is what we think
3047the BSD 4.2 assembler recognizes, and is a subset of what most C
3048compilers recognize. If you are in doubt, do not use an escape
3049sequence.
3050
3051@node Chars
3052@subsubsection Characters
3053
3054@cindex single character constant
3055@cindex character, single
3056@cindex constant, single character
9962fe29
AM
3057A single character may be written as a single quote immediately followed by
3058that character. Some backslash escapes apply to characters, @code{\b},
3059@code{\f}, @code{\n}, @code{\r}, @code{\t}, and @code{\"} with the same meaning
3060as for strings, plus @code{\'} for a single quote. So if you want to write the
3061character backslash, you must write @kbd{'\\} where the first @code{\} escapes
3062the second @code{\}. As you can see, the quote is an acute accent, not a grave
3063accent. A newline
252b5132
RH
3064@ifclear GENERIC
3065@ifclear abnormal-separator
3066(or semicolon @samp{;})
3067@end ifclear
3068@ifset abnormal-separator
252b5132
RH
3069@ifset H8
3070(or dollar sign @samp{$}, for the H8/300; or semicolon @samp{;} for the
7be1c489 3071Renesas SH)
252b5132
RH
3072@end ifset
3073@end ifset
3074@end ifclear
3075immediately following an acute accent is taken as a literal character
3076and does not count as the end of a statement. The value of a character
3077constant in a numeric expression is the machine's byte-wide code for
a4fb0134 3078that character. @command{@value{AS}} assumes your character code is ASCII:
252b5132
RH
3079@kbd{'A} means 65, @kbd{'B} means 66, and so on. @refill
3080
3081@node Numbers
3082@subsection Number Constants
3083
3084@cindex constants, number
3085@cindex number constants
a4fb0134 3086@command{@value{AS}} distinguishes three kinds of numbers according to how they
252b5132
RH
3087are stored in the target machine. @emph{Integers} are numbers that
3088would fit into an @code{int} in the C language. @emph{Bignums} are
3089integers, but they are stored in more than 32 bits. @emph{Flonums}
3090are floating point numbers, described below.
3091
3092@menu
3093* Integers:: Integers
3094* Bignums:: Bignums
3095* Flonums:: Flonums
3096@ifclear GENERIC
252b5132
RH
3097@end ifclear
3098@end menu
3099
3100@node Integers
3101@subsubsection Integers
3102@cindex integers
3103@cindex constants, integer
3104
3105@cindex binary integers
3106@cindex integers, binary
3107A binary integer is @samp{0b} or @samp{0B} followed by zero or more of
3108the binary digits @samp{01}.
3109
3110@cindex octal integers
3111@cindex integers, octal
3112An octal integer is @samp{0} followed by zero or more of the octal
3113digits (@samp{01234567}).
3114
3115@cindex decimal integers
3116@cindex integers, decimal
3117A decimal integer starts with a non-zero digit followed by zero or
3118more digits (@samp{0123456789}).
3119
3120@cindex hexadecimal integers
3121@cindex integers, hexadecimal
3122A hexadecimal integer is @samp{0x} or @samp{0X} followed by one or
3123more hexadecimal digits chosen from @samp{0123456789abcdefABCDEF}.
3124
3125Integers have the usual values. To denote a negative integer, use
3126the prefix operator @samp{-} discussed under expressions
3127(@pxref{Prefix Ops,,Prefix Operators}).
3128
3129@node Bignums
3130@subsubsection Bignums
3131
3132@cindex bignums
3133@cindex constants, bignum
3134A @dfn{bignum} has the same syntax and semantics as an integer
3135except that the number (or its negative) takes more than 32 bits to
3136represent in binary. The distinction is made because in some places
3137integers are permitted while bignums are not.
3138
3139@node Flonums
3140@subsubsection Flonums
3141@cindex flonums
3142@cindex floating point numbers
3143@cindex constants, floating point
3144
3145@cindex precision, floating point
3146A @dfn{flonum} represents a floating point number. The translation is
3147indirect: a decimal floating point number from the text is converted by
a4fb0134 3148@command{@value{AS}} to a generic binary floating point number of more than
252b5132
RH
3149sufficient precision. This generic floating point number is converted
3150to a particular computer's floating point format (or formats) by a
a4fb0134 3151portion of @command{@value{AS}} specialized to that computer.
252b5132
RH
3152
3153A flonum is written by writing (in order)
3154@itemize @bullet
3155@item
3156The digit @samp{0}.
3157@ifset HPPA
3158(@samp{0} is optional on the HPPA.)
3159@end ifset
3160
3161@item
a4fb0134 3162A letter, to tell @command{@value{AS}} the rest of the number is a flonum.
252b5132
RH
3163@ifset GENERIC
3164@kbd{e} is recommended. Case is not important.
3165@ignore
3166@c FIXME: verify if flonum syntax really this vague for most cases
3167(Any otherwise illegal letter works here, but that might be changed. Vax BSD
31684.2 assembler seems to allow any of @samp{defghDEFGH}.)
3169@end ignore
3170
a8eb42a8 3171On the H8/300 and Renesas / SuperH SH architectures, the letter must be
252b5132
RH
3172one of the letters @samp{DFPRSX} (in upper or lower case).
3173
3174On the ARC, the letter must be one of the letters @samp{DFRS}
3175(in upper or lower case).
3176
252b5132
RH
3177On the HPPA architecture, the letter must be @samp{E} (upper case only).
3178@end ifset
3179@ifclear GENERIC
252b5132
RH
3180@ifset ARC
3181One of the letters @samp{DFRS} (in upper or lower case).
3182@end ifset
3183@ifset H8
3184One of the letters @samp{DFPRSX} (in upper or lower case).
3185@end ifset
3186@ifset HPPA
3187The letter @samp{E} (upper case only).
3188@end ifset
252b5132
RH
3189@end ifclear
3190
3191@item
3192An optional sign: either @samp{+} or @samp{-}.
3193
3194@item
3195An optional @dfn{integer part}: zero or more decimal digits.
3196
3197@item
3198An optional @dfn{fractional part}: @samp{.} followed by zero
3199or more decimal digits.
3200
3201@item
3202An optional exponent, consisting of:
3203
3204@itemize @bullet
3205@item
3206An @samp{E} or @samp{e}.
3207@c I can't find a config where "EXP_CHARS" is other than 'eE', but in
3208@c principle this can perfectly well be different on different targets.
3209@item
3210Optional sign: either @samp{+} or @samp{-}.
3211@item
3212One or more decimal digits.
3213@end itemize
3214
3215@end itemize
3216
3217At least one of the integer part or the fractional part must be
3218present. The floating point number has the usual base-10 value.
3219
a4fb0134 3220@command{@value{AS}} does all processing using integers. Flonums are computed
252b5132 3221independently of any floating point hardware in the computer running
a4fb0134 3222@command{@value{AS}}.
252b5132 3223
252b5132
RH
3224@node Sections
3225@chapter Sections and Relocation
3226@cindex sections
3227@cindex relocation
3228
3229@menu
3230* Secs Background:: Background
3231* Ld Sections:: Linker Sections
3232* As Sections:: Assembler Internal Sections
3233* Sub-Sections:: Sub-Sections
3234* bss:: bss Section
3235@end menu
3236
3237@node Secs Background
3238@section Background
3239
3240Roughly, a section is a range of addresses, with no gaps; all data
3241``in'' those addresses is treated the same for some particular purpose.
3242For example there may be a ``read only'' section.
3243
3244@cindex linker, and assembler
3245@cindex assembler, and linker
3246The linker @code{@value{LD}} reads many object files (partial programs) and
a4fb0134 3247combines their contents to form a runnable program. When @command{@value{AS}}
252b5132
RH
3248emits an object file, the partial program is assumed to start at address 0.
3249@code{@value{LD}} assigns the final addresses for the partial program, so that
3250different partial programs do not overlap. This is actually an
a4fb0134 3251oversimplification, but it suffices to explain how @command{@value{AS}} uses
252b5132
RH
3252sections.
3253
3254@code{@value{LD}} moves blocks of bytes of your program to their run-time
3255addresses. These blocks slide to their run-time addresses as rigid
3256units; their length does not change and neither does the order of bytes
3257within them. Such a rigid unit is called a @emph{section}. Assigning
3258run-time addresses to sections is called @dfn{relocation}. It includes
3259the task of adjusting mentions of object-file addresses so they refer to
3260the proper run-time addresses.
3261@ifset H8
7be1c489 3262For the H8/300, and for the Renesas / SuperH SH,
a4fb0134 3263@command{@value{AS}} pads sections if needed to
252b5132
RH
3264ensure they end on a word (sixteen bit) boundary.
3265@end ifset
3266
3267@cindex standard assembler sections
a4fb0134 3268An object file written by @command{@value{AS}} has at least three sections, any
252b5132
RH
3269of which may be empty. These are named @dfn{text}, @dfn{data} and
3270@dfn{bss} sections.
3271
c1253627 3272@ifset COFF-ELF
252b5132 3273@ifset GENERIC
c1253627 3274When it generates COFF or ELF output,
252b5132 3275@end ifset
a4fb0134 3276@command{@value{AS}} can also generate whatever other named sections you specify
252b5132
RH
3277using the @samp{.section} directive (@pxref{Section,,@code{.section}}).
3278If you do not use any directives that place output in the @samp{.text}
3279or @samp{.data} sections, these sections still exist, but are empty.
3280@end ifset
3281
3282@ifset HPPA
3283@ifset GENERIC
a4fb0134 3284When @command{@value{AS}} generates SOM or ELF output for the HPPA,
252b5132 3285@end ifset
a4fb0134 3286@command{@value{AS}} can also generate whatever other named sections you
252b5132
RH
3287specify using the @samp{.space} and @samp{.subspace} directives. See
3288@cite{HP9000 Series 800 Assembly Language Reference Manual}
3289(HP 92432-90001) for details on the @samp{.space} and @samp{.subspace}
3290assembler directives.
3291
3292@ifset SOM
a4fb0134 3293Additionally, @command{@value{AS}} uses different names for the standard
252b5132
RH
3294text, data, and bss sections when generating SOM output. Program text
3295is placed into the @samp{$CODE$} section, data into @samp{$DATA$}, and
3296BSS into @samp{$BSS$}.
3297@end ifset
3298@end ifset
3299
3300Within the object file, the text section starts at address @code{0}, the
3301data section follows, and the bss section follows the data section.
3302
3303@ifset HPPA
3304When generating either SOM or ELF output files on the HPPA, the text
3305section starts at address @code{0}, the data section at address
3306@code{0x4000000}, and the bss section follows the data section.
3307@end ifset
3308
3309To let @code{@value{LD}} know which data changes when the sections are
a4fb0134 3310relocated, and how to change that data, @command{@value{AS}} also writes to the
252b5132
RH
3311object file details of the relocation needed. To perform relocation
3312@code{@value{LD}} must know, each time an address in the object
3313file is mentioned:
3314@itemize @bullet
3315@item
3316Where in the object file is the beginning of this reference to
3317an address?
3318@item
3319How long (in bytes) is this reference?
3320@item
3321Which section does the address refer to? What is the numeric value of
3322@display
3323(@var{address}) @minus{} (@var{start-address of section})?
3324@end display
3325@item
3326Is the reference to an address ``Program-Counter relative''?
3327@end itemize
3328
3329@cindex addresses, format of
3330@cindex section-relative addressing
a4fb0134 3331In fact, every address @command{@value{AS}} ever uses is expressed as
252b5132
RH
3332@display
3333(@var{section}) + (@var{offset into section})
3334@end display
3335@noindent
a4fb0134 3336Further, most expressions @command{@value{AS}} computes have this section-relative
252b5132
RH
3337nature.
3338@ifset SOM
3339(For some object formats, such as SOM for the HPPA, some expressions are
3340symbol-relative instead.)
3341@end ifset
3342
3343In this manual we use the notation @{@var{secname} @var{N}@} to mean ``offset
3344@var{N} into section @var{secname}.''
3345
3346Apart from text, data and bss sections you need to know about the
3347@dfn{absolute} section. When @code{@value{LD}} mixes partial programs,
3348addresses in the absolute section remain unchanged. For example, address
3349@code{@{absolute 0@}} is ``relocated'' to run-time address 0 by
3350@code{@value{LD}}. Although the linker never arranges two partial programs'
3351data sections with overlapping addresses after linking, @emph{by definition}
3352their absolute sections must overlap. Address @code{@{absolute@ 239@}} in one
3353part of a program is always the same address when the program is running as
3354address @code{@{absolute@ 239@}} in any other part of the program.
3355
3356The idea of sections is extended to the @dfn{undefined} section. Any
3357address whose section is unknown at assembly time is by definition
3358rendered @{undefined @var{U}@}---where @var{U} is filled in later.
3359Since numbers are always defined, the only way to generate an undefined
3360address is to mention an undefined symbol. A reference to a named
3361common block would be such a symbol: its value is unknown at assembly
3362time so it has section @emph{undefined}.
3363
3364By analogy the word @emph{section} is used to describe groups of sections in
3365the linked program. @code{@value{LD}} puts all partial programs' text
3366sections in contiguous addresses in the linked program. It is
3367customary to refer to the @emph{text section} of a program, meaning all
3368the addresses of all partial programs' text sections. Likewise for
3369data and bss sections.
3370
3371Some sections are manipulated by @code{@value{LD}}; others are invented for
a4fb0134 3372use of @command{@value{AS}} and have no meaning except during assembly.
252b5132
RH
3373
3374@node Ld Sections
3375@section Linker Sections
3376@code{@value{LD}} deals with just four kinds of sections, summarized below.
3377
3378@table @strong
3379
c1253627 3380@ifset COFF-ELF
252b5132
RH
3381@cindex named sections
3382@cindex sections, named
3383@item named sections
3384@end ifset
a8eb42a8 3385@ifset aout
252b5132
RH
3386@cindex text section
3387@cindex data section
3388@itemx text section
3389@itemx data section
3390@end ifset
a4fb0134 3391These sections hold your program. @command{@value{AS}} and @code{@value{LD}} treat them as
252b5132 3392separate but equal sections. Anything you can say of one section is
c1253627 3393true of another.
a8eb42a8 3394@c @ifset aout
252b5132
RH
3395When the program is running, however, it is
3396customary for the text section to be unalterable. The
3397text section is often shared among processes: it contains
3398instructions, constants and the like. The data section of a running
3399program is usually alterable: for example, C variables would be stored
3400in the data section.
c1253627 3401@c @end ifset
252b5132
RH
3402
3403@cindex bss section
3404@item bss section
3405This section contains zeroed bytes when your program begins running. It
a349d9dd 3406is used to hold uninitialized variables or common storage. The length of
252b5132
RH
3407each partial program's bss section is important, but because it starts
3408out containing zeroed bytes there is no need to store explicit zero
3409bytes in the object file. The bss section was invented to eliminate
3410those explicit zeros from object files.
3411
3412@cindex absolute section
3413@item absolute section
3414Address 0 of this section is always ``relocated'' to runtime address 0.
3415This is useful if you want to refer to an address that @code{@value{LD}} must
3416not change when relocating. In this sense we speak of absolute
3417addresses being ``unrelocatable'': they do not change during relocation.
3418
3419@cindex undefined section
3420@item undefined section
3421This ``section'' is a catch-all for address references to objects not in
3422the preceding sections.
3423@c FIXME: ref to some other doc on obj-file formats could go here.
3424@end table
3425
3426@cindex relocation example
3427An idealized example of three relocatable sections follows.
c1253627 3428@ifset COFF-ELF
252b5132
RH
3429The example uses the traditional section names @samp{.text} and @samp{.data}.
3430@end ifset
3431Memory addresses are on the horizontal axis.
3432
3433@c TEXI2ROFF-KILL
c1253627 3434@ifnottex
252b5132
RH
3435@c END TEXI2ROFF-KILL
3436@smallexample
3437 +-----+----+--+
3438partial program # 1: |ttttt|dddd|00|
3439 +-----+----+--+
3440
3441 text data bss
3442 seg. seg. seg.
3443
3444 +---+---+---+
3445partial program # 2: |TTT|DDD|000|
3446 +---+---+---+
3447
3448 +--+---+-----+--+----+---+-----+~~
3449linked program: | |TTT|ttttt| |dddd|DDD|00000|
3450 +--+---+-----+--+----+---+-----+~~
3451
3452 addresses: 0 @dots{}
3453@end smallexample
3454@c TEXI2ROFF-KILL
c1253627 3455@end ifnottex
252b5132
RH
3456@need 5000
3457@tex
c1253627 3458\bigskip
252b5132
RH
3459\line{\it Partial program \#1: \hfil}
3460\line{\ibox{2.5cm}{\tt text}\ibox{2cm}{\tt data}\ibox{1cm}{\tt bss}\hfil}
3461\line{\boxit{2.5cm}{\tt ttttt}\boxit{2cm}{\tt dddd}\boxit{1cm}{\tt 00}\hfil}
3462
3463\line{\it Partial program \#2: \hfil}
3464\line{\ibox{1cm}{\tt text}\ibox{1.5cm}{\tt data}\ibox{1cm}{\tt bss}\hfil}
3465\line{\boxit{1cm}{\tt TTT}\boxit{1.5cm}{\tt DDDD}\boxit{1cm}{\tt 000}\hfil}
3466
3467\line{\it linked program: \hfil}
3468\line{\ibox{.5cm}{}\ibox{1cm}{\tt text}\ibox{2.5cm}{}\ibox{.75cm}{}\ibox{2cm}{\tt data}\ibox{1.5cm}{}\ibox{2cm}{\tt bss}\hfil}
3469\line{\boxit{.5cm}{}\boxit{1cm}{\tt TTT}\boxit{2.5cm}{\tt
3470ttttt}\boxit{.75cm}{}\boxit{2cm}{\tt dddd}\boxit{1.5cm}{\tt
3471DDDD}\boxit{2cm}{\tt 00000}\ \dots\hfil}
3472
3473\line{\it addresses: \hfil}
3474\line{0\dots\hfil}
3475
3476@end tex
3477@c END TEXI2ROFF-KILL
3478
3479@node As Sections
3480@section Assembler Internal Sections
3481
3482@cindex internal assembler sections
3483@cindex sections in messages, internal
a4fb0134 3484These sections are meant only for the internal use of @command{@value{AS}}. They
252b5132 3485have no meaning at run-time. You do not really need to know about these
a4fb0134 3486sections for most purposes; but they can be mentioned in @command{@value{AS}}
252b5132 3487warning messages, so it might be helpful to have an idea of their
a4fb0134 3488meanings to @command{@value{AS}}. These sections are used to permit the
252b5132
RH
3489value of every expression in your assembly language program to be a
3490section-relative address.
3491
3492@table @b
3493@cindex assembler internal logic error
3494@item ASSEMBLER-INTERNAL-LOGIC-ERROR!
3495An internal assembler logic error has been found. This means there is a
3496bug in the assembler.
3497
3498@cindex expr (internal section)
3499@item expr section
3500The assembler stores complex expression internally as combinations of
3501symbols. When it needs to represent an expression as a symbol, it puts
3502it in the expr section.
3503@c FIXME item debug
3504@c FIXME item transfer[t] vector preload
3505@c FIXME item transfer[t] vector postload
3506@c FIXME item register
3507@end table
3508
3509@node Sub-Sections
3510@section Sub-Sections
3511
3512@cindex numbered subsections
3513@cindex grouping data
a8eb42a8 3514@ifset aout
252b5132 3515Assembled bytes
c1253627 3516@ifset COFF-ELF
252b5132
RH
3517conventionally
3518@end ifset
3519fall into two sections: text and data.
3520@end ifset
3521You may have separate groups of
3522@ifset GENERIC
3523data in named sections
3524@end ifset
3525@ifclear GENERIC
a8eb42a8 3526@ifclear aout
252b5132
RH
3527data in named sections
3528@end ifclear
a8eb42a8 3529@ifset aout
252b5132
RH
3530text or data
3531@end ifset
3532@end ifclear
3533that you want to end up near to each other in the object file, even though they
a4fb0134 3534are not contiguous in the assembler source. @command{@value{AS}} allows you to
252b5132
RH
3535use @dfn{subsections} for this purpose. Within each section, there can be
3536numbered subsections with values from 0 to 8192. Objects assembled into the
3537same subsection go into the object file together with other objects in the same
3538subsection. For example, a compiler might want to store constants in the text
3539section, but might not want to have them interspersed with the program being
3540assembled. In this case, the compiler could issue a @samp{.text 0} before each
3541section of code being output, and a @samp{.text 1} before each group of
3542constants being output.
3543
3544Subsections are optional. If you do not use subsections, everything
3545goes in subsection number zero.
3546
3547@ifset GENERIC
3548Each subsection is zero-padded up to a multiple of four bytes.
3549(Subsections may be padded a different amount on different flavors
a4fb0134 3550of @command{@value{AS}}.)
252b5132
RH
3551@end ifset
3552@ifclear GENERIC
3553@ifset H8
7be1c489 3554On the H8/300 platform, each subsection is zero-padded to a word
252b5132 3555boundary (two bytes).
c2dcd04e 3556The same is true on the Renesas SH.
252b5132 3557@end ifset
252b5132
RH
3558@end ifclear
3559
3560Subsections appear in your object file in numeric order, lowest numbered
3561to highest. (All this to be compatible with other people's assemblers.)
3562The object file contains no representation of subsections; @code{@value{LD}} and
3563other programs that manipulate object files see no trace of them.
3564They just see all your text subsections as a text section, and all your
3565data subsections as a data section.
3566
3567To specify which subsection you want subsequent statements assembled
3568into, use a numeric argument to specify it, in a @samp{.text
3569@var{expression}} or a @samp{.data @var{expression}} statement.
ed9589d4 3570@ifset COFF
252b5132 3571@ifset GENERIC
ed9589d4 3572When generating COFF output, you
252b5132
RH
3573@end ifset
3574@ifclear GENERIC
3575You
3576@end ifclear
3577can also use an extra subsection
3578argument with arbitrary named sections: @samp{.section @var{name},
3579@var{expression}}.
3580@end ifset
ed9589d4
BW
3581@ifset ELF
3582@ifset GENERIC
3583When generating ELF output, you
3584@end ifset
3585@ifclear GENERIC
3586You
3587@end ifclear
3588can also use the @code{.subsection} directive (@pxref{SubSection})
3589to specify a subsection: @samp{.subsection @var{expression}}.
3590@end ifset
96e9638b
BW
3591@var{Expression} should be an absolute expression
3592(@pxref{Expressions}). If you just say @samp{.text} then @samp{.text 0}
252b5132
RH
3593is assumed. Likewise @samp{.data} means @samp{.data 0}. Assembly
3594begins in @code{text 0}. For instance:
3595@smallexample
3596.text 0 # The default subsection is text 0 anyway.
3597.ascii "This lives in the first text subsection. *"
3598.text 1
3599.ascii "But this lives in the second text subsection."
3600.data 0
3601.ascii "This lives in the data section,"
3602.ascii "in the first data subsection."
3603.text 0
3604.ascii "This lives in the first text section,"
3605.ascii "immediately following the asterisk (*)."
3606@end smallexample
3607
3608Each section has a @dfn{location counter} incremented by one for every byte
3609assembled into that section. Because subsections are merely a convenience
a4fb0134 3610restricted to @command{@value{AS}} there is no concept of a subsection location
252b5132
RH
3611counter. There is no way to directly manipulate a location counter---but the
3612@code{.align} directive changes it, and any label definition captures its
3613current value. The location counter of the section where statements are being
3614assembled is said to be the @dfn{active} location counter.
3615
3616@node bss
3617@section bss Section
3618
3619@cindex bss section
3620@cindex common variable storage
3621The bss section is used for local common variable storage.
3622You may allocate address space in the bss section, but you may
3623not dictate data to load into it before your program executes. When
3624your program starts running, all the contents of the bss
3625section are zeroed bytes.
3626
3627The @code{.lcomm} pseudo-op defines a symbol in the bss section; see
3628@ref{Lcomm,,@code{.lcomm}}.
3629
3630The @code{.comm} pseudo-op may be used to declare a common symbol, which is
96e9638b 3631another form of uninitialized symbol; see @ref{Comm,,@code{.comm}}.
252b5132
RH
3632
3633@ifset GENERIC
3634When assembling for a target which supports multiple sections, such as ELF or
3635COFF, you may switch into the @code{.bss} section and define symbols as usual;
3636see @ref{Section,,@code{.section}}. You may only assemble zero values into the
3637section. Typically the section will only contain symbol definitions and
3638@code{.skip} directives (@pxref{Skip,,@code{.skip}}).
3639@end ifset
3640
3641@node Symbols
3642@chapter Symbols
3643
3644@cindex symbols
3645Symbols are a central concept: the programmer uses symbols to name
3646things, the linker uses symbols to link, and the debugger uses symbols
3647to debug.
3648
3649@quotation
3650@cindex debuggers, and symbol order
a4fb0134 3651@emph{Warning:} @command{@value{AS}} does not place symbols in the object file in
252b5132
RH
3652the same order they were declared. This may break some debuggers.
3653@end quotation
3654
3655@menu
3656* Labels:: Labels
3657* Setting Symbols:: Giving Symbols Other Values
3658* Symbol Names:: Symbol Names
3659* Dot:: The Special Dot Symbol
3660* Symbol Attributes:: Symbol Attributes
3661@end menu
3662
3663@node Labels
3664@section Labels
3665
3666@cindex labels
3667A @dfn{label} is written as a symbol immediately followed by a colon
3668@samp{:}. The symbol then represents the current value of the
3669active location counter, and is, for example, a suitable instruction
3670operand. You are warned if you use the same symbol to represent two
3671different locations: the first definition overrides any other
3672definitions.
3673
3674@ifset HPPA
3675On the HPPA, the usual form for a label need not be immediately followed by a
3676colon, but instead must start in column zero. Only one label may be defined on
a4fb0134 3677a single line. To work around this, the HPPA version of @command{@value{AS}} also
252b5132
RH
3678provides a special directive @code{.label} for defining labels more flexibly.
3679@end ifset
3680
3681@node Setting Symbols
3682@section Giving Symbols Other Values
3683
3684@cindex assigning values to symbols
3685@cindex symbol values, assigning
3686A symbol can be given an arbitrary value by writing a symbol, followed
3687by an equals sign @samp{=}, followed by an expression
3688(@pxref{Expressions}). This is equivalent to using the @code{.set}
9497f5ac
NC
3689directive. @xref{Set,,@code{.set}}. In the same way, using a double
3690equals sign @samp{=}@samp{=} here represents an equivalent of the
3691@code{.eqv} directive. @xref{Eqv,,@code{.eqv}}.
252b5132 3692
f8739b83
JZ
3693@ifset Blackfin
3694Blackfin does not support symbol assignment with @samp{=}.
3695@end ifset
3696
252b5132
RH
3697@node Symbol Names
3698@section Symbol Names
3699
3700@cindex symbol names
3701@cindex names, symbol
3702@ifclear SPECIAL-SYMS
3703Symbol names begin with a letter or with one of @samp{._}. On most
3704machines, you can also use @code{$} in symbol names; exceptions are
3705noted in @ref{Machine Dependencies}. That character may be followed by any
96e9638b
BW
3706string of digits, letters, dollar signs (unless otherwise noted for a
3707particular target machine), and underscores.
