|
HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|
|
NAME | SYNOPSIS | TARGET | DESCRIPTION | OPTIONS | SEE ALSO | COPYRIGHT | COLOPHON |
|
|
|
AS(1) GNU Development Tools AS(1)
AS - the portable GNU assembler.
as [-a[cdghilns][=file]]
[--alternate]
[--compress-debug-sections] [--nocompress-debug-sections]
[-D]
[--dump-config]
[--debug-prefix-map old=new]
[--defsym sym=val]
[--elf-stt-common=[no|yes]]
[--emulation=name]
[-f]
[-g] [--gstabs] [--gstabs+]
[--gdwarf-<N>] [--gdwarf-sections]
[--gdwarf-cie-version=VERSION]
[--generate-missing-build-notes=[no|yes]]
[--gsframe]
[--hash-size=N]
[--help] [--target-help]
[--info] [--no-info]
[-I dir]
[-J]
[-K]
[--keep-locals]
[-L]
[--listing-lhs-width=NUM]
[--listing-lhs-width2=NUM]
[--listing-rhs-width=NUM]
[--listing-cont-lines=NUM]
[--multibyte-handling=[allow|warn|warn-sym-only]]
[--no-pad-sections]
[-o objfile] [-R]
[--scfi=experimental]
[--sectname-subst]
[--size-check=[error|warning]]
[--statistics]
[-v] [-version] [--version]
[-W] [--no-warn] [--warn] [--fatal-warnings]
[-w] [-x]
[-Z] [@FILE]
[target-options]
[--|files ...]
Target AArch64 options:
[-EB|-EL]
[-mabi=ABI]
Target Alpha options:
[-mcpu]
[-mdebug | -no-mdebug]
[-replace | -noreplace]
[-relax] [-g] [-Gsize]
[-F] [-32addr]
Target ARC options:
[-mcpu=cpu]
[-mA6|-mARC600|-mARC601|-mA7|-mARC700|-mEM|-mHS]
[-mcode-density]
[-mrelax]
[-EB|-EL]
Target ARM options:
[-mcpu=processor[+extension...]]
[-march=architecture[+extension...]]
[-mfpu=floating-point-format]
[-mfloat-abi=abi]
[-meabi=ver]
[-mthumb]
[-EB|-EL]
[-mapcs-32|-mapcs-26|-mapcs-float|
-mapcs-reentrant]
[-mthumb-interwork] [-k]
Target Blackfin options:
[-mcpu=processor[-sirevision]]
[-mfdpic]
[-mno-fdpic]
[-mnopic]
Target BPF options:
[-EL] [-EB]
Target CRIS options:
[--underscore | --no-underscore]
[--pic] [-N]
[--emulation=criself | --emulation=crisaout]
[--march=v0_v10 | --march=v10 | --march=v32 |
--march=common_v10_v32]
Target C-SKY options:
[-march=arch] [-mcpu=cpu]
[-EL] [-mlittle-endian] [-EB] [-mbig-endian]
[-fpic] [-pic]
[-mljump] [-mno-ljump]
[-force2bsr] [-mforce2bsr] [-no-force2bsr] [-mno-force2bsr]
[-jsri2bsr] [-mjsri2bsr] [-no-jsri2bsr ] [-mno-jsri2bsr]
[-mnolrw ] [-mno-lrw]
[-melrw] [-mno-elrw]
[-mlaf ] [-mliterals-after-func]
[-mno-laf] [-mno-literals-after-func]
[-mlabr] [-mliterals-after-br]
[-mno-labr] [-mnoliterals-after-br]
[-mistack] [-mno-istack]
[-mhard-float] [-mmp] [-mcp] [-mcache]
[-msecurity] [-mtrust]
[-mdsp] [-medsp] [-mvdsp]
Target D10V options:
[-O]
Target D30V options:
[-O|-n|-N]
Target EPIPHANY options:
[-mepiphany|-mepiphany16]
Target H8/300 options:
[-h-tick-hex]
Target i386 options:
[--32|--x32|--64] [-n]
[-march=CPU[+EXTENSION...]] [-mtune=CPU]
Target IA-64 options:
[-mconstant-gp|-mauto-pic]
[-milp32|-milp64|-mlp64|-mp64]
[-mle|mbe]
[-mtune=itanium1|-mtune=itanium2]
[-munwind-check=warning|-munwind-check=error]
[-mhint.b=ok|-mhint.b=warning|-mhint.b=error]
[-x|-xexplicit] [-xauto] [-xdebug]
Target IP2K options:
[-mip2022|-mip2022ext]
Target M32C options:
[-m32c|-m16c] [-relax] [-h-tick-hex]
Target M32R options:
[--m32rx|--[no-]warn-explicit-parallel-conflicts|
--W[n]p]
Target M680X0 options:
[-l] [-m68000|-m68010|-m68020|...]
Target M68HC11 options:
[-m68hc11|-m68hc12|-m68hcs12|-mm9s12x|-mm9s12xg]
[-mshort|-mlong]
[-mshort-double|-mlong-double]
[--force-long-branches] [--short-branches]
[--strict-direct-mode] [--print-insn-syntax]
[--print-opcodes] [--generate-example]
Target MCORE options:
[-jsri2bsr] [-sifilter] [-relax]
[-mcpu=[210|340]]
Target Meta options:
[-mcpu=cpu] [-mfpu=cpu] [-mdsp=cpu] Target MICROBLAZE options:
[-mlittle-endian] [-mbig-endian]
Target MIPS options:
[-nocpp] [-EL] [-EB] [-O[optimization level]]
[-g[debug level]] [-G num] [-KPIC] [-call_shared]
[-non_shared] [-xgot [-mvxworks-pic]
[-mabi=ABI] [-32] [-n32] [-64] [-mfp32] [-mgp32]
[-mfp64] [-mgp64] [-mfpxx]
[-modd-spreg] [-mno-odd-spreg]
[-march=CPU] [-mtune=CPU] [-mips1] [-mips2]
[-mips3] [-mips4] [-mips5] [-mips32] [-mips32r2]
[-mips32r3] [-mips32r5] [-mips32r6] [-mips64] [-mips64r2]
[-mips64r3] [-mips64r5] [-mips64r6]
[-construct-floats] [-no-construct-floats]
[-mignore-branch-isa] [-mno-ignore-branch-isa]
[-mnan=encoding]
[-trap] [-no-break] [-break] [-no-trap]
[-mips16] [-no-mips16]
[-mmips16e2] [-mno-mips16e2]
[-mmicromips] [-mno-micromips]
[-msmartmips] [-mno-smartmips]
[-mips3d] [-no-mips3d]
[-mdmx] [-no-mdmx]
[-mdsp] [-mno-dsp]
[-mdspr2] [-mno-dspr2]
[-mdspr3] [-mno-dspr3]
[-mmsa] [-mno-msa]
[-mxpa] [-mno-xpa]
[-mmt] [-mno-mt]
[-mmcu] [-mno-mcu]
[-mcrc] [-mno-crc]
[-mginv] [-mno-ginv]
[-mloongson-mmi] [-mno-loongson-mmi]
[-mloongson-cam] [-mno-loongson-cam]
[-mloongson-ext] [-mno-loongson-ext]
[-mloongson-ext2] [-mno-loongson-ext2]
[-minsn32] [-mno-insn32]
[-mfix7000] [-mno-fix7000]
[-mfix-rm7000] [-mno-fix-rm7000]
[-mfix-vr4120] [-mno-fix-vr4120]
[-mfix-vr4130] [-mno-fix-vr4130]
[-mfix-r5900] [-mno-fix-r5900]
[-mdebug] [-no-mdebug]
[-mpdr] [-mno-pdr]
Target MMIX options:
[--fixed-special-register-names] [--globalize-symbols]
[--gnu-syntax] [--relax] [--no-predefined-symbols]
[--no-expand] [--no-merge-gregs] [-x]
[--linker-allocated-gregs]
Target NDS32 options:
[-EL] [-EB] [-O] [-Os] [-mcpu=cpu]
[-misa=isa] [-mabi=abi] [-mall-ext]
[-m[no-]16-bit] [-m[no-]perf-ext] [-m[no-]perf2-ext]
[-m[no-]string-ext] [-m[no-]dsp-ext] [-m[no-]mac] [-m[no-]div]
[-m[no-]audio-isa-ext] [-m[no-]fpu-sp-ext] [-m[no-]fpu-dp-ext]
[-m[no-]fpu-fma] [-mfpu-freg=FREG] [-mreduced-regs]
[-mfull-regs] [-m[no-]dx-regs] [-mpic] [-mno-relax]
[-mb2bb]
Target PDP11 options:
[-mpic|-mno-pic] [-mall] [-mno-extensions]
[-mextension|-mno-extension]
[-mcpu] [-mmachine]
Target picoJava options:
[-mb|-me]
Target PowerPC options:
[-a32|-a64]
[-mpwrx|-mpwr2|-mpwr|-m601|-mppc|-mppc32|-m603|-m604|-m403|-m405|
-m440|-m464|-m476|-m7400|-m7410|-m7450|-m7455|-m750cl|-mgekko|
-mbroadway|-mppc64|-m620|-me500|-e500x2|-me500mc|-me500mc64|-me5500|
-me6500|-mppc64bridge|-mbooke|-mpower4|-mpwr4|-mpower5|-mpwr5|-mpwr5x|
-mpower6|-mpwr6|-mpower7|-mpwr7|-mpower8|-mpwr8|-mpower9|-mpwr9-ma2|
-mcell|-mspe|-mspe2|-mtitan|-me300|-mcom]
[-many] [-maltivec|-mvsx|-mhtm|-mvle]
[-mregnames|-mno-regnames]
[-mrelocatable|-mrelocatable-lib|-K PIC] [-memb]
[-mlittle|-mlittle-endian|-le|-mbig|-mbig-endian|-be]
[-msolaris|-mno-solaris]
[-nops=count]
Target PRU options:
[-link-relax]
[-mnolink-relax]
[-mno-warn-regname-label]
Target RISC-V options:
[-fpic|-fPIC|-fno-pic]
[-march=ISA]
[-mabi=ABI]
[-mlittle-endian|-mbig-endian]
Target RL78 options:
[-mg10]
[-m32bit-doubles|-m64bit-doubles]
Target RX options:
[-mlittle-endian|-mbig-endian]
[-m32bit-doubles|-m64bit-doubles]
[-muse-conventional-section-names]
[-msmall-data-limit]
[-mpid]
[-mrelax]
[-mint-register=number]
[-mgcc-abi|-mrx-abi]
Target s390 options:
[-m31|-m64] [-mesa|-mzarch] [-march=CPU]
[-mregnames|-mno-regnames]
[-mwarn-areg-zero]
[-mwarn-regtype-mismatch=strict
-mwarn-regtype-mismatch=relaxed
-mwarn-regtype-mismatch=no
-mno-warn-regtype-mismatch]
Target SCORE options:
[-EB][-EL][-FIXDD][-NWARN]
[-SCORE5][-SCORE5U][-SCORE7][-SCORE3]
[-march=score7][-march=score3]
[-USE_R1][-KPIC][-O0][-G num][-V]
Target SPARC options:
[-Av6|-Av7|-Av8|-Aleon|-Asparclet|-Asparclite
-Av8plus|-Av8plusa|-Av8plusb|-Av8plusc|-Av8plusd
-Av8plusv|-Av8plusm|-Av9|-Av9a|-Av9b|-Av9c
-Av9d|-Av9e|-Av9v|-Av9m|-Asparc|-Asparcvis
-Asparcvis2|-Asparcfmaf|-Asparcima|-Asparcvis3
-Asparcvisr|-Asparc5]
[-xarch=v8plus|-xarch=v8plusa]|-xarch=v8plusb|-xarch=v8plusc
-xarch=v8plusd|-xarch=v8plusv|-xarch=v8plusm|-xarch=v9
-xarch=v9a|-xarch=v9b|-xarch=v9c|-xarch=v9d|-xarch=v9e
-xarch=v9v|-xarch=v9m|-xarch=sparc|-xarch=sparcvis
-xarch=sparcvis2|-xarch=sparcfmaf|-xarch=sparcima
-xarch=sparcvis3|-xarch=sparcvisr|-xarch=sparc5
-bump]
[-32|-64]
[--enforce-aligned-data][--dcti-couples-detect]
Target TIC54X options:
[-mcpu=54[123589]|-mcpu=54[56]lp] [-mfar-mode|-mf]
[-merrors-to-file <filename>|-me <filename>]
Target TIC6X options:
[-march=arch] [-mbig-endian|-mlittle-endian]
[-mdsbt|-mno-dsbt] [-mpid=no|-mpid=near|-mpid=far]
[-mpic|-mno-pic]
Target TILE-Gx options:
[-m32|-m64][-EB][-EL]
Target Visium options:
[-mtune=arch]
Target Xtensa options:
[--[no-]text-section-literals] [--[no-]auto-litpools]
[--[no-]absolute-literals]
[--[no-]target-align] [--[no-]longcalls]
[--[no-]transform]
[--rename-section oldname=newname]
[--[no-]trampolines]
