AS(1)

📦 version 2.35.1, in debian bookworm, ubuntu jammy, ubuntu noble, ubuntu resolute

💖 NAME 💖

AS — the portable GNU assembler. That's the name, bestie. Short, iconic, does exactly what it says on the tin. 💅

✨ SYNOPSIS ✨

okay so here's the whole invocation vibe, fr fr:

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-<N>] [--gdwarf-sections]
 [--gdwarf-cie-version=VERSION]
 [--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 🎯

target options are giving "choose your fighter", bestie. every single one is here, no skips, no cap:

🌸 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:

🌸 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 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|-mgekko|
 -mbroadway|-mppc64|-m620|-me500|-e500x2|-me500mc|-me500mc64|-me5500|
 -me6500|-mppc64bridge|-mbooke|-mpower4|-mpwr4|-mpower5|-mpwr5|-mpwr5x|
 -mpower6|-mpwr6|-mpower7|-mpwr7|-mpower8|-mpwr8|-mpower9|-mpwr9-ma2|
 -mcell|-mspe|-mspe2|-mtitan|-me300|-mcom]
[-many] [-maltivec|-mvsx|-mhtm|-mvle]
[-mregnames|-mno-regnames]
[-mrelocatable|-mrelocatable-lib|-K PIC] [-memb]
[-mlittle|-mlittle-endian|-le|-mbig|-mbig-endian|-be]
[-msolaris|-mno-solaris]
[-nops=count]

🌸 Target PRU options:

[-link-relax]
[-mnolink-relax]
[-mno-warn-regname-label]

🌸 Target RISC-V options:

[-fpic|-fPIC|-fno-pic]
[-march=ISA]
[-mabi=ABI]

🌸 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]
[--abi-windowed|--abi-call0]

🌸 Target Z80 options:

 [-march=CPU[-EXT][+EXT]]
 [-local-prefix=PREFIX]
 [-colonless]
 [-sdcc]
 [-fp-s=FORMAT]
 [-fp-d=FORMAT]

💖 DESCRIPTION 💖

okay so first things first: GNU as is literally not just one assembler, it's a whole family of them. 💅 If you've used the GNU assembler on one architecture, then when you hop to another architecture you'll find a pretty similar vibe. Each version shares so much: object file formats, most assembler directives (aka pseudo-ops), and the assembler syntax itself. no cap.

as is mainly here to assemble the output of the GNU C compiler gcc so the linker ld can use it. 🫶 But bestie, they really tried to make as assemble correctly everything that other assemblers for the same machine would assemble. Any exceptions are documented explicitly. That said, it 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. 💀

Every time you run as, it assembles exactly one source program. That source program is made up of one or more files. (Standard input is also a file, yes really.) ✨

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 tries 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. (iconic minimalism tbh)

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're 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[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. (fake it till you make it 💀)
  • --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. 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.
  • --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 — bestie, this one tells the assembler to stop padding the ends of output sections out to the alignment of that section. Default behaviour is to pad them, but that padding can eat up space you genuinely need on targets with tight memory constraints. so if your target is living that small-memory life, this is your girl 🫶
  • -o objfile — names the object-file output from as as objfile. that's it, that's the whole vibe 💅
  • -R — folds the data section right into the text section. merging era ✨
  • --hash-size=number — sets the default size of GAS's hash tables to a prime number close to number. cranking this value up can cut down how long the assembler takes to do its tasks, but it'll ask for more memory in return. dropping it down does the opposite: less memory, less speed. pick your tradeoff, icon 😌
  • --reduce-memory-overheads — reduces GAS's memory requirements, at the cost of making the assembly process slower. rn this switch is literally just a synonym for --hash-size=4051, but in the future it might have other effects too. so, watch this space 👀
  • --sectname-subst — honors substitution sequences in section names. periodt.
  • --statistics — prints the maximum space (in bytes) and the total time (in seconds) that assembly used. numbers girlies rise 🍓
  • --strip-local-absolute — removes local absolute symbols from the outgoing symbol table. bye babes 👋
  • -v, -version — print the as version.
  • --version — print the as version and exit. gone, no notes.
  • -W, --no-warn — suppress warning messages. shhh 🙈
  • --fatal-warnings — treats warnings as errors. no mercy mode 💀
  • --warn — don't suppress warning messages and don't treat them as errors. we're back to normal, bestie.
  • -w — ignored. it's giving background character energy.
  • -x — ignored. also just vibing in the corner.
  • -Z — generate an object file even after errors. messy but committed 🔥
  • -- | files ... — standard input, or source files to assemble. feed her 💖

🦋 The following options are available when as is configured for the 64-bit mode of the ARM Architecture (AArch64).

  • -EB — says the output generated by the assembler should be marked as being encoded for a big-endian processor.
  • -EL — says the output 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 decide whether the generated object file is in ELF32 or ELF64 format respectively. the default is "lp64".
  • -mcpu=processor[+extension...] — specifies the target processor. the assembler will issue an error message if you try to assemble an instruction that won't execute on the target processor. here's the whole roster of recognized processor names: "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", "ares", "exynos-m1", "falkor", "neoverse-n1", "neoverse-e1", "qdf24xx", "saphira", "thunderx", "vulcan", "xgene1" and "xgene2". the special name "all" can be used to let the assembler accept instructions valid for any supported processor, including all optional extensions.

on top of 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 those extensions are automatically enabled. so you won't normally have to specify any additional extensions. slay 💅

  • -march=architecture[+extension...] — specifies the target architecture. the assembler will issue an error message if you try to assemble an instruction that won't execute on the target architecture. recognized architecture names: "armv8-a", "armv8.1-a", "armv8.2-a", "armv8.3-a", "armv8.4-a" "armv8.5-a", and "armv8.6-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. read that again bestie 👑

  • -mverbose-error — enables verbose error messages for AArch64 gas. this option is enabled by default.
  • -mno-verbose-error — disables verbose error messages in AArch64 gas.

🌸 The following options are available when as is configured for an Alpha processor.

  • -mcpu — specifies the target processor. if you try to assemble an instruction that won't 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.

recognized processor names: 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.

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. iykyk 😌

  • -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 — forces all relocations to be put into the object file, instead of saving space and resolving some relocations at assembly time. heads up though: this option does not propagate all symbol arithmetic into the object file, because not all symbol arithmetic can be represented. still, it can 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 — 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 — 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] — specifies the target processor. the optional sirevision is not used in the assembler. it's here so that GCC can easily pass down its -mcpu= option. the assembler will issue an error message if you try to assemble an instruction that won't execute on the target processor. recognized processor names: "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

   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.
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.

...and no cap, this one is specifically for bare-metal C-SKY V2 ELF targets, where it's already switched on by default. 🫶 But bestie, hear me: it cannot be used in code that's gonna be dynamically linked against shared libraries. Like, that's not a suggestion, that's a hard no. 💀

  • -force2bsr, -mforce2bsr, -no-force2bsr, -mno-force2bsr — turns on/off the transformation of "jbsr" instructions into "bsr". For CK801/CK802 targets this is always enabled (and -mno-force2bsr gets straight-up ignored, rip 💀). It's also always enabled whenever -mbranch-stub is in effect. Slay.
  • -jsri2bsr, -mjsri2bsr, -no-jsri2bsr, -mno-jsri2bsr — turns on/off the transformation of "jsri" instructions into "bsr". This one is enabled by default, periodt. ✨
  • -mnolrw, -mno-lrw — turns on/off the transformation of "lrw" instructions into a "movih"/"ori" pair. Iconic little glow-up, honestly.
  • -melrw, -mno-elrw — turns on/off extended "lrw" instructions. Enabled by default for CK800-series processors. 👑
  • -mlaf, -mliterals-after-func, -mno-laf, -mno-literals-after-func — turns on/off placing literal pools after each function.
  • -mlabr, -mliterals-after-br, -mno-labr, -mnoliterals-after-br — turns on/off placing literal pools after unconditional branches. Enabled by default. 🌸
  • -mistack, -mno-istack — turns on/off interrupt stack instructions. Enabled by default on CK801, CK802, and CK802 processors. (Yes bestie, it literally says CK802 twice. I'm just the messenger. 🙈)

🌈 the "please actually turn these on" instruction options

The following options explicitly enable certain optional instructions. These features are also enabled implicitly by using "-mcpu=" to specify a processor that supports it. So like, you can ask nicely, or you can just let the CPU do it for you. 💅

  • -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.

🦋 Epiphany energy

The following options are available when as is configured for an Epiphany processor.

  • -mepiphany — Specifies that both 32 and 16 bit instructions are allowed. This is the default behavior, iykyk.
  • -mepiphany16 — Restricts the permitted instructions to just the 16 bit set. Small and mighty. 🎀

🍓 H8/300 corner

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. Two hex flavors, no conflict. 🫶
  • -mach=name — Sets the H8300 machine variant. The following machine names are recognised: "h8300h", "h8300hn", "h8300s", "h8300sn", "h8300sx" and "h8300sxn".
(I know, I know, it says "one machine-dependent option" and then shows two. Not my problem. 💀)

💜 i386 things (yes, this part is long)

The following options are available when as is configured for an i386 processor.

  • --32 | --x32 | --64 — Selects 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 they 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", "cmov", "nocmov", "fxsr", "nofxsr", "mmx", "nommx", "sse", "sse2", "sse3", "sse4a", "ssse3", "sse4.1", "sse4.2", "sse4", "nosse", "nosse2", "nosse3", "nosse4a", "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", "enqcmd", "serialize", "tsxldtrk", "avx512f", "avx512cd", "avx512er", "avx512pf", "avx512vl", "avx512bw", "avx512dq", "avx512ifma", "avx512vbmi", "avx512_4fmaps", "avx512_4vnniw", "avx512_vpopcntdq", "avx512_vbmi2", "avx512_vnni", "avx512_bitalg", "avx512_vp2intersect", "avx512_bf16", "noavx512f", "noavx512cd", "noavx512er", "noavx512pf", "noavx512vl", "noavx512bw", "noavx512dq", "noavx512ifma", "noavx512vbmi", "noavx512_4fmaps", "noavx512_4vnniw", "noavx512_vpopcntdq", "noavx512_vbmi2", "noavx512_vnni", "noavx512_bitalg", "noavx512_vp2intersect", "noavx512_bf16", "noenqcmd", "noserialize", "notsxldtrk", "vmx", "vmfunc", "smx", "xsave", "xsaveopt", "xsavec", "xsaves", "aes", "pclmul", "fsgsbase", "rdrnd", "f16c", "bmi2", "fma", "movbe", "ept", "lzcnt", "popcnt", "hle", "rtm", "invpcid", "clflush", "mwaitx", "clzero", "wbnoinvd", "pconfig", "waitpkg", "cldemote", "rdpru", "mcommit", "sev_es", "lwp", "fma4", "xop", "cx16", "syscall", "rdtscp", "3dnow", "3dnowa", "sse4a", "sse5", "svme" 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. (Their spelling, not mine. 🫶)

  • -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. Pick your vibe: unbothered, gentle nudge, or full chaos. 🔥
  • -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. Bestie I am begging you, not in prod. 😭
  • -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. Again. Fr fr. 💀
  • -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. Big object, big energy. 👑
  • -momit-lock-prefix=no, -momit-lock-prefix=yes — these two control how the assembler should encode the lock prefix. It's a workaround for processors that just fail on lock prefix, bless their hearts. 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 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 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.
  • -malign-branch-boundary=NUM — this 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 specifies the types of branches to align. TYPE is a 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 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 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 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 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: lfence won't be generated before indirect near branch via register with -mlfence-after-load=yes, since lfence will be generated after loading the branch target register.
  • -mlfence-before-ret=none, -mlfence-before-ret=shl, -mlfence-before-ret=or, -mlfence-before-ret=yes, -mlfence-before-ret=not — these control whether the assembler should generate lfence before ret. -mlfence-before-ret=or will 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 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 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 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.

💜 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. Normally assembler girlies want this warning to be emitted 💅 but C compilers may want to turn this off.

🦋 the MIPS options 🦋

The following options are available when as is configured for a MIPS processor. so specific, so iconic 💖

  • -G num — sets the largest size of an object that can be referenced implicitly with the gp register. It's only accepted for targets that use ECOFF format, like a DECstation running Ultrix. The default value is 8.
  • -EB — generate "big endian" format output.
  • -EL — generate "little endian" format output.

⭐ the ISA level roster ⭐

Generate code for a particular MIPS Instruction Set Architecture level. Here's the whole lineup, bestie — every single one:

  • -mips1 — an alias for -march=r3000.
  • -mips2 — an alias for -march=r6000.
  • -mips3 — an alias for -march=r4000.
  • -mips4 — an alias for -march=r8000.
  • -mips5 — corresponds to generic MIPS V ISA processors.
  • -mips32 — corresponds to MIPS32.
  • -mips32r2 — corresponds to MIPS32 Release 2.
  • -mips32r3 — corresponds to MIPS32 Release 3.
  • -mips32r5 — corresponds to MIPS32 Release 5.
  • -mips32r6 — corresponds to MIPS32 Release 6.
  • -mips64 — corresponds to MIPS64.
  • -mips64r2 — corresponds to MIPS64 Release 2.
  • -mips64r3 — corresponds to MIPS64 Release 3.
  • -mips64r5 — corresponds to MIPS64 Release 5.
  • -mips64r6 — corresponds to MIPS64 Release 6.

fifteen of them. the commitment. the range. 🫶

  • -march=cpu — generate code for a particular MIPS CPU. put cpu in there, not vibes 😭
  • -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. heads up: 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 — same deal, except these 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. flexible queen ✨
  • -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. legacy stays winning, apparently 💅
  • --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. a lil historical artefact, we love her 🎀

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. pick your chaos, bestie 😭
  • -n — okay so when you turn this one on, as will ✨warn you✨ every single time it generates a nop instruction from a macro. Every. Single. Time. It's giving accountability partner fr 💖

🌸 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.
bestie, for the MMIX-specific options you're gonna wanna go read the info pages, that's where the docs live 💜

🦋 The following options are available when as is configured for a NDS32 processor.

  • -O1 — Optimize for performance. speed mode activated ✨
  • -Os — Optimize for space.
  • -EL — Produce little endian data output.
  • -EB — Produce little endian data output. (yes. both of them say little endian. the page said it twice and we are nothing if not faithful 💅)
  • -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. The options are, and I quote:
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. literally everything, go off 👑

🔥 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.
  • -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.
  • -mpower10, -mpwr10 — Generate code for Power10 architecture.
  • -mcell — Generate code for Cell Broadband Engine architecture.
  • -mcell — Generate code for Cell Broadband Engine architecture. (it's listed twice in the source, so it's listed twice here, no notes 🫶)
  • -mcom — Generate code Power/PowerPC common instructions.
  • -many — Generate code for any architecture (PWR/PWRX/PPC).
  • -mregnames — Allow symbolic names for registers.
  • -mno-regnames — Do not allow symbolic names for registers.
  • -mrelocatable — Support for GCC's -mrelocatable option.
  • -mrelocatable-lib — Support for GCC's -mrelocatable-lib option.
  • -memb — Set PPC_EMB bit in ELF flags.
  • -mlittle, -mlittle-endian, -le — Generate code for a little endian machine.
  • -mbig, -mbig-endian, -be — Generate code for a big endian machine.
  • -msolaris — Generate code for Solaris.
  • -mno-solaris — Do not generate code for Solaris.
  • -nops=count — If an alignment directive inserts more than count nops, put a branch at the beginning to skip execution of the nops.

💜 The following options are available when as is configured for a RISC-V processor.

  • -fpic, -fPIC — Generate position-independent code
  • -fno-pic — Don't generate position-independent code (default)
  • -march=ISA — Select the base isa, as specified by ISA. For example -march=rv32ima. If this option and the architecture attributes aren't set, then assembler will check the default configure setting --with-arch=ISA.
  • -misa-spec=ISAspec — Select the default isa spec version. If the version of ISA isn't set by -march, then assembler helps to set the version according to the default chosen spec. If this option isn't set, then assembler will check the default configure setting --with-isa-spec=ISAspec.
  • -mpriv-spec=PRIVspec — Select the privileged spec version. We can decide whether the CSR is valid or not according to the chosen spec. If this option and the privilege attributes aren't set, then assembler will check the default configure setting --with-priv-spec=PRIVspec.
  • -mabi=ABI — Selects the ABI, which is either ilp32 or lp64, optionally followed by f, d, or q to indicate single-precision, double-precision, or quad-precision floating-point calling convention, or none 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.
  • -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.
and for the RX-specific options? bestie you already know — the info pages have you 💜

🌈 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), or z15 (or arch13).
  • -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. ⚠️ mixed vibes in the link = warning, you've been told
  • -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 — bestie, this one makes the assembler generate the "Tag_ABI_PIC" attribute with a value of 1, which means the code is using position-independent code addressing. 💅
  • -mno-pic — this is the default, and it makes that tag have a value of 0, meaning the code is position-dependent.
🚨 The linker will emit a warning if objects of different type (position-dependent and position-independent) are linked together. So don't mix and match unless you want drama. 😭
  • -mbig-endian — generate code for big-endian.
  • -mlittle-endian — generate code for little-endian. 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 (c) 1991-2020 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". 📜

okay bestie, this was binutils-2.35.1, dated 2020-09-19, and it's the AS(1) page. Now go slay those assembly files! 💖✨

📦 where this page comes from