252b5132 3708@end ifclear
252b5132
RH
3709@ifset SPECIAL-SYMS
3710@ifset H8
3711Symbol names begin with a letter or with one of @samp{._}. On the
7be1c489 3712Renesas SH you can also use @code{$} in symbol names. That
c2dcd04e
NC
3713character may be followed by any string of digits, letters, dollar signs (save
3714on the H8/300), and underscores.
252b5132
RH
3715@end ifset
3716@end ifset
3717
3718Case of letters is significant: @code{foo} is a different symbol name
3719than @code{Foo}.
3720
ed1fcdd1
NC
3721Symbol names do not start with a digit. An exception to this rule is made for
3722Local Labels. See below.
3723
7bfd842d
NC
3724Multibyte characters are supported. To generate a symbol name containing
3725multibyte characters enclose it within double quotes and use escape codes. cf
3726@xref{Strings}. Generating a multibyte symbol name from a label is not
3727currently supported.
3728
252b5132
RH
3729Each symbol has exactly one name. Each name in an assembly language program
3730refers to exactly one symbol. You may use that symbol name any number of times
3731in a program.
3732
3733@subheading Local Symbol Names
3734
3735@cindex local symbol names
3736@cindex symbol names, local
ba83aca1
BW
3737A local symbol is any symbol beginning with certain local label prefixes.
3738By default, the local label prefix is @samp{.L} for ELF systems or
3739@samp{L} for traditional a.out systems, but each target may have its own
3740set of local label prefixes.
3741@ifset HPPA
3742On the HPPA local symbols begin with @samp{L$}.
3743@end ifset
3744
3745Local symbols are defined and used within the assembler, but they are
3746normally not saved in object files. Thus, they are not visible when debugging.
5c9352f3
AM
3747You may use the @samp{-L} option (@pxref{L, ,Include Local Symbols})
3748to retain the local symbols in the object files.
ba83aca1
BW
3749
3750@subheading Local Labels
3751
3752@cindex local labels
252b5132
RH
3753@cindex temporary symbol names
3754@cindex symbol names, temporary
ed1fcdd1
NC
3755Local labels are different from local symbols. Local labels help compilers and
3756programmers use names temporarily. They create symbols which are guaranteed to
3757be unique over the entire scope of the input source code and which can be
3758referred to by a simple notation. To define a local label, write a label of
9791c250
AM
3759the form @samp{@b{N}:} (where @b{N} represents any non-negative integer).
3760To refer to the most recent previous definition of that label write
3761@samp{@b{N}b}, using the same number as when you defined the label. To refer
3762to the next definition of a local label, write @samp{@b{N}f}. The @samp{b}
3763stands for ``backwards'' and the @samp{f} stands for ``forwards''.
2d5aaba0
NC
3764
3765There is no restriction on how you can use these labels, and you can reuse them
3766too. So that it is possible to repeatedly define the same local label (using
3767the same number @samp{@b{N}}), although you can only refer to the most recently
3768defined local label of that number (for a backwards reference) or the next
3769definition of a specific local label for a forward reference. It is also worth
3770noting that the first 10 local labels (@samp{@b{0:}}@dots{}@samp{@b{9:}}) are
3771implemented in a slightly more efficient manner than the others.
3772
3773Here is an example:
3774
3775@smallexample
37761: branch 1f
37772: branch 1b
37781: branch 2f
37792: branch 1b
3780@end smallexample
3781
3782Which is the equivalent of:
3783
3784@smallexample
3785label_1: branch label_3
3786label_2: branch label_1
3787label_3: branch label_4
3788label_4: branch label_3
3789@end smallexample
3790
ba83aca1 3791Local label names are only a notational device. They are immediately
2d5aaba0 3792transformed into more conventional symbol names before the assembler uses them.
96e9638b
BW
3793The symbol names are stored in the symbol table, appear in error messages, and
3794are optionally emitted to the object file. The names are constructed using
3795these parts:
252b5132
RH
3796
3797@table @code
ba83aca1
BW
3798@item @emph{local label prefix}
3799All local symbols begin with the system-specific local label prefix.
3800Normally both @command{@value{AS}} and @code{@value{LD}} forget symbols
3801that start with the local label prefix. These labels are
252b5132 3802used for symbols you are never intended to see. If you use the
a4fb0134 3803@samp{-L} option then @command{@value{AS}} retains these symbols in the
252b5132
RH
3804object file. If you also instruct @code{@value{LD}} to retain these symbols,
3805you may use them in debugging.
3806
2d5aaba0
NC
3807@item @var{number}
3808This is the number that was used in the local label definition. So if the
01642c12 3809label is written @samp{55:} then the number is @samp{55}.
252b5132 3810
2d5aaba0
NC
3811@item @kbd{C-B}
3812This unusual character is included so you do not accidentally invent a symbol
3813of the same name. The character has ASCII value of @samp{\002} (control-B).
252b5132
RH
3814
3815@item @emph{ordinal number}
2d5aaba0 3816This is a serial number to keep the labels distinct. The first definition of
01642c12 3817@samp{0:} gets the number @samp{1}. The 15th definition of @samp{0:} gets the
2d5aaba0 3818number @samp{15}, and so on. Likewise the first definition of @samp{1:} gets
b45619c0 3819the number @samp{1} and its 15th definition gets @samp{15} as well.
252b5132
RH
3820@end table
3821
ba83aca1
BW
3822So for example, the first @code{1:} may be named @code{.L1@kbd{C-B}1}, and
3823the 44th @code{3:} may be named @code{.L3@kbd{C-B}44}.
2d5aaba0
NC
3824
3825@subheading Dollar Local Labels
3826@cindex dollar local symbols
3827
ed1fcdd1
NC
3828On some targets @code{@value{AS}} also supports an even more local form of
3829local labels called dollar labels. These labels go out of scope (i.e., they
3830become undefined) as soon as a non-local label is defined. Thus they remain
3831valid for only a small region of the input source code. Normal local labels,
3832by contrast, remain in scope for the entire file, or until they are redefined
3833by another occurrence of the same local label.
2d5aaba0
NC
3834
3835Dollar labels are defined in exactly the same way as ordinary local labels,
77cca80f
NC
3836except that they have a dollar sign suffix to their numeric value, e.g.,
3837@samp{@b{55$:}}.
2d5aaba0
NC
3838
3839They can also be distinguished from ordinary local labels by their transformed
96e9638b
BW
3840names which use ASCII character @samp{\001} (control-A) as the magic character
3841to distinguish them from ordinary labels. For example, the fifth definition of
ba83aca1 3842@samp{6$} may be named @samp{.L6@kbd{C-A}5}.
252b5132
RH
3843
3844@node Dot
3845@section The Special Dot Symbol
3846
3847@cindex dot (symbol)
3848@cindex @code{.} (symbol)
3849@cindex current address
3850@cindex location counter
3851The special symbol @samp{.} refers to the current address that
a4fb0134 3852@command{@value{AS}} is assembling into. Thus, the expression @samp{melvin:
252b5132
RH
3853.long .} defines @code{melvin} to contain its own address.
3854Assigning a value to @code{.} is treated the same as a @code{.org}
884f0d36 3855directive.
252b5132 3856@ifclear no-space-dir
884f0d36 3857Thus, the expression @samp{.=.+4} is the same as saying
252b5132
RH
3858@samp{.space 4}.
3859@end ifclear
252b5132
RH
3860
3861@node Symbol Attributes
3862@section Symbol Attributes
3863
3864@cindex symbol attributes
3865@cindex attributes, symbol
3866Every symbol has, as well as its name, the attributes ``Value'' and
3867``Type''. Depending on output format, symbols can also have auxiliary
3868attributes.
3869@ifset INTERNALS
3870The detailed definitions are in @file{a.out.h}.
3871@end ifset
3872
a4fb0134 3873If you use a symbol without defining it, @command{@value{AS}} assumes zero for
252b5132
RH
3874all these attributes, and probably won't warn you. This makes the
3875symbol an externally defined symbol, which is generally what you
3876would want.
3877
3878@menu
3879* Symbol Value:: Value
3880* Symbol Type:: Type
a8eb42a8 3881@ifset aout
252b5132
RH
3882* a.out Symbols:: Symbol Attributes: @code{a.out}
3883@end ifset
252b5132
RH
3884@ifset COFF
3885* COFF Symbols:: Symbol Attributes for COFF
3886@end ifset
3887@ifset SOM
3888* SOM Symbols:: Symbol Attributes for SOM
3889@end ifset
3890@end menu
3891
3892@node Symbol Value
3893@subsection Value
3894
3895@cindex value of a symbol
3896@cindex symbol value
3897The value of a symbol is (usually) 32 bits. For a symbol which labels a
3898location in the text, data, bss or absolute sections the value is the
3899number of addresses from the start of that section to the label.
3900Naturally for text, data and bss sections the value of a symbol changes
3901as @code{@value{LD}} changes section base addresses during linking. Absolute
3902symbols' values do not change during linking: that is why they are
3903called absolute.
3904
3905The value of an undefined symbol is treated in a special way. If it is
39060 then the symbol is not defined in this assembler source file, and
3907@code{@value{LD}} tries to determine its value from other files linked into the
3908same program. You make this kind of symbol simply by mentioning a symbol
3909name without defining it. A non-zero value represents a @code{.comm}
3910common declaration. The value is how much common storage to reserve, in
3911bytes (addresses). The symbol refers to the first address of the
3912allocated storage.
3913
3914@node Symbol Type
3915@subsection Type
3916
3917@cindex type of a symbol
3918@cindex symbol type
3919The type attribute of a symbol contains relocation (section)
3920information, any flag settings indicating that a symbol is external, and
3921(optionally), other information for linkers and debuggers. The exact
3922format depends on the object-code output format in use.
3923
a8eb42a8 3924@ifset aout
252b5132
RH
3925@node a.out Symbols
3926@subsection Symbol Attributes: @code{a.out}
3927
3928@cindex @code{a.out} symbol attributes
3929@cindex symbol attributes, @code{a.out}
3930
252b5132
RH
3931@menu
3932* Symbol Desc:: Descriptor
3933* Symbol Other:: Other
3934@end menu
3935
3936@node Symbol Desc
3937@subsubsection Descriptor
3938
3939@cindex descriptor, of @code{a.out} symbol
3940This is an arbitrary 16-bit value. You may establish a symbol's
3941descriptor value by using a @code{.desc} statement
3942(@pxref{Desc,,@code{.desc}}). A descriptor value means nothing to
a4fb0134 3943@command{@value{AS}}.
252b5132
RH
3944
3945@node Symbol Other
3946@subsubsection Other
3947
3948@cindex other attribute, of @code{a.out} symbol
a4fb0134 3949This is an arbitrary 8-bit value. It means nothing to @command{@value{AS}}.
252b5132
RH
3950@end ifset
3951
3952@ifset COFF
3953@node COFF Symbols
3954@subsection Symbol Attributes for COFF
3955
3956@cindex COFF symbol attributes
3957@cindex symbol attributes, COFF
3958
3959The COFF format supports a multitude of auxiliary symbol attributes;
3960like the primary symbol attributes, they are set between @code{.def} and
3961@code{.endef} directives.
3962
3963@subsubsection Primary Attributes
3964
3965@cindex primary attributes, COFF symbols
3966The symbol name is set with @code{.def}; the value and type,
3967respectively, with @code{.val} and @code{.type}.
3968
3969@subsubsection Auxiliary Attributes
3970
3971@cindex auxiliary attributes, COFF symbols
a4fb0134 3972The @command{@value{AS}} directives @code{.dim}, @code{.line}, @code{.scl},
c87db184
CF
3973@code{.size}, @code{.tag}, and @code{.weak} can generate auxiliary symbol
3974table information for COFF.
252b5132
RH
3975@end ifset
3976
3977@ifset SOM
3978@node SOM Symbols
3979@subsection Symbol Attributes for SOM
3980
3981@cindex SOM symbol attributes
3982@cindex symbol attributes, SOM
3983
3984The SOM format for the HPPA supports a multitude of symbol attributes set with
3985the @code{.EXPORT} and @code{.IMPORT} directives.
3986
01642c12 3987The attributes are described in @cite{HP9000 Series 800 Assembly
252b5132
RH
3988Language Reference Manual} (HP 92432-90001) under the @code{IMPORT} and
3989@code{EXPORT} assembler directive documentation.
3990@end ifset
3991
3992@node Expressions
3993@chapter Expressions
3994
3995@cindex expressions
3996@cindex addresses
3997@cindex numeric values
3998An @dfn{expression} specifies an address or numeric value.
3999Whitespace may precede and/or follow an expression.
4000
4001The result of an expression must be an absolute number, or else an offset into
4002a particular section. If an expression is not absolute, and there is not
a4fb0134 4003enough information when @command{@value{AS}} sees the expression to know its
252b5132
RH
4004section, a second pass over the source program might be necessary to interpret
4005the expression---but the second pass is currently not implemented.
a4fb0134 4006@command{@value{AS}} aborts with an error message in this situation.
252b5132
RH
4007
4008@menu
4009* Empty Exprs:: Empty Expressions
4010* Integer Exprs:: Integer Expressions
4011@end menu
4012
4013@node Empty Exprs
4014@section Empty Expressions
4015
4016@cindex empty expressions
4017@cindex expressions, empty
4018An empty expression has no value: it is just whitespace or null.
4019Wherever an absolute expression is required, you may omit the
a4fb0134 4020expression, and @command{@value{AS}} assumes a value of (absolute) 0. This
252b5132
RH
4021is compatible with other assemblers.
4022
4023@node Integer Exprs
4024@section Integer Expressions
4025
4026@cindex integer expressions
4027@cindex expressions, integer
4028An @dfn{integer expression} is one or more @emph{arguments} delimited
4029by @emph{operators}.
4030
4031@menu
4032* Arguments:: Arguments
4033* Operators:: Operators
4034* Prefix Ops:: Prefix Operators
4035* Infix Ops:: Infix Operators
4036@end menu
4037
4038@node Arguments
4039@subsection Arguments
4040
4041@cindex expression arguments
4042@cindex arguments in expressions
4043@cindex operands in expressions
4044@cindex arithmetic operands
4045@dfn{Arguments} are symbols, numbers or subexpressions. In other
4046contexts arguments are sometimes called ``arithmetic operands''. In
4047this manual, to avoid confusing them with the ``instruction operands'' of
4048the machine language, we use the term ``argument'' to refer to parts of
4049expressions only, reserving the word ``operand'' to refer only to machine
4050instruction operands.
4051
4052Symbols are evaluated to yield @{@var{section} @var{NNN}@} where
4053@var{section} is one of text, data, bss, absolute,
4054or undefined. @var{NNN} is a signed, 2's complement 32 bit
4055integer.
4056
4057Numbers are usually integers.
4058
4059A number can be a flonum or bignum. In this case, you are warned
a4fb0134 4060that only the low order 32 bits are used, and @command{@value{AS}} pretends
252b5132
RH
4061these 32 bits are an integer. You may write integer-manipulating
4062instructions that act on exotic constants, compatible with other
4063assemblers.
4064
4065@cindex subexpressions
4066Subexpressions are a left parenthesis @samp{(} followed by an integer
4067expression, followed by a right parenthesis @samp{)}; or a prefix
4068operator followed by an argument.
4069
4070@node Operators
4071@subsection Operators
4072
4073@cindex operators, in expressions
4074@cindex arithmetic functions
4075@cindex functions, in expressions
4076@dfn{Operators} are arithmetic functions, like @code{+} or @code{%}. Prefix
4077operators are followed by an argument. Infix operators appear
4078between their arguments. Operators may be preceded and/or followed by
4079whitespace.
4080
4081@node Prefix Ops
4082@subsection Prefix Operator
4083
4084@cindex prefix operators
a4fb0134 4085@command{@value{AS}} has the following @dfn{prefix operators}. They each take
252b5132
RH
4086one argument, which must be absolute.
4087
4088@c the tex/end tex stuff surrounding this small table is meant to make
4089@c it align, on the printed page, with the similar table in the next
4090@c section (which is inside an enumerate).
4091@tex
4092\global\advance\leftskip by \itemindent
4093@end tex
4094
4095@table @code
4096@item -
4097@dfn{Negation}. Two's complement negation.
4098@item ~
4099@dfn{Complementation}. Bitwise not.
4100@end table
4101
4102@tex
4103\global\advance\leftskip by -\itemindent
4104@end tex
4105
4106@node Infix Ops
4107@subsection Infix Operators
4108
4109@cindex infix operators
4110@cindex operators, permitted arguments
4111@dfn{Infix operators} take two arguments, one on either side. Operators
4112have precedence, but operations with equal precedence are performed left
a4fb0134 4113to right. Apart from @code{+} or @option{-}, both arguments must be
252b5132
RH
4114absolute, and the result is absolute.
4115
4116@enumerate
4117@cindex operator precedence
4118@cindex precedence of operators
4119
4120@item
4121Highest Precedence
4122
4123@table @code
4124@item *
4125@dfn{Multiplication}.
4126
4127@item /
4128@dfn{Division}. Truncation is the same as the C operator @samp{/}
4129
4130@item %
4131@dfn{Remainder}.
4132
d1eac9d9 4133@item <<
252b5132
RH
4134@dfn{Shift Left}. Same as the C operator @samp{<<}.
4135
d1eac9d9 4136@item >>
252b5132
RH
4137@dfn{Shift Right}. Same as the C operator @samp{>>}.
4138@end table
4139
4140@item
4141Intermediate precedence
4142
4143@table @code
4144@item |
4145
4146@dfn{Bitwise Inclusive Or}.
4147
4148@item &
4149@dfn{Bitwise And}.
4150
4151@item ^
4152@dfn{Bitwise Exclusive Or}.
4153
4154@item !
4155@dfn{Bitwise Or Not}.
4156@end table
4157
4158@item
b131d4dc 4159Low Precedence
252b5132
RH
4160
4161@table @code
4162@cindex addition, permitted arguments
4163@cindex plus, permitted arguments
4164@cindex arguments for addition
4165@item +
4166@dfn{Addition}. If either argument is absolute, the result has the section of
4167the other argument. You may not add together arguments from different
4168sections.
4169
4170@cindex subtraction, permitted arguments
4171@cindex minus, permitted arguments
4172@cindex arguments for subtraction
4173@item -
4174@dfn{Subtraction}. If the right argument is absolute, the
4175result has the section of the left argument.
4176If both arguments are in the same section, the result is absolute.
4177You may not subtract arguments from different sections.
4178@c FIXME is there still something useful to say about undefined - undefined ?
b131d4dc
NC
4179
4180@cindex comparison expressions
4181@cindex expressions, comparison
4182@item ==
4183@dfn{Is Equal To}
4184@item <>
723a8472 4185@itemx !=
b131d4dc
NC
4186@dfn{Is Not Equal To}
4187@item <
4188@dfn{Is Less Than}
d1eac9d9 4189@item >
b131d4dc 4190@dfn{Is Greater Than}
d1eac9d9 4191@item >=
b131d4dc 4192@dfn{Is Greater Than Or Equal To}
d1eac9d9 4193@item <=
b131d4dc
NC
4194@dfn{Is Less Than Or Equal To}
4195
4196The comparison operators can be used as infix operators. A true results has a
4197value of -1 whereas a false result has a value of 0. Note, these operators
4198perform signed comparisons.
4199@end table
4200
4201@item Lowest Precedence
4202
4203@table @code
4204@item &&
4205@dfn{Logical And}.
4206
4207@item ||
4208@dfn{Logical Or}.
4209
4210These two logical operations can be used to combine the results of sub
4211expressions. Note, unlike the comparison operators a true result returns a
4212value of 1 but a false results does still return 0. Also note that the logical
4213or operator has a slightly lower precedence than logical and.
4214
252b5132
RH
4215@end table
4216@end enumerate
4217
4218In short, it's only meaningful to add or subtract the @emph{offsets} in an
4219address; you can only have a defined section in one of the two arguments.
4220
4221@node Pseudo Ops
4222@chapter Assembler Directives
4223
4224@cindex directives, machine independent
4225@cindex pseudo-ops, machine independent
4226@cindex machine independent directives
4227All assembler directives have names that begin with a period (@samp{.}).
7e302352
RS
4228The names are case insensitive for most targets, and usually written
4229in lower case.
252b5132
RH
4230
4231This chapter discusses directives that are available regardless of the
4232target machine configuration for the @sc{gnu} assembler.
4233@ifset GENERIC
4234Some machine configurations provide additional directives.
4235@xref{Machine Dependencies}.
4236@end ifset
4237@ifclear GENERIC
4238@ifset machine-directives
96e9638b 4239@xref{Machine Dependencies}, for additional directives.
252b5132
RH
4240@end ifset
4241@end ifclear
4242
4243@menu
4244* Abort:: @code{.abort}
4245@ifset COFF
38a57ae7 4246* ABORT (COFF):: @code{.ABORT}
252b5132 4247@end ifset
f0dc282c 4248
252b5132 4249* Align:: @code{.align @var{abs-expr} , @var{abs-expr}}
caa32fe5 4250* Altmacro:: @code{.altmacro}
252b5132
RH
4251* Ascii:: @code{.ascii "@var{string}"}@dots{}
4252* Asciz:: @code{.asciz "@var{string}"}@dots{}
4253* Balign:: @code{.balign @var{abs-expr} , @var{abs-expr}}
d3b47e2b 4254* Bundle directives:: @code{.bundle_align_mode @var{abs-expr}}, etc
252b5132 4255* Byte:: @code{.byte @var{expressions}}
4b7d318b 4256* CFI directives:: @code{.cfi_startproc [simple]}, @code{.cfi_endproc}, etc.
ccf8a69b 4257* Comm:: @code{.comm @var{symbol} , @var{length} }
252b5132 4258* Data:: @code{.data @var{subsection}}
340d33e5
NC
4259* Dc:: @code{.dc[@var{size}] @var{expressions}}
4260* Dcb:: @code{.dcb[@var{size}] @var{number} [,@var{fill}]}
4261* Ds:: @code{.ds[@var{size}] @var{number} [,@var{fill}]}
252b5132
RH
4262@ifset COFF
4263* Def:: @code{.def @var{name}}
4264@end ifset
a8eb42a8 4265@ifset aout
252b5132
RH
4266* Desc:: @code{.desc @var{symbol}, @var{abs-expression}}
4267@end ifset
4268@ifset COFF
4269* Dim:: @code{.dim}
4270@end ifset
f0dc282c 4271
252b5132
RH
4272* Double:: @code{.double @var{flonums}}
4273* Eject:: @code{.eject}
4274* Else:: @code{.else}
3fd9f047 4275* Elseif:: @code{.elseif}
252b5132
RH
4276* End:: @code{.end}
4277@ifset COFF
4278* Endef:: @code{.endef}
4279@end ifset
f0dc282c 4280
252b5132
RH
4281* Endfunc:: @code{.endfunc}
4282* Endif:: @code{.endif}
4283* Equ:: @code{.equ @var{symbol}, @var{expression}}
4284* Equiv:: @code{.equiv @var{symbol}, @var{expression}}
9497f5ac 4285* Eqv:: @code{.eqv @var{symbol}, @var{expression}}
252b5132 4286* Err:: @code{.err}
d190d046 4287* Error:: @code{.error @var{string}}
252b5132
RH
4288* Exitm:: @code{.exitm}
4289* Extern:: @code{.extern}
4290* Fail:: @code{.fail}
14082c76 4291* File:: @code{.file}
252b5132
RH
4292* Fill:: @code{.fill @var{repeat} , @var{size} , @var{value}}
4293* Float:: @code{.float @var{flonums}}
01642c12 4294* Func:: @code{.func}
252b5132 4295* Global:: @code{.global @var{symbol}}, @code{.globl @var{symbol}}
c91d2e08 4296@ifset ELF
3a99f02f 4297* Gnu_attribute:: @code{.gnu_attribute @var{tag},@var{value}}
c91d2e08
NC
4298* Hidden:: @code{.hidden @var{names}}
4299@end ifset
f0dc282c 4300
252b5132
RH
4301* hword:: @code{.hword @var{expressions}}
4302* Ident:: @code{.ident}
4303* If:: @code{.if @var{absolute expression}}
7e005732 4304* Incbin:: @code{.incbin "@var{file}"[,@var{skip}[,@var{count}]]}
252b5132
RH
4305* Include:: @code{.include "@var{file}"}
4306* Int:: @code{.int @var{expressions}}
c91d2e08
NC
4307@ifset ELF
4308* Internal:: @code{.internal @var{names}}
4309@end ifset
f0dc282c 4310
252b5132
RH
4311* Irp:: @code{.irp @var{symbol},@var{values}}@dots{}
4312* Irpc:: @code{.irpc @var{symbol},@var{values}}@dots{}
4313* Lcomm:: @code{.lcomm @var{symbol} , @var{length}}
4314* Lflags:: @code{.lflags}
4315@ifclear no-line-dir
4316* Line:: @code{.line @var{line-number}}
4317@end ifclear
f0dc282c 4318
252b5132
RH
4319* Linkonce:: @code{.linkonce [@var{type}]}
4320* List:: @code{.list}
bd0eb99b 4321* Ln:: @code{.ln @var{line-number}}
14082c76
BW
4322* Loc:: @code{.loc @var{fileno} @var{lineno}}
4323* Loc_mark_labels:: @code{.loc_mark_labels @var{enable}}
4d4175af
BW
4324@ifset ELF
4325* Local:: @code{.local @var{names}}
4326@end ifset
bd0eb99b 4327
252b5132
RH
4328* Long:: @code{.long @var{expressions}}
4329@ignore
4330* Lsym:: @code{.lsym @var{symbol}, @var{expression}}
4331@end ignore
f0dc282c 4332
252b5132
RH
4333* Macro:: @code{.macro @var{name} @var{args}}@dots{}
4334* MRI:: @code{.mri @var{val}}
caa32fe5 4335* Noaltmacro:: @code{.noaltmacro}
252b5132 4336* Nolist:: @code{.nolist}
8f065d3b 4337* Nops:: @code{.nops @var{size}[, @var{control}]}
252b5132 4338* Octa:: @code{.octa @var{bignums}}
9aec2026 4339* Offset:: @code{.offset @var{loc}}
85234291
L
4340* Org:: @code{.org @var{new-lc}, @var{fill}}
4341* P2align:: @code{.p2align @var{abs-expr}, @var{abs-expr}, @var{abs-expr}}
c91d2e08
NC
4342@ifset ELF
4343* PopSection:: @code{.popsection}
4344* Previous:: @code{.previous}
4345@end ifset
f0dc282c 4346
252b5132 4347* Print:: @code{.print @var{string}}
c91d2e08
NC
4348@ifset ELF
4349* Protected:: @code{.protected @var{names}}
4350@end ifset
f0dc282c 4351
252b5132
RH
4352* Psize:: @code{.psize @var{lines}, @var{columns}}
4353* Purgem:: @code{.purgem @var{name}}
c91d2e08
NC
4354@ifset ELF
4355* PushSection:: @code{.pushsection @var{name}}
4356@end ifset
f0dc282c 4357
252b5132 4358* Quad:: @code{.quad @var{bignums}}
05e9452c 4359* Reloc:: @code{.reloc @var{offset}, @var{reloc_name}[, @var{expression}]}
252b5132
RH
4360* Rept:: @code{.rept @var{count}}
4361* Sbttl:: @code{.sbttl "@var{subheading}"}
4362@ifset COFF
4363* Scl:: @code{.scl @var{class}}
c1253627
NC
4364@end ifset
4365@ifset COFF-ELF
7337fc21 4366* Section:: @code{.section @var{name}[, @var{flags}]}
252b5132 4367@end ifset
f0dc282c 4368
252b5132
RH
4369* Set:: @code{.set @var{symbol}, @var{expression}}
4370* Short:: @code{.short @var{expressions}}
4371* Single:: @code{.single @var{flonums}}
c1253627 4372@ifset COFF-ELF
c91d2e08 4373* Size:: @code{.size [@var{name} , @var{expression}]}
c1253627 4374@end ifset
884f0d36 4375@ifclear no-space-dir
340d33e5 4376* Skip:: @code{.skip @var{size} [,@var{fill}]}
884f0d36
BW
4377@end ifclear
4378
252b5132 4379* Sleb128:: @code{.sleb128 @var{expressions}}
884f0d36 4380@ifclear no-space-dir
340d33e5 4381* Space:: @code{.space @var{size} [,@var{fill}]}
884f0d36 4382@end ifclear
252b5132
RH
4383@ifset have-stabs
4384* Stab:: @code{.stabd, .stabn, .stabs}
4385@end ifset
f0dc282c 4386
38a57ae7 4387* String:: @code{.string "@var{str}"}, @code{.string8 "@var{str}"}, @code{.string16 "@var{str}"}, @code{.string32 "@var{str}"}, @code{.string64 "@var{str}"}
252b5132
RH
4388* Struct:: @code{.struct @var{expression}}
4389@ifset ELF
c91d2e08 4390* SubSection:: @code{.subsection}
252b5132
RH
4391* Symver:: @code{.symver @var{name},@var{name2@@nodename}}
4392@end ifset
f0dc282c 4393
252b5132
RH
4394@ifset COFF
4395* Tag:: @code{.tag @var{structname}}
4396@end ifset
f0dc282c 4397
252b5132
RH
4398* Text:: @code{.text @var{subsection}}
4399* Title:: @code{.title "@var{heading}"}
c1253627 4400@ifset COFF-ELF
c91d2e08 4401* Type:: @code{.type <@var{int} | @var{name} , @var{type description}>}
c1253627
NC
4402@end ifset
4403
c91d2e08 4404* Uleb128:: @code{.uleb128 @var{expressions}}
252b5132 4405@ifset COFF
252b5132
RH
4406* Val:: @code{.val @var{addr}}
4407@end ifset
f0dc282c 4408
2e13b764 4409@ifset ELF
c91d2e08 4410* Version:: @code{.version "@var{string}"}
c91d2e08
NC
4411* VTableEntry:: @code{.vtable_entry @var{table}, @var{offset}}
4412* VTableInherit:: @code{.vtable_inherit @var{child}, @var{parent}}
2e13b764 4413@end ifset
f0dc282c 4414
d190d046 4415* Warning:: @code{.warning @var{string}}
c87db184 4416* Weak:: @code{.weak @var{names}}
06e77878 4417* Weakref:: @code{.weakref @var{alias}, @var{symbol}}
252b5132 4418* Word:: @code{.word @var{expressions}}
7ce98c16
NC
4419@ifclear no-space-dir
4420* Zero:: @code{.zero @var{size}}
4421@end ifclear
2b841ec2
AM
4422@ifset ELF
4423* 2byte:: @code{.2byte @var{expressions}}
4424* 4byte:: @code{.4byte @var{expressions}}
4425* 8byte:: @code{.8byte @var{bignums}}
4426@end ifset
252b5132
RH
4427* Deprecated:: Deprecated Directives
4428@end menu
4429
4430@node Abort
4431@section @code{.abort}
4432
4433@cindex @code{abort} directive
4434@cindex stopping the assembly
4435This directive stops the assembly immediately. It is for
4436compatibility with other assemblers. The original idea was that the
4437assembly language source would be piped into the assembler. If the sender
a4fb0134 4438of the source quit, it could use this directive tells @command{@value{AS}} to
252b5132
RH
4439quit also. One day @code{.abort} will not be supported.
