AS - the portable GNU assembler.
as [-a[cdghlns][=file]] [--alternate]
[-D]
[--compress-debug-sections] [--nocompress-debug-sections]
[--debug-prefix-map old=new]
[--defsym sym=val] [-f] [-g]
[--gstabs]
[--gstabs+] [--gdwarf-2] [--gdwarf-sections]
[--help] [-I dir] [-J]
[-K] [-L] [--listing-lhs-width=NUM]
[--listing-lhs-width2=NUM]
[--listing-rhs-width=NUM]
[--listing-cont-lines=NUM] [--keep-locals]
[--no-pad-sections]
[-o objfile] [-R]
[--hash-size=NUM] [--reduce-memory-overheads]
[--statistics]
[-v] [-version] [--version]
[-W] [--warn] [--fatal-warnings] [-w] [-x]
[-Z] [@FILE]
[--sectname-subst] [--size-check=[error|warning]]
[--elf-stt-common=[no|yes]]
[--generate-missing-build-notes=[no|yes]]
[--target-help] [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 CRIS options:
[--underscore | --no-underscore]
[--pic] [-N]
[--emulation=criself | --emulation=crisaout]
[--march=v0_v10 | --march=v10 | --march=v32 |
--march=common_v10_v32]
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:
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]
[-minsn32] [-mno-insn32]
[-mfix7000] [-mno-fix7000]
[-mfix-rm7000] [-mno-fix-rm7000]
[-mfix-vr4120] [-mno-fix-vr4120]
[-mfix-vr4130] [-mno-fix-vr4130]
[-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 Nios II options:
[-relax-all] [-relax-section] [-no-relax]
[-EB] [-EL]
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|-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]
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]
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]
Target Z80 options:
[-z80] [-r800]
[ -ignore-undocumented-instructions] [-Wnud]
[ -ignore-unportable-instructions] [-Wnup]
[ -warn-undocumented-instructions] [-Wud]
[ -warn-unportable-instructions] [-Wup]
[ -forbid-undocumented-instructions] [-Fud]
[ -forbid-unportable-instructions] [-Fup]
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[cdghlmns]
- 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
- -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
- 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 zlib. The debug sections are renamed to begin with .zdebug.
Note if compression would make a given 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
- 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.
- -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.
- --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-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.
- --size-check=error
- --size-check=warning
- Issue an error or warning for invalid ELF .size directive.
- --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.
- --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.
- --help
- Print a summary of the command line options and exit.
- --target-help
- Print a summary of all target specific options and exit.
- -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.
- --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.
- --hash-size=number
- Set the default size of GAS's hash tables to a prime number close to
number. Increasing this value can reduce the length of time it
takes the assembler to perform its tasks, at the expense of increasing the
assembler's memory requirements. Similarly reducing this value can reduce
the memory requirements at the expense of speed.
- --reduce-memory-overheads
- This option reduces GAS's memory requirements, at the expense of making
the assembly processes slower. Currently this switch is a synonym for
--hash-size=4051, but in the future it may have other effects as
well.
- --sectname-subst
- Honor substitution sequences in section names.
- --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.
- --fatal-warnings
- Treat warnings as errors.
- --warn
- Don't suppress warning messages or treat them 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-a35",
"cortex-a53",
"cortex-a55",
"cortex-a57",
"cortex-a72",
"cortex-a73",
"cortex-a75",
"cortex-a76",
"exynos-m1",
"falkor",
"qdf24xx",
"saphira",
"thunderx",
"vulcan",
"xgene1" and
"xgene2". 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" and
"armv8.4-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 extenssion 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.
See the info pages for documentation of the CRIS-specific
options.
The following options are available when as is configured for a
D10V processor.
- -O
- Optimize output by parallelizing instructions.
The following options are available when as is configured for a
D30V processor.
- -O
- Optimize output by parallelizing instructions.
- -n
- Warn when nops are generated.
- -N
- Warn when a nop after a 32-bit multiply instruction is generated.
