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AS - the portable GNU assembler.

 

NAME

        AS - the portable GNU assembler.
 

SYNOPSIS

        as [-a[cdhlns][=file]] [-D] [--defsym sym=val]
         [-f] [--gstabs] [--gstabs+] [--gdwarf2] [--help]
         [-I dir] [-J] [-K] [-L]
         [--listing-lhs-width=NUM] [--listing-lhs-width2=NUM]
         [--listing-rhs-width=NUM] [--listing-cont-lines=NUM]
         [--keep-locals] [-o objfile] [-R] [--statistics] [-v]
         [-version] [--version] [-W] [--warn] [--fatal-warnings]
         [-w] [-x] [-Z] [--target-help] [target-options]
         [--│files ...]
 
        Target Alpha options:
           [-mcpu]
           [-mdebug │ -no-mdebug]
           [-relax] [-g] [-Gsize]
           [-F] [-32addr]
 
        Target ARC options:
           [-marc[5     6     7     8]]
           [-EB│-EL]
 
        Target ARM options:
           [-mcpu=processor[+extension...]]
           [-march=architecture[+extension...]]
           [-mfpu=floating-point-format]
           [-mfloat-abi=abi]
           [-mthumb]
           [-EB│-EL]
           [-mapcs-32│-mapcs-26│-mapcs-float│
            -mapcs-reentrant]
           [-mthumb-interwork] [-moabi] [-k]
 
        Target CRIS options:
           [--underscore │ --no-underscore]
           [--pic] [-N]
           [--emulation=criself │ --emulation=crisaout]
 
        Target D10V options:
           [-O]
 
        Target D30V options:
           [-O│-n│-N]
 
        Target i386 options:
           [--32│--64] [-n]
 
        Target i960 options:
           [-ACA│-ACA_A│-ACB│-ACC│-AKA│-AKB│
            -AKC│-AMC]
           [-b] [-no-relax]
 
        Target IP2K options:
           [-mip2022│-mip2022ext]
 
        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]
           [-mshort│-mlong]
           [-mshort-double│-mlong-double]
           [--force-long-branchs] [--short-branchs]
           [--strict-direct-mode] [--print-insn-syntax]
           [--print-opcodes] [--generate-example]
 
        Target MCORE options:
           [-jsri2bsr] [-sifilter] [-relax]
           [-mcpu=[210     340]]
 
        Target MIPS options:
           [-nocpp] [-EL] [-EB] [-O[optimization level]]
           [-g[debug level]] [-G num] [-KPIC] [-call_shared]
           [-non_shared] [-xgot] [--membedded-pic]
           [-mabi=ABI] [-32] [-n32] [-64] [-mfp32] [-mgp32]
           [-march=CPU] [-mtune=CPU] [-mips1] [-mips2]
           [-mips3] [-mips4] [-mips5] [-mips32] [-mips32r2]
           [-mips64] [-mips64r2]
           [-construct-floats] [-no-construct-floats]
           [-trap] [-no-break] [-break] [-no-trap]
           [-mfix7000] [-mno-fix7000]
           [-mips16] [-no-mips16]
           [-mips3d] [-no-mips3d]
           [-mdmx] [-no-mdmx]
           [-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 PDP11 options:
           [-mpic│-mno-pic] [-mall] [-mno-extensions]
           [-mextension│-mno-extension]
           [-mcpu] [-mmachine]
 
        Target picoJava options:
           [-mb│-me]
 
        Target PowerPC options:
           [-mpwrx│-mpwr2│-mpwr│-m601│-mppc│-mppc32│-m603│-m604│
            -m403│-m405│-mppc64│-m620│-mppc64bridge│-mbooke│
            -mbooke32│-mbooke64]
           [-mcom│-many│-maltivec] [-memb]
           [-mregnames│-mno-regnames]
           [-mrelocatable│-mrelocatable-lib]
           [-mlittle│-mlittle-endian│-mbig│-mbig-endian]
           [-msolaris│-mno-solaris]
 
        Target SPARC options:
           [-Av6│-Av7│-Av8│-Asparclet│-Asparclite
            -Av8plus│-Av8plusa│-Av9│-Av9a]
           [-xarch=v8plus│-xarch=v8plusa] [-bump]
           [-32│-64]
 