4440
4441@ifset COFF
370b66a1
CD
4442@node ABORT (COFF)
4443@section @code{.ABORT} (COFF)
252b5132
RH
4444
4445@cindex @code{ABORT} directive
a4fb0134 4446When producing COFF output, @command{@value{AS}} accepts this directive as a
252b5132
RH
4447synonym for @samp{.abort}.
4448
252b5132
RH
4449@end ifset
4450
4451@node Align
4452@section @code{.align @var{abs-expr}, @var{abs-expr}, @var{abs-expr}}
4453
4454@cindex padding the location counter
4455@cindex @code{align} directive
4456Pad the location counter (in the current subsection) to a particular storage
4457boundary. The first expression (which must be absolute) is the alignment
4458required, as described below.
4459
4460The second expression (also absolute) gives the fill value to be stored in the
4461padding bytes. It (and the comma) may be omitted. If it is omitted, the
2ca23e65 4462padding bytes are normally zero. However, on most systems, if the section is
252b5132
RH
4463marked as containing code and the fill value is omitted, the space is filled
4464with no-op instructions.
4465
4466The third expression is also absolute, and is also optional. If it is present,
4467it is the maximum number of bytes that should be skipped by this alignment
4468directive. If doing the alignment would require skipping more bytes than the
4469specified maximum, then the alignment is not done at all. You can omit the
4470fill value (the second argument) entirely by simply using two commas after the
4471required alignment; this can be useful if you want the alignment to be filled
4472with no-op instructions when appropriate.
4473
4474The way the required alignment is specified varies from system to system.
a8eb42a8 4475For the arc, hppa, i386 using ELF, iq2000, m68k, or1k,
60946ad0 4476s390, sparc, tic4x, tic80 and xtensa, the first expression is the
252b5132
RH
4477alignment request in bytes. For example @samp{.align 8} advances
4478the location counter until it is a multiple of 8. If the location counter
60946ad0
AM
4479is already a multiple of 8, no change is needed. For the tic54x, the
4480first expression is the alignment request in words.
252b5132 4481
9e9a9798 4482For other systems, including ppc, i386 using a.out format, arm and
adcf07e6 4483strongarm, it is the
252b5132
RH
4484number of low-order zero bits the location counter must have after
4485advancement. For example @samp{.align 3} advances the location
4486counter until it a multiple of 8. If the location counter is already a
4487multiple of 8, no change is needed.
4488
4489This inconsistency is due to the different behaviors of the various
4490native assemblers for these systems which GAS must emulate.
4491GAS also provides @code{.balign} and @code{.p2align} directives,
4492described later, which have a consistent behavior across all
4493architectures (but are specific to GAS).
4494
ccf8a69b
BW
4495@node Altmacro
4496@section @code{.altmacro}
4497Enable alternate macro mode, enabling:
4498
4499@ftable @code
4500@item LOCAL @var{name} [ , @dots{} ]
4501One additional directive, @code{LOCAL}, is available. It is used to
4502generate a string replacement for each of the @var{name} arguments, and
4503replace any instances of @var{name} in each macro expansion. The
4504replacement string is unique in the assembly, and different for each
4505separate macro expansion. @code{LOCAL} allows you to write macros that
4506define symbols, without fear of conflict between separate macro expansions.
4507
4508@item String delimiters
4509You can write strings delimited in these other ways besides
4510@code{"@var{string}"}:
4511
4512@table @code
4513@item '@var{string}'
4514You can delimit strings with single-quote characters.
4515
4516@item <@var{string}>
4517You can delimit strings with matching angle brackets.
4518@end table
4519
4520@item single-character string escape
4521To include any single character literally in a string (even if the
4522character would otherwise have some special meaning), you can prefix the
4523character with @samp{!} (an exclamation mark). For example, you can
4524write @samp{<4.3 !> 5.4!!>} to get the literal text @samp{4.3 > 5.4!}.
4525
4526@item Expression results as strings
4527You can write @samp{%@var{expr}} to evaluate the expression @var{expr}
01642c12 4528and use the result as a string.
ccf8a69b
BW
4529@end ftable
4530
252b5132
RH
4531@node Ascii
4532@section @code{.ascii "@var{string}"}@dots{}
4533
4534@cindex @code{ascii} directive
4535@cindex string literals
4536@code{.ascii} expects zero or more string literals (@pxref{Strings})
4537separated by commas. It assembles each string (with no automatic
4538trailing zero byte) into consecutive addresses.
4539
4540@node Asciz
4541@section @code{.asciz "@var{string}"}@dots{}
4542
4543@cindex @code{asciz} directive
4544@cindex zero-terminated strings
4545@cindex null-terminated strings
4546@code{.asciz} is just like @code{.ascii}, but each string is followed by
4547a zero byte. The ``z'' in @samp{.asciz} stands for ``zero''.
4548
4549@node Balign
4550@section @code{.balign[wl] @var{abs-expr}, @var{abs-expr}, @var{abs-expr}}
4551
4552@cindex padding the location counter given number of bytes
4553@cindex @code{balign} directive
4554Pad the location counter (in the current subsection) to a particular
4555storage boundary. The first expression (which must be absolute) is the
4556alignment request in bytes. For example @samp{.balign 8} advances
4557the location counter until it is a multiple of 8. If the location counter
4558is already a multiple of 8, no change is needed.
4559
4560The second expression (also absolute) gives the fill value to be stored in the
4561padding bytes. It (and the comma) may be omitted. If it is omitted, the
2ca23e65 4562padding bytes are normally zero. However, on most systems, if the section is
252b5132
RH
4563marked as containing code and the fill value is omitted, the space is filled
4564with no-op instructions.
4565
4566The third expression is also absolute, and is also optional. If it is present,
4567it is the maximum number of bytes that should be skipped by this alignment
4568directive. If doing the alignment would require skipping more bytes than the
4569specified maximum, then the alignment is not done at all. You can omit the
4570fill value (the second argument) entirely by simply using two commas after the
4571required alignment; this can be useful if you want the alignment to be filled
4572with no-op instructions when appropriate.
4573
4574@cindex @code{balignw} directive
4575@cindex @code{balignl} directive
4576The @code{.balignw} and @code{.balignl} directives are variants of the
4577@code{.balign} directive. The @code{.balignw} directive treats the fill
4578pattern as a two byte word value. The @code{.balignl} directives treats the
4579fill pattern as a four byte longword value. For example, @code{.balignw
45804,0x368d} will align to a multiple of 4. If it skips two bytes, they will be
4581filled in with the value 0x368d (the exact placement of the bytes depends upon
4582the endianness of the processor). If it skips 1 or 3 bytes, the fill value is
4583undefined.
4584
fa94de6b 4585@node Bundle directives
d3b47e2b
L
4586@section Bundle directives
4587@subsection @code{.bundle_align_mode @var{abs-expr}}
fa94de6b
RM
4588@cindex @code{bundle_align_mode} directive
4589@cindex bundle
4590@cindex instruction bundle
4591@cindex aligned instruction bundle
ec82c18e 4592@code{.bundle_align_mode} enables or disables @dfn{aligned instruction
fa94de6b 4593bundle} mode. In this mode, sequences of adjacent instructions are grouped
ec82c18e 4594into fixed-sized @dfn{bundles}. If the argument is zero, this mode is
27dcf5c0 4595disabled (which is the default state). If the argument it not zero, it
fa94de6b
RM
4596gives the size of an instruction bundle as a power of two (as for the
4597@code{.p2align} directive, @pxref{P2align}).
4598
4599For some targets, it's an ABI requirement that no instruction may span a
ec82c18e 4600certain aligned boundary. A @dfn{bundle} is simply a sequence of
fa94de6b
RM
4601instructions that starts on an aligned boundary. For example, if
4602@var{abs-expr} is @code{5} then the bundle size is 32, so each aligned
4603chunk of 32 bytes is a bundle. When aligned instruction bundle mode is in
4604effect, no single instruction may span a boundary between bundles. If an
4605instruction would start too close to the end of a bundle for the length of
4606that particular instruction to fit within the bundle, then the space at the
4607end of that bundle is filled with no-op instructions so the instruction
4608starts in the next bundle. As a corollary, it's an error if any single
4609instruction's encoding is longer than the bundle size.
4610
d3b47e2b 4611@subsection @code{.bundle_lock} and @code{.bundle_unlock}
fa94de6b
RM
4612@cindex @code{bundle_lock} directive
4613@cindex @code{bundle_unlock} directive
4614The @code{.bundle_lock} and directive @code{.bundle_unlock} directives
4615allow explicit control over instruction bundle padding. These directives
4616are only valid when @code{.bundle_align_mode} has been used to enable
4617aligned instruction bundle mode. It's an error if they appear when
4618@code{.bundle_align_mode} has not been used at all, or when the last
4619directive was @w{@code{.bundle_align_mode 0}}.
4620
4621@cindex bundle-locked
4622For some targets, it's an ABI requirement that certain instructions may
4623appear only as part of specified permissible sequences of multiple
4624instructions, all within the same bundle. A pair of @code{.bundle_lock}
ec82c18e 4625and @code{.bundle_unlock} directives define a @dfn{bundle-locked}
fa94de6b
RM
4626instruction sequence. For purposes of aligned instruction bundle mode, a
4627sequence starting with @code{.bundle_lock} and ending with
4628@code{.bundle_unlock} is treated as a single instruction. That is, the
4629entire sequence must fit into a single bundle and may not span a bundle
4630boundary. If necessary, no-op instructions will be inserted before the
4631first instruction of the sequence so that the whole sequence starts on an
4632aligned bundle boundary. It's an error if the sequence is longer than the
4633bundle size.
4634
d416e51d
RM
4635For convenience when using @code{.bundle_lock} and @code{.bundle_unlock}
4636inside assembler macros (@pxref{Macro}), bundle-locked sequences may be
4637nested. That is, a second @code{.bundle_lock} directive before the next
4638@code{.bundle_unlock} directive has no effect except that it must be
4639matched by another closing @code{.bundle_unlock} so that there is the
4640same number of @code{.bundle_lock} and @code{.bundle_unlock} directives.
fa94de6b 4641
252b5132
RH
4642@node Byte
4643@section @code{.byte @var{expressions}}
4644
4645@cindex @code{byte} directive
4646@cindex integers, one byte
4647@code{.byte} expects zero or more expressions, separated by commas.
4648Each expression is assembled into the next byte.
4649
54cfded0 4650@node CFI directives
d3b47e2b
L
4651@section CFI directives
4652@subsection @code{.cfi_sections @var{section_list}}
38462edf
JJ
4653@cindex @code{cfi_sections} directive
4654@code{.cfi_sections} may be used to specify whether CFI directives
4655should emit @code{.eh_frame} section and/or @code{.debug_frame} section.
4656If @var{section_list} is @code{.eh_frame}, @code{.eh_frame} is emitted,
4657if @var{section_list} is @code{.debug_frame}, @code{.debug_frame} is emitted.
4658To emit both use @code{.eh_frame, .debug_frame}. The default if this
4659directive is not used is @code{.cfi_sections .eh_frame}.
4660
2f0c68f2
CM
4661On targets that support compact unwinding tables these can be generated
4662by specifying @code{.eh_frame_entry} instead of @code{.eh_frame}.
4663
bd5608dc
NC
4664Some targets may support an additional name, such as @code{.c6xabi.exidx}
4665which is used by the @value{TIC6X} target.
4666
4667The @code{.cfi_sections} directive can be repeated, with the same or different
4668arguments, provided that CFI generation has not yet started. Once CFI
4669generation has started however the section list is fixed and any attempts to
4670redefine it will result in an error.
4671
d3b47e2b 4672@subsection @code{.cfi_startproc [simple]}
54cfded0
AM
4673@cindex @code{cfi_startproc} directive
4674@code{.cfi_startproc} is used at the beginning of each function that
4675should have an entry in @code{.eh_frame}. It initializes some internal
4b7d318b 4676data structures. Don't forget to close the function by
54cfded0
AM
4677@code{.cfi_endproc}.
4678
01642c12 4679Unless @code{.cfi_startproc} is used along with parameter @code{simple}
4b7d318b 4680it also emits some architecture dependent initial CFI instructions.
01642c12 4681
d3b47e2b 4682@subsection @code{.cfi_endproc}
54cfded0
AM
4683@cindex @code{cfi_endproc} directive
4684@code{.cfi_endproc} is used at the end of a function where it closes its
4685unwind entry previously opened by
b45619c0 4686@code{.cfi_startproc}, and emits it to @code{.eh_frame}.
54cfded0 4687
d3b47e2b 4688@subsection @code{.cfi_personality @var{encoding} [, @var{exp}]}
2f0c68f2 4689@cindex @code{cfi_personality} directive
9b8ae42e
JJ
4690@code{.cfi_personality} defines personality routine and its encoding.
4691@var{encoding} must be a constant determining how the personality
4692should be encoded. If it is 255 (@code{DW_EH_PE_omit}), second
4693argument is not present, otherwise second argument should be
4694a constant or a symbol name. When using indirect encodings,
4695the symbol provided should be the location where personality
4696can be loaded from, not the personality routine itself.
4697The default after @code{.cfi_startproc} is @code{.cfi_personality 0xff},
4698no personality routine.
4699
2f0c68f2
CM
4700@subsection @code{.cfi_personality_id @var{id}}
4701@cindex @code{cfi_personality_id} directive
4702@code{cfi_personality_id} defines a personality routine by its index as
4703defined in a compact unwinding format.
4704Only valid when generating compact EH frames (i.e.
4705with @code{.cfi_sections eh_frame_entry}.
4706
4707@subsection @code{.cfi_fde_data [@var{opcode1} [, @dots{}]]}
4708@cindex @code{cfi_fde_data} directive
4709@code{cfi_fde_data} is used to describe the compact unwind opcodes to be
4710used for the current function. These are emitted inline in the
4711@code{.eh_frame_entry} section if small enough and there is no LSDA, or
4712in the @code{.gnu.extab} section otherwise.
4713Only valid when generating compact EH frames (i.e.
4714with @code{.cfi_sections eh_frame_entry}.
4715
d3b47e2b 4716@subsection @code{.cfi_lsda @var{encoding} [, @var{exp}]}
9b8ae42e
JJ
4717@code{.cfi_lsda} defines LSDA and its encoding.
4718@var{encoding} must be a constant determining how the LSDA
2f0c68f2
CM
4719should be encoded. If it is 255 (@code{DW_EH_PE_omit}), the second
4720argument is not present, otherwise the second argument should be a constant
9b8ae42e 4721or a symbol name. The default after @code{.cfi_startproc} is @code{.cfi_lsda 0xff},
2f0c68f2
CM
4722meaning that no LSDA is present.
4723
4724@subsection @code{.cfi_inline_lsda} [@var{align}]
4725@code{.cfi_inline_lsda} marks the start of a LSDA data section and
4726switches to the corresponding @code{.gnu.extab} section.
4727Must be preceded by a CFI block containing a @code{.cfi_lsda} directive.
4728Only valid when generating compact EH frames (i.e.
4729with @code{.cfi_sections eh_frame_entry}.
4730
4731The table header and unwinding opcodes will be generated at this point,
4732so that they are immediately followed by the LSDA data. The symbol
4733referenced by the @code{.cfi_lsda} directive should still be defined
4734in case a fallback FDE based encoding is used. The LSDA data is terminated
4735by a section directive.
4736
4737The optional @var{align} argument specifies the alignment required.
4738The alignment is specified as a power of two, as with the
4739@code{.p2align} directive.
9b8ae42e 4740
d3b47e2b 4741@subsection @code{.cfi_def_cfa @var{register}, @var{offset}}
01642c12 4742@code{.cfi_def_cfa} defines a rule for computing CFA as: @i{take
54cfded0
AM
4743address from @var{register} and add @var{offset} to it}.
4744
d3b47e2b 4745@subsection @code{.cfi_def_cfa_register @var{register}}
54cfded0
AM
4746@code{.cfi_def_cfa_register} modifies a rule for computing CFA. From
4747now on @var{register} will be used instead of the old one. Offset
4748remains the same.
4749
d3b47e2b 4750@subsection @code{.cfi_def_cfa_offset @var{offset}}
54cfded0
AM
4751@code{.cfi_def_cfa_offset} modifies a rule for computing CFA. Register
4752remains the same, but @var{offset} is new. Note that it is the
4753absolute offset that will be added to a defined register to compute
4754CFA address.
4755
d3b47e2b 4756@subsection @code{.cfi_adjust_cfa_offset @var{offset}}
54cfded0 4757Same as @code{.cfi_def_cfa_offset} but @var{offset} is a relative
33eaf5de 4758value that is added/subtracted from the previous offset.
54cfded0 4759
d3b47e2b 4760@subsection @code{.cfi_offset @var{register}, @var{offset}}
54cfded0 4761Previous value of @var{register} is saved at offset @var{offset} from
01642c12 4762CFA.
54cfded0 4763
084303b8
AK
4764@subsection @code{.cfi_val_offset @var{register}, @var{offset}}
4765Previous value of @var{register} is CFA + @var{offset}.
4766
d3b47e2b 4767@subsection @code{.cfi_rel_offset @var{register}, @var{offset}}
17076204
RH
4768Previous value of @var{register} is saved at offset @var{offset} from
4769the current CFA register. This is transformed to @code{.cfi_offset}
4770using the known displacement of the CFA register from the CFA.
4771This is often easier to use, because the number will match the
4772code it's annotating.
54cfded0 4773
d3b47e2b 4774@subsection @code{.cfi_register @var{register1}, @var{register2}}
4b7d318b
L
4775Previous value of @var{register1} is saved in register @var{register2}.
4776
d3b47e2b 4777@subsection @code{.cfi_restore @var{register}}
01642c12
RM
4778@code{.cfi_restore} says that the rule for @var{register} is now the
4779same as it was at the beginning of the function, after all initial
4b7d318b
L
4780instruction added by @code{.cfi_startproc} were executed.
4781
d3b47e2b 4782@subsection @code{.cfi_undefined @var{register}}
4b7d318b
L
4783From now on the previous value of @var{register} can't be restored anymore.
4784
d3b47e2b 4785@subsection @code{.cfi_same_value @var{register}}
01642c12 4786Current value of @var{register} is the same like in the previous frame,
4b7d318b
L
4787i.e. no restoration needed.
4788
48eac74c
MG
4789@subsection @code{.cfi_remember_state} and @code{.cfi_restore_state}
4790@code{.cfi_remember_state} pushes the set of rules for every register onto an
4791implicit stack, while @code{.cfi_restore_state} pops them off the stack and
4792places them in the current row. This is useful for situations where you have
4793multiple @code{.cfi_*} directives that need to be undone due to the control
4794flow of the program. For example, we could have something like this (assuming
4795the CFA is the value of @code{rbp}):
4796
4797@smallexample
4798 je label
4799 popq %rbx
4800 .cfi_restore %rbx
4801 popq %r12
4802 .cfi_restore %r12
4803 popq %rbp
4804 .cfi_restore %rbp
4805 .cfi_def_cfa %rsp, 8
4806 ret
4807label:
4808 /* Do something else */
4809@end smallexample
4810
4811Here, we want the @code{.cfi} directives to affect only the rows corresponding
4812to the instructions before @code{label}. This means we'd have to add multiple
4813@code{.cfi} directives after @code{label} to recreate the original save
4814locations of the registers, as well as setting the CFA back to the value of
4815@code{rbp}. This would be clumsy, and result in a larger binary size. Instead,
4816we can write:
4817
4818@smallexample
4819 je label
4820 popq %rbx
4821 .cfi_remember_state
4822 .cfi_restore %rbx
4823 popq %r12
4824 .cfi_restore %r12
4825 popq %rbp
4826 .cfi_restore %rbp
4827 .cfi_def_cfa %rsp, 8
4828 ret
4829label:
4830 .cfi_restore_state
4831 /* Do something else */
4832@end smallexample
4833
4834That way, the rules for the instructions after @code{label} will be the same
4835as before the first @code{.cfi_restore} without having to use multiple
4836@code{.cfi} directives.
4b7d318b 4837
d3b47e2b 4838@subsection @code{.cfi_return_column @var{register}}
01642c12 4839Change return column @var{register}, i.e. the return address is either
4b7d318b
L
4840directly in @var{register} or can be accessed by rules for @var{register}.
4841
d3b47e2b 4842@subsection @code{.cfi_signal_frame}
63752a75
JJ
4843Mark current function as signal trampoline.
4844
d3b47e2b 4845@subsection @code{.cfi_window_save}
364b6d8b
JJ
4846SPARC register window has been saved.
4847
d3b47e2b 4848@subsection @code{.cfi_escape} @var{expression}[, @dots{}]
cdfbf930
RH
4849Allows the user to add arbitrary bytes to the unwind info. One
4850might use this to add OS-specific CFI opcodes, or generic CFI
4851opcodes that GAS does not yet support.
252b5132 4852
d3b47e2b 4853@subsection @code{.cfi_val_encoded_addr @var{register}, @var{encoding}, @var{label}}
f1c4cc75
RH
4854The current value of @var{register} is @var{label}. The value of @var{label}
4855will be encoded in the output file according to @var{encoding}; see the
4856description of @code{.cfi_personality} for details on this encoding.
4857
4858The usefulness of equating a register to a fixed label is probably
4859limited to the return address register. Here, it can be useful to
4860mark a code segment that has only one return address which is reached
4861by a direct branch and no copy of the return address exists in memory
4862or another register.
4863
ccf8a69b
BW
4864@node Comm
4865@section @code{.comm @var{symbol} , @var{length} }
bd0eb99b 4866
ccf8a69b
BW
4867@cindex @code{comm} directive
4868@cindex symbol, common
4869@code{.comm} declares a common symbol named @var{symbol}. When linking, a
4870common symbol in one object file may be merged with a defined or common symbol
4871of the same name in another object file. If @code{@value{LD}} does not see a
4872definition for the symbol--just one or more common symbols--then it will
4873allocate @var{length} bytes of uninitialized memory. @var{length} must be an
4874absolute expression. If @code{@value{LD}} sees multiple common symbols with
4875the same name, and they do not all have the same size, it will allocate space
4876using the largest size.
07a53e5c 4877
c1711530
DK
4878@ifset COFF-ELF
4879When using ELF or (as a GNU extension) PE, the @code{.comm} directive takes
01642c12 4880an optional third argument. This is the desired alignment of the symbol,
c1711530
DK
4881specified for ELF as a byte boundary (for example, an alignment of 16 means
4882that the least significant 4 bits of the address should be zero), and for PE
4883as a power of two (for example, an alignment of 5 means aligned to a 32-byte
01642c12 4884boundary). The alignment must be an absolute expression, and it must be a
c1711530 4885power of two. If @code{@value{LD}} allocates uninitialized memory for the
01642c12 4886common symbol, it will use the alignment when placing the symbol. If no
c1711530 4887alignment is specified, @command{@value{AS}} will set the alignment to the
ccf8a69b 4888largest power of two less than or equal to the size of the symbol, up to a
c1711530
DK
4889maximum of 16 on ELF, or the default section alignment of 4 on PE@footnote{This
4890is not the same as the executable image file alignment controlled by @code{@value{LD}}'s
4891@samp{--section-alignment} option; image file sections in PE are aligned to
4892multiples of 4096, which is far too large an alignment for ordinary variables.