[--abi-windowed|--abi-call0]
Target Z80 options:
[-march=CPU[-EXT][+EXT]]
[-local-prefix=PREFIX]
[-colonless]
[-sdcc]
[-fp-s=FORMAT]
[-fp-d=FORMAT]
GNU as is really a family of assemblers. If you use (or have
used) the GNU assembler on one architecture, you should find a
fairly similar environment when you use it on another
architecture. Each version has much in common with the others,
including object file formats, most assembler directives (often
called pseudo-ops) and assembler syntax.
as is primarily intended to assemble the output of the GNU C
compiler "gcc" for use by the linker "ld". Nevertheless, we've
tried to make as assemble correctly everything that other
assemblers for the same machine would assemble. Any exceptions
are documented explicitly. This doesn't mean as always uses the
same syntax as another assembler for the same architecture; for
example, we know of several incompatible versions of 680x0
assembly language syntax.
Each time you run as it assembles exactly one source program. The
source program is made up of one or more files. (The standard
input is also a file.)
You give as a command line that has zero or more input file names.
The input files are read (from left file name to right). A
command-line argument (in any position) that has no special
meaning is taken to be an input file name.
If you give as no file names it attempts to read one input file
from the as standard input, which is normally your terminal. You
may have to type ctl-D to tell as there is no more program to
assemble.
Use -- if you need to explicitly name the standard input file in
your command line.
If the source is empty, as produces a small, empty object file.
as may write warnings and error messages to the standard error
file (usually your terminal). This should not happen when a
compiler runs as automatically. Warnings report an assumption
made so that as could keep assembling a flawed program; errors
report a grave problem that stops the assembly.
If you are invoking as via the GNU C compiler, you can use the -Wa
option to pass arguments through to the assembler. The assembler
arguments must be separated from each other (and the -Wa) by
commas. For example:
gcc -c -g -O -Wa,-alh,-L file.c
This passes two options to the assembler: -alh (emit a listing to
standard output with high-level and assembly source) and -L
(retain local symbols in the symbol table).
Usually you do not need to use this -Wa mechanism, since many
compiler command-line options are automatically passed to the
assembler by the compiler. (You can call the GNU compiler driver
with the -v option to see precisely what options it passes to each
compilation pass, including the assembler.)
@file
Read command-line options from file. The options read are
inserted in place of the original @file option. If file does
not exist, or cannot be read, then the option will be treated
literally, and not removed.
Options in file are separated by whitespace. A whitespace
character may be included in an option by surrounding the
entire option in either single or double quotes. Any
character (including a backslash) may be included by prefixing
the character to be included with a backslash. The file may
itself contain additional @file options; any such options will
be processed recursively.
-a[cdghilmns]
Turn on listings, in any of a variety of ways:
-ac omit false conditionals
-ad omit debugging directives
-ag include general information, like as version and options
passed
-ah include high-level source
-al include assembly
-ali
include assembly with ginsn
-am include macro expansions
-an omit forms processing
-as include symbols
=file
set the name of the listing file
You may combine these options; for example, use -aln for
assembly listing without forms processing. The =file option,
if used, must be the last one. By itself, -a defaults to
-ahls.
--alternate
Begin in alternate macro mode.
--compress-debug-sections
Compress DWARF debug sections using zlib with SHF_COMPRESSED
from the ELF ABI. The resulting object file may not be
compatible with older linkers and object file utilities. Note
if compression would make a given section larger then it is
not compressed.
--compress-debug-sections=none
--compress-debug-sections=zlib
--compress-debug-sections=zlib-gnu
--compress-debug-sections=zlib-gabi
--compress-debug-sections=zstd
These options control how DWARF debug sections are compressed.
--compress-debug-sections=none is equivalent to
--nocompress-debug-sections. --compress-debug-sections=zlib
and --compress-debug-sections=zlib-gabi are equivalent to
--compress-debug-sections. --compress-debug-sections=zlib-gnu
compresses DWARF debug sections using the obsoleted zlib-gnu
format. The debug sections are renamed to begin with .zdebug.
--compress-debug-sections=zstd compresses DWARF debug sections
using zstd. Note - if compression would actually make a
section larger, then it is not compressed nor renamed.
--nocompress-debug-sections
Do not compress DWARF debug sections. This is usually the
default for all targets except the x86/x86_64, but a configure
time option can be used to override this.
-D Enable debugging in target specific backends, if supported.
Otherwise ignored. Even if ignored, this option is accepted
for script compatibility with calls to other assemblers.
--debug-prefix-map old=new
When assembling files in directory old, record debugging
information describing them as in new instead.
--defsym sym=value
Define the symbol sym to be value before assembling the input
file. value must be an integer constant. As in C, a leading
0x indicates a hexadecimal value, and a leading 0 indicates an
octal value. The value of the symbol can be overridden inside
a source file via the use of a ".set" pseudo-op.
--dump-config
Displays how the assembler is configured and then exits.
--elf-stt-common=no
--elf-stt-common=yes
These options control whether the ELF assembler should
generate common symbols with the "STT_COMMON" type. The
default can be controlled by a configure option
--enable-elf-stt-common.
--emulation=name
If the assembler is configured to support multiple different
target configurations then this option can be used to select
the desired form.
-f "fast"---skip whitespace and comment preprocessing (assume
source is compiler output).
-g
--gen-debug
Generate debugging information for each assembler source line
using whichever debug format is preferred by the target. This
currently means either STABS, ECOFF or DWARF2. When the debug
format is DWARF then a ".debug_info" and ".debug_line" section
is only emitted when the assembly file doesn't generate one
itself.
--gstabs
Generate stabs debugging information for each assembler line.
This may help debugging assembler code, if the debugger can
handle it.
--gstabs+
Generate stabs debugging information for each assembler line,
with GNU extensions that probably only gdb can handle, and
that could make other debuggers crash or refuse to read your
program. This may help debugging assembler code. Currently
the only GNU extension is the location of the current working
directory at assembling time.
--gdwarf-2
Generate DWARF2 debugging information for each assembler line.
This may help debugging assembler code, if the debugger can
handle it. Note---this option is only supported by some
targets, not all of them.
--gdwarf-3
This option is the same as the --gdwarf-2 option, except that
it allows for the possibility of the generation of extra debug
information as per version 3 of the DWARF specification. Note
- enabling this option does not guarantee the generation of
any extra information, the choice to do so is on a per target
basis.
--gdwarf-4
This option is the same as the --gdwarf-2 option, except that
it allows for the possibility of the generation of extra debug
information as per version 4 of the DWARF specification. Note
- enabling this option does not guarantee the generation of
any extra information, the choice to do so is on a per target
basis.
--gdwarf-5
This option is the same as the --gdwarf-2 option, except that
it allows for the possibility of the generation of extra debug
information as per version 5 of the DWARF specification. Note
- enabling this option does not guarantee the generation of
any extra information, the choice to do so is on a per target
basis.
