AS(1) GNU Development Tools AS(1)
NAME
AS - the portable GNU assembler.
SYNOPSIS
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] [--gsframe=[no|yes]]
[--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] [--verbose]
[-version] [--version]
[-W] [--no-warn] [--warn] [--fatal-warnings]
[-w] [-x]
[-Z] [@FILE]
[target-options]
[--|files ...]
TARGET
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|Profiles|Profiles_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]
DESCRIPTION
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.)
OPTIONS
@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.
--emit-local-absolute
Emit even pre-defined (local) absolute symbols to the outgoing
symbol table. Note that this isn't the exact opposite of
--strip-local-absolute.
--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
--gsframe=no
--gsframe=yes
Create .sframe section from CFI directives. The explicit
--gsframe=yes option behaves the same as --gsframe. Generation can
be suppressed with --gsframe=no.
--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
--verbose
Print the as version.
--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.
-menable-sysreg-checking
This option enables error messages that are issued if an attempt is
made to assemble a system register access which will not execute on
the target architecture.
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", "rmpquery", "rmpread", "svme",
"gmism2", "gmiccs", "padlockrng2", "padlockphe2", "padlockxmodx"
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|Profiles|Profiles_ISA
Select the base isa, as specified by ISA or Profiles or
Profies_ISA. For example -march=rv32ima -march=RVI20U64
-march=RVI20U64_d. 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 z17 (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).
SEE ALSO
gcc(1), ld(1), and the Info entries for binutils and ld.
COPYRIGHT
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".
binutils-2.45.0 2025-08-13 AS(1)
AS \- the portable GNU assembler.