4893It is rather the default alignment for (non-debug) sections within object
4894(@samp{*.o}) files, which are less strictly aligned.}.
ccf8a69b 4895@end ifset
cd1fcb49 4896
ccf8a69b
BW
4897@ifset HPPA
4898The syntax for @code{.comm} differs slightly on the HPPA. The syntax is
4899@samp{@var{symbol} .comm, @var{length}}; @var{symbol} is optional.
4900@end ifset
07a53e5c 4901
252b5132
RH
4902@node Data
4903@section @code{.data @var{subsection}}
252b5132 4904@cindex @code{data} directive
340d33e5 4905
a4fb0134 4906@code{.data} tells @command{@value{AS}} to assemble the following statements onto the
252b5132
RH
4907end of the data subsection numbered @var{subsection} (which is an
4908absolute expression). If @var{subsection} is omitted, it defaults
4909to zero.
4910
340d33e5
NC
4911@node Dc
4912@section @code{.dc[@var{size}] @var{expressions}}
4913@cindex @code{dc} directive
4914
46c685ac 4915The @code{.dc} directive expects zero or more @var{expressions} separated by
340d33e5
NC
4916commas. These expressions are evaluated and their values inserted into the
4917current section. The size of the emitted value depends upon the suffix to the
4918@code{.dc} directive:
4919
4920@table @code
4921@item @samp{.a}
4922Emits N-bit values, where N is the size of an address on the target system.
4923@item @samp{.b}
4924Emits 8-bit values.
4925@item @samp{.d}
4926Emits double precision floating-point values.
4927@item @samp{.l}
4928Emits 32-bit values.
4929@item @samp{.s}
4930Emits single precision floating-point values.
4931@item @samp{.w}
4932Emits 16-bit values.
4933Note - this is true even on targets where the @code{.word} directive would emit
493432-bit values.
4935@item @samp{.x}
4936Emits long double precision floating-point values.
4937@end table
4938
4939If no suffix is used then @samp{.w} is assumed.
4940
d7c79856
MR
4941The byte ordering is target dependent, as is the size and format of floating
4942point values.
340d33e5
NC
4943
4944@node Dcb
4945@section @code{.dcb[@var{size}] @var{number} [,@var{fill}]}
4946@cindex @code{dcb} directive
4947This directive emits @var{number} copies of @var{fill}, each of @var{size}
4948bytes. Both @var{number} and @var{fill} are absolute expressions. If the
4949comma and @var{fill} are omitted, @var{fill} is assumed to be zero. The
4950@var{size} suffix, if present, must be one of:
4951
4952@table @code
4953@item @samp{.b}
4954Emits single byte values.
4955@item @samp{.d}
4956Emits double-precision floating point values.
4957@item @samp{.l}
4958Emits 4-byte values.
4959@item @samp{.s}
4960Emits single-precision floating point values.
4961@item @samp{.w}
4962Emits 2-byte values.
4963@item @samp{.x}
4964Emits long double-precision floating point values.
4965@end table
4966
4967If the @var{size} suffix is omitted then @samp{.w} is assumed.
4968
4969The byte ordering is target dependent, as is the size and format of floating
4970point values.
4971
4972@node Ds
4973@section @code{.ds[@var{size}] @var{number} [,@var{fill}]}
4974@cindex @code{ds} directive
4975This directive emits @var{number} copies of @var{fill}, each of @var{size}
4976bytes. Both @var{number} and @var{fill} are absolute expressions. If the
4977comma and @var{fill} are omitted, @var{fill} is assumed to be zero. The
4978@var{size} suffix, if present, must be one of:
4979
4980@table @code
4981@item @samp{.b}
4982Emits single byte values.
4983@item @samp{.d}
4984Emits 8-byte values.
4985@item @samp{.l}
4986Emits 4-byte values.
4987@item @samp{.p}
4988Emits 12-byte values.
4989@item @samp{.s}
4990Emits 4-byte values.
4991@item @samp{.w}
4992Emits 2-byte values.
4993@item @samp{.x}
4994Emits 12-byte values.
4995@end table
4996
4997Note - unlike the @code{.dcb} directive the @samp{.d}, @samp{.s} and @samp{.x}
d7c79856 4998suffixes do not indicate that floating-point values are to be inserted.
340d33e5
NC
4999
5000If the @var{size} suffix is omitted then @samp{.w} is assumed.
5001
d7c79856 5002The byte ordering is target dependent.
340d33e5
NC
5003
5004
252b5132
RH
5005@ifset COFF
5006@node Def
5007@section @code{.def @var{name}}
5008
5009@cindex @code{def} directive
5010@cindex COFF symbols, debugging
5011@cindex debugging COFF symbols
5012Begin defining debugging information for a symbol @var{name}; the
5013definition extends until the @code{.endef} directive is encountered.
252b5132
RH
5014@end ifset
5015
a8eb42a8 5016@ifset aout
252b5132
RH
5017@node Desc
5018@section @code{.desc @var{symbol}, @var{abs-expression}}
5019
5020@cindex @code{desc} directive
5021@cindex COFF symbol descriptor
5022@cindex symbol descriptor, COFF
5023This directive sets the descriptor of the symbol (@pxref{Symbol Attributes})
5024to the low 16 bits of an absolute expression.
5025
5026@ifset COFF
a4fb0134 5027The @samp{.desc} directive is not available when @command{@value{AS}} is
252b5132 5028configured for COFF output; it is only for @code{a.out} or @code{b.out}
a4fb0134 5029object format. For the sake of compatibility, @command{@value{AS}} accepts
252b5132
RH
5030it, but produces no output, when configured for COFF.
5031@end ifset
5032@end ifset
5033
5034@ifset COFF
5035@node Dim
5036@section @code{.dim}
5037
5038@cindex @code{dim} directive
5039@cindex COFF auxiliary symbol information
5040@cindex auxiliary symbol information, COFF
5041This directive is generated by compilers to include auxiliary debugging
5042information in the symbol table. It is only permitted inside
5043@code{.def}/@code{.endef} pairs.
252b5132
RH
5044@end ifset
5045
5046@node Double
5047@section @code{.double @var{flonums}}
5048
5049@cindex @code{double} directive
5050@cindex floating point numbers (double)
5051@code{.double} expects zero or more flonums, separated by commas. It
5052assembles floating point numbers.
5053@ifset GENERIC
5054The exact kind of floating point numbers emitted depends on how
a4fb0134 5055@command{@value{AS}} is configured. @xref{Machine Dependencies}.
252b5132
RH
5056@end ifset
5057@ifclear GENERIC
5058@ifset IEEEFLOAT
5059On the @value{TARGET} family @samp{.double} emits 64-bit floating-point numbers
5060in @sc{ieee} format.
5061@end ifset
5062@end ifclear
5063
5064@node Eject
5065@section @code{.eject}
5066
5067@cindex @code{eject} directive
5068@cindex new page, in listings
5069@cindex page, in listings
5070@cindex listing control: new page
5071Force a page break at this point, when generating assembly listings.
5072
5073@node Else
5074@section @code{.else}
5075
5076@cindex @code{else} directive
a4fb0134 5077@code{.else} is part of the @command{@value{AS}} support for conditional
96e9638b 5078assembly; see @ref{If,,@code{.if}}. It marks the beginning of a section
252b5132
RH
5079of code to be assembled if the condition for the preceding @code{.if}
5080was false.
5081
3fd9f047
TW
5082@node Elseif
5083@section @code{.elseif}
5084
5085@cindex @code{elseif} directive
a4fb0134 5086@code{.elseif} is part of the @command{@value{AS}} support for conditional
96e9638b 5087assembly; see @ref{If,,@code{.if}}. It is shorthand for beginning a new
3fd9f047
TW
5088@code{.if} block that would otherwise fill the entire @code{.else} section.
5089
252b5132
RH
5090@node End
5091@section @code{.end}
5092
5093@cindex @code{end} directive
a4fb0134 5094@code{.end} marks the end of the assembly file. @command{@value{AS}} does not
252b5132
RH
5095process anything in the file past the @code{.end} directive.
5096
5097@ifset COFF
5098@node Endef
5099@section @code{.endef}
5100
5101@cindex @code{endef} directive
5102This directive flags the end of a symbol definition begun with
5103@code{.def}.
252b5132
RH
5104@end ifset
5105
5106@node Endfunc
5107@section @code{.endfunc}
5108@cindex @code{endfunc} directive
5109@code{.endfunc} marks the end of a function specified with @code{.func}.
5110
5111@node Endif
5112@section @code{.endif}
5113
5114@cindex @code{endif} directive
a4fb0134 5115@code{.endif} is part of the @command{@value{AS}} support for conditional assembly;
252b5132
RH
5116it marks the end of a block of code that is only assembled
5117conditionally. @xref{If,,@code{.if}}.
5118
5119@node Equ
5120@section @code{.equ @var{symbol}, @var{expression}}
5121
5122@cindex @code{equ} directive
5123@cindex assigning values to symbols
5124@cindex symbols, assigning values to
5125This directive sets the value of @var{symbol} to @var{expression}.
96e9638b 5126It is synonymous with @samp{.set}; see @ref{Set,,@code{.set}}.
252b5132
RH
5127
5128@ifset HPPA
01642c12 5129The syntax for @code{equ} on the HPPA is
252b5132
RH
5130@samp{@var{symbol} .equ @var{expression}}.
5131@end ifset
5132
3c9b82ba 5133@ifset Z80
01642c12
RM
5134The syntax for @code{equ} on the Z80 is
5135@samp{@var{symbol} equ @var{expression}}.
33eaf5de 5136On the Z80 it is an error if @var{symbol} is already defined,
01642c12 5137but the symbol is not protected from later redefinition.
96e9638b 5138Compare @ref{Equiv}.
3c9b82ba
NC
5139@end ifset
5140
252b5132
RH
5141@node Equiv
5142@section @code{.equiv @var{symbol}, @var{expression}}
5143@cindex @code{equiv} directive
5144The @code{.equiv} directive is like @code{.equ} and @code{.set}, except that
8dfa0188
NC
5145the assembler will signal an error if @var{symbol} is already defined. Note a
5146symbol which has been referenced but not actually defined is considered to be
5147undefined.
252b5132 5148
01642c12 5149Except for the contents of the error message, this is roughly equivalent to
252b5132
RH
5150@smallexample
5151.ifdef SYM
5152.err
5153.endif
5154.equ SYM,VAL
5155@end smallexample
9497f5ac
NC
5156plus it protects the symbol from later redefinition.
5157
5158@node Eqv
5159@section @code{.eqv @var{symbol}, @var{expression}}
5160@cindex @code{eqv} directive
5161The @code{.eqv} directive is like @code{.equiv}, but no attempt is made to
5162evaluate the expression or any part of it immediately. Instead each time
5163the resulting symbol is used in an expression, a snapshot of its current
5164value is taken.
252b5132
RH
5165
5166@node Err
5167@section @code{.err}
5168@cindex @code{err} directive
a4fb0134
SC
5169If @command{@value{AS}} assembles a @code{.err} directive, it will print an error
5170message and, unless the @option{-Z} option was used, it will not generate an
f9eb6721 5171object file. This can be used to signal an error in conditionally compiled code.
252b5132 5172
d190d046
HPN
5173@node Error
5174@section @code{.error "@var{string}"}
5175@cindex error directive
5176
5177Similarly to @code{.err}, this directive emits an error, but you can specify a
5178string that will be emitted as the error message. If you don't specify the
5179message, it defaults to @code{".error directive invoked in source file"}.
5180@xref{Errors, ,Error and Warning Messages}.
5181
5182@smallexample
5183 .error "This code has not been assembled and tested."
5184@end smallexample
5185
252b5132
RH
5186@node Exitm
5187@section @code{.exitm}
5188Exit early from the current macro definition. @xref{Macro}.
5189
5190@node Extern
5191@section @code{.extern}
5192
5193@cindex @code{extern} directive
5194@code{.extern} is accepted in the source program---for compatibility
a4fb0134 5195with other assemblers---but it is ignored. @command{@value{AS}} treats
252b5132
RH
5196all undefined symbols as external.
5197
5198@node Fail
5199@section @code{.fail @var{expression}}
5200
5201@cindex @code{fail} directive
5202Generates an error or a warning. If the value of the @var{expression} is 500
a4fb0134
SC
5203or more, @command{@value{AS}} will print a warning message. If the value is less
5204than 500, @command{@value{AS}} will print an error message. The message will
252b5132
RH
5205include the value of @var{expression}. This can occasionally be useful inside
5206complex nested macros or conditional assembly.
5207
252b5132 5208@node File
14082c76 5209@section @code{.file}
252b5132 5210@cindex @code{file} directive
14082c76
BW
5211
5212@ifclear no-file-dir
5213There are two different versions of the @code{.file} directive. Targets
5214that support DWARF2 line number information use the DWARF2 version of
5215@code{.file}. Other targets use the default version.
5216
5217@subheading Default Version
5218
252b5132
RH
5219@cindex logical file name
5220@cindex file name, logical
14082c76
BW
5221This version of the @code{.file} directive tells @command{@value{AS}} that we
5222are about to start a new logical file. The syntax is:
5223
5224@smallexample
5225.file @var{string}
5226@end smallexample
5227
5228@var{string} is the new file name. In general, the filename is
252b5132
RH
5229recognized whether or not it is surrounded by quotes @samp{"}; but if you wish
5230to specify an empty file name, you must give the quotes--@code{""}. This
5231statement may go away in future: it is only recognized to be compatible with
a4fb0134 5232old @command{@value{AS}} programs.
14082c76
BW
5233
5234@subheading DWARF2 Version
252b5132
RH
5235@end ifclear
5236
14082c76
BW
5237When emitting DWARF2 line number information, @code{.file} assigns filenames
5238to the @code{.debug_line} file name table. The syntax is:
5239
5240@smallexample
5241.file @var{fileno} @var{filename}
5242@end smallexample
5243
5244The @var{fileno} operand should be a unique positive integer to use as the
5245index of the entry in the table. The @var{filename} operand is a C string
5246literal.
5247
5248The detail of filename indices is exposed to the user because the filename
5249table is shared with the @code{.debug_info} section of the DWARF2 debugging
5250information, and thus the user must know the exact indices that table
5251entries will have.
5252
252b5132
RH
5253@node Fill
5254@section @code{.fill @var{repeat} , @var{size} , @var{value}}
5255
5256@cindex @code{fill} directive
5257@cindex writing patterns in memory
5258@cindex patterns, writing in memory
bc64be0c 5259@var{repeat}, @var{size} and @var{value} are absolute expressions.
252b5132
RH
5260This emits @var{repeat} copies of @var{size} bytes. @var{Repeat}
5261may be zero or more. @var{Size} may be zero or more, but if it is
5262more than 8, then it is deemed to have the value 8, compatible with
5263other people's assemblers. The contents of each @var{repeat} bytes
5264is taken from an 8-byte number. The highest order 4 bytes are
5265zero. The lowest order 4 bytes are @var{value} rendered in the
a4fb0134 5266byte-order of an integer on the computer @command{@value{AS}} is assembling for.
252b5132
RH
5267Each @var{size} bytes in a repetition is taken from the lowest order
5268@var{size} bytes of this number. Again, this bizarre behavior is
5269compatible with other people's assemblers.
5270
5271@var{size} and @var{value} are optional.
5272If the second comma and @var{value} are absent, @var{value} is
5273assumed zero. If the first comma and following tokens are absent,
5274@var{size} is assumed to be 1.
5275
5276@node Float
5277@section @code{.float @var{flonums}}
5278
5279@cindex floating point numbers (single)
5280@cindex @code{float} directive
5281This directive assembles zero or more flonums, separated by commas. It
5282has the same effect as @code{.single}.
5283@ifset GENERIC
5284The exact kind of floating point numbers emitted depends on how
a4fb0134 5285@command{@value{AS}} is configured.
252b5132
RH
5286@xref{Machine Dependencies}.
5287@end ifset
5288@ifclear GENERIC
5289@ifset IEEEFLOAT
5290On the @value{TARGET} family, @code{.float} emits 32-bit floating point numbers
5291in @sc{ieee} format.
5292@end ifset
5293@end ifclear
5294
5295@node Func
5296@section @code{.func @var{name}[,@var{label}]}
5297@cindex @code{func} directive
5298@code{.func} emits debugging information to denote function @var{name}, and
5299is ignored unless the file is assembled with debugging enabled.
05da4302 5300Only @samp{--gstabs[+]} is currently supported.
252b5132
RH
5301@var{label} is the entry point of the function and if omitted @var{name}
5302prepended with the @samp{leading char} is used.
5303@samp{leading char} is usually @code{_} or nothing, depending on the target.
5304All functions are currently defined to have @code{void} return type.
5305The function must be terminated with @code{.endfunc}.
5306
5307@node Global
5308@section @code{.global @var{symbol}}, @code{.globl @var{symbol}}
5309
5310@cindex @code{global} directive
5311@cindex symbol, making visible to linker
5312@code{.global} makes the symbol visible to @code{@value{LD}}. If you define
5313@var{symbol} in your partial program, its value is made available to
5314other partial programs that are linked with it. Otherwise,
5315@var{symbol} takes its attributes from a symbol of the same name
5316from another file linked into the same program.
5317
5318Both spellings (@samp{.globl} and @samp{.global}) are accepted, for
5319compatibility with other assemblers.
5320
5321@ifset HPPA
5322On the HPPA, @code{.global} is not always enough to make it accessible to other
5323partial programs. You may need the HPPA-only @code{.EXPORT} directive as well.
96e9638b 5324@xref{HPPA Directives, ,HPPA Assembler Directives}.
252b5132
RH
5325@end ifset
5326
c91d2e08 5327@ifset ELF
3a99f02f
DJ
5328@node Gnu_attribute
5329@section @code{.gnu_attribute @var{tag},@var{value}}
5330Record a @sc{gnu} object attribute for this file. @xref{Object Attributes}.
5331
c91d2e08
NC
5332@node Hidden
5333@section @code{.hidden @var{names}}
5334
c1253627
NC
5335@cindex @code{hidden} directive
5336@cindex visibility
ed9589d4 5337This is one of the ELF visibility directives. The other two are
01642c12 5338@code{.internal} (@pxref{Internal,,@code{.internal}}) and
a349d9dd 5339@code{.protected} (@pxref{Protected,,@code{.protected}}).
c91d2e08
NC
5340
5341This directive overrides the named symbols default visibility (which is set by
5342their binding: local, global or weak). The directive sets the visibility to
5343@code{hidden} which means that the symbols are not visible to other components.
01642c12 5344Such symbols are always considered to be @code{protected} as well.
c91d2e08
NC
5345@end ifset
5346
252b5132
RH
5347@node hword
5348@section @code{.hword @var{expressions}}
5349
5350@cindex @code{hword} directive
5351@cindex integers, 16-bit
5352@cindex numbers, 16-bit
5353@cindex sixteen bit integers
5354This expects zero or more @var{expressions}, and emits
5355a 16 bit number for each.
5356
5357@ifset GENERIC
5358This directive is a synonym for @samp{.short}; depending on the target
5359architecture, it may also be a synonym for @samp{.word}.
5360@end ifset
5361@ifclear GENERIC
5362@ifset W32
5363This directive is a synonym for @samp{.short}.
5364@end ifset
5365@ifset W16
5366This directive is a synonym for both @samp{.short} and @samp{.word}.
5367@end ifset
5368@end ifclear
5369
5370@node Ident
5371@section @code{.ident}
5372
5373@cindex @code{ident} directive
cb4c78d6
BE
5374
5375This directive is used by some assemblers to place tags in object files. The
5376behavior of this directive varies depending on the target. When using the
5377a.out object file format, @command{@value{AS}} simply accepts the directive for
5378source-file compatibility with existing assemblers, but does not emit anything
5379for it. When using COFF, comments are emitted to the @code{.comment} or
5380@code{.rdata} section, depending on the target. When using ELF, comments are
5381emitted to the @code{.comment} section.
252b5132
RH
5382
5383@node If
5384@section @code{.if @var{absolute expression}}
5385
5386@cindex conditional assembly
5387@cindex @code{if} directive
5388@code{.if} marks the beginning of a section of code which is only
5389considered part of the source program being assembled if the argument
5390(which must be an @var{absolute expression}) is non-zero. The end of
5391the conditional section of code must be marked by @code{.endif}
5392(@pxref{Endif,,@code{.endif}}); optionally, you may include code for the
5393alternative condition, flagged by @code{.else} (@pxref{Else,,@code{.else}}).
3fd9f047
TW
5394If you have several conditions to check, @code{.elseif} may be used to avoid
5395nesting blocks if/else within each subsequent @code{.else} block.
252b5132
RH
5396
5397The following variants of @code{.if} are also supported:
5398@table @code
5399@cindex @code{ifdef} directive
5400@item .ifdef @var{symbol}
5401Assembles the following section of code if the specified @var{symbol}
8dfa0188
NC
5402has been defined. Note a symbol which has been referenced but not yet defined
5403is considered to be undefined.
252b5132 5404
26aca5f6
JB
5405@cindex @code{ifb} directive
5406@item .ifb @var{text}
5407Assembles the following section of code if the operand is blank (empty).
5408
252b5132
RH
5409@cindex @code{ifc} directive
5410@item .ifc @var{string1},@var{string2}
5411Assembles the following section of code if the two strings are the same. The
5412strings may be optionally quoted with single quotes. If they are not quoted,
5413the first string stops at the first comma, and the second string stops at the
5414end of the line. Strings which contain whitespace should be quoted. The
5415string comparison is case sensitive.
5416
5417@cindex @code{ifeq} directive
5418@item .ifeq @var{absolute expression}
5419Assembles the following section of code if the argument is zero.
5420
5421@cindex @code{ifeqs} directive
5422@item .ifeqs @var{string1},@var{string2}
5423Another form of @code{.ifc}. The strings must be quoted using double quotes.
5424
5425@cindex @code{ifge} directive
5426@item .ifge @var{absolute expression}
5427Assembles the following section of code if the argument is greater than or
5428equal to zero.
5429
5430@cindex @code{ifgt} directive
5431@item .ifgt @var{absolute expression}
5432Assembles the following section of code if the argument is greater than zero.
5433
5434@cindex @code{ifle} directive
5435@item .ifle @var{absolute expression}
5436Assembles the following section of code if the argument is less than or equal
5437to zero.
5438
5439@cindex @code{iflt} directive
5440@item .iflt @var{absolute expression}
5441Assembles the following section of code if the argument is less than zero.
5442
26aca5f6
JB
5443@cindex @code{ifnb} directive
5444@item .ifnb @var{text}
5445Like @code{.ifb}, but the sense of the test is reversed: this assembles the
5446following section of code if the operand is non-blank (non-empty).
5447
252b5132
RH
5448@cindex @code{ifnc} directive
5449@item .ifnc @var{string1},@var{string2}.
5450Like @code{.ifc}, but the sense of the test is reversed: this assembles the
5451following section of code if the two strings are not the same.
5452
5453@cindex @code{ifndef} directive
5454@cindex @code{ifnotdef} directive
5455@item .ifndef @var{symbol}
5456@itemx .ifnotdef @var{symbol}
5457Assembles the following section of code if the specified @var{symbol}
8dfa0188
NC
5458has not been defined. Both spelling variants are equivalent. Note a symbol
5459which has been referenced but not yet defined is considered to be undefined.
252b5132
RH
5460
5461@cindex @code{ifne} directive
5462@item .ifne @var{absolute expression}
5463Assembles the following section of code if the argument is not equal to zero
5464(in other words, this is equivalent to @code{.if}).
5465
5466@cindex @code{ifnes} directive
5467@item .ifnes @var{string1},@var{string2}
5468Like @code{.ifeqs}, but the sense of the test is reversed: this assembles the
5469following section of code if the two strings are not the same.
5470@end table
5471
7e005732
NC
5472@node Incbin
5473@section @code{.incbin "@var{file}"[,@var{skip}[,@var{count}]]}
5474
5475@cindex @code{incbin} directive
5476@cindex binary files, including
5477The @code{incbin} directive includes @var{file} verbatim at the current
5478location. You can control the search paths used with the @samp{-I} command-line
5479option (@pxref{Invoking,,Command-Line Options}). Quotation marks are required
5480around @var{file}.
5481
5482The @var{skip} argument skips a number of bytes from the start of the
5483@var{file}. The @var{count} argument indicates the maximum number of bytes to
15dcfbc3
NC
5484read. Note that the data is not aligned in any way, so it is the user's
5485responsibility to make sure that proper alignment is provided both before and
5486after the @code{incbin} directive.
7e005732 5487
252b5132
RH
5488@node Include
5489@section @code{.include "@var{file}"}
5490
5491@cindex @code{include} directive
5492@cindex supporting files, including
5493@cindex files, including
5494This directive provides a way to include supporting files at specified
5495points in your source program. The code from @var{file} is assembled as
5496if it followed the point of the @code{.include}; when the end of the
5497included file is reached, assembly of the original file continues. You
5498can control the search paths used with the @samp{-I} command-line option
5499(@pxref{Invoking,,Command-Line Options}). Quotation marks are required
5500around @var{file}.
5501
5502@node Int
5503@section @code{.int @var{expressions}}
5504
5505@cindex @code{int} directive
5506@cindex integers, 32-bit
5507Expect zero or more @var{expressions}, of any section, separated by commas.
5508For each expression, emit a number that, at run time, is the value of that
5509expression. The byte order and bit size of the number depends on what kind
5510of target the assembly is for.
5511
5512@ifclear GENERIC
5513@ifset H8
7be1c489 5514On most forms of the H8/300, @code{.int} emits 16-bit
c2dcd04e 5515integers. On the H8/300H and the Renesas SH, however, @code{.int} emits
252b5132
RH
551632-bit integers.
5517@end ifset
5518@end ifclear
5519
c91d2e08
NC
5520@ifset ELF
5521@node Internal
5522@section @code{.internal @var{names}}
5523
c1253627
NC
5524@cindex @code{internal} directive
5525@cindex visibility
ed9589d4 5526This is one of the ELF visibility directives. The other two are
01642c12 5527@code{.hidden} (@pxref{Hidden,,@code{.hidden}}) and
a349d9dd 5528@code{.protected} (@pxref{Protected,,@code{.protected}}).
c91d2e08
NC
5529
5530This directive overrides the named symbols default visibility (which is set by
5531their binding: local, global or weak). The directive sets the visibility to
5532@code{internal} which means that the symbols are considered to be @code{hidden}
c1253627 5533(i.e., not visible to other components), and that some extra, processor specific
c91d2e08
NC
5534processing must also be performed upon the symbols as well.
5535@end ifset
5536
252b5132
RH
5537@node Irp
5538@section @code{.irp @var{symbol},@var{values}}@dots{}
5539
5540@cindex @code{irp} directive
5541Evaluate a sequence of statements assigning different values to @var{symbol}.