--gdwarf-sections
Instead of creating a .debug_line section, create a series of
.debug_line.foo sections where foo is the name of the
corresponding code section. For example a code section called
.text.func will have its dwarf line number information placed
into a section called .debug_line.text.func. If the code
section is just called .text then debug line section will
still be called just .debug_line without any suffix.
--gdwarf-cie-version=version
Control which version of DWARF Common Information Entries
(CIEs) are produced. When this flag is not specified the
default is version 1, though some targets can modify this
default. Other possible values for version are 3 or 4.
--generate-missing-build-notes=yes
--generate-missing-build-notes=no
These options control whether the ELF assembler should
generate GNU Build attribute notes if none are present in the
input sources. The default can be controlled by the
--enable-generate-build-notes configure option.
--gsframe
--gsframe
Create .sframe section from CFI directives.
--hash-size N
Ignored. Supported for command line compatibility with other
assemblers.
--help
Print a summary of the command-line options and exit.
--target-help
Print a summary of all target specific options and exit.
--info
Don't suppress informational messages.
--no-info
Suppress informational messages.
-I dir
Add directory dir to the search list for ".include"
directives.
-J Don't warn about signed overflow.
-K Issue warnings when difference tables altered for long
displacements.
-L
--keep-locals
Keep (in the symbol table) local symbols. These symbols start
with system-specific local label prefixes, typically .L for
ELF systems or L for traditional a.out systems.
--listing-lhs-width=number
Set the maximum width, in words, of the output data column for
an assembler listing to number.
--listing-lhs-width2=number
Set the maximum width, in words, of the output data column for
continuation lines in an assembler listing to number.
--listing-rhs-width=number
Set the maximum width of an input source line, as displayed in
a listing, to number bytes.
--listing-cont-lines=number
Set the maximum number of lines printed in a listing for a
single line of input to number + 1.
--multibyte-handling=allow
--multibyte-handling=warn
--multibyte-handling=warn-sym-only
--multibyte-handling=warn_sym_only
Controls how the assembler handles multibyte characters in the
input. The default (which can be restored by using the allow
argument) is to allow such characters without complaint.
Using the warn argument will make the assembler generate a
warning message whenever any multibyte character is
encountered. Using the warn-sym-only argument will only cause
a warning to be generated when a symbol is defined with a name
that contains multibyte characters. (References to undefined
symbols will not generate a warning).
--no-pad-sections
Stop the assembler for padding the ends of output sections to
the alignment of that section. The default is to pad the
sections, but this can waste space which might be needed on
targets which have tight memory constraints.
-o objfile
Name the object-file output from as objfile.
-R Fold the data section into the text section.
--reduce-memory-overheads
Ignored. Supported for compatibility with tools that pass the
same option to both the assembler and the linker.
--scfi=experimental
This option controls whether the assembler should synthesize
CFI for hand-written input. If the input already contains
some synthesizable CFI directives, the assembler ignores them
and emits a warning. Note that "--scfi=experimental" is not
intended to be used for compiler-generated code, including
inline assembly. This experimental support is work in
progress. Only System V AMD64 ABI is supported.
Each input function in assembly must begin with the ".type"
directive, and should ideally be closed off using a ".size"
directive. When using SCFI, each ".type" directive prompts
GAS to start a new FDE (a.k.a., Function Descriptor Entry).
This implies that with each ".type" directive, a previous
block of instructions, if any, is finalised as a distinct FDE.
--sectname-subst
Honor substitution sequences in section names.
--size-check=error
--size-check=warning
Issue an error or warning for invalid ELF .size directive.
--statistics
Print the maximum space (in bytes) and total time (in seconds)
used by assembly.
--strip-local-absolute
Remove local absolute symbols from the outgoing symbol table.
-v
-version
Print the as version.
--version
Print the as version and exit.
-W
--no-warn
Suppress warning messages.
--warn
Don't suppress warning messages or treat them as errors.
--fatal-warnings
Treat warnings as errors.
-w Ignored.
-x Ignored.
-Z Generate an object file even after errors.
-- | files ...
Standard input, or source files to assemble.
The following options are available when as is configured for the
64-bit mode of the ARM Architecture (AArch64).
-EB This option specifies that the output generated by the
assembler should be marked as being encoded for a big-endian
processor.
-EL This option specifies that the output generated by the
assembler should be marked as being encoded for a
little-endian processor.
-mabi=abi
Specify which ABI the source code uses. The recognized
arguments are: "ilp32" and "lp64", which decides the generated
object file in ELF32 and ELF64 format respectively. The
default is "lp64".
-mcpu=processor[+extension...]
This option specifies the target processor. The assembler
will issue an error message if an attempt is made to assemble
an instruction which will not execute on the target processor.
The following processor names are recognized: "cortex-a34",
"cortex-a35", "cortex-a53", "cortex-a55", "cortex-a57",
"cortex-a65", "cortex-a65ae", "cortex-a72", "cortex-a73",
"cortex-a75", "cortex-a76", "cortex-a76ae", "cortex-a77",
"cortex-a78", "cortex-a78ae", "cortex-a78c", "cortex-a510",
"cortex-a520", "cortex-a710", "cortex-a720", "ares",
"exynos-m1", "falkor", "neoverse-n1", "neoverse-n2",
"neoverse-e1", "neoverse-v1", "qdf24xx", "saphira",
"thunderx", "vulcan", "xgene1" "xgene2", "cortex-r82",
"cortex-x1", "cortex-x2", "cortex-x3", and "cortex-x4". The
special name "all" may be used to allow the assembler to
accept instructions valid for any supported processor,
including all optional extensions.
In addition to the basic instruction set, the assembler can be
told to accept, or restrict, various extension mnemonics that
extend the processor.
If some implementations of a particular processor can have an
extension, then then those extensions are automatically
enabled. Consequently, you will not normally have to specify
any additional extensions.
-march=architecture[+extension...]
This option specifies the target architecture. The assembler
will issue an error message if an attempt is made to assemble
an instruction which will not execute on the target
architecture. The following architecture names are
recognized: "armv8-a", "armv8.1-a", "armv8.2-a", "armv8.3-a",
"armv8.4-a" "armv8.5-a", "armv8.6-a", "armv8.7-a",
"armv8.8-a", "armv8.9-a", "armv8-r", "armv9-a", "armv9.1-a",
"armv9.2-a", "armv9.3-a", "armv9.4-a" and "armv9.5-a".
If both -mcpu and -march are specified, the assembler will use
the setting for -mcpu. If neither are specified, the
assembler will default to -mcpu=all.
The architecture option can be extended with the same
instruction set extension options as the -mcpu option. Unlike
-mcpu, extensions are not always enabled by default.
-mverbose-error
This option enables verbose error messages for AArch64 gas.
This option is enabled by default.
-mno-verbose-error
This option disables verbose error messages in AArch64 gas.
The following options are available when as is configured for an
Alpha processor.
-mcpu
This option specifies the target processor. If an attempt is
made to assemble an instruction which will not execute on the
target processor, the assembler may either expand the
instruction as a macro or issue an error message. This option
is equivalent to the ".arch" directive.
The following processor names are recognized: 21064, "21064a",
21066, 21068, 21164, "21164a", "21164pc", 21264, "21264a",
"21264b", "ev4", "ev5", "lca45", "ev5", "ev56", "pca56",
"ev6", "ev67", "ev68". The special name "all" may be used to
allow the assembler to accept instructions valid for any Alpha
processor.
In order to support existing practice in OSF/1 with respect to
".arch", and existing practice within MILO (the Linux ARC
bootloader), the numbered processor names (e.g. 21064) enable
the processor-specific PALcode instructions, while the
"electro-vlasic" names (e.g. "ev4") do not.
-mdebug
-no-mdebug
Enables or disables the generation of ".mdebug" encapsulation
for stabs directives and procedure descriptors. The default
is to automatically enable ".mdebug" when the first stabs
directive is seen.
-relax
This option forces all relocations to be put into the object
file, instead of saving space and resolving some relocations
at assembly time. Note that this option does not propagate
all symbol arithmetic into the object file, because not all
symbol arithmetic can be represented. However, the option can
still be useful in specific applications.
-replace
-noreplace
Enables or disables the optimization of procedure calls, both
at assemblage and at link time. These options are only
available for VMS targets and "-replace" is the default. See
section 1.4.1 of the OpenVMS Linker Utility Manual.
-g This option is used when the compiler generates debug
information. When gcc is using mips-tfile to generate debug
information for ECOFF, local labels must be passed through to
the object file. Otherwise this option has no effect.
-Gsize
A local common symbol larger than size is placed in ".bss",
while smaller symbols are placed in ".sbss".
-F
-32addr
These options are ignored for backward compatibility.
The following options are available when as is configured for an
ARC processor.
-mcpu=cpu
This option selects the core processor variant.
-EB | -EL
Select either big-endian (-EB) or little-endian (-EL) output.
-mcode-density
Enable Code Density extension instructions.
The following options are available when as is configured for the
ARM processor family.
-mcpu=processor[+extension...]
Specify which ARM processor variant is the target.
-march=architecture[+extension...]
Specify which ARM architecture variant is used by the target.
-mfpu=floating-point-format
Select which Floating Point architecture is the target.
-mfloat-abi=abi
Select which floating point ABI is in use.
-mthumb
Enable Thumb only instruction decoding.
-mapcs-32 | -mapcs-26 | -mapcs-float | -mapcs-reentrant
Select which procedure calling convention is in use.
-EB | -EL
Select either big-endian (-EB) or little-endian (-EL) output.
-mthumb-interwork
Specify that the code has been generated with interworking
between Thumb and ARM code in mind.
-mccs
Turns on CodeComposer Studio assembly syntax compatibility
mode.
-k Specify that PIC code has been generated.
The following options are available when as is configured for the
Blackfin processor family.
-mcpu=processor[-sirevision]
This option specifies the target processor. The optional
sirevision is not used in assembler. It's here such that GCC
can easily pass down its "-mcpu=" option. The assembler will
issue an error message if an attempt is made to assemble an
instruction which will not execute on the target processor.