        Target TIC54X options:
         [-mcpu=54[123589]│-mcpu=54[56]lp] [-mfar-mode│-mf]
         [-merrors-to-file <filename>│-me <filename>]
 
        Target Xtensa options:
         [--[no-]density] [--[no-]relax] [--[no-]generics]
         [--[no-]text-section-literals]
         [--[no-]target-align] [--[no-]longcalls]
 

DESCRIPTION

        GNU as is really a family of assemblers.  If you use (or have used) the
        GNU assembler on one architecture, you should  find  a  fairly  similar
        environment  when you use it on another architecture.  Each version has
        much in common with the others, including  object  file  formats,  most
        assembler directives (often called pseudo-ops) and assembler syntax.
 
        as  is  primarily intended to assemble the output of the GNU C compiler
        "gcc" for use by the linker "ld".  Nevertheless, we’ve tried to make as
        assemble  correctly  everything  that  other  assemblers  for  the same
        machine would assemble.   Any  exceptions  are  documented  explicitly.
        This  doesn’t  mean as always uses the same syntax as another assembler
        for the same architecture; for example, we know of several incompatible
        versions of 680x0 assembly language syntax.
 
        Each  time  you  run  as  it assembles exactly one source program.  The
        source program is made up of one or more files.  (The standard input is
        also a file.)
 
        You give as a command line that has zero or more input file names.  The
        input files are read (from left file name to right).   A  command  line
        argument  (in  any position) that has no special meaning is taken to be
        an input file name.
 
        If you give as no file names it attempts to read one  input  file  from
        the  as  standard input, which is normally your terminal.  You may have
        to type ctl-D to tell as there is no more program to assemble.
 
        Use -- if you need to explicitly name the standard input file  in  your
        command line.
 
        If the source is empty, as produces a small, empty object file.
 
        as  may  write  warnings  and error messages to the standard error file
        (usually your terminal).  This should not happen when  a compiler  runs
        as  automatically.  Warnings report an assumption made so that as could
        keep assembling a flawed program; errors report a  grave  problem  that
        stops the assembly.
 
        If  you  are  invoking  as  via the GNU C compiler, you can use the -Wa
        option to pass arguments through to the assembler.  The assembler argu‐
        ments  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 stan‐
        dard  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, includ‐
        ing the assembler.)
 

OPTIONS

        -a[cdhlmns]
            Turn on listings, in any of a variety of ways:
 
            -ac omit false conditionals
 
            -ad omit debugging directives
 
            -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.
 
        -D  Ignored.  This option is accepted  for  script  compatibility  with
            calls to other assemblers.
 
        --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.
 
        -f  ‘‘fast’’---skip whitespace and comment preprocessing (assume source
            is compiler output).
 
        --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  exten‐
            sion is the location of the current working directory at assembling
            time.
 
        --gdwarf2
            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.
 
        --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 displace‐
            ments.
 
        -L
        --keep-locals
            Keep (in the symbol table) local  symbols.   On  traditional  a.out
            systems  these  start  with L, but different systems have different
            local label prefixes.
 
        --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 con‐
            tinuation 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.
 
        -o objfile
            Name the object-file output from as objfile.
 
        -R  Fold the data section into the text section.
 
        --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 an ARC
        processor.
 
        -marc[5     6     7     8]
            This option selects the core processor variant.
 
        -EB       -EL
            Select either big-endian (-EB) or little-endian (-EL) output.
 
        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       -moabi
            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.
 
        -k  Specify that PIC code has been generated.
 
        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 the Intel
        80960 processor.
 
        -ACA       -ACA_A       -ACB       -ACC       -AKA       -AKB       -AKC       -AMC
            Specify which variant of the 960 architecture is the target.
 
        -b  Add code to collect statistics about branches taken.
 
        -no-relax
            Do  not  alter  compare-and-branch  instructions for long displace‐
            ments; error if necessary.
 
        The following options are available when as is configured for the  Ubi‐
        com 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 Rene‐
        sas 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  con‐
            structs 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  configu‐
            ration time.
 