5542The sequence of statements starts at the @code{.irp} directive, and is
5543terminated by an @code{.endr} directive. For each @var{value}, @var{symbol} is
5544set to @var{value}, and the sequence of statements is assembled. If no
5545@var{value} is listed, the sequence of statements is assembled once, with
5546@var{symbol} set to the null string. To refer to @var{symbol} within the
5547sequence of statements, use @var{\symbol}.
5548
5549For example, assembling
5550
5551@example
5552 .irp param,1,2,3
5553 move d\param,sp@@-
5554 .endr
5555@end example
5556
5557is equivalent to assembling
5558
5559@example
5560 move d1,sp@@-
5561 move d2,sp@@-
5562 move d3,sp@@-
5563@end example
5564
96e9638b 5565For some caveats with the spelling of @var{symbol}, see also @ref{Macro}.
5e75c3ab 5566
252b5132
RH
5567@node Irpc
5568@section @code{.irpc @var{symbol},@var{values}}@dots{}
5569
5570@cindex @code{irpc} directive
5571Evaluate a sequence of statements assigning different values to @var{symbol}.
5572The sequence of statements starts at the @code{.irpc} directive, and is
5573terminated by an @code{.endr} directive. For each character in @var{value},
5574@var{symbol} is set to the character, and the sequence of statements is
5575assembled. If no @var{value} is listed, the sequence of statements is
5576assembled once, with @var{symbol} set to the null string. To refer to
5577@var{symbol} within the sequence of statements, use @var{\symbol}.
5578
5579For example, assembling
5580
5581@example
5582 .irpc param,123
5583 move d\param,sp@@-
5584 .endr
5585@end example
5586
5587is equivalent to assembling
5588
5589@example
5590 move d1,sp@@-
5591 move d2,sp@@-
5592 move d3,sp@@-
5593@end example
5594
5e75c3ab
JB
5595For some caveats with the spelling of @var{symbol}, see also the discussion
5596at @xref{Macro}.
5597
252b5132
RH
5598@node Lcomm
5599@section @code{.lcomm @var{symbol} , @var{length}}
5600
5601@cindex @code{lcomm} directive
5602@cindex local common symbols
5603@cindex symbols, local common
5604Reserve @var{length} (an absolute expression) bytes for a local common
5605denoted by @var{symbol}. The section and value of @var{symbol} are
5606those of the new local common. The addresses are allocated in the bss
5607section, so that at run-time the bytes start off zeroed. @var{Symbol}
5608is not declared global (@pxref{Global,,@code{.global}}), so is normally
5609not visible to @code{@value{LD}}.
5610
5611@ifset GENERIC
5612Some targets permit a third argument to be used with @code{.lcomm}. This
5613argument specifies the desired alignment of the symbol in the bss section.
5614@end ifset
5615
5616@ifset HPPA
5617The syntax for @code{.lcomm} differs slightly on the HPPA. The syntax is
5618@samp{@var{symbol} .lcomm, @var{length}}; @var{symbol} is optional.
5619@end ifset
5620
5621@node Lflags
5622@section @code{.lflags}
5623
5624@cindex @code{lflags} directive (ignored)
a4fb0134 5625@command{@value{AS}} accepts this directive, for compatibility with other
252b5132
RH
5626assemblers, but ignores it.
5627
5628@ifclear no-line-dir
5629@node Line
5630@section @code{.line @var{line-number}}
5631
5632@cindex @code{line} directive
252b5132 5633@cindex logical line number
a8eb42a8 5634@ifset aout
252b5132
RH
5635Change the logical line number. @var{line-number} must be an absolute
5636expression. The next line has that logical line number. Therefore any other
5637statements on the current line (after a statement separator character) are
5638reported as on logical line number @var{line-number} @minus{} 1. One day
a4fb0134 5639@command{@value{AS}} will no longer support this directive: it is recognized only
252b5132 5640for compatibility with existing assembler programs.
252b5132
RH
5641@end ifset
5642
252b5132 5643Even though this is a directive associated with the @code{a.out} or
a4fb0134 5644@code{b.out} object-code formats, @command{@value{AS}} still recognizes it
252b5132
RH
5645when producing COFF output, and treats @samp{.line} as though it
5646were the COFF @samp{.ln} @emph{if} it is found outside a
5647@code{.def}/@code{.endef} pair.
5648
5649Inside a @code{.def}, @samp{.line} is, instead, one of the directives
5650used by compilers to generate auxiliary symbol information for
5651debugging.
5652@end ifclear
5653
5654@node Linkonce
5655@section @code{.linkonce [@var{type}]}
5656@cindex COMDAT
5657@cindex @code{linkonce} directive
5658@cindex common sections
5659Mark the current section so that the linker only includes a single copy of it.
5660This may be used to include the same section in several different object files,
5661but ensure that the linker will only include it once in the final output file.
5662The @code{.linkonce} pseudo-op must be used for each instance of the section.
5663Duplicate sections are detected based on the section name, so it should be
5664unique.
5665
5666This directive is only supported by a few object file formats; as of this
5667writing, the only object file format which supports it is the Portable
5668Executable format used on Windows NT.
5669
5670The @var{type} argument is optional. If specified, it must be one of the
5671following strings. For example:
5672@smallexample
5673.linkonce same_size
5674@end smallexample
5675Not all types may be supported on all object file formats.
5676
5677@table @code
5678@item discard
5679Silently discard duplicate sections. This is the default.
5680
5681@item one_only
5682Warn if there are duplicate sections, but still keep only one copy.
5683
5684@item same_size
5685Warn if any of the duplicates have different sizes.
5686
5687@item same_contents
5688Warn if any of the duplicates do not have exactly the same contents.
5689@end table
5690
ccf8a69b
BW
5691@node List
5692@section @code{.list}
5693
5694@cindex @code{list} directive
5695@cindex listing control, turning on
5696Control (in conjunction with the @code{.nolist} directive) whether or
5697not assembly listings are generated. These two directives maintain an
5698internal counter (which is zero initially). @code{.list} increments the
5699counter, and @code{.nolist} decrements it. Assembly listings are
5700generated whenever the counter is greater than zero.
5701
5702By default, listings are disabled. When you enable them (with the
5703@samp{-a} command line option; @pxref{Invoking,,Command-Line Options}),
5704the initial value of the listing counter is one.
5705
252b5132
RH
5706@node Ln
5707@section @code{.ln @var{line-number}}
5708
5709@cindex @code{ln} directive
5710@ifclear no-line-dir
5711@samp{.ln} is a synonym for @samp{.line}.
5712@end ifclear
5713@ifset no-line-dir
a4fb0134 5714Tell @command{@value{AS}} to change the logical line number. @var{line-number}
252b5132
RH
5715must be an absolute expression. The next line has that logical
5716line number, so any other statements on the current line (after a
5717statement separator character @code{;}) are reported as on logical
5718line number @var{line-number} @minus{} 1.
252b5132
RH
5719@end ifset
5720
ccf8a69b
BW
5721@node Loc
5722@section @code{.loc @var{fileno} @var{lineno} [@var{column}] [@var{options}]}
5723@cindex @code{loc} directive
5724When emitting DWARF2 line number information,
5725the @code{.loc} directive will add a row to the @code{.debug_line} line
5726number matrix corresponding to the immediately following assembly
5727instruction. The @var{fileno}, @var{lineno}, and optional @var{column}
5728arguments will be applied to the @code{.debug_line} state machine before
5729the row is added.
252b5132 5730
ccf8a69b
BW
5731The @var{options} are a sequence of the following tokens in any order:
5732
5733@table @code
5734@item basic_block
5735This option will set the @code{basic_block} register in the
5736@code{.debug_line} state machine to @code{true}.
5737
5738@item prologue_end
5739This option will set the @code{prologue_end} register in the
5740@code{.debug_line} state machine to @code{true}.
5741
5742@item epilogue_begin
5743This option will set the @code{epilogue_begin} register in the
5744@code{.debug_line} state machine to @code{true}.
5745
5746@item is_stmt @var{value}
5747This option will set the @code{is_stmt} register in the
01642c12 5748@code{.debug_line} state machine to @code{value}, which must be
ccf8a69b
BW
5749either 0 or 1.
5750
5751@item isa @var{value}
5752This directive will set the @code{isa} register in the @code{.debug_line}
5753state machine to @var{value}, which must be an unsigned integer.
5754
92846e72
CC
5755@item discriminator @var{value}
5756This directive will set the @code{discriminator} register in the @code{.debug_line}
5757state machine to @var{value}, which must be an unsigned integer.
5758
ba8826a8
AO
5759@item view @var{value}
5760This option causes a row to be added to @code{.debug_line} in reference to the
5761current address (which might not be the same as that of the following assembly
5762instruction), and to associate @var{value} with the @code{view} register in the
5763@code{.debug_line} state machine. If @var{value} is a label, both the
5764@code{view} register and the label are set to the number of prior @code{.loc}
5765directives at the same program location. If @var{value} is the literal
5766@code{0}, the @code{view} register is set to zero, and the assembler asserts
5767that there aren't any prior @code{.loc} directives at the same program
5768location. If @var{value} is the literal @code{-0}, the assembler arrange for
5769the @code{view} register to be reset in this row, even if there are prior
5770@code{.loc} directives at the same program location.
5771
ccf8a69b
BW
5772@end table
5773
5774@node Loc_mark_labels
5775@section @code{.loc_mark_labels @var{enable}}
5776@cindex @code{loc_mark_labels} directive
5777When emitting DWARF2 line number information,
5778the @code{.loc_mark_labels} directive makes the assembler emit an entry
5779to the @code{.debug_line} line number matrix with the @code{basic_block}
5780register in the state machine set whenever a code label is seen.
5781The @var{enable} argument should be either 1 or 0, to enable or disable
5782this function respectively.
252b5132 5783
4d4175af
BW
5784@ifset ELF
5785@node Local
5786@section @code{.local @var{names}}
5787
5788@cindex @code{local} directive
5789This directive, which is available for ELF targets, marks each symbol in
5790the comma-separated list of @code{names} as a local symbol so that it
5791will not be externally visible. If the symbols do not already exist,
5792they will be created.
5793
5794For targets where the @code{.lcomm} directive (@pxref{Lcomm}) does not
5795accept an alignment argument, which is the case for most ELF targets,
5796the @code{.local} directive can be used in combination with @code{.comm}
5797(@pxref{Comm}) to define aligned local common data.
5798@end ifset
5799
252b5132
RH
5800@node Long
5801@section @code{.long @var{expressions}}
5802
5803@cindex @code{long} directive
96e9638b 5804@code{.long} is the same as @samp{.int}. @xref{Int,,@code{.int}}.
252b5132
RH
5805
5806@ignore
5807@c no one seems to know what this is for or whether this description is
5808@c what it really ought to do
5809@node Lsym
5810@section @code{.lsym @var{symbol}, @var{expression}}
5811
5812@cindex @code{lsym} directive
5813@cindex symbol, not referenced in assembly
5814@code{.lsym} creates a new symbol named @var{symbol}, but does not put it in
5815the hash table, ensuring it cannot be referenced by name during the
5816rest of the assembly. This sets the attributes of the symbol to be
5817the same as the expression value:
5818@smallexample
5819@var{other} = @var{descriptor} = 0
5820@var{type} = @r{(section of @var{expression})}
5821@var{value} = @var{expression}
5822@end smallexample
5823@noindent
5824The new symbol is not flagged as external.
5825@end ignore
5826
5827@node Macro
5828@section @code{.macro}
5829
5830@cindex macros
5831The commands @code{.macro} and @code{.endm} allow you to define macros that
5832generate assembly output. For example, this definition specifies a macro
5833@code{sum} that puts a sequence of numbers into memory:
5834
5835@example
5836 .macro sum from=0, to=5
5837 .long \from
5838 .if \to-\from
5839 sum "(\from+1)",\to
5840 .endif
5841 .endm
5842@end example
5843
5844@noindent
5845With that definition, @samp{SUM 0,5} is equivalent to this assembly input:
5846
5847@example
5848 .long 0
5849 .long 1
5850 .long 2
5851 .long 3
5852 .long 4
5853 .long 5
5854@end example
5855
5856@ftable @code
5857@item .macro @var{macname}
5858@itemx .macro @var{macname} @var{macargs} @dots{}
5859@cindex @code{macro} directive
5860Begin the definition of a macro called @var{macname}. If your macro
5861definition requires arguments, specify their names after the macro name,
6eaeac8a
JB
5862separated by commas or spaces. You can qualify the macro argument to
5863indicate whether all invocations must specify a non-blank value (through
5864@samp{:@code{req}}), or whether it takes all of the remaining arguments
5865(through @samp{:@code{vararg}}). You can supply a default value for any
fffeaa5f
JB
5866macro argument by following the name with @samp{=@var{deflt}}. You
5867cannot define two macros with the same @var{macname} unless it has been
96e9638b 5868subject to the @code{.purgem} directive (@pxref{Purgem}) between the two
fffeaa5f 5869definitions. For example, these are all valid @code{.macro} statements:
252b5132
RH
5870
5871@table @code
5872@item .macro comm
5873Begin the definition of a macro called @code{comm}, which takes no
5874arguments.
5875
6258339f 5876@item .macro plus1 p, p1
252b5132
RH
5877@itemx .macro plus1 p p1
5878Either statement begins the definition of a macro called @code{plus1},
5879which takes two arguments; within the macro definition, write
5880@samp{\p} or @samp{\p1} to evaluate the arguments.
5881
5882@item .macro reserve_str p1=0 p2
5883Begin the definition of a macro called @code{reserve_str}, with two
5884arguments. The first argument has a default value, but not the second.
5885After the definition is complete, you can call the macro either as
5886@samp{reserve_str @var{a},@var{b}} (with @samp{\p1} evaluating to
5887@var{a} and @samp{\p2} evaluating to @var{b}), or as @samp{reserve_str
5888,@var{b}} (with @samp{\p1} evaluating as the default, in this case
5889@samp{0}, and @samp{\p2} evaluating to @var{b}).
252b5132 5890
6eaeac8a
JB
5891@item .macro m p1:req, p2=0, p3:vararg
5892Begin the definition of a macro called @code{m}, with at least three
5893arguments. The first argument must always have a value specified, but
5894not the second, which instead has a default value. The third formal
5895will get assigned all remaining arguments specified at invocation time.
5896
252b5132
RH
5897When you call a macro, you can specify the argument values either by
5898position, or by keyword. For example, @samp{sum 9,17} is equivalent to
5899@samp{sum to=17, from=9}.
5900
6258339f
NC
5901@end table
5902
5e75c3ab
JB
5903Note that since each of the @var{macargs} can be an identifier exactly
5904as any other one permitted by the target architecture, there may be
5905occasional problems if the target hand-crafts special meanings to certain
6258339f 5906characters when they occur in a special position. For example, if the colon
5e75c3ab 5907(@code{:}) is generally permitted to be part of a symbol name, but the
6258339f 5908architecture specific code special-cases it when occurring as the final
5e75c3ab
JB
5909character of a symbol (to denote a label), then the macro parameter
5910replacement code will have no way of knowing that and consider the whole
5911construct (including the colon) an identifier, and check only this
6258339f
NC
5912identifier for being the subject to parameter substitution. So for example
5913this macro definition:
5914
5915@example
5916 .macro label l
5917\l:
5918 .endm
5919@end example
5920
5921might not work as expected. Invoking @samp{label foo} might not create a label
5922called @samp{foo} but instead just insert the text @samp{\l:} into the
5923assembler source, probably generating an error about an unrecognised
5924identifier.
5925
5926Similarly problems might occur with the period character (@samp{.})
5927which is often allowed inside opcode names (and hence identifier names). So
5928for example constructing a macro to build an opcode from a base name and a
5929length specifier like this:
5930
5931@example
5932 .macro opcode base length
5933 \base.\length
5934 .endm
5935@end example
5936
5937and invoking it as @samp{opcode store l} will not create a @samp{store.l}
5938instruction but instead generate some kind of error as the assembler tries to
5939interpret the text @samp{\base.\length}.
5940
5941There are several possible ways around this problem:
5942
5943@table @code
5944@item Insert white space
5945If it is possible to use white space characters then this is the simplest
5946solution. eg:
5947
5948@example
5949 .macro label l
5950\l :
5951 .endm
5952@end example
5953
5954@item Use @samp{\()}
5955The string @samp{\()} can be used to separate the end of a macro argument from
5956the following text. eg:
5957
5958@example
5959 .macro opcode base length
5960 \base\().\length
5961 .endm
5962@end example
5963
5964@item Use the alternate macro syntax mode
5965In the alternative macro syntax mode the ampersand character (@samp{&}) can be
5966used as a separator. eg:
5e75c3ab
JB
5967
5968@example
5969 .altmacro
5970 .macro label l
5971l&:
5972 .endm
5973@end example
6258339f 5974@end table
5e75c3ab 5975
96e9638b 5976Note: this problem of correctly identifying string parameters to pseudo ops
01642c12 5977also applies to the identifiers used in @code{.irp} (@pxref{Irp})
96e9638b 5978and @code{.irpc} (@pxref{Irpc}) as well.
5e75c3ab 5979
252b5132
RH
5980@item .endm
5981@cindex @code{endm} directive
5982Mark the end of a macro definition.
5983
5984@item .exitm
5985@cindex @code{exitm} directive
5986Exit early from the current macro definition.
5987
5988@cindex number of macros executed
5989@cindex macros, count executed
5990@item \@@
a4fb0134 5991@command{@value{AS}} maintains a counter of how many macros it has
252b5132
RH
5992executed in this pseudo-variable; you can copy that number to your
5993output with @samp{\@@}, but @emph{only within a macro definition}.
5994
252b5132
RH
5995@item LOCAL @var{name} [ , @dots{} ]
5996@emph{Warning: @code{LOCAL} is only available if you select ``alternate
caa32fe5
NC
5997macro syntax'' with @samp{--alternate} or @code{.altmacro}.}
5998@xref{Altmacro,,@code{.altmacro}}.
5999@end ftable
252b5132 6000
ccf8a69b
BW
6001@node MRI
6002@section @code{.mri @var{val}}
caa32fe5 6003
ccf8a69b
BW
6004@cindex @code{mri} directive
6005@cindex MRI mode, temporarily
6006If @var{val} is non-zero, this tells @command{@value{AS}} to enter MRI mode. If
6007@var{val} is zero, this tells @command{@value{AS}} to exit MRI mode. This change
6008affects code assembled until the next @code{.mri} directive, or until the end
6009of the file. @xref{M, MRI mode, MRI mode}.
252b5132 6010
caa32fe5
NC
6011@node Noaltmacro
6012@section @code{.noaltmacro}
96e9638b 6013Disable alternate macro mode. @xref{Altmacro}.
caa32fe5 6014
252b5132
RH
6015@node Nolist
6016@section @code{.nolist}
6017
6018@cindex @code{nolist} directive
6019@cindex listing control, turning off
6020Control (in conjunction with the @code{.list} directive) whether or
6021not assembly listings are generated. These two directives maintain an
6022internal counter (which is zero initially). @code{.list} increments the
6023counter, and @code{.nolist} decrements it. Assembly listings are
6024generated whenever the counter is greater than zero.
6025
8f065d3b
L
6026@node Nops
6027@section @code{.nops @var{size}[, @var{control}]}
62a02d25 6028
8f065d3b 6029@cindex @code{nops} directive
62a02d25
L
6030@cindex filling memory with no-op instructions
6031This directive emits @var{size} bytes filled with no-op instructions.
6032@var{size} is absolute expression, which must be a positve value.
6033@var{control} controls how no-op instructions should be generated. If
6034the comma and @var{control} are omitted, @var{control} is assumed to be
6035zero.
6036
6037Note: For Intel 80386 and AMD x86-64 targets, @var{control} specifies
6038the size limit of a no-op instruction. The valid values of @var{control}
3ae729d5
L
6039are between 0 and 4 in 16-bit mode, between 0 and 7 when tuning for
6040older processors in 32-bit mode, between 0 and 11 in 64-bit mode or when
6041tuning for newer processors in 32-bit mode. When 0 is used, the no-op
6042instruction size limit is set to the maximum supported size.
62a02d25 6043
252b5132
RH
6044@node Octa
6045@section @code{.octa @var{bignums}}
6046
a8eb42a8 6047@c FIXME: double size emitted for "octa" on some? Or warn?
252b5132
RH
6048@cindex @code{octa} directive
6049@cindex integer, 16-byte
6050@cindex sixteen byte integer
6051This directive expects zero or more bignums, separated by commas. For each
6052bignum, it emits a 16-byte integer.
6053
6054The term ``octa'' comes from contexts in which a ``word'' is two bytes;
6055hence @emph{octa}-word for 16 bytes.
6056
9aec2026
NC
6057@node Offset
6058@section @code{.offset @var{loc}}
6059
6060@cindex @code{offset} directive
6061Set the location counter to @var{loc} in the absolute section. @var{loc} must
6062be an absolute expression. This directive may be useful for defining
6063symbols with absolute values. Do not confuse it with the @code{.org}
fa94de6b 6064directive.
9aec2026 6065
252b5132
RH
6066@node Org
6067@section @code{.org @var{new-lc} , @var{fill}}
6068
6069@cindex @code{org} directive
6070@cindex location counter, advancing
6071@cindex advancing location counter
6072@cindex current address, advancing
6073Advance the location counter of the current section to
6074@var{new-lc}. @var{new-lc} is either an absolute expression or an
6075expression with the same section as the current subsection. That is,
6076you can't use @code{.org} to cross sections: if @var{new-lc} has the
6077wrong section, the @code{.org} directive is ignored. To be compatible
6078with former assemblers, if the section of @var{new-lc} is absolute,
a4fb0134 6079@command{@value{AS}} issues a warning, then pretends the section of @var{new-lc}
252b5132
RH
6080is the same as the current subsection.
6081
6082@code{.org} may only increase the location counter, or leave it
6083unchanged; you cannot use @code{.org} to move the location counter
6084backwards.
6085
6086@c double negative used below "not undefined" because this is a specific
6087@c reference to "undefined" (as SEG_UNKNOWN is called in this manual)
6088@c section. doc@cygnus.com 18feb91
a4fb0134 6089Because @command{@value{AS}} tries to assemble programs in one pass, @var{new-lc}
252b5132
RH
6090may not be undefined. If you really detest this restriction we eagerly await
6091a chance to share your improved assembler.
6092
6093Beware that the origin is relative to the start of the section, not
6094to the start of the subsection. This is compatible with other
6095people's assemblers.
6096
6097When the location counter (of the current subsection) is advanced, the
6098intervening bytes are filled with @var{fill} which should be an
6099absolute expression. If the comma and @var{fill} are omitted,
6100@var{fill} defaults to zero.
6101
6102@node P2align
6103@section @code{.p2align[wl] @var{abs-expr}, @var{abs-expr}, @var{abs-expr}}
6104
6105@cindex padding the location counter given a power of two
6106@cindex @code{p2align} directive
6107Pad the location counter (in the current subsection) to a particular
6108storage boundary. The first expression (which must be absolute) is the
6109number of low-order zero bits the location counter must have after
6110advancement. For example @samp{.p2align 3} advances the location
6111counter until it a multiple of 8. If the location counter is already a
6112multiple of 8, no change is needed.
6113
6114The second expression (also absolute) gives the fill value to be stored in the
6115padding bytes. It (and the comma) may be omitted. If it is omitted, the
2ca23e65 6116padding bytes are normally zero. However, on most systems, if the section is
252b5132
RH
6117marked as containing code and the fill value is omitted, the space is filled
6118with no-op instructions.
6119
6120The third expression is also absolute, and is also optional. If it is present,
6121it is the maximum number of bytes that should be skipped by this alignment
6122directive. If doing the alignment would require skipping more bytes than the
6123specified maximum, then the alignment is not done at all. You can omit the
6124fill value (the second argument) entirely by simply using two commas after the
6125required alignment; this can be useful if you want the alignment to be filled
6126with no-op instructions when appropriate.
6127
6128@cindex @code{p2alignw} directive
6129@cindex @code{p2alignl} directive
6130The @code{.p2alignw} and @code{.p2alignl} directives are variants of the
6131@code{.p2align} directive. The @code{.p2alignw} directive treats the fill
6132pattern as a two byte word value. The @code{.p2alignl} directives treats the
6133fill pattern as a four byte longword value. For example, @code{.p2alignw
61342,0x368d} will align to a multiple of 4. If it skips two bytes, they will be
6135filled in with the value 0x368d (the exact placement of the bytes depends upon
6136the endianness of the processor). If it skips 1 or 3 bytes, the fill value is
6137undefined.
6138
ccf8a69b
BW
6139@ifset ELF
6140@node PopSection
6141@section @code{.popsection}
6142
6143@cindex @code{popsection} directive
6144@cindex Section Stack
6145This is one of the ELF section stack manipulation directives. The others are
01642c12
RM
6146@code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}),
6147@code{.pushsection} (@pxref{PushSection}), and @code{.previous}
ccf8a69b
BW
6148(@pxref{Previous}).
6149
6150This directive replaces the current section (and subsection) with the top
6151section (and subsection) on the section stack. This section is popped off the
01642c12 6152stack.
ccf8a69b
BW
6153@end ifset
6154
c91d2e08
NC
6155@ifset ELF
6156@node Previous
6157@section @code{.previous}
6158
c1253627 6159@cindex @code{previous} directive
c91d2e08
NC
6160@cindex Section Stack
6161This is one of the ELF section stack manipulation directives. The others are
a349d9dd
PB
6162@code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}),
6163@code{.pushsection} (@pxref{PushSection}), and @code{.popsection}
6164(@pxref{PopSection}).
c91d2e08
NC
6165
6166This directive swaps the current section (and subsection) with most recently
8b040e0a 6167referenced section/subsection pair prior to this one. Multiple
c91d2e08 6168@code{.previous} directives in a row will flip between two sections (and their
8b040e0a
NC
6169subsections). For example:
6170
6171@smallexample
6172.section A
6173 .subsection 1
6174 .word 0x1234
6175 .subsection 2
6176 .word 0x5678
6177.previous
6178 .word 0x9abc
6179@end smallexample
6180
6181Will place 0x1234 and 0x9abc into subsection 1 and 0x5678 into subsection 2 of
6182section A. Whilst:
6183
6184@smallexample
6185.section A
6186.subsection 1
6187 # Now in section A subsection 1
6188 .word 0x1234
6189.section B
6190.subsection 0
6191 # Now in section B subsection 0
6192 .word 0x5678
6193.subsection 1
6194 # Now in section B subsection 1
6195 .word 0x9abc
6196.previous
6197 # Now in section B subsection 0
6198 .word 0xdef0
6199@end smallexample
6200
6201Will place 0x1234 into section A, 0x5678 and 0xdef0 into subsection 0 of
6202section B and 0x9abc into subsection 1 of section B.
c91d2e08
NC
6203
6204In terms of the section stack, this directive swaps the current section with
6205the top section on the section stack.
6206@end ifset
6207
252b5132
RH
6208@node Print
6209@section @code{.print @var{string}}
6210
6211@cindex @code{print} directive
a4fb0134 6212@command{@value{AS}} will print @var{string} on the standard output during
252b5132
RH
6213assembly. You must put @var{string} in double quotes.