The following processor names are recognized: "bf504",
"bf506", "bf512", "bf514", "bf516", "bf518", "bf522", "bf523",
"bf524", "bf525", "bf526", "bf527", "bf531", "bf532", "bf533",
"bf534", "bf535" (not implemented yet), "bf536", "bf537",
"bf538", "bf539", "bf542", "bf542m", "bf544", "bf544m",
"bf547", "bf547m", "bf548", "bf548m", "bf549", "bf549m",
"bf561", and "bf592".
-mfdpic
Assemble for the FDPIC ABI.
-mno-fdpic
-mnopic
Disable -mfdpic.
The following options are available when as is configured for the
Linux kernel BPF processor family.
@chapter BPF Dependent Features
BPF Options
-EB This option specifies that the assembler should emit
big-endian eBPF.
-EL This option specifies that the assembler should emit
little-endian eBPF.
-mdialect=dialect
This option specifies the assembly language dialect to
recognize while assembling. The assembler supports normal and
pseudoc.
-misa-spec=spec
This option specifies the version of the BPF instruction set
to use when assembling. The BPF ISA versions supported are v1
v2, v3 and v4.
The value xbpf can be specified to recognize extra
instructions that are used by GCC for testing purposes. But
beware this is not valid BPF.
-mno-relax
This option tells the assembler to not relax instructions.
Note that if no endianness option is specified in the command
line, the host endianness is used. See the info pages for
documentation of the CRIS-specific options.
The following options are available when as is configured for the
C-SKY processor family.
-march=archname
Assemble for architecture archname. The --help option lists
valid values for archname.
-mcpu=cpuname
Assemble for architecture cpuname. The --help option lists
valid values for cpuname.
-EL
-mlittle-endian
Generate little-endian output.
-EB
-mbig-endian
Generate big-endian output.
-fpic
-pic
Generate position-independent code.
-mljump
-mno-ljump
Enable/disable transformation of the short branch instructions
"jbf", "jbt", and "jbr" to "jmpi". This option is for V2
processors only. It is ignored on CK801 and CK802 targets,
which do not support the "jmpi" instruction, and is enabled by
default for other processors.
-mbranch-stub
-mno-branch-stub
Pass through "R_CKCORE_PCREL_IMM26BY2" relocations for "bsr"
instructions to the linker.
This option is only available for bare-metal C-SKY V2 ELF
targets, where it is enabled by default. It cannot be used in
code that will be dynamically linked against shared libraries.
-force2bsr
-mforce2bsr
-no-force2bsr
-mno-force2bsr
Enable/disable transformation of "jbsr" instructions to "bsr".
This option is always enabled (and -mno-force2bsr is ignored)
for CK801/CK802 targets. It is also always enabled when
-mbranch-stub is in effect.
-jsri2bsr
-mjsri2bsr
-no-jsri2bsr
-mno-jsri2bsr
Enable/disable transformation of "jsri" instructions to "bsr".
This option is enabled by default.
-mnolrw
-mno-lrw
Enable/disable transformation of "lrw" instructions into a
"movih"/"ori" pair.
-melrw
-mno-elrw
Enable/disable extended "lrw" instructions. This option is
enabled by default for CK800-series processors.
-mlaf
-mliterals-after-func
-mno-laf
-mno-literals-after-func
Enable/disable placement of literal pools after each function.
-mlabr
-mliterals-after-br
-mno-labr
-mnoliterals-after-br
Enable/disable placement of literal pools after unconditional
branches. This option is enabled by default.
-mistack
-mno-istack
Enable/disable interrupt stack instructions. This option is
enabled by default on CK801, CK802, and CK802 processors.
The following options explicitly enable certain optional
instructions. These features are also enabled implicitly by using
"-mcpu=" to specify a processor that supports it.
-mhard-float
Enable hard float instructions.
-mmp
Enable multiprocessor instructions.
-mcp
Enable coprocessor instructions.
-mcache
Enable cache prefetch instruction.
-msecurity
Enable C-SKY security instructions.
-mtrust
Enable C-SKY trust instructions.
-mdsp
Enable DSP instructions.
-medsp
Enable enhanced DSP instructions.
-mvdsp
Enable vector DSP instructions.
The following options are available when as is configured for an
Epiphany processor.
-mepiphany
Specifies that the both 32 and 16 bit instructions are
allowed. This is the default behavior.
-mepiphany16
Restricts the permitted instructions to just the 16 bit set.
The following options are available when as is configured for an
H8/300 processor. @chapter H8/300 Dependent Features
Options
The Renesas H8/300 version of "as" has one machine-dependent
option:
-h-tick-hex
Support H'00 style hex constants in addition to 0x00 style.
-mach=name
Sets the H8300 machine variant. The following machine names
are recognised: "h8300h", "h8300hn", "h8300s", "h8300sn",
"h8300sx" and "h8300sxn".
The following options are available when as is configured for an
i386 processor.
--32 | --x32 | --64
Select the word size, either 32 bits or 64 bits. --32 implies
Intel i386 architecture, while --x32 and --64 imply AMD x86-64
architecture with 32-bit or 64-bit word-size respectively.
These options are only available with the ELF object file
format, and require that the necessary BFD support has been
included (on a 32-bit platform you have to add
--enable-64-bit-bfd to configure enable 64-bit usage and use
x86-64 as target platform).
-n By default, x86 GAS replaces multiple nop instructions used
for alignment within code sections with multi-byte nop
instructions such as leal 0(%esi,1),%esi. This switch
disables the optimization if a single byte nop (0x90) is
explicitly specified as the fill byte for alignment.
--divide
On SVR4-derived platforms, the character / is treated as a
comment character, which means that it cannot be used in
expressions. The --divide option turns / into a normal
character. This does not disable / at the beginning of a line
starting a comment, or affect using # for starting a comment.
-march=CPU[+EXTENSION...]
This option specifies the target processor. The assembler
will issue an error message if an attempt is made to assemble
an instruction which will not execute on the target processor.
The following processor names are recognized: "i8086", "i186",
"i286", "i386", "i486", "i586", "i686", "pentium",
"pentiumpro", "pentiumii", "pentiumiii", "pentium4",
"prescott", "nocona", "core", "core2", "corei7", "iamcu",
"k6", "k6_2", "athlon", "opteron", "k8", "amdfam10", "bdver1",
"bdver2", "bdver3", "bdver4", "znver1", "znver2", "znver3",
"znver4", "znver5", "btver1", "btver2", "generic32" and
"generic64".
In addition to the basic instruction set, the assembler can be
told to accept various extension mnemonics. For example,
"-march=i686+sse4+vmx" extends i686 with sse4 and vmx. The
following extensions are currently supported: 8087, 287, 387,
687, "cmov", "fxsr", "mmx", "sse", "sse2", "sse3", "sse4a",
"ssse3", "sse4.1", "sse4.2", "sse4", "avx", "avx2",
"lahf_sahf", "monitor", "adx", "rdseed", "prfchw", "smap",
"mpx", "sha", "rdpid", "ptwrite", "cet", "gfni", "vaes",
"vpclmulqdq", "prefetchwt1", "clflushopt", "se1", "clwb",
"movdiri", "movdir64b", "enqcmd", "serialize", "tsxldtrk",
"kl", "widekl", "hreset", "avx512f", "avx512cd", "avx512er",
"avx512pf", "avx512vl", "avx512bw", "avx512dq", "avx512ifma",
"avx512vbmi", "avx512_4fmaps", "avx512_4vnniw",
"avx512_vpopcntdq", "avx512_vbmi2", "avx512_vnni",
"avx512_bitalg", "avx512_vp2intersect", "tdx", "avx512_bf16",
"avx_vnni", "avx512_fp16", "prefetchi", "avx_ifma",
"avx_vnni_int8", "cmpccxadd", "wrmsrns", "msrlist",
"avx_ne_convert", "rao_int", "fred", "lkgs", "avx_vnni_int16",
"sha512", "sm3", "sm4", "pbndkb", "avx10.1", "avx10.1/512",
"avx10.1/256", "avx10.1/128", "user_msr", "msr_imm", "apx_f",
"avx10.2", "avx10.2/512", "avx10.2/256", "avx10.2/128",
"movrs", "amx_int8", "amx_bf16", "amx_fp16", "amx_complex",
"amx_transpose", "amx_tf32", "amx_fp8" "amx_movrs",
"amx_avx512", "amx_tile", "vmx", "vmfunc", "smx", "xsave",
"xsaveopt", "xsavec", "xsaves", "aes", "pclmul", "fsgsbase",
"rdrnd", "f16c", "bmi2", "fma", "movbe", "ept", "lzcnt",
"popcnt", "hle", "rtm", "tsx", "invpcid", "clflush", "mwaitx",
"clzero", "wbnoinvd", "pconfig", "waitpkg", "uintr",
"cldemote", "rdpru", "mcommit", "sev_es", "lwp", "fma4",
"xop", "cx16", "syscall", "rdtscp", "3dnow", "3dnowa",
"sse4a", "sse5", "snp", "invlpgb", "tlbsync", "svme",
"gmism2", "gmiccs", "padlockrng2", "padlockphe2" and
"padlock". Note that these extension mnemonics can be
prefixed with "no" to revoke the respective (and any
dependent) functionality. Note further that the suffixes
permitted on "-march=avx10.<N>" enforce a vector length
restriction, i.e. despite these otherwise being "enabling"
options, using these suffixes will disable all insns with
wider vector or mask register operands.
When the ".arch" directive is used with -march, the ".arch"
directive will take precedent.
-mtune=CPU
This option specifies a processor to optimize for. When used
in conjunction with the -march option, only instructions of
the processor specified by the -march option will be
generated.
Valid CPU values are identical to the processor list of
-march=CPU.
-moperand-check=none
-moperand-check=warning
-moperand-check=error
These options control if the assembler should check certain
instruction operands or operand combinations. An example
instructions where operand size cannot be inferred from its
operands and also hasn't been specified by way of an
instruction suffix. -moperand-check=none will make the
assembler not perform these checks. -moperand-check=warning
will make the assembler issue a warning when respective checks
fail, which is the default. -moperand-check=error will make
the assembler issue an error when respective checks fail.