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
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",
"l1om",
"k1om",
"iamcu",
"k6",
"k6_2",
"athlon",
"opteron",
"k8",
"amdfam10",
"bdver1",
"bdver2",
"bdver3",
"bdver4",
"znver1",
"znver2",
"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, "no87",
"no287",
"no387",
"no687",
"mmx",
"nommx",
"sse",
"sse2",
"sse3",
"ssse3",
"sse4.1",
"sse4.2",
"sse4",
"nosse",
"nosse2",
"nosse3",
"nossse3",
"nosse4.1",
"nosse4.2",
"nosse4",
"avx",
"avx2",
"noavx",
"noavx2",
"adx",
"rdseed",
"prfchw",
"smap",
"mpx",
"sha",
"rdpid",
"ptwrite",
"cet",
"gfni",
"vaes",
"vpclmulqdq",
"prefetchwt1",
"clflushopt",
"se1",
"clwb",
"movdiri",
"movdir64b",
"avx512f",
"avx512cd",
"avx512er",
"avx512pf",
"avx512vl",
"avx512bw",
"avx512dq",
"avx512ifma",
"avx512vbmi",
"avx512_4fmaps",
"avx512_4vnniw",
"avx512_vpopcntdq",
"avx512_vbmi2",
"avx512_vnni",
"avx512_bitalg",
"noavx512f",
"noavx512cd",
"noavx512er",
"noavx512pf",
"noavx512vl",
"noavx512bw",
"noavx512dq",
"noavx512ifma",
"noavx512vbmi",
"noavx512_4fmaps",
"noavx512_4vnniw",
"noavx512_vpopcntdq",
"noavx512_vbmi2",
"noavx512_vnni",
"noavx512_bitalg",
"vmx",
"vmfunc",
"smx",
"xsave",
"xsaveopt",
"xsavec",
"xsaves",
"aes",
"pclmul",
"fsgsbase",
"rdrnd",
"f16c",
"bmi2",
"fma",
"movbe",
"ept",
"lzcnt",
"hle",
"rtm",
"invpcid",
"clflush",
"mwaitx",
"clzero",
"wbnoinvd",
"pconfig",
"waitpkg",
"cldemote",
"lwp",
"fma4",
"xop",
"cx16",
"syscall",
"rdtscp",
"3dnow",
"3dnowa",
"sse4a",
"sse5",
"svme",
"abm" and
"padlock". Note that rather than
extending a basic instruction set, the extension mnemonics starting with
"no" revoke the respective
functionality.
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.
- -msse2avx
- This option specifies that the assembler should encode SSE instructions
with VEX prefix.
- -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.
- -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 x86-64 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.
- -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 both.
- -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 and
encode 64-bit register clearing instructions with 32-bit register clearing
instructions. -O2 includes -O1 optimization plus encodes
256-bit and 512-bit vector register clearing instructions with 128-bit
vector register clearing instructions. -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.
The following options are available when as is configured for an
Altera Nios II processor.
- -relax-section
- Replace identified out-of-range branches with PC-relative
"jmp" sequences when possible. The
generated code sequences are suitable for use in position-independent
code, but there is a practical limit on the extended branch range because
of the length of the sequences. This option is the default.
- -relax-all
- Replace branch instructions not determinable to be in range and all call
instructions with "jmp" and
"callr" sequences (respectively). This
option generates absolute relocations against the target symbols and is
not appropriate for position-independent code.
- -no-relax
- Do not replace any branches or calls.
- -EB
- Generate big-endian output.
- -EL
- Generate little-endian output. This is the default.
- -march=architecture
- This option specifies the target architecture. The assembler issues 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: "r1",
"r2". The default is
"r1".
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.
- -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.
- -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
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
- Generate code for PowerPC 750CL.
- -m821, -m850,
-m860
- Generate code for PowerPC 821/850/860.
- -mppc64,
-m620
- Generate code for PowerPC 620/625/630.
- -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.
- -mspe
- Generate code for Motorola SPE instructions.
- -mspe2
- Generate code for Freescale SPE2 instructions.
- -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.
- -me300
- Generate code for PowerPC e300 family.
- -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.
- -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.
- -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 to indicate the soft-float
calling convention. Also, "ilp32" can optionally be followed by
"e" to indicate the RVE ABI, which is always soft-float.
- -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.
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), or z14 (or
arch12).
- -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.
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.
The following options are available when as is configured for a
Z80 family processor.
- -z80
- Assemble for Z80 processor.
- -r800
- Assemble for R800 processor.
- -ignore-undocumented-instructions
- -Wnud
- Assemble undocumented Z80 instructions that also work on R800 without
warning.
- -ignore-unportable-instructions
- -Wnup
- Assemble all undocumented Z80 instructions without warning.
- -warn-undocumented-instructions
- -Wud
- Issue a warning for undocumented Z80 instructions that also work on
R800.
- -warn-unportable-instructions
- -Wup
- Issue a warning for undocumented Z80 instructions that do not work on
R800.
- -forbid-undocumented-instructions
- -Fud
- Treat all undocumented instructions as errors.
- -forbid-unportable-instructions
- -Fup
- Treat undocumented Z80 instructions that do not work on R800 as
errors.
gcc(1), ld(1), and the Info entries for
binutils and ld.
Copyright (c) 1991-2018 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".