6214
c91d2e08
NC
6215@ifset ELF
6216@node Protected
6217@section @code{.protected @var{names}}
6218
c1253627
NC
6219@cindex @code{protected} directive
6220@cindex visibility
ed9589d4 6221This is one of the ELF visibility directives. The other two are
a349d9dd 6222@code{.hidden} (@pxref{Hidden}) and @code{.internal} (@pxref{Internal}).
c91d2e08
NC
6223
6224This directive overrides the named symbols default visibility (which is set by
6225their binding: local, global or weak). The directive sets the visibility to
6226@code{protected} which means that any references to the symbols from within the
6227components that defines them must be resolved to the definition in that
6228component, even if a definition in another component would normally preempt
01642c12 6229this.
c91d2e08
NC
6230@end ifset
6231
252b5132
RH
6232@node Psize
6233@section @code{.psize @var{lines} , @var{columns}}
6234
6235@cindex @code{psize} directive
6236@cindex listing control: paper size
6237@cindex paper size, for listings
6238Use this directive to declare the number of lines---and, optionally, the
6239number of columns---to use for each page, when generating listings.
6240
6241If you do not use @code{.psize}, listings use a default line-count
6242of 60. You may omit the comma and @var{columns} specification; the
6243default width is 200 columns.
6244
a4fb0134 6245@command{@value{AS}} generates formfeeds whenever the specified number of
252b5132
RH
6246lines is exceeded (or whenever you explicitly request one, using
6247@code{.eject}).
6248
6249If you specify @var{lines} as @code{0}, no formfeeds are generated save
6250those explicitly specified with @code{.eject}.
6251
6252@node Purgem
6253@section @code{.purgem @var{name}}
6254
6255@cindex @code{purgem} directive
6256Undefine the macro @var{name}, so that later uses of the string will not be
6257expanded. @xref{Macro}.
6258
c91d2e08
NC
6259@ifset ELF
6260@node PushSection
9cfc3331 6261@section @code{.pushsection @var{name} [, @var{subsection}] [, "@var{flags}"[, @@@var{type}[,@var{arguments}]]]}
c91d2e08 6262
c1253627 6263@cindex @code{pushsection} directive
c91d2e08
NC
6264@cindex Section Stack
6265This is one of the ELF section stack manipulation directives. The others are
01642c12
RM
6266@code{.section} (@pxref{Section}), @code{.subsection} (@pxref{SubSection}),
6267@code{.popsection} (@pxref{PopSection}), and @code{.previous}
a349d9dd 6268(@pxref{Previous}).
c91d2e08 6269
e9863d7f
DJ
6270This directive pushes the current section (and subsection) onto the
6271top of the section stack, and then replaces the current section and
9cfc3331
L
6272subsection with @code{name} and @code{subsection}. The optional
6273@code{flags}, @code{type} and @code{arguments} are treated the same
6274as in the @code{.section} (@pxref{Section}) directive.
c91d2e08
NC
6275@end ifset
6276
252b5132
RH
6277@node Quad
6278@section @code{.quad @var{bignums}}
6279
6280@cindex @code{quad} directive
6281@code{.quad} expects zero or more bignums, separated by commas. For
6282each bignum, it emits
6283@ifclear bignum-16
6284an 8-byte integer. If the bignum won't fit in 8 bytes, it prints a
6285warning message; and just takes the lowest order 8 bytes of the bignum.
6286@cindex eight-byte integer
6287@cindex integer, 8-byte
6288
6289The term ``quad'' comes from contexts in which a ``word'' is two bytes;
6290hence @emph{quad}-word for 8 bytes.
6291@end ifclear
6292@ifset bignum-16
6293a 16-byte integer. If the bignum won't fit in 16 bytes, it prints a
6294warning message; and just takes the lowest order 16 bytes of the bignum.
6295@cindex sixteen-byte integer
6296@cindex integer, 16-byte
6297@end ifset
6298
05e9452c
AM
6299@node Reloc
6300@section @code{.reloc @var{offset}, @var{reloc_name}[, @var{expression}]}
6301
6302@cindex @code{reloc} directive
6303Generate a relocation at @var{offset} of type @var{reloc_name} with value
6304@var{expression}. If @var{offset} is a number, the relocation is generated in
6305the current section. If @var{offset} is an expression that resolves to a
6306symbol plus offset, the relocation is generated in the given symbol's section.
6307@var{expression}, if present, must resolve to a symbol plus addend or to an
6308absolute value, but note that not all targets support an addend. e.g. ELF REL
6309targets such as i386 store an addend in the section contents rather than in the
6310relocation. This low level interface does not support addends stored in the
6311section.
6312
252b5132
RH
6313@node Rept
6314@section @code{.rept @var{count}}
6315
6316@cindex @code{rept} directive
6317Repeat the sequence of lines between the @code{.rept} directive and the next
6318@code{.endr} directive @var{count} times.
6319
6320For example, assembling
6321
6322@example
6323 .rept 3
6324 .long 0
6325 .endr
6326@end example
6327
6328is equivalent to assembling
6329
6330@example
6331 .long 0
6332 .long 0
6333 .long 0
6334@end example
6335
808811a3
NC
6336A count of zero is allowed, but nothing is generated. Negative counts are not
6337allowed and if encountered will be treated as if they were zero.
6338
252b5132
RH
6339@node Sbttl
6340@section @code{.sbttl "@var{subheading}"}
6341
6342@cindex @code{sbttl} directive
6343@cindex subtitles for listings
6344@cindex listing control: subtitle
6345Use @var{subheading} as the title (third line, immediately after the
6346title line) when generating assembly listings.
6347
6348This directive affects subsequent pages, as well as the current page if
6349it appears within ten lines of the top of a page.
6350
6351@ifset COFF
6352@node Scl
6353@section @code{.scl @var{class}}
6354
6355@cindex @code{scl} directive
6356@cindex symbol storage class (COFF)
6357@cindex COFF symbol storage class
6358Set the storage-class value for a symbol. This directive may only be
6359used inside a @code{.def}/@code{.endef} pair. Storage class may flag
6360whether a symbol is static or external, or it may record further
6361symbolic debugging information.
252b5132
RH
6362@end ifset
6363
c1253627 6364@ifset COFF-ELF
252b5132 6365@node Section
c1253627 6366@section @code{.section @var{name}}
252b5132 6367
252b5132
RH
6368@cindex named section
6369Use the @code{.section} directive to assemble the following code into a section
6370named @var{name}.
6371
6372This directive is only supported for targets that actually support arbitrarily
6373named sections; on @code{a.out} targets, for example, it is not accepted, even
6374with a standard @code{a.out} section name.
6375
c1253627
NC
6376@ifset COFF
6377@ifset ELF
6378@c only print the extra heading if both COFF and ELF are set
6379@subheading COFF Version
6380@end ifset
6381
6382@cindex @code{section} directive (COFF version)
252b5132
RH
6383For COFF targets, the @code{.section} directive is used in one of the following
6384ways:
c91d2e08 6385
252b5132
RH
6386@smallexample
6387.section @var{name}[, "@var{flags}"]
4e188d17 6388.section @var{name}[, @var{subsection}]
252b5132
RH
6389@end smallexample
6390
6391If the optional argument is quoted, it is taken as flags to use for the
6392section. Each flag is a single character. The following flags are recognized:
eda683bb 6393
252b5132
RH
6394@table @code
6395@item b
6396bss section (uninitialized data)
6397@item n
6398section is not loaded
6399@item w
6400writable section
6401@item d
6402data section
70e0ee1a
KT
6403@item e
6404exclude section from linking
252b5132
RH
6405@item r
6406read-only section
6407@item x
6408executable section
2dcc60be
ILT
6409@item s
6410shared section (meaningful for PE targets)
6ff96af6
NC
6411@item a
6412ignored. (For compatibility with the ELF version)
63ad59ae
KT
6413@item y
6414section is not readable (meaningful for PE targets)
31907d5e
DK
6415@item 0-9
6416single-digit power-of-two section alignment (GNU extension)
252b5132
RH
6417@end table
6418
6419If no flags are specified, the default flags depend upon the section name. If
6420the section name is not recognized, the default will be for the section to be
7e84d676
NC
6421loaded and writable. Note the @code{n} and @code{w} flags remove attributes
6422from the section, rather than adding them, so if they are used on their own it
6423will be as if no flags had been specified at all.
252b5132
RH
6424
6425If the optional argument to the @code{.section} directive is not quoted, it is
4e188d17 6426taken as a subsection number (@pxref{Sub-Sections}).
c1253627 6427@end ifset
252b5132
RH
6428
6429@ifset ELF
c1253627
NC
6430@ifset COFF
6431@c only print the extra heading if both COFF and ELF are set
6432@subheading ELF Version
6433@end ifset
6434
c91d2e08
NC
6435@cindex Section Stack
6436This is one of the ELF section stack manipulation directives. The others are
01642c12 6437@code{.subsection} (@pxref{SubSection}), @code{.pushsection}
a349d9dd
PB
6438(@pxref{PushSection}), @code{.popsection} (@pxref{PopSection}), and
6439@code{.previous} (@pxref{Previous}).
c91d2e08 6440
c1253627 6441@cindex @code{section} directive (ELF version)
252b5132 6442For ELF targets, the @code{.section} directive is used like this:
c91d2e08 6443
252b5132 6444@smallexample
7047dd1e 6445.section @var{name} [, "@var{flags}"[, @@@var{type}[,@var{flag_specific_arguments}]]]
252b5132 6446@end smallexample
c91d2e08 6447
451133ce
NP
6448@anchor{Section Name Substitutions}
6449@kindex --sectname-subst
6450@cindex section name substitution
6451If the @samp{--sectname-subst} command-line option is provided, the @var{name}
6452argument may contain a substitution sequence. Only @code{%S} is supported
6453at the moment, and substitutes the current section name. For example:
6454
6455@smallexample
6456.macro exception_code
6457.section %S.exception
6458[exception code here]
6459.previous
6460.endm
6461
6462.text
6463[code]
6464exception_code
6465[...]
6466
6467.section .init
6468[init code]
6469exception_code
6470[...]
6471@end smallexample
6472
6473The two @code{exception_code} invocations above would create the
6474@code{.text.exception} and @code{.init.exception} sections respectively.
33eaf5de
NC
6475This is useful e.g. to discriminate between ancillary sections that are
6476tied to setup code to be discarded after use from ancillary sections that
451133ce
NP
6477need to stay resident without having to define multiple @code{exception_code}
6478macros just for that purpose.
6479
252b5132 6480The optional @var{flags} argument is a quoted string which may contain any
a349d9dd 6481combination of the following characters:
eda683bb 6482
252b5132
RH
6483@table @code
6484@item a
6485section is allocatable
a91e1603
L
6486@item d
6487section is a GNU_MBIND section
18ae9cc1
L
6488@item e
6489section is excluded from executable and shared library.
252b5132
RH
6490@item w
6491section is writable
6492@item x
6493section is executable
ec38dd05
JJ
6494@item M
6495section is mergeable
6496@item S
6497section contains zero terminated strings
22fe14ad
NC
6498@item G
6499section is a member of a section group
6500@item T
6501section is used for thread-local-storage
01642c12
RM
6502@item ?
6503section is a member of the previously-current section's group, if any
eda683bb 6504@item @code{<number>}
9fb71ee4
NC
6505a numeric value indicating the bits to be set in the ELF section header's flags
6506field. Note - if one or more of the alphabetic characters described above is
6507also included in the flags field, their bit values will be ORed into the
6508resulting value.
eda683bb
NC
6509@item @code{<target specific>}
6510some targets extend this list with their own flag characters
252b5132
RH
6511@end table
6512
9fb71ee4
NC
6513Note - once a section's flags have been set they cannot be changed. There are
6514a few exceptions to this rule however. Processor and application specific
6515flags can be added to an already defined section. The @code{.interp},
6516@code{.strtab} and @code{.symtab} sections can have the allocate flag
6517(@code{a}) set after they are initially defined, and the @code{.note-GNU-stack}
eda683bb 6518section may have the executable (@code{x}) flag added.
9fb71ee4 6519
252b5132 6520The optional @var{type} argument may contain one of the following constants:
eda683bb 6521
252b5132
RH
6522@table @code
6523@item @@progbits
6524section contains data
6525@item @@nobits
6526section does not contain data (i.e., section only occupies space)
22fe14ad
NC
6527@item @@note
6528section contains data which is used by things other than the program
10b016c2
PB
6529@item @@init_array
6530section contains an array of pointers to init functions
6531@item @@fini_array
6532section contains an array of pointers to finish functions
6533@item @@preinit_array
6534section contains an array of pointers to pre-init functions
eda683bb 6535@item @@@code{<number>}
9fb71ee4 6536a numeric value to be set as the ELF section header's type field.
eda683bb 6537@item @@@code{<target specific>}
9fb71ee4 6538some targets extend this list with their own types
252b5132
RH
6539@end table
6540
9fb71ee4
NC
6541Many targets only support the first three section types. The type may be
6542enclosed in double quotes if necessary.
10b016c2 6543
ececec60
NC
6544Note on targets where the @code{@@} character is the start of a comment (eg
6545ARM) then another character is used instead. For example the ARM port uses the
6546@code{%} character.
6547
9fb71ee4
NC
6548Note - some sections, eg @code{.text} and @code{.data} are considered to be
6549special and have fixed types. Any attempt to declare them with a different
6550type will generate an error from the assembler.
6551
22fe14ad 6552If @var{flags} contains the @code{M} symbol then the @var{type} argument must
96e9638b 6553be specified as well as an extra argument---@var{entsize}---like this:
22fe14ad
NC
6554
6555@smallexample
6556.section @var{name} , "@var{flags}"M, @@@var{type}, @var{entsize}
6557@end smallexample
6558
6559Sections with the @code{M} flag but not @code{S} flag must contain fixed size
6560constants, each @var{entsize} octets long. Sections with both @code{M} and
6561@code{S} must contain zero terminated strings where each character is
6562@var{entsize} bytes long. The linker may remove duplicates within sections with
6563the same name, same entity size and same flags. @var{entsize} must be an
90dce00a
AM
6564absolute expression. For sections with both @code{M} and @code{S}, a string
6565which is a suffix of a larger string is considered a duplicate. Thus
6566@code{"def"} will be merged with @code{"abcdef"}; A reference to the first
6567@code{"def"} will be changed to a reference to @code{"abcdef"+3}.
22fe14ad
NC
6568
6569If @var{flags} contains the @code{G} symbol then the @var{type} argument must
6570be present along with an additional field like this:
6571
6572@smallexample
6573.section @var{name} , "@var{flags}"G, @@@var{type}, @var{GroupName}[, @var{linkage}]
6574@end smallexample
6575
6576The @var{GroupName} field specifies the name of the section group to which this
6577particular section belongs. The optional linkage field can contain:
eda683bb 6578
22fe14ad
NC
6579@table @code
6580@item comdat
6581indicates that only one copy of this section should be retained
6582@item .gnu.linkonce
6583an alias for comdat
6584@end table
6585
96e9638b 6586Note: if both the @var{M} and @var{G} flags are present then the fields for
22fe14ad
NC
6587the Merge flag should come first, like this:
6588
6589@smallexample
6590.section @var{name} , "@var{flags}"MG, @@@var{type}, @var{entsize}, @var{GroupName}[, @var{linkage}]
6591@end smallexample
ec38dd05 6592
01642c12
RM
6593If @var{flags} contains the @code{?} symbol then it may not also contain the
6594@code{G} symbol and the @var{GroupName} or @var{linkage} fields should not be
6595present. Instead, @code{?} says to consider the section that's current before
6596this directive. If that section used @code{G}, then the new section will use
6597@code{G} with those same @var{GroupName} and @var{linkage} fields implicitly.
6598If not, then the @code{?} symbol has no effect.
6599
252b5132
RH
6600If no flags are specified, the default flags depend upon the section name. If
6601the section name is not recognized, the default will be for the section to have
6602none of the above flags: it will not be allocated in memory, nor writable, nor
6603executable. The section will contain data.
6604
6605For ELF targets, the assembler supports another type of @code{.section}
6606directive for compatibility with the Solaris assembler:
c91d2e08 6607
252b5132
RH
6608@smallexample
6609.section "@var{name}"[, @var{flags}...]
6610@end smallexample
c91d2e08 6611
252b5132
RH
6612Note that the section name is quoted. There may be a sequence of comma
6613separated flags:
eda683bb 6614
252b5132
RH
6615@table @code
6616@item #alloc
6617section is allocatable
6618@item #write
6619section is writable
6620@item #execinstr
6621section is executable
18ae9cc1
L
6622@item #exclude
6623section is excluded from executable and shared library.
22fe14ad
NC
6624@item #tls
6625section is used for thread local storage
252b5132 6626@end table
c91d2e08 6627
e9863d7f
DJ
6628This directive replaces the current section and subsection. See the
6629contents of the gas testsuite directory @code{gas/testsuite/gas/elf} for
6630some examples of how this directive and the other section stack directives
6631work.
c1253627
NC
6632@end ifset
6633@end ifset
252b5132
RH
6634
6635@node Set
6636@section @code{.set @var{symbol}, @var{expression}}
6637
6638@cindex @code{set} directive
6639@cindex symbol value, setting
6640Set the value of @var{symbol} to @var{expression}. This
6641changes @var{symbol}'s value and type to conform to
6642@var{expression}. If @var{symbol} was flagged as external, it remains
6643flagged (@pxref{Symbol Attributes}).
6644
5d239759
NC
6645You may @code{.set} a symbol many times in the same assembly provided that the
6646values given to the symbol are constants. Values that are based on expressions
6647involving other symbols are allowed, but some targets may restrict this to only
6648being done once per assembly. This is because those targets do not set the
6649addresses of symbols at assembly time, but rather delay the assignment until a
6650final link is performed. This allows the linker a chance to change the code in
6651the files, changing the location of, and the relative distance between, various
6652different symbols.
252b5132
RH
6653
6654If you @code{.set} a global symbol, the value stored in the object
6655file is the last value stored into it.
6656
3c9b82ba
NC
6657@ifset Z80
6658On Z80 @code{set} is a real instruction, use
6659@samp{@var{symbol} defl @var{expression}} instead.
6660@end ifset
6661
252b5132
RH
6662@node Short
6663@section @code{.short @var{expressions}}
6664
6665@cindex @code{short} directive
6666@ifset GENERIC
6667@code{.short} is normally the same as @samp{.word}.
6668@xref{Word,,@code{.word}}.
6669
6670In some configurations, however, @code{.short} and @code{.word} generate
96e9638b 6671numbers of different lengths. @xref{Machine Dependencies}.
252b5132
RH
6672@end ifset
6673@ifclear GENERIC
6674@ifset W16
6675@code{.short} is the same as @samp{.word}. @xref{Word,,@code{.word}}.
6676@end ifset
6677@ifset W32
6678This expects zero or more @var{expressions}, and emits
6679a 16 bit number for each.
6680@end ifset
6681@end ifclear
6682
6683@node Single
6684@section @code{.single @var{flonums}}
6685
6686@cindex @code{single} directive
6687@cindex floating point numbers (single)
6688This directive assembles zero or more flonums, separated by commas. It
6689has the same effect as @code{.float}.
6690@ifset GENERIC
6691The exact kind of floating point numbers emitted depends on how
a4fb0134 6692@command{@value{AS}} is configured. @xref{Machine Dependencies}.
252b5132
RH
6693@end ifset
6694@ifclear GENERIC
6695@ifset IEEEFLOAT
6696On the @value{TARGET} family, @code{.single} emits 32-bit floating point
6697numbers in @sc{ieee} format.
6698@end ifset
6699@end ifclear
6700
c1253627 6701@ifset COFF-ELF
252b5132 6702@node Size
c1253627 6703@section @code{.size}
c91d2e08 6704
c1253627
NC
6705This directive is used to set the size associated with a symbol.
6706
6707@ifset COFF
6708@ifset ELF
6709@c only print the extra heading if both COFF and ELF are set
6710@subheading COFF Version
6711@end ifset
6712
6713@cindex @code{size} directive (COFF version)
6714For COFF targets, the @code{.size} directive is only permitted inside
6715@code{.def}/@code{.endef} pairs. It is used like this:
6716
6717@smallexample
6718.size @var{expression}
6719@end smallexample
252b5132 6720
c1253627 6721@end ifset
c91d2e08 6722
c1253627
NC
6723@ifset ELF
6724@ifset COFF
6725@c only print the extra heading if both COFF and ELF are set
6726@subheading ELF Version
6727@end ifset
6728
6729@cindex @code{size} directive (ELF version)
6730For ELF targets, the @code{.size} directive is used like this:
c91d2e08 6731
c1253627
NC
6732@smallexample
6733.size @var{name} , @var{expression}
6734@end smallexample
6735
6736This directive sets the size associated with a symbol @var{name}.
c91d2e08
NC
6737The size in bytes is computed from @var{expression} which can make use of label
6738arithmetic. This directive is typically used to set the size of function
6739symbols.
c1253627
NC
6740@end ifset
6741@end ifset
252b5132 6742
252b5132
RH
6743@ifclear no-space-dir
6744@node Skip
340d33e5 6745@section @code{.skip @var{size} [,@var{fill}]}
252b5132
RH
6746
6747@cindex @code{skip} directive
6748@cindex filling memory
6749This directive emits @var{size} bytes, each of value @var{fill}. Both
6750@var{size} and @var{fill} are absolute expressions. If the comma and
6751@var{fill} are omitted, @var{fill} is assumed to be zero. This is the same as
6752@samp{.space}.
884f0d36 6753@end ifclear
252b5132 6754
ccf8a69b
BW
6755@node Sleb128
6756@section @code{.sleb128 @var{expressions}}
6757
6758@cindex @code{sleb128} directive
01642c12 6759@var{sleb128} stands for ``signed little endian base 128.'' This is a
ccf8a69b
BW
6760compact, variable length representation of numbers used by the DWARF
6761symbolic debugging format. @xref{Uleb128, ,@code{.uleb128}}.
6762
884f0d36 6763@ifclear no-space-dir
252b5132 6764@node Space
340d33e5 6765@section @code{.space @var{size} [,@var{fill}]}
252b5132
RH
6766
6767@cindex @code{space} directive
6768@cindex filling memory
6769This directive emits @var{size} bytes, each of value @var{fill}. Both
6770@var{size} and @var{fill} are absolute expressions. If the comma
6771and @var{fill} are omitted, @var{fill} is assumed to be zero. This is the same
6772as @samp{.skip}.
6773
6774@ifset HPPA
6775@quotation
6776@emph{Warning:} @code{.space} has a completely different meaning for HPPA
6777targets; use @code{.block} as a substitute. See @cite{HP9000 Series 800
6778Assembly Language Reference Manual} (HP 92432-90001) for the meaning of the
6779@code{.space} directive. @xref{HPPA Directives,,HPPA Assembler Directives},
6780for a summary.
6781@end quotation
6782@end ifset
6783@end ifclear
6784
252b5132
RH
6785@ifset have-stabs
6786@node Stab
6787@section @code{.stabd, .stabn, .stabs}
6788
6789@cindex symbolic debuggers, information for
6790@cindex @code{stab@var{x}} directives
6791There are three directives that begin @samp{.stab}.
6792All emit symbols (@pxref{Symbols}), for use by symbolic debuggers.
a4fb0134 6793The symbols are not entered in the @command{@value{AS}} hash table: they
252b5132
RH
6794cannot be referenced elsewhere in the source file.
6795Up to five fields are required:
6796
6797@table @var
6798@item string
6799This is the symbol's name. It may contain any character except
6800@samp{\000}, so is more general than ordinary symbol names. Some
6801debuggers used to code arbitrarily complex structures into symbol names
6802using this field.
6803
6804@item type
6805An absolute expression. The symbol's type is set to the low 8 bits of
6806this expression. Any bit pattern is permitted, but @code{@value{LD}}
6807and debuggers choke on silly bit patterns.
6808
6809@item other
6810An absolute expression. The symbol's ``other'' attribute is set to the
6811low 8 bits of this expression.
6812
6813@item desc
6814An absolute expression. The symbol's descriptor is set to the low 16
6815bits of this expression.
6816
6817@item value
6818An absolute expression which becomes the symbol's value.
6819@end table
6820
6821If a warning is detected while reading a @code{.stabd}, @code{.stabn},
6822or @code{.stabs} statement, the symbol has probably already been created;
6823you get a half-formed symbol in your object file. This is
6824compatible with earlier assemblers!
6825
6826@table @code
6827@cindex @code{stabd} directive
6828@item .stabd @var{type} , @var{other} , @var{desc}
6829
6830The ``name'' of the symbol generated is not even an empty string.
6831It is a null pointer, for compatibility. Older assemblers used a
6832null pointer so they didn't waste space in object files with empty
6833strings.
6834
6835The symbol's value is set to the location counter,
6836relocatably. When your program is linked, the value of this symbol
6837is the address of the location counter when the @code{.stabd} was
6838assembled.
6839
6840@cindex @code{stabn} directive
6841@item .stabn @var{type} , @var{other} , @var{desc} , @var{value}
6842The name of the symbol is set to the empty string @code{""}.
6843
6844@cindex @code{stabs} directive
6845@item .stabs @var{string} , @var{type} , @var{other} , @var{desc} , @var{value}
6846All five fields are specified.
6847@end table
6848@end ifset
6849@c end have-stabs
6850
6851@node String
38a57ae7 6852@section @code{.string} "@var{str}", @code{.string8} "@var{str}", @code{.string16}
01642c12 6853"@var{str}", @code{.string32} "@var{str}", @code{.string64} "@var{str}"
252b5132
RH
6854
6855@cindex string, copying to object file
38a57ae7
NC
6856@cindex string8, copying to object file
6857@cindex string16, copying to object file
6858@cindex string32, copying to object file
6859@cindex string64, copying to object file
252b5132 6860@cindex @code{string} directive
38a57ae7
NC
6861@cindex @code{string8} directive
6862@cindex @code{string16} directive
6863@cindex @code{string32} directive
6864@cindex @code{string64} directive
252b5132
RH
6865
6866Copy the characters in @var{str} to the object file. You may specify more than
6867one string to copy, separated by commas. Unless otherwise specified for a
6868particular machine, the assembler marks the end of each string with a 0 byte.
6869You can use any of the escape sequences described in @ref{Strings,,Strings}.
6870
01642c12 6871The variants @code{string16}, @code{string32} and @code{string64} differ from
38a57ae7
NC
6872the @code{string} pseudo opcode in that each 8-bit character from @var{str} is
6873copied and expanded to 16, 32 or 64 bits respectively. The expanded characters
6874are stored in target endianness byte order.