-msse2avx
This option specifies that the assembler should encode SSE
instructions with VEX prefix, requiring AVX to be available.
SSE instructions using extended GPRs will be encoded with EVEX
prefix, requiring AVX512 or AVX10 to be available.
-muse-unaligned-vector-move
This option specifies that the assembler should encode aligned
vector move as unaligned vector move.
-msse-check=none
-msse-check=warning
-msse-check=error
These options control if the assembler should check SSE
instructions. -msse-check=none will make the assembler not to
check SSE instructions, which is the default.
-msse-check=warning will make the assembler issue a warning
for any SSE instruction. -msse-check=error will make the
assembler issue an error for any SSE instruction.
-mavxscalar=128
-mavxscalar=256
These options control how the assembler should encode scalar
AVX instructions. -mavxscalar=128 will encode scalar AVX
instructions with 128bit vector length, which is the default.
-mavxscalar=256 will encode scalar AVX instructions with
256bit vector length.
WARNING: Don't use this for production code - due to CPU
errata the resulting code may not work on certain models.
-mvexwig=0
-mvexwig=1
These options control how the assembler should encode
VEX.W-ignored (WIG) VEX instructions. -mvexwig=0 will encode
WIG VEX instructions with vex.w = 0, which is the default.
-mvexwig=1 will encode WIG EVEX instructions with vex.w = 1.
WARNING: Don't use this for production code - due to CPU
errata the resulting code may not work on certain models.
-mevexlig=128
-mevexlig=256
-mevexlig=512
These options control how the assembler should encode
length-ignored (LIG) EVEX instructions. -mevexlig=128 will
encode LIG EVEX instructions with 128bit vector length, which
is the default. -mevexlig=256 and -mevexlig=512 will encode
LIG EVEX instructions with 256bit and 512bit vector length,
respectively.
-mevexwig=0
-mevexwig=1
These options control how the assembler should encode
w-ignored (WIG) EVEX instructions. -mevexwig=0 will encode
WIG EVEX instructions with evex.w = 0, which is the default.
-mevexwig=1 will encode WIG EVEX instructions with evex.w = 1.
-mmnemonic=att
-mmnemonic=intel
This option specifies instruction mnemonic for matching
instructions. The ".att_mnemonic" and ".intel_mnemonic"
directives will take precedent.
-msyntax=att
-msyntax=intel
This option specifies instruction syntax when processing
instructions. The ".att_syntax" and ".intel_syntax"
directives will take precedent.
-mnaked-reg
This option specifies that registers don't require a % prefix.
The ".att_syntax" and ".intel_syntax" directives will take
precedent.
-madd-bnd-prefix
This option forces the assembler to add BND prefix to all
branches, even if such prefix was not explicitly specified in
the source code.
-mno-shared
On ELF target, the assembler normally optimizes out non-PLT
relocations against defined non-weak global branch targets
with default visibility. The -mshared option tells the
assembler to generate code which may go into a shared library
where all non-weak global branch targets with default
visibility can be preempted. The resulting code is slightly
bigger. This option only affects the handling of branch
instructions.
-mbig-obj
On PE/COFF target this option forces the use of big object
file format, which allows more than 32768 sections.
-momit-lock-prefix=no
-momit-lock-prefix=yes
These options control how the assembler should encode lock
prefix. This option is intended as a workaround for
processors, that fail on lock prefix. This option can only be
safely used with single-core, single-thread computers
-momit-lock-prefix=yes will omit all lock prefixes.
-momit-lock-prefix=no will encode lock prefix as usual, which
is the default.
-mfence-as-lock-add=no
-mfence-as-lock-add=yes
These options control how the assembler should encode lfence,
mfence and sfence. -mfence-as-lock-add=yes will encode
lfence, mfence and sfence as lock addl $0x0, (%rsp) in 64-bit
mode and lock addl $0x0, (%esp) in 32-bit mode.
-mfence-as-lock-add=no will encode lfence, mfence and sfence
as usual, which is the default.
-mrelax-relocations=no
-mrelax-relocations=yes
These options control whether the assembler should generate
relax relocations, R_386_GOT32X, in 32-bit mode, or
R_X86_64_GOTPCRELX and R_X86_64_REX_GOTPCRELX, in 64-bit mode.
-mrelax-relocations=yes will generate relax relocations.
-mrelax-relocations=no will not generate relax relocations.
The default can be controlled by a configure option
--enable-x86-relax-relocations.
-mtls-check=no
-mtls-check=yes
These options control whether the assembler check tls
relocation. -mtls-check=yes will check tls relocation.
-mtls-check=no will not check tls relocation The default can
be controlled by a configure option --enable-x86-tls-check.
-malign-branch-boundary=NUM
This option controls how the assembler should align branches
with segment prefixes or NOP. NUM must be a power of 2. It
should be 0 or no less than 16. Branches will be aligned
within NUM byte boundary. -malign-branch-boundary=0, which is
the default, doesn't align branches.
-malign-branch=TYPE[+TYPE...]
This option specifies types of branches to align. TYPE is
combination of jcc, which aligns conditional jumps, fused,
which aligns fused conditional jumps, jmp, which aligns
unconditional jumps, call which aligns calls, ret, which
aligns rets, indirect, which aligns indirect jumps and calls.
The default is -malign-branch=jcc+fused+jmp.
-malign-branch-prefix-size=NUM
This option specifies the maximum number of prefixes on an
instruction to align branches. NUM should be between 0 and 5.
The default NUM is 5.
-mbranches-within-32B-boundaries
This option aligns conditional jumps, fused conditional jumps
and unconditional jumps within 32 byte boundary with up to 5
segment prefixes on an instruction. It is equivalent to
-malign-branch-boundary=32 -malign-branch=jcc+fused+jmp
-malign-branch-prefix-size=5. The default doesn't align
branches.
-mlfence-after-load=no
-mlfence-after-load=yes
These options control whether the assembler should generate
lfence after load instructions. -mlfence-after-load=yes will
generate lfence. -mlfence-after-load=no will not generate
lfence, which is the default.
-mlfence-before-indirect-branch=none
-mlfence-before-indirect-branch=all
-mlfence-before-indirect-branch=register
-mlfence-before-indirect-branch=memory
These options control whether the assembler should generate
lfence before indirect near branch instructions.
-mlfence-before-indirect-branch=all will generate lfence
before indirect near branch via register and issue a warning
before indirect near branch via memory. It also implicitly
sets -mlfence-before-ret=shl when there's no explicit
-mlfence-before-ret=.
-mlfence-before-indirect-branch=register will generate lfence
before indirect near branch via register.
-mlfence-before-indirect-branch=memory will issue a warning
before indirect near branch via memory.
-mlfence-before-indirect-branch=none will not generate lfence
nor issue warning, which is the default. Note that lfence
won't be generated before indirect near branch via register
with -mlfence-after-load=yes since lfence will be generated
after loading branch target register.
-mlfence-before-ret=none
-mlfence-before-ret=shl
-mlfence-before-ret=or
-mlfence-before-ret=yes
-mlfence-before-ret=not
These options control whether the assembler should generate
lfence before ret. -mlfence-before-ret=or will generate
generate or instruction with lfence.
-mlfence-before-ret=shl/yes will generate shl instruction with
lfence. -mlfence-before-ret=not will generate not instruction
with lfence. -mlfence-before-ret=none will not generate
lfence, which is the default.
-mx86-used-note=no
-mx86-used-note=yes
These options control whether the assembler should generate
GNU_PROPERTY_X86_ISA_1_USED and
GNU_PROPERTY_X86_FEATURE_2_USED GNU property notes. The
default can be controlled by the --enable-x86-used-note
configure option.
-mevexrcig=rne
-mevexrcig=rd
-mevexrcig=ru
-mevexrcig=rz
These options control how the assembler should encode SAE-only
EVEX instructions. -mevexrcig=rne will encode RC bits of EVEX
instruction with 00, which is the default. -mevexrcig=rd,
-mevexrcig=ru and -mevexrcig=rz will encode SAE-only EVEX
instructions with 01, 10 and 11 RC bits, respectively.
-mamd64
-mintel64
This option specifies that the assembler should accept only
AMD64 or Intel64 ISA in 64-bit mode. The default is to accept
common, Intel64 only and AMD64 ISAs.
-O0 | -O | -O1 | -O2 | -Os
Optimize instruction encoding with smaller instruction size.
-O and -O1 encode 64-bit register load instructions with
64-bit immediate as 32-bit register load instructions with
31-bit or 32-bits immediates, encode 64-bit register clearing
instructions with 32-bit register clearing instructions,
encode 256-bit/512-bit VEX/EVEX vector register clearing
instructions with 128-bit VEX vector register clearing
instructions, encode 128-bit/256-bit EVEX vector register
load/store instructions with VEX vector register load/store
instructions, and encode 128-bit/256-bit EVEX packed integer
logical instructions with 128-bit/256-bit VEX packed integer
logical.
-O2 includes -O1 optimization plus encodes 256-bit/512-bit
EVEX vector register clearing instructions with 128-bit EVEX
vector register clearing instructions. In 64-bit mode VEX
encoded instructions with commutative source operands will
also have their source operands swapped if this allows using
the 2-byte VEX prefix form instead of the 3-byte one. Certain
forms of AND as well as OR with the same (register) operand
specified twice will also be changed to TEST.
-Os includes -O2 optimization plus encodes 16-bit, 32-bit and
64-bit register tests with immediate as 8-bit register test
with immediate. -O0 turns off this optimization.
The following options are available when as is configured for the
Ubicom IP2K series.
-mip2022ext
Specifies that the extended IP2022 instructions are allowed.
-mip2022
Restores the default behaviour, which restricts the permitted
instructions to just the basic IP2022 ones.
The following options are available when as is configured for the
Renesas M32C and M16C processors.
-m32c
Assemble M32C instructions.
-m16c
Assemble M16C instructions (the default).