        -m68881       -m68882       -mno-68881       -mno-68882
            The  target machine does (or does not) have a floating-point copro‐
            cessor.  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 possi‐
            ble  to  do emulation of the coprocessor instructions with the main
            processor.
 
        -m68851       -mno-68851
            The target machine does (or does not) have a memory-management unit
            coprocessor.  The default is to assume an MMU for 68020 and up.
 
        For  details  about  the PDP-11 machine dependent features options, see
        @ref{PDP-11-Options}.
 
        -mpic       -mno-pic
            Generate position-independent (or  position-dependent)  code.   The
            default is -mpic.
 
        -mall
        -mall-extensions
            Enable all instruction set extensions.  This is the default.
 
        -mno-extensions
            Disable all instruction set extensions.
 
        -mextension       -mno-extension
            Enable (or disable) a particular instruction set extension.
 
        -mcpu
            Enable  the  instruction  set  extensions supported by a particular
            CPU, and disable all other extensions.
 
        -mmachine
            Enable the instruction set extensions  supported  by  a  particular
            machine model, and disable all other extensions.
 
        The  following  options are available when as is configured for a pico‐
        Java processor.
 
        -mb Generate ‘‘big endian’’ format output.
 
        -ml Generate ‘‘little endian’’ format output.
 
        The following options are available  when  as  is  configured  for  the
        Motorola 68HC11 or 68HC12 series.
 
        -m68hc11       -m68hc12       -m68hcs12
            Specify  what  processor  is the target.  The default is defined by
            the configuration option when building the assembler.
 
        -mshort
            Specify to use the 16-bit integer ABI.
 
        -mlong
            Specify to use the 32-bit integer ABI.
 
        -mshort-double
            Specify to use the 32-bit double ABI.
 
        -mlong-double
            Specify to use the 64-bit double ABI.
 
        --force-long-branchs
            Relative branches are turned into absolute ones. This concerns con‐
            ditional  branches,  unconditional  branches  and branches to a sub
            routine.
 
        -S       --short-branchs
            Do not turn relative branchs into absolute ones when the offset  is
            out of range.
 
        --strict-direct-mode
            Do  not  turn  the  direct addressing mode into extended addressing
            mode when the instruction does not support direct addressing  mode.
 
        --print-insn-syntax
            Print the syntax of instruction in case of error.
 
        --print-opcodes
            print the list of instructions with syntax and then exit.
 
        --generate-example
            print  an  example of instruction for each possible instruction and
            then exit.  This option is only useful for testing as.
 
        The following options are available when as is configured for the SPARC
        architecture:
 
        -Av6       -Av7       -Av8       -Asparclet       -Asparclite
        -Av8plus       -Av8plusa       -Av9       -Av9a
            Explicitly select a variant of the SPARC architecture.
 
            -Av8plus and -Av8plusa select a 32 bit environment.  -Av9 and -Av9a
            select a 64 bit environment.
 
            -Av8plusa and -Av9a enable the SPARC V9 instruction set with Ultra‐
            SPARC extensions.
 
        -xarch=v8plus       -xarch=v8plusa
            For compatibility with the Solaris v9 assembler.  These options are
            equivalent to -Av8plus and -Av8plusa, respectively.
 
        -bump
            Warn when the assembler switches to another architecture.
 
        The following options are available when as is configured for the ’c54x
        architecture.
 
        -mfar-mode
            Enable  extended  addressing  mode.   All addresses and relocations
            will assume extended addressing (usually 23 bits).
 
        -mcpu=CPU_VERSION
            Sets the CPU version being compiled for.
 
        -merrors-to-file FILENAME
            Redirect error output to a file, for  broken  systems  which  don’t
            support such behaviour in the shell.
 
        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  refer‐
            enced  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
        -mips64
        -mips64r2
            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,  -mips64,  and
            -mips64r2  correspond  to generic MIPS V, MIPS32, MIPS32 Release 2,
            MIPS64, and MIPS64 Release 2 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 instruc‐
            tions.
 
        -mdebug
        -no-mdebug
            Cause stabs-style debugging output to go into an ECOFF-style  .mde‐
            bug 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-pur‐
            pose registers and -mfp32 controls the size of floating-point  reg‐
            isters.
 
        -mips16
        -no-mips16
            Generate  code  for  the  MIPS 16 processor.  This is equivalent to
            putting  ".set  mips16"  at  the  start  of  the   assembly   file.
            -no-mips16 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.
 
        --construct-floats
        --no-construct-floats
            The  --no-construct-floats option disables the construction of dou‐
            ble 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.
 
        --emulation=name
            This option causes as to emulate as configured for some other  tar‐
            get, in all respects, including output format (choosing between ELF
            and ECOFF only), handling  of  pseudo-opcodes  which  may  generate
            debugging  information  or  store  symbol  table  information,  and
            default endianness.  The available configuration names are: mipsec     
            off,  mipself,  mipslecoff,  mipsbecoff,  mipslelf,  mipsbelf.  The
            first two do not alter the default endianness from that of the pri‐
            mary  target  for  which  the  assembler was configured; the others
            change the default to little- or big-endian as indicated by  the  b
            or  l  in  the name.  Using -EB or -EL will override the endianness
            selection in any case.
 
            This option is currently supported only when the primary target  as
            is  configured for is a MIPS ELF or ECOFF target.  Furthermore, the
            primary target or others  specified  with  --enable-targets=...  at
            configuration  time  must  include support for the other format, if
            both are to be available.  For example, the  Irix  5  configuration
            includes support for both.
 
            Eventually, this option will support more configurations, with more
            fine-grained control over the assembler’s  behavior,  and  will  be
            supported for more processors.
 
        -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 an MCore
        processor.
 
        -jsri2bsr
        -nojsri2bsr
            Enable or disable the JSRI to BSR transformation.  By default  this
            is  enabled.   The  command  line option -nojsri2bsr can be used to
            disable it.
 
        -sifilter
        -nosifilter
            Enable or disable the silicon filter behaviour.  By default this is
            disabled.   The  default can be overridden by the -sifilter command
            line option.
 
        -relax
            Alter jump instructions for long displacements.
 
        -mcpu=[210     340]
            Select the cpu type on the target hardware.   This  controls  which
            instructions can be assembled.
 
        -EB Assemble for a big endian target.
 
        -EL Assemble for a little endian target.
 
        See the info pages for documentation of the MMIX-specific options.
 
        The following options are available when as is configured for an Xtensa
        processor.
 
        --density       --no-density
            Enable or disable use of instructions from the Xtensa code  density
            option.   This is enabled by default when the Xtensa processor sup‐
            ports the code density option.
 
        --relax       --no-relax
            Enable or disable  instruction  relaxation.   This  is  enabled  by
            default.   Note:  In the current implementation, these options also
            control whether assembler optimizations are performed, making these
            options equivalent to --generics and --no-generics.
 
        --generics       --no-generics
            Enable  or disable all assembler transformations of Xtensa instruc‐
            tions.  The default is --generics;  --no-generics  should  be  used
            only  in  the  rare  cases when the instructions must be exactly as
            specified in the assembly source.
 
        --text-section-literals       --no-text-section-literals
            With --text-section-literals, literal pools are interspersed in the
            text  section.   The  default  is --no-text-section-literals, which
            places literals in a separate section in the output file.
 
        --target-align       --no-target-align
            Enable or disable automatic alignment to reduce branch penalties at
            the expense of some code density.  The default is --target-align.
 
        --longcalls       --no-longcalls
            Enable  or  disable  transformation  of  call instructions to allow
            calls  across  a  greater  range  of  addresses.   The  default  is
            --no-longcalls.
        gcc(1), ld(1), and the Info entries for binutils and ld.
 

COPYRIGHT

        Copyright  (C)  1991,  92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001, 2002
        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 1.1 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’’.
 

Sections

Based on BSD UNIX
FreeBSD is an advanced operating system for x86 compatible (including Pentium and Athlon), amd64 compatible (including Opteron, Athlon64, and EM64T), UltraSPARC, IA-64, PC-98 and ARM architectures. It is derived from BSD, the version of UNIX developed at the University of California, Berkeley. It is developed and maintained by a large team of individuals. Additional platforms are in various stages of development.