6875
6876Example:
6877@smallexample
6878 .string32 "BYE"
6879expands to:
6880 .string "B\0\0\0Y\0\0\0E\0\0\0" /* On little endian targets. */
6881 .string "\0\0\0B\0\0\0Y\0\0\0E" /* On big endian targets. */
6882@end smallexample
6883
6884
252b5132
RH
6885@node Struct
6886@section @code{.struct @var{expression}}
6887
6888@cindex @code{struct} directive
6889Switch to the absolute section, and set the section offset to @var{expression},
6890which must be an absolute expression. You might use this as follows:
6891@smallexample
6892 .struct 0
6893field1:
6894 .struct field1 + 4
6895field2:
6896 .struct field2 + 4
6897field3:
6898@end smallexample
6899This would define the symbol @code{field1} to have the value 0, the symbol
6900@code{field2} to have the value 4, and the symbol @code{field3} to have the
6901value 8. Assembly would be left in the absolute section, and you would need to
6902use a @code{.section} directive of some sort to change to some other section
6903before further assembly.
6904
c91d2e08
NC
6905@ifset ELF
6906@node SubSection
6907@section @code{.subsection @var{name}}
6908
c1253627 6909@cindex @code{subsection} directive
c91d2e08
NC
6910@cindex Section Stack
6911This is one of the ELF section stack manipulation directives. The others are
01642c12
RM
6912@code{.section} (@pxref{Section}), @code{.pushsection} (@pxref{PushSection}),
6913@code{.popsection} (@pxref{PopSection}), and @code{.previous}
a349d9dd 6914(@pxref{Previous}).
c91d2e08
NC
6915
6916This directive replaces the current subsection with @code{name}. The current
6917section is not changed. The replaced subsection is put onto the section stack
6918in place of the then current top of stack subsection.
c91d2e08
NC
6919@end ifset
6920
252b5132
RH
6921@ifset ELF
6922@node Symver
6923@section @code{.symver}
6924@cindex @code{symver} directive
6925@cindex symbol versioning
6926@cindex versions of symbols
6927Use the @code{.symver} directive to bind symbols to specific version nodes
6928within a source file. This is only supported on ELF platforms, and is
6929typically used when assembling files to be linked into a shared library.
6930There are cases where it may make sense to use this in objects to be bound
6931into an application itself so as to override a versioned symbol from a
6932shared library.
6933
79082ff0 6934For ELF targets, the @code{.symver} directive can be used like this:
252b5132
RH
6935@smallexample
6936.symver @var{name}, @var{name2@@nodename}
6937@end smallexample
339681c0 6938If the symbol @var{name} is defined within the file
79082ff0 6939being assembled, the @code{.symver} directive effectively creates a symbol
252b5132
RH
6940alias with the name @var{name2@@nodename}, and in fact the main reason that we
6941just don't try and create a regular alias is that the @var{@@} character isn't
6942permitted in symbol names. The @var{name2} part of the name is the actual name
6943of the symbol by which it will be externally referenced. The name @var{name}
6944itself is merely a name of convenience that is used so that it is possible to
6945have definitions for multiple versions of a function within a single source
6946file, and so that the compiler can unambiguously know which version of a
6947function is being mentioned. The @var{nodename} portion of the alias should be
6948the name of a node specified in the version script supplied to the linker when
6949building a shared library. If you are attempting to override a versioned
6950symbol from a shared library, then @var{nodename} should correspond to the
6951nodename of the symbol you are trying to override.
339681c0
L
6952
6953If the symbol @var{name} is not defined within the file being assembled, all
6954references to @var{name} will be changed to @var{name2@@nodename}. If no
6955reference to @var{name} is made, @var{name2@@nodename} will be removed from the
6956symbol table.
79082ff0
L
6957
6958Another usage of the @code{.symver} directive is:
6959@smallexample
6960.symver @var{name}, @var{name2@@@@nodename}
6961@end smallexample
6962In this case, the symbol @var{name} must exist and be defined within
a349d9dd 6963the file being assembled. It is similar to @var{name2@@nodename}. The
79082ff0
L
6964difference is @var{name2@@@@nodename} will also be used to resolve
6965references to @var{name2} by the linker.
6966
6967The third usage of the @code{.symver} directive is:
6968@smallexample
6969.symver @var{name}, @var{name2@@@@@@nodename}
6970@end smallexample
6971When @var{name} is not defined within the
6972file being assembled, it is treated as @var{name2@@nodename}. When
6973@var{name} is defined within the file being assembled, the symbol
6974name, @var{name}, will be changed to @var{name2@@@@nodename}.
252b5132
RH
6975@end ifset
6976
6977@ifset COFF
6978@node Tag
6979@section @code{.tag @var{structname}}
6980
6981@cindex COFF structure debugging
6982@cindex structure debugging, COFF
6983@cindex @code{tag} directive
6984This directive is generated by compilers to include auxiliary debugging
6985information in the symbol table. It is only permitted inside
6986@code{.def}/@code{.endef} pairs. Tags are used to link structure
6987definitions in the symbol table with instances of those structures.
252b5132
RH
6988@end ifset
6989
6990@node Text
6991@section @code{.text @var{subsection}}
6992
6993@cindex @code{text} directive
a4fb0134 6994Tells @command{@value{AS}} to assemble the following statements onto the end of
252b5132
RH
6995the text subsection numbered @var{subsection}, which is an absolute
6996expression. If @var{subsection} is omitted, subsection number zero
6997is used.
6998
6999@node Title
7000@section @code{.title "@var{heading}"}
7001
7002@cindex @code{title} directive
7003@cindex listing control: title line
7004Use @var{heading} as the title (second line, immediately after the
7005source file name and pagenumber) when generating assembly listings.
7006
7007This directive affects subsequent pages, as well as the current page if
7008it appears within ten lines of the top of a page.
7009
c1253627 7010@ifset COFF-ELF
252b5132 7011@node Type
c1253627
NC
7012@section @code{.type}
7013
7014This directive is used to set the type of a symbol.
7015
7016@ifset COFF
7017@ifset ELF
7018@c only print the extra heading if both COFF and ELF are set
7019@subheading COFF Version
7020@end ifset
252b5132
RH
7021
7022@cindex COFF symbol type
7023@cindex symbol type, COFF
c1253627
NC
7024@cindex @code{type} directive (COFF version)
7025For COFF targets, this directive is permitted only within
7026@code{.def}/@code{.endef} pairs. It is used like this:
7027
7028@smallexample
7029.type @var{int}
7030@end smallexample
7031
7032This records the integer @var{int} as the type attribute of a symbol table
7033entry.
252b5132 7034
c1253627 7035@end ifset
c91d2e08 7036
c1253627
NC
7037@ifset ELF
7038@ifset COFF
7039@c only print the extra heading if both COFF and ELF are set
7040@subheading ELF Version
7041@end ifset
c91d2e08
NC
7042
7043@cindex ELF symbol type
7044@cindex symbol type, ELF
c1253627
NC
7045@cindex @code{type} directive (ELF version)
7046For ELF targets, the @code{.type} directive is used like this:
7047
7048@smallexample
7049.type @var{name} , @var{type description}
7050@end smallexample
7051
7052This sets the type of symbol @var{name} to be either a
a349d9dd 7053function symbol or an object symbol. There are five different syntaxes
c91d2e08 7054supported for the @var{type description} field, in order to provide
28c9d252 7055compatibility with various other assemblers.
58ab4f3d
MM
7056
7057Because some of the characters used in these syntaxes (such as @samp{@@} and
7058@samp{#}) are comment characters for some architectures, some of the syntaxes
7059below do not work on all architectures. The first variant will be accepted by
7060the GNU assembler on all architectures so that variant should be used for
7061maximum portability, if you do not need to assemble your code with other
7062assemblers.
7063
7064The syntaxes supported are:
c91d2e08
NC
7065
7066@smallexample
5671778d
NC
7067 .type <name> STT_<TYPE_IN_UPPER_CASE>
7068 .type <name>,#<type>
7069 .type <name>,@@<type>
e7c33416 7070 .type <name>,%<type>
5671778d
NC
7071 .type <name>,"<type>"
7072@end smallexample
7073
7074The types supported are:
58ab4f3d 7075
5671778d
NC
7076@table @gcctabopt
7077@item STT_FUNC
7078@itemx function
7079Mark the symbol as being a function name.
c91d2e08 7080
d8045f23
NC
7081@item STT_GNU_IFUNC
7082@itemx gnu_indirect_function
7083Mark the symbol as an indirect function when evaluated during reloc
9c55345c 7084processing. (This is only supported on assemblers targeting GNU systems).
d8045f23 7085
5671778d
NC
7086@item STT_OBJECT
7087@itemx object
7088Mark the symbol as being a data object.
7089
7090@item STT_TLS
7091@itemx tls_object
33eaf5de 7092Mark the symbol as being a thread-local data object.
5671778d
NC
7093
7094@item STT_COMMON
7095@itemx common
7096Mark the symbol as being a common data object.
e7c33416
NC
7097
7098@item STT_NOTYPE
7099@itemx notype
7100Does not mark the symbol in any way. It is supported just for completeness.
7101
3e7a7d11
NC
7102@item gnu_unique_object
7103Marks the symbol as being a globally unique data object. The dynamic linker
7104will make sure that in the entire process there is just one symbol with this
9c55345c
TS
7105name and type in use. (This is only supported on assemblers targeting GNU
7106systems).
3e7a7d11 7107
5671778d
NC
7108@end table
7109
7110Note: Some targets support extra types in addition to those listed above.
c91d2e08 7111
c1253627
NC
7112@end ifset
7113@end ifset
c91d2e08
NC
7114
7115@node Uleb128
7116@section @code{.uleb128 @var{expressions}}
7117
7118@cindex @code{uleb128} directive
01642c12 7119@var{uleb128} stands for ``unsigned little endian base 128.'' This is a
c91d2e08 7120compact, variable length representation of numbers used by the DWARF
96e9638b 7121symbolic debugging format. @xref{Sleb128, ,@code{.sleb128}}.
252b5132
RH
7122
7123@ifset COFF
7124@node Val
7125@section @code{.val @var{addr}}
7126
7127@cindex @code{val} directive
7128@cindex COFF value attribute
7129@cindex value attribute, COFF
7130This directive, permitted only within @code{.def}/@code{.endef} pairs,
7131records the address @var{addr} as the value attribute of a symbol table
7132entry.
252b5132
RH
7133@end ifset
7134
2e13b764 7135@ifset ELF
c91d2e08
NC
7136@node Version
7137@section @code{.version "@var{string}"}
2e13b764 7138
c1253627 7139@cindex @code{version} directive
c91d2e08
NC
7140This directive creates a @code{.note} section and places into it an ELF
7141formatted note of type NT_VERSION. The note's name is set to @code{string}.
9a297610 7142@end ifset
2e13b764 7143
c91d2e08
NC
7144@ifset ELF
7145@node VTableEntry
7146@section @code{.vtable_entry @var{table}, @var{offset}}
2e13b764 7147
653cfe85 7148@cindex @code{vtable_entry} directive
c91d2e08
NC
7149This directive finds or creates a symbol @code{table} and creates a
7150@code{VTABLE_ENTRY} relocation for it with an addend of @code{offset}.
2e13b764 7151
c91d2e08
NC
7152@node VTableInherit
7153@section @code{.vtable_inherit @var{child}, @var{parent}}
2e13b764 7154
653cfe85 7155@cindex @code{vtable_inherit} directive
c91d2e08
NC
7156This directive finds the symbol @code{child} and finds or creates the symbol
7157@code{parent} and then creates a @code{VTABLE_INHERIT} relocation for the
a349d9dd 7158parent whose addend is the value of the child symbol. As a special case the
96e9638b 7159parent name of @code{0} is treated as referring to the @code{*ABS*} section.
c91d2e08 7160@end ifset
2e13b764 7161
d190d046
HPN
7162@node Warning
7163@section @code{.warning "@var{string}"}
7164@cindex warning directive
7165Similar to the directive @code{.error}
7166(@pxref{Error,,@code{.error "@var{string}"}}), but just emits a warning.
7167
c91d2e08
NC
7168@node Weak
7169@section @code{.weak @var{names}}
2e13b764 7170
c1253627 7171@cindex @code{weak} directive
a349d9dd 7172This directive sets the weak attribute on the comma separated list of symbol
c91d2e08 7173@code{names}. If the symbols do not already exist, they will be created.
c87db184 7174
01642c12 7175On COFF targets other than PE, weak symbols are a GNU extension. This
977cdf5a 7176directive sets the weak attribute on the comma separated list of symbol
c87db184
CF
7177@code{names}. If the symbols do not already exist, they will be created.
7178
977cdf5a 7179On the PE target, weak symbols are supported natively as weak aliases.
01642c12 7180When a weak symbol is created that is not an alias, GAS creates an
977cdf5a 7181alternate symbol to hold the default value.
2e13b764 7182
06e77878
AO
7183@node Weakref
7184@section @code{.weakref @var{alias}, @var{target}}
7185
7186@cindex @code{weakref} directive
7187This directive creates an alias to the target symbol that enables the symbol to
7188be referenced with weak-symbol semantics, but without actually making it weak.
7189If direct references or definitions of the symbol are present, then the symbol
7190will not be weak, but if all references to it are through weak references, the
7191symbol will be marked as weak in the symbol table.
7192
7193The effect is equivalent to moving all references to the alias to a separate
7194assembly source file, renaming the alias to the symbol in it, declaring the
7195symbol as weak there, and running a reloadable link to merge the object files
7196resulting from the assembly of the new source file and the old source file that
7197had the references to the alias removed.
7198
7199The alias itself never makes to the symbol table, and is entirely handled
7200within the assembler.
7201
252b5132
RH
7202@node Word
7203@section @code{.word @var{expressions}}
7204
7205@cindex @code{word} directive
7206This directive expects zero or more @var{expressions}, of any section,
7207separated by commas.
7208@ifclear GENERIC
7209@ifset W32
a4fb0134 7210For each expression, @command{@value{AS}} emits a 32-bit number.
252b5132
RH
7211@end ifset
7212@ifset W16
a4fb0134 7213For each expression, @command{@value{AS}} emits a 16-bit number.
252b5132
RH
7214@end ifset
7215@end ifclear
7216@ifset GENERIC
7217
7218The size of the number emitted, and its byte order,
7219depend on what target computer the assembly is for.
7220@end ifset
7221
a8eb42a8 7222@c on sparc the "special treatment to support compilers" doesn't
252b5132
RH
7223@c happen---32-bit addressability, period; no long/short jumps.
7224@ifset DIFF-TBL-KLUGE
7225@cindex difference tables altered
7226@cindex altered difference tables
7227@quotation
7228@emph{Warning: Special Treatment to support Compilers}
7229@end quotation
7230
7231@ifset GENERIC
7232Machines with a 32-bit address space, but that do less than 32-bit
7233addressing, require the following special treatment. If the machine of
7234interest to you does 32-bit addressing (or doesn't require it;
7235@pxref{Machine Dependencies}), you can ignore this issue.
7236
7237@end ifset
7238In order to assemble compiler output into something that works,
a4fb0134 7239@command{@value{AS}} occasionally does strange things to @samp{.word} directives.
252b5132 7240Directives of the form @samp{.word sym1-sym2} are often emitted by
a4fb0134 7241compilers as part of jump tables. Therefore, when @command{@value{AS}} assembles a
252b5132 7242directive of the form @samp{.word sym1-sym2}, and the difference between
a4fb0134 7243@code{sym1} and @code{sym2} does not fit in 16 bits, @command{@value{AS}}
252b5132
RH
7244creates a @dfn{secondary jump table}, immediately before the next label.
7245This secondary jump table is preceded by a short-jump to the
7246first byte after the secondary table. This short-jump prevents the flow
7247of control from accidentally falling into the new table. Inside the
7248table is a long-jump to @code{sym2}. The original @samp{.word}
7249contains @code{sym1} minus the address of the long-jump to
7250@code{sym2}.
7251
7252If there were several occurrences of @samp{.word sym1-sym2} before the
7253secondary jump table, all of them are adjusted. If there was a
7254@samp{.word sym3-sym4}, that also did not fit in sixteen bits, a
7255long-jump to @code{sym4} is included in the secondary jump table,
7256and the @code{.word} directives are adjusted to contain @code{sym3}
7257minus the address of the long-jump to @code{sym4}; and so on, for as many
7258entries in the original jump table as necessary.
7259
7260@ifset INTERNALS
a4fb0134 7261@emph{This feature may be disabled by compiling @command{@value{AS}} with the
252b5132
RH
7262@samp{-DWORKING_DOT_WORD} option.} This feature is likely to confuse
7263assembly language programmers.
7264@end ifset
7265@end ifset
7266@c end DIFF-TBL-KLUGE
7267
7ce98c16
NC
7268@ifclear no-space-dir
7269@node Zero
7270@section @code{.zero @var{size}}
7271
7272@cindex @code{zero} directive
7273@cindex filling memory with zero bytes
7274This directive emits @var{size} 0-valued bytes. @var{size} must be an absolute
7275expression. This directive is actually an alias for the @samp{.skip} directive
7276so in can take an optional second argument of the value to store in the bytes
7277instead of zero. Using @samp{.zero} in this way would be confusing however.
7278@end ifclear
7279
2b841ec2
AM
7280@ifset ELF
7281@node 2byte
ea86f534 7282@section @code{.2byte @var{expression} [, @var{expression}]*}
2b841ec2
AM
7283@cindex @code{2byte} directive
7284@cindex two-byte integer
7285@cindex integer, 2-byte
2b841ec2 7286
e406e428
NC
7287This directive expects zero or more expressions, separated by commas. If there
7288are no expressions then the directive does nothing. Otherwise each expression
7289is evaluated in turn and placed in the next two bytes of the current output
7290section, using the endian model of the target. If an expression will not fit
7291in two bytes, a warning message is displayed and the least significant two
7292bytes of the expression's value are used. If an expression cannot be evaluated
7293at assembly time then relocations will be generated in order to compute the
7294value at link time.
7295
7296This directive does not apply any alignment before or after inserting the
7297values. As a result of this, if relocations are generated, they may be
7298different from those used for inserting values with a guaranteed alignment.
7299
8b1e5da1 7300This directive is only available for ELF targets,
2b841ec2
AM
7301
7302@node 4byte
ea86f534 7303@section @code{.4byte @var{expression} [, @var{expression}]*}
2b841ec2
AM
7304@cindex @code{4byte} directive
7305@cindex four-byte integer
7306@cindex integer, 4-byte
2b841ec2 7307
e406e428
NC
7308Like the @option{.2byte} directive, except that it inserts unaligned, four byte
7309long values into the output.
2b841ec2
AM
7310
7311@node 8byte
ea86f534 7312@section @code{.8byte @var{expression} [, @var{expression}]*}
2b841ec2
AM
7313@cindex @code{8byte} directive
7314@cindex eight-byte integer
7315@cindex integer, 8-byte
2b841ec2 7316
e21126b7 7317Like the @option{.2byte} directive, except that it inserts unaligned, eight
e406e428
NC
7318byte long bignum values into the output.
7319
2b841ec2
AM
7320@end ifset
7321
252b5132
RH
7322@node Deprecated
7323@section Deprecated Directives
7324
7325@cindex deprecated directives
7326@cindex obsolescent directives
7327One day these directives won't work.
7328They are included for compatibility with older assemblers.
7329@table @t
7330@item .abort
7331@item .line
7332@end table
7333
3a99f02f
DJ
7334@ifset ELF
7335@node Object Attributes
7336@chapter Object Attributes
7337@cindex object attributes
7338
7339@command{@value{AS}} assembles source files written for a specific architecture
7340into object files for that architecture. But not all object files are alike.
7341Many architectures support incompatible variations. For instance, floating
7342point arguments might be passed in floating point registers if the object file
7343requires hardware floating point support---or floating point arguments might be
7344passed in integer registers if the object file supports processors with no
7345hardware floating point unit. Or, if two objects are built for different
7346generations of the same architecture, the combination may require the
7347newer generation at run-time.
7348
7349This information is useful during and after linking. At link time,
7350@command{@value{LD}} can warn about incompatible object files. After link
7351time, tools like @command{gdb} can use it to process the linked file
7352correctly.
7353
7354Compatibility information is recorded as a series of object attributes. Each
7355attribute has a @dfn{vendor}, @dfn{tag}, and @dfn{value}. The vendor is a
7356string, and indicates who sets the meaning of the tag. The tag is an integer,
7357and indicates what property the attribute describes. The value may be a string
7358or an integer, and indicates how the property affects this object. Missing
7359attributes are the same as attributes with a zero value or empty string value.
7360
7361Object attributes were developed as part of the ABI for the ARM Architecture.
7362The file format is documented in @cite{ELF for the ARM Architecture}.
7363
7364@menu
7365* GNU Object Attributes:: @sc{gnu} Object Attributes
7366* Defining New Object Attributes:: Defining New Object Attributes
7367@end menu
7368
7369@node GNU Object Attributes
7370@section @sc{gnu} Object Attributes
7371
7372The @code{.gnu_attribute} directive records an object attribute
7373with vendor @samp{gnu}.
7374
7375Except for @samp{Tag_compatibility}, which has both an integer and a string for
7376its value, @sc{gnu} attributes have a string value if the tag number is odd and
7377an integer value if the tag number is even. The second bit (@code{@var{tag} &
73782} is set for architecture-independent attributes and clear for
7379architecture-dependent ones.
7380
7381@subsection Common @sc{gnu} attributes
7382
7383These attributes are valid on all architectures.
7384
7385@table @r
7386@item Tag_compatibility (32)
7387The compatibility attribute takes an integer flag value and a vendor name. If
7388the flag value is 0, the file is compatible with other toolchains. If it is 1,
7389then the file is only compatible with the named toolchain. If it is greater
7390than 1, the file can only be processed by other toolchains under some private
7391arrangement indicated by the flag value and the vendor name.
7392@end table
7393
7394@subsection MIPS Attributes
7395
7396@table @r
7397@item Tag_GNU_MIPS_ABI_FP (4)
7398The floating-point ABI used by this object file. The value will be:
7399
7400@itemize @bullet
7401@item
74020 for files not affected by the floating-point ABI.
7403@item
f179c512
MF
74041 for files using the hardware floating-point ABI with a standard
7405double-precision FPU.
3a99f02f
DJ
7406@item
74072 for files using the hardware floating-point ABI with a single-precision FPU.
7408@item
74093 for files using the software floating-point ABI.
42554f6a 7410@item
f179c512
MF
74114 for files using the deprecated hardware floating-point ABI which used 64-bit
7412floating-point registers, 32-bit general-purpose registers and increased the
7413number of callee-saved floating-point registers.
7414@item
74155 for files using the hardware floating-point ABI with a double-precision FPU
7416with either 32-bit or 64-bit floating-point registers and 32-bit
7417general-purpose registers.
7418@item
74196 for files using the hardware floating-point ABI with 64-bit floating-point
7420registers and 32-bit general-purpose registers.
7421@item
74227 for files using the hardware floating-point ABI with 64-bit floating-point
7423registers, 32-bit general-purpose registers and a rule that forbids the
7424direct use of odd-numbered single-precision floating-point registers.
3a99f02f
DJ
7425@end itemize
7426@end table
7427
7428@subsection PowerPC Attributes
7429
7430@table @r
7431@item Tag_GNU_Power_ABI_FP (4)
7432The floating-point ABI used by this object file. The value will be:
7433
7434@itemize @bullet
7435@item
74360 for files not affected by the floating-point ABI.
7437@item
3c7b9897 74381 for files using double-precision hardware floating-point ABI.
3a99f02f
DJ
7439@item
74402 for files using the software floating-point ABI.
3c7b9897
AM
7441@item
74423 for files using single-precision hardware floating-point ABI.
3a99f02f
DJ
7443@end itemize
7444
7445@item Tag_GNU_Power_ABI_Vector (8)
7446The vector ABI used by this object file. The value will be:
7447
7448@itemize @bullet
7449@item
74500 for files not affected by the vector ABI.
7451@item
74521 for files using general purpose registers to pass vectors.
7453@item
74542 for files using AltiVec registers to pass vectors.
7455@item
74563 for files using SPE registers to pass vectors.
7457@end itemize
7458@end table
7459
643f7afb
AK
7460@subsection IBM z Systems Attributes
7461
7462@table @r
7463@item Tag_GNU_S390_ABI_Vector (8)
7464The vector ABI used by this object file. The value will be:
7465
7466@itemize @bullet
7467@item
74680 for files not affected by the vector ABI.
7469@item
74701 for files using software vector ABI.
7471@item
74722 for files using hardware vector ABI.
7473@end itemize
7474@end table
7475
3a99f02f
DJ
7476@node Defining New Object Attributes
7477@section Defining New Object Attributes
7478
7479If you want to define a new @sc{gnu} object attribute, here are the places you
7480will need to modify. New attributes should be discussed on the @samp{binutils}
7481mailing list.
7482
7483@itemize @bullet
7484@item
7485This manual, which is the official register of attributes.
7486@item
7487The header for your architecture @file{include/elf}, to define the tag.
7488@item
7489The @file{bfd} support file for your architecture, to merge the attribute
7490and issue any appropriate link warnings.
7491@item
7492Test cases in @file{ld/testsuite} for merging and link warnings.
7493@item
7494@file{binutils/readelf.c} to display your attribute.
7495@item
7496GCC, if you want the compiler to mark the attribute automatically.
7497@end itemize
7498
7499@end ifset
7500
252b5132
RH
7501@ifset GENERIC
7502@node Machine Dependencies
7503@chapter Machine Dependent Features
7504
7505@cindex machine dependencies
7506The machine instruction sets are (almost by definition) different on
a4fb0134
SC
7507each machine where @command{@value{AS}} runs. Floating point representations
7508vary as well, and @command{@value{AS}} often supports a few additional
252b5132
RH
7509directives or command-line options for compatibility with other
7510assemblers on a particular platform. Finally, some versions of
a4fb0134 7511@command{@value{AS}} support special pseudo-instructions for branch
252b5132
RH
7512optimization.
7513
7514This chapter discusses most of these differences, though it does not
7515include details on any machine's instruction set. For details on that
7516subject, see the hardware manufacturer's manual.