-relax
Enable support for link-time relaxations.
-h-tick-hex
Support H'00 style hex constants in addition to 0x00 style.
The following options are available when as is configured for the
Renesas M32R (formerly Mitsubishi M32R) series.
--m32rx
Specify which processor in the M32R family is the target. The
default is normally the M32R, but this option changes it to
the M32RX.
--warn-explicit-parallel-conflicts or --Wp
Produce warning messages when questionable parallel constructs
are encountered.
--no-warn-explicit-parallel-conflicts or --Wnp
Do not produce warning messages when questionable parallel
constructs are encountered.
The following options are available when as is configured for the
Motorola 68000 series.
-l Shorten references to undefined symbols, to one word instead
of two.
-m68000 | -m68008 | -m68010 | -m68020 | -m68030
| -m68040 | -m68060 | -m68302 | -m68331 | -m68332
| -m68333 | -m68340 | -mcpu32 | -m5200
Specify what processor in the 68000 family is the target. The
default is normally the 68020, but this can be changed at
configuration time.
-m68881 | -m68882 | -mno-68881 | -mno-68882
The target machine does (or does not) have a floating-point
coprocessor. The default is to assume a coprocessor for
68020, 68030, and cpu32. Although the basic 68000 is not
compatible with the 68881, a combination of the two can be
specified, since it's possible to do emulation of the
coprocessor instructions with the main processor.
-m68851 | -mno-68851
The target machine does (or does not) have a memory-management
unit coprocessor. The default is to assume an MMU for 68020
and up.
For details about the PDP-11 machine dependent features options,
see PDP-11-Options.
-mpic | -mno-pic
Generate position-independent (or position-dependent) code.
The default is -mpic.
-mall
-mall-extensions
Enable all instruction set extensions. This is the default.
-mno-extensions
Disable all instruction set extensions.
-mextension | -mno-extension
Enable (or disable) a particular instruction set extension.
-mcpu
Enable the instruction set extensions supported by a
particular CPU, and disable all other extensions.
-mmachine
Enable the instruction set extensions supported by a
particular machine model, and disable all other extensions.
The following options are available when as is configured for a
picoJava processor.
-mb Generate "big endian" format output.
-ml Generate "little endian" format output.
The following options are available when as is configured for a
PRU processor.
-mlink-relax
Assume that LD would optimize LDI32 instructions by checking
the upper 16 bits of the expression. If they are all zeros,
then LD would shorten the LDI32 instruction to a single LDI.
In such case "as" will output DIFF relocations for diff
expressions.
-mno-link-relax
Assume that LD would not optimize LDI32 instructions. As a
consequence, DIFF relocations will not be emitted.
-mno-warn-regname-label
Do not warn if a label name matches a register name. Usually
assembler programmers will want this warning to be emitted. C
compilers may want to turn this off.
The following options are available when as is configured for a
MIPS processor.
-G num
This option sets the largest size of an object that can be
referenced implicitly with the "gp" register. It is only
accepted for targets that use ECOFF format, such as a
DECstation running Ultrix. The default value is 8.
-EB Generate "big endian" format output.
-EL Generate "little endian" format output.
-mips1
-mips2
-mips3
-mips4
-mips5
-mips32
-mips32r2
-mips32r3
-mips32r5
-mips32r6
-mips64
-mips64r2
-mips64r3
-mips64r5
-mips64r6
Generate code for a particular MIPS Instruction Set
Architecture level. -mips1 is an alias for -march=r3000,
-mips2 is an alias for -march=r6000, -mips3 is an alias for
-march=r4000 and -mips4 is an alias for -march=r8000. -mips5,
-mips32, -mips32r2, -mips32r3, -mips32r5, -mips32r6, -mips64,
-mips64r2, -mips64r3, -mips64r5, and -mips64r6 correspond to
generic MIPS V, MIPS32, MIPS32 Release 2, MIPS32 Release 3,
MIPS32 Release 5, MIPS32 Release 6, MIPS64, MIPS64 Release 2,
MIPS64 Release 3, MIPS64 Release 5, and MIPS64 Release 6 ISA
processors, respectively.
-march=cpu
Generate code for a particular MIPS CPU.
-mtune=cpu
Schedule and tune for a particular MIPS CPU.
-mfix7000
-mno-fix7000
Cause nops to be inserted if the read of the destination
register of an mfhi or mflo instruction occurs in the
following two instructions.
-mfix-rm7000
-mno-fix-rm7000
Cause nops to be inserted if a dmult or dmultu instruction is
followed by a load instruction.
-mfix-r5900
-mno-fix-r5900
Do not attempt to schedule the preceding instruction into the
delay slot of a branch instruction placed at the end of a
short loop of six instructions or fewer and always schedule a
"nop" instruction there instead. The short loop bug under
certain conditions causes loops to execute only once or twice,
due to a hardware bug in the R5900 chip.
-mdebug
-no-mdebug
Cause stabs-style debugging output to go into an ECOFF-style
.mdebug section instead of the standard ELF .stabs sections.
-mpdr
-mno-pdr
Control generation of ".pdr" sections.
-mgp32
-mfp32
The register sizes are normally inferred from the ISA and ABI,
but these flags force a certain group of registers to be
treated as 32 bits wide at all times. -mgp32 controls the
size of general-purpose registers and -mfp32 controls the size
of floating-point registers.
-mgp64
-mfp64
The register sizes are normally inferred from the ISA and ABI,
but these flags force a certain group of registers to be
treated as 64 bits wide at all times. -mgp64 controls the
size of general-purpose registers and -mfp64 controls the size
of floating-point registers.
-mfpxx
The register sizes are normally inferred from the ISA and ABI,
but using this flag in combination with -mabi=32 enables an
ABI variant which will operate correctly with floating-point
registers which are 32 or 64 bits wide.
-modd-spreg
-mno-odd-spreg
Enable use of floating-point operations on odd-numbered
single-precision registers when supported by the ISA. -mfpxx
implies -mno-odd-spreg, otherwise the default is -modd-spreg.
-mips16
-no-mips16
Generate code for the MIPS 16 processor. This is equivalent
to putting ".module mips16" at the start of the assembly file.
-no-mips16 turns off this option.
-mmips16e2
-mno-mips16e2
Enable the use of MIPS16e2 instructions in MIPS16 mode. This
is equivalent to putting ".module mips16e2" at the start of
the assembly file. -mno-mips16e2 turns off this option.
-mmicromips
-mno-micromips
Generate code for the microMIPS processor. This is equivalent
to putting ".module micromips" at the start of the assembly
file. -mno-micromips turns off this option. This is
equivalent to putting ".module nomicromips" at the start of
the assembly file.
-msmartmips
-mno-smartmips
Enables the SmartMIPS extension to the MIPS32 instruction set.
This is equivalent to putting ".module smartmips" at the start
of the assembly file. -mno-smartmips turns off this option.
-mips3d
-no-mips3d
Generate code for the MIPS-3D Application Specific Extension.
This tells the assembler to accept MIPS-3D instructions.
-no-mips3d turns off this option.
-mdmx
-no-mdmx
Generate code for the MDMX Application Specific Extension.
This tells the assembler to accept MDMX instructions.
-no-mdmx turns off this option.
-mdsp
-mno-dsp
Generate code for the DSP Release 1 Application Specific
Extension. This tells the assembler to accept DSP Release 1
instructions. -mno-dsp turns off this option.
-mdspr2
-mno-dspr2
Generate code for the DSP Release 2 Application Specific
Extension. This option implies -mdsp. This tells the
assembler to accept DSP Release 2 instructions. -mno-dspr2
turns off this option.
-mdspr3
-mno-dspr3
Generate code for the DSP Release 3 Application Specific
Extension. This option implies -mdsp and -mdspr2. This tells
the assembler to accept DSP Release 3 instructions.
-mno-dspr3 turns off this option.
-mmsa
-mno-msa
Generate code for the MIPS SIMD Architecture Extension. This
tells the assembler to accept MSA instructions. -mno-msa
turns off this option.
-mxpa
-mno-xpa
Generate code for the MIPS eXtended Physical Address (XPA)
Extension. This tells the assembler to accept XPA
instructions. -mno-xpa turns off this option.
-mmt
-mno-mt
Generate code for the MT Application Specific Extension. This
tells the assembler to accept MT instructions. -mno-mt turns
off this option.
-mmcu
-mno-mcu
Generate code for the MCU Application Specific Extension.
This tells the assembler to accept MCU instructions. -mno-mcu
turns off this option.
-mcrc
-mno-crc
Generate code for the MIPS cyclic redundancy check (CRC)
Application Specific Extension. This tells the assembler to
accept CRC instructions. -mno-crc turns off this option.
-mginv
-mno-ginv
Generate code for the Global INValidate (GINV) Application
Specific Extension. This tells the assembler to accept GINV
instructions. -mno-ginv turns off this option.
-mloongson-mmi
-mno-loongson-mmi
Generate code for the Loongson MultiMedia extensions
Instructions (MMI) Application Specific Extension. This tells
the assembler to accept MMI instructions. -mno-loongson-mmi
turns off this option.
-mloongson-cam
-mno-loongson-cam
Generate code for the Loongson Content Address Memory (CAM)
instructions. This tells the assembler to accept Loongson CAM
instructions. -mno-loongson-cam turns off this option.
-mloongson-ext
-mno-loongson-ext
Generate code for the Loongson EXTensions (EXT) instructions.
This tells the assembler to accept Loongson EXT instructions.
-mno-loongson-ext turns off this option.
-mloongson-ext2
-mno-loongson-ext2
Generate code for the Loongson EXTensions R2 (EXT2)
instructions. This option implies -mloongson-ext. This tells
the assembler to accept Loongson EXT2 instructions.
-mno-loongson-ext2 turns off this option.
-minsn32
-mno-insn32
Only use 32-bit instruction encodings when generating code for
the microMIPS processor. This option inhibits the use of any
16-bit instructions. This is equivalent to putting ".set
insn32" at the start of the assembly file. -mno-insn32 turns
off this option. This is equivalent to putting ".set
noinsn32" at the start of the assembly file. By default
-mno-insn32 is selected, allowing all instructions to be used.
--construct-floats
--no-construct-floats
The --no-construct-floats option disables the construction of
double width floating point constants by loading the two
halves of the value into the two single width floating point
registers that make up the double width register. By default
--construct-floats is selected, allowing construction of these
floating point constants.
--relax-branch
--no-relax-branch
The --relax-branch option enables the relaxation of
out-of-range branches. By default --no-relax-branch is
selected, causing any out-of-range branches to produce an
error.
-mignore-branch-isa
-mno-ignore-branch-isa
Ignore branch checks for invalid transitions between ISA
modes. The semantics of branches does not provide for an ISA
mode switch, so in most cases the ISA mode a branch has been
encoded for has to be the same as the ISA mode of the branch's
target label. Therefore GAS has checks implemented that
verify in branch assembly that the two ISA modes match.
-mignore-branch-isa disables these checks. By default
-mno-ignore-branch-isa is selected, causing any invalid branch
requiring a transition between ISA modes to produce an error.
-mnan=encoding
Select between the IEEE 754-2008 (-mnan=2008) or the legacy
(-mnan=legacy) NaN encoding format. The latter is the
default.
--emulation=name
This option was formerly used to switch between ELF and ECOFF
output on targets like IRIX 5 that supported both. MIPS ECOFF
support was removed in GAS 2.24, so the option now serves
little purpose. It is retained for backwards compatibility.
The available configuration names are: mipself, mipslelf and
mipsbelf. Choosing mipself now has no effect, since the
output is always ELF. mipslelf and mipsbelf select little-
and big-endian output respectively, but -EL and -EB are now
the preferred options instead.
-nocpp
as ignores this option. It is accepted for compatibility with
the native tools.
--trap
--no-trap
--break
--no-break
Control how to deal with multiplication overflow and division
by zero. --trap or --no-break (which are synonyms) take a
trap exception (and only work for Instruction Set Architecture
level 2 and higher); --break or --no-trap (also synonyms, and
the default) take a break exception.
-n When this option is used, as will issue a warning every time
it generates a nop instruction from a macro.
The following options are available when as is configured for a
LoongArch processor.
-fpic
-fPIC
Generate position-independent code
-fno-pic
Don't generate position-independent code (default)
The following options are available when as is configured for a
Meta processor.
"-mcpu=metac11"
Generate code for Meta 1.1.
"-mcpu=metac12"
Generate code for Meta 1.2.
"-mcpu=metac21"
Generate code for Meta 2.1.
"-mfpu=metac21"
Allow code to use FPU hardware of Meta 2.1.
See the info pages for documentation of the MMIX-specific options.
The following options are available when as is configured for a
NDS32 processor.
"-O1"
Optimize for performance.
"-Os"
Optimize for space.
"-EL"
Produce little endian data output.
"-EB"
Produce little endian data output.
"-mpic"
Generate PIC.
"-mno-fp-as-gp-relax"
Suppress fp-as-gp relaxation for this file.
"-mb2bb-relax"
Back-to-back branch optimization.
"-mno-all-relax"
Suppress all relaxation for this file.
"-march=<arch name>"
Assemble for architecture <arch name> which could be v3, v3j,
v3m, v3f, v3s, v2, v2j, v2f, v2s.
"-mbaseline=<baseline>"
Assemble for baseline <baseline> which could be v2, v3, v3m.
"-mfpu-freg=FREG"
Specify a FPU configuration.
"0 8 SP / 4 DP registers"
"1 16 SP / 8 DP registers"
"2 32 SP / 16 DP registers"
"3 32 SP / 32 DP registers"
"-mabi=abi"
Specify a abi version <abi> could be v1, v2, v2fp, v2fpp.
"-m[no-]mac"
Enable/Disable Multiply instructions support.
"-m[no-]div"
Enable/Disable Divide instructions support.
"-m[no-]16bit-ext"
Enable/Disable 16-bit extension
"-m[no-]dx-regs"
Enable/Disable d0/d1 registers
"-m[no-]perf-ext"
Enable/Disable Performance extension
"-m[no-]perf2-ext"
Enable/Disable Performance extension 2
"-m[no-]string-ext"
Enable/Disable String extension
"-m[no-]reduced-regs"
Enable/Disable Reduced Register configuration (GPR16) option
"-m[no-]audio-isa-ext"
Enable/Disable AUDIO ISA extension
"-m[no-]fpu-sp-ext"
Enable/Disable FPU SP extension
"-m[no-]fpu-dp-ext"
Enable/Disable FPU DP extension
"-m[no-]fpu-fma"
Enable/Disable FPU fused-multiply-add instructions
"-mall-ext"
Turn on all extensions and instructions support
The following options are available when as is configured for a
PowerPC processor.
-a32
Generate ELF32 or XCOFF32.
-a64
Generate ELF64 or XCOFF64.
-K PIC
Set EF_PPC_RELOCATABLE_LIB in ELF flags.
-mpwrx | -mpwr2
Generate code for POWER/2 (RIOS2).
-mpwr
Generate code for POWER (RIOS1)
-m601
Generate code for PowerPC 601.
-mppc, -mppc32, -m603, -m604
Generate code for PowerPC 603/604.
-m403, -m405
Generate code for PowerPC 403/405.
-m440
Generate code for PowerPC 440. BookE and some 405
instructions.
-m464
Generate code for PowerPC 464.
-m476
Generate code for PowerPC 476.
-m7400, -m7410, -m7450, -m7455
Generate code for PowerPC 7400/7410/7450/7455.
-m750cl, -mgekko, -mbroadway
Generate code for PowerPC 750CL/Gekko/Broadway.
-m821, -m850, -m860
Generate code for PowerPC 821/850/860.
-mppc64, -m620
Generate code for PowerPC 620/625/630.
-me200z2, -me200z4
Generate code for e200 variants, e200z2 with LSP, e200z4 with
SPE.
-me300
Generate code for PowerPC e300 family.
-me500, -me500x2
Generate code for Motorola e500 core complex.
-me500mc
Generate code for Freescale e500mc core complex.
-me500mc64
Generate code for Freescale e500mc64 core complex.
-me5500
Generate code for Freescale e5500 core complex.
-me6500
Generate code for Freescale e6500 core complex.
-mlsp
Enable LSP instructions. (Disables SPE and SPE2.)
-mspe
Generate code for Motorola SPE instructions. (Disables LSP.)
-mspe2
Generate code for Freescale SPE2 instructions. (Disables
LSP.)
-mtitan
Generate code for AppliedMicro Titan core complex.
-mppc64bridge
Generate code for PowerPC 64, including bridge insns.
-mbooke
Generate code for 32-bit BookE.
-ma2
Generate code for A2 architecture.
-maltivec
Generate code for processors with AltiVec instructions.
-mvle
Generate code for Freescale PowerPC VLE instructions.
-mvsx
Generate code for processors with Vector-Scalar (VSX)
instructions.
-mhtm
Generate code for processors with Hardware Transactional
Memory instructions.
-mpower4, -mpwr4
Generate code for Power4 architecture.
-mpower5, -mpwr5, -mpwr5x
Generate code for Power5 architecture.
-mpower6, -mpwr6
Generate code for Power6 architecture.
-mpower7, -mpwr7
Generate code for Power7 architecture.
-mpower8, -mpwr8
Generate code for Power8 architecture.
-mpower9, -mpwr9
Generate code for Power9 architecture.
-mpower10, -mpwr10
Generate code for Power10 architecture.
-mpower11, -mpwr11
Generate code for Power11 architecture.
-mfuture
Generate code for 'future' architecture.
-mcell
-mcell
Generate code for Cell Broadband Engine architecture.
-mcom
Generate code Power/PowerPC common instructions.
-many
Generate code for any architecture (PWR/PWRX/PPC).
-mregnames
Allow symbolic names for registers.
-mno-regnames
Do not allow symbolic names for registers.
-mrelocatable
Support for GCC's -mrelocatable option.
-mrelocatable-lib
Support for GCC's -mrelocatable-lib option.
-memb
Set PPC_EMB bit in ELF flags.
-mlittle, -mlittle-endian, -le
Generate code for a little endian machine.
-mbig, -mbig-endian, -be
Generate code for a big endian machine.
-msolaris
Generate code for Solaris.
-mno-solaris
Do not generate code for Solaris.
-nops=count
If an alignment directive inserts more than count nops, put a
branch at the beginning to skip execution of the nops.
The following options are available when as is configured for a
RISC-V processor.
-fpic
-fPIC
Generate position-independent code
-fno-pic
Don't generate position-independent code (default)
-march=ISA
Select the base isa, as specified by ISA. For example
-march=rv32ima. If this option and the architecture
attributes aren't set, then assembler will check the default
configure setting --with-arch=ISA.
-misa-spec=ISAspec
Select the default isa spec version. If the version of ISA
isn't set by -march, then assembler helps to set the version
according to the default chosen spec. If this option isn't
set, then assembler will check the default configure setting
--with-isa-spec=ISAspec.
-mpriv-spec=PRIVspec
Select the privileged spec version. We can decide whether the
CSR is valid or not according to the chosen spec. If this
option and the privilege attributes aren't set, then assembler
will check the default configure setting
--with-priv-spec=PRIVspec.
-mabi=ABI
Selects the ABI, which is either "ilp32" or "lp64", optionally
followed by "f", "d", or "q" to indicate single-precision,
double-precision, or quad-precision floating-point calling
convention, or none or "e" to indicate the soft-float calling
convention ("e" indicates a soft-float RVE ABI).
-mrelax
Take advantage of linker relaxations to reduce the number of
instructions required to materialize symbol addresses.
(default)
-mno-relax
Don't do linker relaxations.
-march-attr
Generate the default contents for the riscv elf attribute
section if the .attribute directives are not set. This
section is used to record the information that a linker or
runtime loader needs to check compatibility. This information
includes ISA string, stack alignment requirement, unaligned
memory accesses, and the major, minor and revision version of
privileged specification.
-mno-arch-attr
Don't generate the default riscv elf attribute section if the
.attribute directives are not set.
-mcsr-check
Enable the CSR checking for the ISA-dependent CRS and the
read-only CSR. The ISA-dependent CSR are only valid when the
specific ISA is set. The read-only CSR can not be written by
the CSR instructions.
-mno-csr-check
Don't do CSR checking.
-mlittle-endian
Generate code for a little endian machine.
-mbig-endian
Generate code for a big endian machine.
See the info pages for documentation of the RX-specific options.
The following options are available when as is configured for the
s390 processor family.
-m31
-m64
Select the word size, either 31/32 bits or 64 bits.
-mesa
-mzarch
Select the architecture mode, either the Enterprise System
Architecture (esa) or the z/Architecture mode (zarch).
-march=processor
Specify which s390 processor variant is the target, g5 (or
arch3), g6, z900 (or arch5), z990 (or arch6), z9-109, z9-ec
(or arch7), z10 (or arch8), z196 (or arch9), zEC12 (or
arch10), z13 (or arch11), z14 (or arch12), z15 (or arch13),
z16 (or arch14), or arch15.
-mregnames
-mno-regnames
Allow or disallow symbolic names for registers.
-mwarn-areg-zero
Warn whenever the operand for a base or index register has
been specified but evaluates to zero.
-mwarn-regtype-mismatch=strict
-mwarn-regtype-mismatch=relaxed
-mwarn-regtype-mismatch=no
-mno-warn-regtype-mismatch
Controls whether the assembler performs register name type
checks and generates a warning message in case of a mismatch
with the operand register type. The default (which can be
restored by using the relaxed argument) is to perform relaxed
register name type checks, which allow floating point register
(FPR) names %f0 to %f15 to be specified as argument to vector
register (VR) operands and vector register (VR) names %v0 to
%v15 to be specified as argument to floating point register
(FPR) operands. This is acceptable as the FPR are embedded
into the lower half of the VR. Using the strict argument
strict register name type checks are performed. The no
argument, which is equivalent to -mno-warn-regtype-mismatch,
disables any register name type checks.
The following options are available when as is configured for a
TMS320C6000 processor.
-march=arch
Enable (only) instructions from architecture arch. By
default, all instructions are permitted.
The following values of arch are accepted: "c62x", "c64x",
"c64x+", "c67x", "c67x+", "c674x".
-mdsbt
-mno-dsbt
The -mdsbt option causes the assembler to generate the
"Tag_ABI_DSBT" attribute with a value of 1, indicating that
the code is using DSBT addressing. The -mno-dsbt option, the
default, causes the tag to have a value of 0, indicating that
the code does not use DSBT addressing. The linker will emit a
warning if objects of different type (DSBT and non-DSBT) are
linked together.
-mpid=no
-mpid=near
-mpid=far
The -mpid= option causes the assembler to generate the
"Tag_ABI_PID" attribute with a value indicating the form of
data addressing used by the code. -mpid=no, the default,
indicates position-dependent data addressing, -mpid=near
indicates position-independent addressing with GOT accesses
using near DP addressing, and -mpid=far indicates
position-independent addressing with GOT accesses using far DP
addressing. The linker will emit a warning if objects built
with different settings of this option are linked together.
-mpic
-mno-pic
The -mpic option causes the assembler to generate the
"Tag_ABI_PIC" attribute with a value of 1, indicating that the
code is using position-independent code addressing, The
"-mno-pic" option, the default, causes the tag to have a value
of 0, indicating position-dependent code addressing. The
linker will emit a warning if objects of different type
(position-dependent and position-independent) are linked
together.
-mbig-endian
-mlittle-endian
Generate code for the specified endianness. The default is
little-endian.
The following options are available when as is configured for a
TILE-Gx processor.
-m32 | -m64
Select the word size, either 32 bits or 64 bits.
-EB | -EL
Select the endianness, either big-endian (-EB) or
little-endian (-EL).
The following option is available when as is configured for a
Visium processor.
-mtune=arch
This option specifies the target architecture. If an attempt
is made to assemble an instruction that will not execute on
the target architecture, the assembler will issue an error
message.
The following names are recognized: "mcm24" "mcm" "gr5" "gr6"
The following options are available when as is configured for an
Xtensa processor.
--text-section-literals | --no-text-section-literals
Control the treatment of literal pools. The default is
--no-text-section-literals, which places literals in separate
sections in the output file. This allows the literal pool to
be placed in a data RAM/ROM. With --text-section-literals,
the literals are interspersed in the text section in order to
keep them as close as possible to their references. This may
be necessary for large assembly files, where the literals
would otherwise be out of range of the "L32R" instructions in
the text section. Literals are grouped into pools following
".literal_position" directives or preceding "ENTRY"
instructions. These options only affect literals referenced
via PC-relative "L32R" instructions; literals for absolute
mode "L32R" instructions are handled separately.
--auto-litpools | --no-auto-litpools
Control the treatment of literal pools. The default is
--no-auto-litpools, which in the absence of
--text-section-literals places literals in separate sections
in the output file. This allows the literal pool to be placed
in a data RAM/ROM. With --auto-litpools, the literals are
interspersed in the text section in order to keep them as
close as possible to their references, explicit
".literal_position" directives are not required. This may be
necessary for very large functions, where single literal pool
at the beginning of the function may not be reachable by
"L32R" instructions at the end. These options only affect
literals referenced via PC-relative "L32R" instructions;
literals for absolute mode "L32R" instructions are handled
separately. When used together with --text-section-literals,
--auto-litpools takes precedence.
--absolute-literals | --no-absolute-literals
Indicate to the assembler whether "L32R" instructions use
absolute or PC-relative addressing. If the processor includes
the absolute addressing option, the default is to use absolute
"L32R" relocations. Otherwise, only the PC-relative "L32R"
relocations can be used.
--target-align | --no-target-align
Enable or disable automatic alignment to reduce branch
penalties at some expense in code size. This optimization
is enabled by default. Note that the assembler will always
align instructions like "LOOP" that have fixed alignment
requirements.
--longcalls | --no-longcalls
Enable or disable transformation of call instructions to allow
calls across a greater range of addresses. This option
should be used when call targets can potentially be out of
range. It may degrade both code size and performance, but the
linker can generally optimize away the unnecessary overhead
when a call ends up within range. The default is
--no-longcalls.
--transform | --no-transform
Enable or disable all assembler transformations of Xtensa
instructions, including both relaxation and optimization. The
default is --transform; --no-transform should only be used in
the rare cases when the instructions must be exactly as
specified in the assembly source. Using --no-transform causes
out of range instruction operands to be errors.
--rename-section oldname=newname
Rename the oldname section to newname. This option can be
used multiple times to rename multiple sections.
--trampolines | --no-trampolines
Enable or disable transformation of jump instructions to allow
jumps across a greater range of addresses. This option
should be used when jump targets can potentially be out of
range. In the absence of such jumps this option does not
affect code size or performance. The default is
--trampolines.
--abi-windowed | --abi-call0
Choose ABI tag written to the ".xtensa.info" section. ABI tag
indicates ABI of the assembly code. A warning is issued by
the linker on an attempt to link object files with
inconsistent ABI tags. Default ABI is chosen by the Xtensa
core configuration.
The following options are available when as is configured for an
Z80 processor.
@chapter Z80 Dependent Features
Command-line Options
-march=CPU[-EXT...][+EXT...]
This option specifies the target processor. The assembler will
issue an error message if an attempt is made to assemble an
instruction which will not execute on the target processor.
The following processor names are recognized: "z80", "z180",
"ez80", "gbz80", "z80n", "r800". In addition to the basic
instruction set, the assembler can be told to accept some
extension mnemonics. For example, "-march=z180+sli+infc"
extends z180 with SLI instructions and IN F,(C). The following
extensions are currently supported: "full" (all known
instructions), "adl" (ADL CPU mode by default, eZ80 only),
"sli" (instruction known as SLI, SLL or SL1), "xyhl"
(instructions with halves of index registers: IXL, IXH, IYL,
IYH), "xdcb" (instructions like RotOp (II+d),R and BitOp
n,(II+d),R), "infc" (instruction IN F,(C) or IN (C)), "outc0"
(instruction OUT (C),0). Note that rather than extending a
basic instruction set, the extension mnemonics starting with
"-" revoke the respective functionality:
"-march=z80-full+xyhl" first removes all default extensions
and adds support for index registers halves only.
If this option is not specified then "-march=z80+xyhl+infc" is
assumed.
-local-prefix=prefix
Mark all labels with specified prefix as local. But such label
can be marked global explicitly in the code. This option do
not change default local label prefix ".L", it is just adds
new one.
-colonless
Accept colonless labels. All symbols at line begin are treated
as labels.
-sdcc
Accept assembler code produced by SDCC.
-fp-s=FORMAT
Single precision floating point numbers format. Default:
ieee754 (32 bit).
-fp-d=FORMAT
Double precision floating point numbers format. Default:
ieee754 (64 bit).
gcc(1), ld(1), and the Info entries for binutils and ld.
Copyright (c) 1991-2025 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License,
Version 1.3 or any later version published by the Free Software
Foundation; with no Invariant Sections, with no Front-Cover Texts,
and with no Back-Cover Texts. A copy of the license is included
in the section entitled "GNU Free Documentation License".
This page is part of the binutils (a collection of tools for
working with executable binaries) project. Information about the
project can be found at ⟨http://www.gnu.org/software/binutils/⟩.
If you have a bug report for this manual page, see
⟨http://sourceware.org/bugzilla/enter_bug.cgi?product=binutils⟩.
This page was obtained from the tarball binutils-with-
gold-2.44.tar.gz fetched from ⟨https://ftp.gnu.org/gnu/binutils/⟩
on 2025-08-11. If you discover any rendering problems in this
HTML version of the page, or you believe there is a better or more
up-to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
[email protected]
binutils-2.44 2025-08-11 AS(1)
Pages that refer to this page: elf(5)
|
HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|