7517
7518@menu
a06ea964
NC
7519@ifset AARCH64
7520* AArch64-Dependent:: AArch64 Dependent Features
7521@end ifset
625e1353
RH
7522@ifset ALPHA
7523* Alpha-Dependent:: Alpha Dependent Features
7524@end ifset
252b5132
RH
7525@ifset ARC
7526* ARC-Dependent:: ARC Dependent Features
7527@end ifset
7528@ifset ARM
7529* ARM-Dependent:: ARM Dependent Features
7530@end ifset
8473f7a4
DC
7531@ifset AVR
7532* AVR-Dependent:: AVR Dependent Features
7533@end ifset
3b4e1885
JZ
7534@ifset Blackfin
7535* Blackfin-Dependent:: Blackfin Dependent Features
07c1b327 7536@end ifset
3d3d428f
NC
7537@ifset CR16
7538* CR16-Dependent:: CR16 Dependent Features
7539@end ifset
8bf549a8 7540@ifset CRIS
328eb32e
HPN
7541* CRIS-Dependent:: CRIS Dependent Features
7542@end ifset
252b5132
RH
7543@ifset D10V
7544* D10V-Dependent:: D10V Dependent Features
7545@end ifset
7546@ifset D30V
7547* D30V-Dependent:: D30V Dependent Features
7548@end ifset
cfb8c092
NC
7549@ifset EPIPHANY
7550* Epiphany-Dependent:: EPIPHANY Dependent Features
7551@end ifset
252b5132 7552@ifset H8/300
c2dcd04e 7553* H8/300-Dependent:: Renesas H8/300 Dependent Features
252b5132 7554@end ifset
252b5132
RH
7555@ifset HPPA
7556* HPPA-Dependent:: HPPA Dependent Features
7557@end ifset
7558@ifset I80386
55b62671 7559* i386-Dependent:: Intel 80386 and AMD x86-64 Dependent Features
252b5132 7560@end ifset
5cb53c21
L
7561@ifset IA64
7562* IA-64-Dependent:: Intel IA-64 Dependent Features
7563@end ifset
a40cbfa3
NC
7564@ifset IP2K
7565* IP2K-Dependent:: IP2K Dependent Features
7566@end ifset
84e94c90
NC
7567@ifset LM32
7568* LM32-Dependent:: LM32 Dependent Features
7569@end ifset
49f58d10
JB
7570@ifset M32C
7571* M32C-Dependent:: M32C Dependent Features
7572@end ifset
ec694b89
NC
7573@ifset M32R
7574* M32R-Dependent:: M32R Dependent Features
7575@end ifset
252b5132
RH
7576@ifset M680X0
7577* M68K-Dependent:: M680x0 Dependent Features
7578@end ifset
60bcf0fa
NC
7579@ifset M68HC11
7580* M68HC11-Dependent:: M68HC11 and 68HC12 Dependent Features
7581@end ifset
7b4ae824
JD
7582@ifset S12Z
7583* S12Z-Dependent:: S12Z Dependent Features
7584@end ifset
a3c62988
NC
7585@ifset METAG
7586* Meta-Dependent :: Meta Dependent Features
7587@end ifset
7ba29e2a
NC
7588@ifset MICROBLAZE
7589* MicroBlaze-Dependent:: MICROBLAZE Dependent Features
7590@end ifset
252b5132
RH
7591@ifset MIPS
7592* MIPS-Dependent:: MIPS Dependent Features
7593@end ifset
3c3bdf30
NC
7594@ifset MMIX
7595* MMIX-Dependent:: MMIX Dependent Features
7596@end ifset
2469cfa2
NC
7597@ifset MSP430
7598* MSP430-Dependent:: MSP430 Dependent Features
7599@end ifset
35c08157
KLC
7600@ifset NDS32
7601* NDS32-Dependent:: Andes NDS32 Dependent Features
7602@end ifset
36591ba1
SL
7603@ifset NIOSII
7604* NiosII-Dependent:: Altera Nios II Dependent Features
7605@end ifset
7c31ae13
NC
7606@ifset NS32K
7607* NS32K-Dependent:: NS32K Dependent Features
7608@end ifset
e135f41b
NC
7609@ifset PDP11
7610* PDP-11-Dependent:: PDP-11 Dependent Features
7611@end ifset
041dd5a9
ILT
7612@ifset PJ
7613* PJ-Dependent:: picoJava Dependent Features
7614@end ifset
418c1742
MG
7615@ifset PPC
7616* PPC-Dependent:: PowerPC Dependent Features
7617@end ifset
93f11b16
DD
7618@ifset PRU
7619* PRU-Dependent:: PRU Dependent Features
7620@end ifset
4f7eddc4
PD
7621@ifset RISCV
7622* RISC-V-Dependent:: RISC-V Dependent Features
7623@end ifset
b57e49f7
JW
7624@ifset RL78
7625* RL78-Dependent:: RL78 Dependent Features
7626@end ifset
046d31c2
NC
7627@ifset RX
7628* RX-Dependent:: RX Dependent Features
7629@end ifset
11c19e16
MS
7630@ifset S390
7631* S/390-Dependent:: IBM S/390 Dependent Features
7632@end ifset
c0157db4
NC
7633@ifset SCORE
7634* SCORE-Dependent:: SCORE Dependent Features
7635@end ifset
d3b47e2b
L
7636@ifset SH
7637* SH-Dependent:: Renesas / SuperH SH Dependent Features
d3b47e2b 7638@end ifset
252b5132
RH
7639@ifset SPARC
7640* Sparc-Dependent:: SPARC Dependent Features
7641@end ifset
39bec121
TW
7642@ifset TIC54X
7643* TIC54X-Dependent:: TI TMS320C54x Dependent Features
7644@end ifset
40b36596
JM
7645@ifset TIC6X
7646* TIC6X-Dependent :: TI TMS320C6x Dependent Features
7647@end ifset
aa137e4d
NC
7648@ifset TILEGX
7649* TILE-Gx-Dependent :: Tilera TILE-Gx Dependent Features
7650@end ifset
7651@ifset TILEPRO
7652* TILEPro-Dependent :: Tilera TILEPro Dependent Features
7653@end ifset
252b5132
RH
7654@ifset V850
7655* V850-Dependent:: V850 Dependent Features
7656@end ifset
b6605ddd
EB
7657@ifset VAX
7658* Vax-Dependent:: VAX Dependent Features
7659@end ifset
7660@ifset VISIUM
7661* Visium-Dependent:: Visium Dependent Features
7662@end ifset
f96bd6c2
PC
7663@ifset WASM32
7664* WebAssembly-Dependent:: WebAssembly Dependent Features
7665@end ifset
f6c1a2d5 7666@ifset XGATE
f96bd6c2 7667* XGATE-Dependent:: XGATE Dependent Features
f6c1a2d5 7668@end ifset
6753e72f
NC
7669@ifset XSTORMY16
7670* XSTORMY16-Dependent:: XStormy16 Dependent Features
7671@end ifset
e0001a05
NC
7672@ifset XTENSA
7673* Xtensa-Dependent:: Xtensa Dependent Features
7674@end ifset
3c9b82ba
NC
7675@ifset Z80
7676* Z80-Dependent:: Z80 Dependent Features
7677@end ifset
252b5132
RH
7678@ifset Z8000
7679* Z8000-Dependent:: Z8000 Dependent Features
7680@end ifset
252b5132
RH
7681@end menu
7682
7683@lowersections
7684@end ifset
7685
7686@c The following major nodes are *sections* in the GENERIC version, *chapters*
7687@c in single-cpu versions. This is mainly achieved by @lowersections. There is a
7688@c peculiarity: to preserve cross-references, there must be a node called
7689@c "Machine Dependencies". Hence the conditional nodenames in each
7690@c major node below. Node defaulting in makeinfo requires adjacency of
7691@c node and sectioning commands; hence the repetition of @chapter BLAH
7692@c in both conditional blocks.
7693
a06ea964
NC
7694@ifset AARCH64
7695@include c-aarch64.texi
7696@end ifset
7697
625e1353
RH
7698@ifset ALPHA
7699@include c-alpha.texi
7700@end ifset
7701
7702@ifset ARC
7703@include c-arc.texi
7704@end ifset
7705
252b5132
RH
7706@ifset ARM
7707@include c-arm.texi
7708@end ifset
7709
8473f7a4
DC
7710@ifset AVR
7711@include c-avr.texi
7712@end ifset
7713
3b4e1885 7714@ifset Blackfin
07c1b327
CM
7715@include c-bfin.texi
7716@end ifset
7717
3d3d428f
NC
7718@ifset CR16
7719@include c-cr16.texi
7720@end ifset
7721
328eb32e
HPN
7722@ifset CRIS
7723@include c-cris.texi
7724@end ifset
7725
c2dcd04e 7726@ifset Renesas-all
252b5132
RH
7727@ifclear GENERIC
7728@node Machine Dependencies
7729@chapter Machine Dependent Features
7730
c2dcd04e 7731The machine instruction sets are different on each Renesas chip family,
252b5132 7732and there are also some syntax differences among the families. This
a4fb0134 7733chapter describes the specific @command{@value{AS}} features for each
252b5132
RH
7734family.
7735
7736@menu
c2dcd04e 7737* H8/300-Dependent:: Renesas H8/300 Dependent Features
c2dcd04e 7738* SH-Dependent:: Renesas SH Dependent Features
252b5132
RH
7739@end menu
7740@lowersections
7741@end ifclear
7742@end ifset
7743
7744@ifset D10V
7745@include c-d10v.texi
7746@end ifset
7747
7748@ifset D30V
7749@include c-d30v.texi
7750@end ifset
7751
cfb8c092
NC
7752@ifset EPIPHANY
7753@include c-epiphany.texi
7754@end ifset
7755
252b5132
RH
7756@ifset H8/300
7757@include c-h8300.texi
7758@end ifset
7759
252b5132
RH
7760@ifset HPPA
7761@include c-hppa.texi
7762@end ifset
7763
7764@ifset I80386
7765@include c-i386.texi
7766@end ifset
7767
9e32ca89
NC
7768@ifset IA64
7769@include c-ia64.texi
7770@end ifset
7771
a40cbfa3
NC
7772@ifset IP2K
7773@include c-ip2k.texi
7774@end ifset
7775
84e94c90
NC
7776@ifset LM32
7777@include c-lm32.texi
7778@end ifset
7779
49f58d10
JB
7780@ifset M32C
7781@include c-m32c.texi
7782@end ifset
7783
ec694b89
NC
7784@ifset M32R
7785@include c-m32r.texi
7786@end ifset
252b5132
RH
7787
7788@ifset M680X0
7789@include c-m68k.texi
7790@end ifset
7791
60bcf0fa
NC
7792@ifset M68HC11
7793@include c-m68hc11.texi
7794@end ifset
7795
7b4ae824
JD
7796@ifset S12Z
7797@include c-s12z.texi
7798@end ifset
7799
a3c62988
NC
7800@ifset METAG
7801@include c-metag.texi
7802@end ifset
7803
01642c12 7804@ifset MICROBLAZE
7ba29e2a
NC
7805@include c-microblaze.texi
7806@end ifset
7807
252b5132
RH
7808@ifset MIPS
7809@include c-mips.texi
7810@end ifset
7811
3c3bdf30
NC
7812@ifset MMIX
7813@include c-mmix.texi
7814@end ifset
7815
2469cfa2
NC
7816@ifset MSP430
7817@include c-msp430.texi
7818@end ifset
7819
35c08157
KLC
7820@ifset NDS32
7821@include c-nds32.texi
7822@end ifset
7823
36591ba1
SL
7824@ifset NIOSII
7825@include c-nios2.texi
7826@end ifset
7827
252b5132
RH
7828@ifset NS32K
7829@include c-ns32k.texi
7830@end ifset
7831
e135f41b
NC
7832@ifset PDP11
7833@include c-pdp11.texi
7834@end ifset
7835
041dd5a9
ILT
7836@ifset PJ
7837@include c-pj.texi
7838@end ifset
7839
418c1742
MG
7840@ifset PPC
7841@include c-ppc.texi
7842@end ifset
7843
93f11b16
DD
7844@ifset PRU
7845@include c-pru.texi
7846@end ifset
7847
4f7eddc4
PD
7848@ifset RISCV
7849@include c-riscv.texi
7850@end ifset
7851
b57e49f7
JW
7852@ifset RL78
7853@include c-rl78.texi
7854@end ifset
7855
046d31c2
NC
7856@ifset RX
7857@include c-rx.texi
7858@end ifset
7859
11c19e16
MS
7860@ifset S390
7861@include c-s390.texi
7862@end ifset
7863
c0157db4
NC
7864@ifset SCORE
7865@include c-score.texi
7866@end ifset
7867
252b5132
RH
7868@ifset SH
7869@include c-sh.texi
7870@end ifset
7871
7872@ifset SPARC
7873@include c-sparc.texi
7874@end ifset
7875
39bec121
TW
7876@ifset TIC54X
7877@include c-tic54x.texi
7878@end ifset
7879
40b36596
JM
7880@ifset TIC6X
7881@include c-tic6x.texi
7882@end ifset
7883
aa137e4d
NC
7884@ifset TILEGX
7885@include c-tilegx.texi
7886@end ifset
7887
7888@ifset TILEPRO
7889@include c-tilepro.texi
7890@end ifset
7891
b6605ddd
EB
7892@ifset V850
7893@include c-v850.texi
252b5132
RH
7894@end ifset
7895
7896@ifset VAX
7897@include c-vax.texi
7898@end ifset
7899
b6605ddd
EB
7900@ifset VISIUM
7901@include c-visium.texi
252b5132
RH
7902@end ifset
7903
f96bd6c2
PC
7904@ifset WASM32
7905@include c-wasm32.texi
7906@end ifset
7907
f6c1a2d5
NC
7908@ifset XGATE
7909@include c-xgate.texi
7910@end ifset
7911
6753e72f
NC
7912@ifset XSTORMY16
7913@include c-xstormy16.texi
7914@end ifset
7915
e0001a05
NC
7916@ifset XTENSA
7917@include c-xtensa.texi
7918@end ifset
7919
b6605ddd
EB
7920@ifset Z80
7921@include c-z80.texi
7922@end ifset
7923
7924@ifset Z8000
7925@include c-z8k.texi
7926@end ifset
7927
252b5132
RH
7928@ifset GENERIC
7929@c reverse effect of @down at top of generic Machine-Dep chapter
7930@raisesections
7931@end ifset
7932
7933@node Reporting Bugs
7934@chapter Reporting Bugs
7935@cindex bugs in assembler
7936@cindex reporting bugs in assembler
7937
a4fb0134 7938Your bug reports play an essential role in making @command{@value{AS}} reliable.
252b5132
RH
7939
7940Reporting a bug may help you by bringing a solution to your problem, or it may
7941not. But in any case the principal function of a bug report is to help the
a4fb0134
SC
7942entire community by making the next version of @command{@value{AS}} work better.
7943Bug reports are your contribution to the maintenance of @command{@value{AS}}.
252b5132
RH
7944
7945In order for a bug report to serve its purpose, you must include the
7946information that enables us to fix the bug.
7947
7948@menu
7949* Bug Criteria:: Have you found a bug?
7950* Bug Reporting:: How to report bugs
7951@end menu
7952
7953@node Bug Criteria
c1253627 7954@section Have You Found a Bug?
252b5132
RH
7955@cindex bug criteria
7956
7957If you are not sure whether you have found a bug, here are some guidelines:
7958
7959@itemize @bullet
7960@cindex fatal signal
7961@cindex assembler crash
7962@cindex crash of assembler
7963@item
7964If the assembler gets a fatal signal, for any input whatever, that is a
a4fb0134 7965@command{@value{AS}} bug. Reliable assemblers never crash.
252b5132
RH
7966
7967@cindex error on valid input
7968@item
a4fb0134 7969If @command{@value{AS}} produces an error message for valid input, that is a bug.
252b5132
RH
7970
7971@cindex invalid input
7972@item
a4fb0134 7973If @command{@value{AS}} does not produce an error message for invalid input, that
252b5132
RH
7974is a bug. However, you should note that your idea of ``invalid input'' might
7975be our idea of ``an extension'' or ``support for traditional practice''.
7976
7977@item
7978If you are an experienced user of assemblers, your suggestions for improvement
a4fb0134 7979of @command{@value{AS}} are welcome in any case.
252b5132
RH
7980@end itemize
7981
7982@node Bug Reporting
c1253627 7983@section How to Report Bugs
252b5132
RH
7984@cindex bug reports
7985@cindex assembler bugs, reporting
7986
7987A number of companies and individuals offer support for @sc{gnu} products. If
a4fb0134 7988you obtained @command{@value{AS}} from a support organization, we recommend you
252b5132
RH
7989contact that organization first.
7990
7991You can find contact information for many support companies and
7992individuals in the file @file{etc/SERVICE} in the @sc{gnu} Emacs
7993distribution.
7994
ad22bfe8 7995@ifset BUGURL
a4fb0134 7996In any event, we also recommend that you send bug reports for @command{@value{AS}}
ad22bfe8
JM
7997to @value{BUGURL}.
7998@end ifset
252b5132
RH
7999
8000The fundamental principle of reporting bugs usefully is this:
8001@strong{report all the facts}. If you are not sure whether to state a
8002fact or leave it out, state it!
8003
8004Often people omit facts because they think they know what causes the problem
8005and assume that some details do not matter. Thus, you might assume that the
8006name of a symbol you use in an example does not matter. Well, probably it does
8007not, but one cannot be sure. Perhaps the bug is a stray memory reference which
8008happens to fetch from the location where that name is stored in memory;
8009perhaps, if the name were different, the contents of that location would fool
8010the assembler into doing the right thing despite the bug. Play it safe and
8011give a specific, complete example. That is the easiest thing for you to do,
8012and the most helpful.
8013
8014Keep in mind that the purpose of a bug report is to enable us to fix the bug if
8015it is new to us. Therefore, always write your bug reports on the assumption
8016that the bug has not been reported previously.
8017
8018Sometimes people give a few sketchy facts and ask, ``Does this ring a
c1253627
NC
8019bell?'' This cannot help us fix a bug, so it is basically useless. We
8020respond by asking for enough details to enable us to investigate.
8021You might as well expedite matters by sending them to begin with.
252b5132
RH
8022
8023To enable us to fix the bug, you should include all these things:
8024
8025@itemize @bullet
8026@item
a4fb0134 8027The version of @command{@value{AS}}. @command{@value{AS}} announces it if you start
252b5132
RH
8028it with the @samp{--version} argument.
8029
8030Without this, we will not know whether there is any point in looking for
a4fb0134 8031the bug in the current version of @command{@value{AS}}.
252b5132
RH
8032
8033@item
a4fb0134 8034Any patches you may have applied to the @command{@value{AS}} source.
252b5132
RH
8035
8036@item
8037The type of machine you are using, and the operating system name and
8038version number.
8039
8040@item
a4fb0134 8041What compiler (and its version) was used to compile @command{@value{AS}}---e.g.
252b5132
RH
8042``@code{gcc-2.7}''.
8043
8044@item
8045The command arguments you gave the assembler to assemble your example and
8046observe the bug. To guarantee you will not omit something important, list them
8047all. A copy of the Makefile (or the output from make) is sufficient.
8048
8049If we were to try to guess the arguments, we would probably guess wrong
8050and then we might not encounter the bug.
8051
8052@item
8053A complete input file that will reproduce the bug. If the bug is observed when
8054the assembler is invoked via a compiler, send the assembler source, not the
8055high level language source. Most compilers will produce the assembler source
8056when run with the @samp{-S} option. If you are using @code{@value{GCC}}, use
8057the options @samp{-v --save-temps}; this will save the assembler source in a
8058file with an extension of @file{.s}, and also show you exactly how
a4fb0134 8059@command{@value{AS}} is being run.
252b5132
RH
8060
8061@item
8062A description of what behavior you observe that you believe is
8063incorrect. For example, ``It gets a fatal signal.''
8064
a4fb0134 8065Of course, if the bug is that @command{@value{AS}} gets a fatal signal, then we
252b5132
RH
8066will certainly notice it. But if the bug is incorrect output, we might not
8067notice unless it is glaringly wrong. You might as well not give us a chance to
8068make a mistake.
8069
8070Even if the problem you experience is a fatal signal, you should still say so
8071explicitly. Suppose something strange is going on, such as, your copy of
b45619c0 8072@command{@value{AS}} is out of sync, or you have encountered a bug in the C
252b5132
RH
8073library on your system. (This has happened!) Your copy might crash and ours
8074would not. If you told us to expect a crash, then when ours fails to crash, we
8075would know that the bug was not happening for us. If you had not told us to
8076expect a crash, then we would not be able to draw any conclusion from our
8077observations.
8078
8079@item
a4fb0134 8080If you wish to suggest changes to the @command{@value{AS}} source, send us context
252b5132
RH
8081diffs, as generated by @code{diff} with the @samp{-u}, @samp{-c}, or @samp{-p}
8082option. Always send diffs from the old file to the new file. If you even
a4fb0134 8083discuss something in the @command{@value{AS}} source, refer to it by context, not
252b5132
RH
8084by line number.
8085
8086The line numbers in our development sources will not match those in your
8087sources. Your line numbers would convey no useful information to us.
8088@end itemize
8089
8090Here are some things that are not necessary:
8091
8092@itemize @bullet
8093@item
8094A description of the envelope of the bug.
8095
8096Often people who encounter a bug spend a lot of time investigating
8097which changes to the input file will make the bug go away and which
8098changes will not affect it.
8099
8100This is often time consuming and not very useful, because the way we
8101will find the bug is by running a single example under the debugger
8102with breakpoints, not by pure deduction from a series of examples.
8103We recommend that you save your time for something else.
8104
8105Of course, if you can find a simpler example to report @emph{instead}
8106of the original one, that is a convenience for us. Errors in the
8107output will be easier to spot, running under the debugger will take
8108less time, and so on.
8109
8110However, simplification is not vital; if you do not want to do this,
8111report the bug anyway and send us the entire test case you used.
8112
8113@item
8114A patch for the bug.
8115
8116A patch for the bug does help us if it is a good one. But do not omit
8117the necessary information, such as the test case, on the assumption that
8118a patch is all we need. We might see problems with your patch and decide
8119to fix the problem another way, or we might not understand it at all.
8120
a4fb0134 8121Sometimes with a program as complicated as @command{@value{AS}} it is very hard to
252b5132
RH
8122construct an example that will make the program follow a certain path through
8123the code. If you do not send us the example, we will not be able to construct
8124one, so we will not be able to verify that the bug is fixed.
8125
8126And if we cannot understand what bug you are trying to fix, or why your
8127patch should be an improvement, we will not install it. A test case will
8128help us to understand.
8129
8130@item
8131A guess about what the bug is or what it depends on.
8132
8133Such guesses are usually wrong. Even we cannot guess right about such
8134things without first using the debugger to find the facts.
8135@end itemize
8136
8137@node Acknowledgements
8138@chapter Acknowledgements
8139
653cfe85 8140If you have contributed to GAS and your name isn't listed here,
252b5132 8141it is not meant as a slight. We just don't know about it. Send mail to the
01642c12 8142maintainer, and we'll correct the situation. Currently
3bfcb652
NC
8143@c (October 2012),
8144the maintainer is Nick Clifton (email address @code{nickc@@redhat.com}).
252b5132
RH
8145
8146Dean Elsner wrote the original @sc{gnu} assembler for the VAX.@footnote{Any
8147more details?}
8148
8149Jay Fenlason maintained GAS for a while, adding support for GDB-specific debug
8150information and the 68k series machines, most of the preprocessing pass, and
8151extensive changes in @file{messages.c}, @file{input-file.c}, @file{write.c}.
8152
8153K. Richard Pixley maintained GAS for a while, adding various enhancements and
8154many bug fixes, including merging support for several processors, breaking GAS
8155up to handle multiple object file format back ends (including heavy rewrite,
8156testing, an integration of the coff and b.out back ends), adding configuration
8157including heavy testing and verification of cross assemblers and file splits
8158and renaming, converted GAS to strictly ANSI C including full prototypes, added
8159support for m680[34]0 and cpu32, did considerable work on i960 including a COFF
8160port (including considerable amounts of reverse engineering), a SPARC opcode
8161file rewrite, DECstation, rs6000, and hp300hpux host ports, updated ``know''
8162assertions and made them work, much other reorganization, cleanup, and lint.
8163
8164Ken Raeburn wrote the high-level BFD interface code to replace most of the code
8165in format-specific I/O modules.
8166
8167The original VMS support was contributed by David L. Kashtan. Eric Youngdale
8168has done much work with it since.
8169
8170The Intel 80386 machine description was written by Eliot Dresselhaus.
8171
8172Minh Tran-Le at IntelliCorp contributed some AIX 386 support.
8173
8174The Motorola 88k machine description was contributed by Devon Bowen of Buffalo
8175University and Torbjorn Granlund of the Swedish Institute of Computer Science.
8176
8177Keith Knowles at the Open Software Foundation wrote the original MIPS back end
8178(@file{tc-mips.c}, @file{tc-mips.h}), and contributed Rose format support
8179(which hasn't been merged in yet). Ralph Campbell worked with the MIPS code to
8180support a.out format.
8181
7be1c489
AM
8182Support for the Zilog Z8k and Renesas H8/300 processors (tc-z8k,
8183tc-h8300), and IEEE 695 object file format (obj-ieee), was written by
252b5132
RH
8184Steve Chamberlain of Cygnus Support. Steve also modified the COFF back end to
8185use BFD for some low-level operations, for use with the H8/300 and AMD 29k
8186targets.
8187
8188John Gilmore built the AMD 29000 support, added @code{.include} support, and
8189simplified the configuration of which versions accept which directives. He
8190updated the 68k machine description so that Motorola's opcodes always produced
c1253627 8191fixed-size instructions (e.g., @code{jsr}), while synthetic instructions
252b5132
RH
8192remained shrinkable (@code{jbsr}). John fixed many bugs, including true tested
8193cross-compilation support, and one bug in relaxation that took a week and
8194required the proverbial one-bit fix.
8195
8196Ian Lance Taylor of Cygnus Support merged the Motorola and MIT syntax for the
819768k, completed support for some COFF targets (68k, i386 SVR3, and SCO Unix),
8198added support for MIPS ECOFF and ELF targets, wrote the initial RS/6000 and
8199PowerPC assembler, and made a few other minor patches.
8200
653cfe85 8201Steve Chamberlain made GAS able to generate listings.
252b5132
RH
8202
8203Hewlett-Packard contributed support for the HP9000/300.
8204
8205Jeff Law wrote GAS and BFD support for the native HPPA object format (SOM)
8206along with a fairly extensive HPPA testsuite (for both SOM and ELF object
8207formats). This work was supported by both the Center for Software Science at
8208the University of Utah and Cygnus Support.
8209
8210Support for ELF format files has been worked on by Mark Eichin of Cygnus
8211Support (original, incomplete implementation for SPARC), Pete Hoogenboom and
8212Jeff Law at the University of Utah (HPPA mainly), Michael Meissner of the Open
8213Software Foundation (i386 mainly), and Ken Raeburn of Cygnus Support (sparc,
8214and some initial 64-bit support).
8215
c1253627 8216Linas Vepstas added GAS support for the ESA/390 ``IBM 370'' architecture.
5b93d8bb 8217
252b5132
RH
8218Richard Henderson rewrote the Alpha assembler. Klaus Kaempf wrote GAS and BFD
8219support for openVMS/Alpha.
8220
39bec121
TW
8221Timothy Wall, Michael Hayes, and Greg Smart contributed to the various tic*
8222flavors.
8223
e0001a05 8224David Heine, Sterling Augustine, Bob Wilson and John Ruttenberg from Tensilica,
b45619c0 8225Inc.@: added support for Xtensa processors.
e0001a05 8226
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8227Several engineers at Cygnus Support have also provided many small bug fixes and
8228configuration enhancements.
8229
84e94c90
NC
8230Jon Beniston added support for the Lattice Mico32 architecture.
8231
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RH
8232Many others have contributed large or small bugfixes and enhancements. If
8233you have contributed significant work and are not mentioned on this list, and
8234want to be, let us know. Some of the history has been lost; we are not
8235intentionally leaving anyone out.
8236
793c5807
NC
8237@node GNU Free Documentation License
8238@appendix GNU Free Documentation License
c1253627 8239@include fdl.texi
cf055d54 8240
370b66a1
CD
8241@node AS Index
8242@unnumbered AS Index
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RH
8243
8244@printindex cp
8245
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8246@bye
8247@c Local Variables:
8248@c fill-column: 79
8249@c End: