-@c Copyright 1991, 1992, 1993, 1994, 1995, 1997, 1998, 1999, 2000,
-@c 2001, 2003, 2004
-@c Free Software Foundation, Inc.
+@c Copyright (C) 1991-2015 Free Software Foundation, Inc.
@c This is part of the GAS manual.
@c For copying conditions, see the file as.texinfo.
+@c man end
+
@ifset GENERIC
@page
@node i386-Dependent
@end ifclear
@cindex i386 support
-@cindex i80306 support
+@cindex i80386 support
@cindex x86-64 support
The i386 version @code{@value{AS}} supports both the original Intel 386
@menu
* i386-Options:: Options
* i386-Directives:: X86 specific directives
-* i386-Syntax:: AT&T Syntax versus Intel Syntax
+* i386-Syntax:: Syntactical considerations
* i386-Mnemonics:: Instruction Naming
* i386-Regs:: Register Naming
* i386-Prefixes:: Instruction Prefixes
* i386-Jumps:: Handling of Jump Instructions
* i386-Float:: Floating Point
* i386-SIMD:: Intel's MMX and AMD's 3DNow! SIMD Operations
+* i386-LWP:: AMD's Lightweight Profiling Instructions
+* i386-BMI:: Bit Manipulation Instruction
+* i386-TBM:: AMD's Trailing Bit Manipulation Instructions
* i386-16bit:: Writing 16-bit Code
* i386-Arch:: Specifying an x86 CPU architecture
* i386-Bugs:: AT&T Syntax bugs
@cindex options for i386
@cindex options for x86-64
@cindex i386 options
-@cindex x86-64 options
+@cindex x86-64 options
The i386 version of @code{@value{AS}} has a few machine
dependent options:
-@table @code
+@c man begin OPTIONS
+@table @gcctabopt
@cindex @samp{--32} option, i386
@cindex @samp{--32} option, x86-64
+@cindex @samp{--x32} option, i386
+@cindex @samp{--x32} option, x86-64
@cindex @samp{--64} option, i386
@cindex @samp{--64} option, x86-64
-@item --32 | --64
-Select the word size, either 32 bits or 64 bits. Selecting 32-bit
-implies Intel i386 architecture, while 64-bit implies AMD x86-64
-architecture.
+@item --32 | --x32 | --64
+Select the word size, either 32 bits or 64 bits. @samp{--32}
+implies Intel i386 architecture, while @samp{--x32} and @samp{--64}
+imply AMD x86-64 architecture with 32-bit or 64-bit word-size
+respectively.
These options are only available with the ELF object file format, and
require that the necessary BFD support has been included (on a 32-bit
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:
+processor names are recognized:
@code{i8086},
@code{i186},
@code{i286},
@code{nocona},
@code{core},
@code{core2},
+@code{corei7},
+@code{l1om},
+@code{k1om},
@code{k6},
@code{k6_2},
@code{athlon},
@code{opteron},
@code{k8},
@code{amdfam10},
+@code{bdver1},
+@code{bdver2},
+@code{bdver3},
+@code{bdver4},
+@code{znver1},
+@code{btver1},
+@code{btver2},
@code{generic32} and
@code{generic64}.
-In addition to the basic instruction set, the assembler can be told to
+In addition to the basic instruction set, the assembler can be told to
accept various extension mnemonics. For example,
@code{-march=i686+sse4+vmx} extends @var{i686} with @var{sse4} and
@var{vmx}. The following extensions are currently supported:
+@code{8087},
+@code{287},
+@code{387},
+@code{no87},
@code{mmx},
+@code{nommx},
@code{sse},
@code{sse2},
@code{sse3},
@code{sse4.1},
@code{sse4.2},
@code{sse4},
+@code{nosse},
@code{avx},
+@code{avx2},
+@code{adx},
+@code{rdseed},
+@code{prfchw},
+@code{smap},
+@code{mpx},
+@code{sha},
+@code{prefetchwt1},
+@code{clflushopt},
+@code{se1},
+@code{clwb},
+@code{pcommit},
+@code{avx512f},
+@code{avx512cd},
+@code{avx512er},
+@code{avx512pf},
+@code{avx512vl},
+@code{avx512bw},
+@code{avx512dq},
+@code{avx512ifma},
+@code{avx512vbmi},
+@code{noavx},
@code{vmx},
+@code{vmfunc},
@code{smx},
@code{xsave},
+@code{xsaveopt},
+@code{xsavec},
+@code{xsaves},
@code{aes},
@code{pclmul},
+@code{fsgsbase},
+@code{rdrnd},
+@code{f16c},
+@code{bmi2},
@code{fma},
@code{movbe},
@code{ept},
+@code{lzcnt},
+@code{hle},
+@code{rtm},
+@code{invpcid},
+@code{clflush},
+@code{clzero},
+@code{lwp},
+@code{fma4},
+@code{xop},
+@code{cx16},
+@code{syscall},
+@code{rdtscp},
@code{3dnow},
@code{3dnowa},
@code{sse4a},
@code{svme},
@code{abm} and
@code{padlock}.
+Note that rather than extending a basic instruction set, the extension
+mnemonics starting with @code{no} revoke the respective functionality.
When the @code{.arch} directive is used with @option{-march}, the
@code{.arch} directive will take precedent.
@cindex @samp{-msse-check=} option, i386
@cindex @samp{-msse-check=} option, x86-64
@item -msse-check=@var{none}
-@item -msse-check=@var{warning}
-@item -msse-check=@var{error}
-These options control if the assembler should check SSE intructions.
+@itemx -msse-check=@var{warning}
+@itemx -msse-check=@var{error}
+These options control if the assembler should check SSE instructions.
@option{-msse-check=@var{none}} will make the assembler not to check SSE
instructions, which is the default. @option{-msse-check=@var{warning}}
-will make the assembler issue a warning for any SSE intruction.
+will make the assembler issue a warning for any SSE instruction.
@option{-msse-check=@var{error}} will make the assembler issue an error
-for any SSE intruction.
+for any SSE instruction.
+
+@cindex @samp{-mavxscalar=} option, i386
+@cindex @samp{-mavxscalar=} option, x86-64
+@item -mavxscalar=@var{128}
+@itemx -mavxscalar=@var{256}
+These options control how the assembler should encode scalar AVX
+instructions. @option{-mavxscalar=@var{128}} will encode scalar
+AVX instructions with 128bit vector length, which is the default.
+@option{-mavxscalar=@var{256}} will encode scalar AVX instructions
+with 256bit vector length.
+
+@cindex @samp{-mevexlig=} option, i386
+@cindex @samp{-mevexlig=} option, x86-64
+@item -mevexlig=@var{128}
+@itemx -mevexlig=@var{256}
+@itemx -mevexlig=@var{512}
+These options control how the assembler should encode length-ignored
+(LIG) EVEX instructions. @option{-mevexlig=@var{128}} will encode LIG
+EVEX instructions with 128bit vector length, which is the default.
+@option{-mevexlig=@var{256}} and @option{-mevexlig=@var{512}} will
+encode LIG EVEX instructions with 256bit and 512bit vector length,
+respectively.
+
+@cindex @samp{-mevexwig=} option, i386
+@cindex @samp{-mevexwig=} option, x86-64
+@item -mevexwig=@var{0}
+@itemx -mevexwig=@var{1}
+These options control how the assembler should encode w-ignored (WIG)
+EVEX instructions. @option{-mevexwig=@var{0}} will encode WIG
+EVEX instructions with evex.w = 0, which is the default.
+@option{-mevexwig=@var{1}} will encode WIG EVEX instructions with
+evex.w = 1.
@cindex @samp{-mmnemonic=} option, i386
@cindex @samp{-mmnemonic=} option, x86-64
@item -mmnemonic=@var{att}
-@item -mmnemonic=@var{intel}
-This option specifies instruction mnemonic for matching instructions.
+@itemx -mmnemonic=@var{intel}
+This option specifies instruction mnemonic for matching instructions.
The @code{.att_mnemonic} and @code{.intel_mnemonic} directives will
take precedent.
@cindex @samp{-msyntax=} option, i386
@cindex @samp{-msyntax=} option, x86-64
@item -msyntax=@var{att}
-@item -msyntax=@var{intel}
-This option specifies instruction syntax when processing instructions.
+@itemx -msyntax=@var{intel}
+This option specifies instruction syntax when processing instructions.
The @code{.att_syntax} and @code{.intel_syntax} directives will
take precedent.
This opetion specifies that registers don't require a @samp{%} prefix.
The @code{.att_syntax} and @code{.intel_syntax} directives will take precedent.
+@cindex @samp{-madd-bnd-prefix} option, i386
+@cindex @samp{-madd-bnd-prefix} option, x86-64
+@item -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.
+
+@cindex @samp{-mbig-obj} option, x86-64
+@item -mbig-obj
+On x86-64 PE/COFF target this option forces the use of big object file
+format, which allows more than 32768 sections.
+
+@cindex @samp{-momit-lock-prefix=} option, i386
+@cindex @samp{-momit-lock-prefix=} option, x86-64
+@item -momit-lock-prefix=@var{no}
+@itemx -momit-lock-prefix=@var{yes}
+These options control how the assembler should encode lock prefix.
+This option is intended as a workaround for processors, that fail on
+lock prefix. This option can only be safely used with single-core,
+single-thread computers
+@option{-momit-lock-prefix=@var{yes}} will omit all lock prefixes.
+@option{-momit-lock-prefix=@var{no}} will encode lock prefix as usual,
+which is the default.
+
+@cindex @samp{-mevexrcig=} option, i386
+@cindex @samp{-mevexrcig=} option, x86-64
+@item -mevexrcig=@var{rne}
+@itemx -mevexrcig=@var{rd}
+@itemx -mevexrcig=@var{ru}
+@itemx -mevexrcig=@var{rz}
+These options control how the assembler should encode SAE-only
+EVEX instructions. @option{-mevexrcig=@var{rne}} will encode RC bits
+of EVEX instruction with 00, which is the default.
+@option{-mevexrcig=@var{rd}}, @option{-mevexrcig=@var{ru}}
+and @option{-mevexrcig=@var{rz}} will encode SAE-only EVEX instructions
+with 01, 10 and 11 RC bits, respectively.
+
@end table
+@c man end
@node i386-Directives
@section x86 specific Directives
Reserve @var{length} (an absolute expression) bytes for a local common
denoted by @var{symbol}. The section and value of @var{symbol} are
those of the new local common. The addresses are allocated in the bss
-section, so that at run-time the bytes start off zeroed. @var{Symbol}
-is not declared global (@pxref{Global,,@code{.global}}), so is normally
-not visible to @code{@value{LD}}. The optional third parameter,
-@var{alignment}, specifies the desired alignment of the symbol in the
-bss section.
+section, so that at run-time the bytes start off zeroed. Since
+@var{symbol} is not declared global, it is normally not visible to
+@code{@value{LD}}. The optional third parameter, @var{alignment},
+specifies the desired alignment of the symbol in the bss section.
This directive is only available for COFF based x86 targets.
@end table
@node i386-Syntax
-@section AT&T Syntax versus Intel Syntax
+@section i386 Syntactical Considerations
+@menu
+* i386-Variations:: AT&T Syntax versus Intel Syntax
+* i386-Chars:: Special Characters
+@end menu
+
+@node i386-Variations
+@subsection AT&T Syntax versus Intel Syntax
@cindex i386 intel_syntax pseudo op
@cindex intel_syntax pseudo op, i386
Intel @samp{mov al, byte ptr @var{foo}} is @samp{movb @var{foo}, %al} in AT&T
syntax.
+In 64-bit code, @samp{movabs} can be used to encode the @samp{mov}
+instruction with the 64-bit displacement or immediate operand.
+
@cindex return instructions, i386
@cindex i386 jump, call, return
@cindex return instructions, x86-64
programs. Unix style systems expect all programs to be single sections.
@end itemize
+@node i386-Chars
+@subsection Special Characters
+
+@cindex line comment character, i386
+@cindex i386 line comment character
+The presence of a @samp{#} appearing anywhere on a line indicates the
+start of a comment that extends to the end of that line.
+
+If a @samp{#} appears as the first character of a line then the whole
+line is treated as a comment, but in this case the line can also be a
+logical line number directive (@pxref{Comments}) or a preprocessor
+control command (@pxref{Preprocessing}).
+
+If the @option{--divide} command line option has not been specified
+then the @samp{/} character appearing anywhere on a line also
+introduces a line comment.
+
+@cindex line separator, i386
+@cindex statement separator, i386
+@cindex i386 line separator
+The @samp{;} character can be used to separate statements on the same
+line.
+
@node i386-Mnemonics
-@section Instruction Naming
+@section i386-Mnemonics
+@subsection Instruction Naming
@cindex i386 instruction naming
@cindex instruction naming, i386
@samp{wq} (from word to quadruple word), and @samp{lq} (from long to
quadruple word).
+@cindex encoding options, i386
+@cindex encoding options, x86-64
+
+Different encoding options can be specified via optional mnemonic
+suffix. @samp{.s} suffix swaps 2 register operands in encoding when
+moving from one register to another. @samp{.d8} or @samp{.d32} suffix
+prefers 8bit or 32bit displacement in encoding.
+
@cindex conversion instructions, i386
@cindex i386 conversion instructions
@cindex conversion instructions, x86-64
AT&T syntax, but are @samp{call far} and @samp{jump far} in Intel
convention.
-@section AT&T Mnemonic versus Intel Mnemonic
+@subsection AT&T Mnemonic versus Intel Mnemonic
@cindex i386 mnemonic compatibility
@cindex mnemonic compatibility, i386
See Intel and AMD documentation, keeping in mind that the operand order in
instructions is reversed from the Intel syntax.
+@node i386-LWP
+@section AMD's Lightweight Profiling Instructions
+
+@cindex LWP, i386
+@cindex LWP, x86-64
+
+@code{@value{AS}} supports AMD's Lightweight Profiling (LWP)
+instruction set, available on AMD's Family 15h (Orochi) processors.
+
+LWP enables applications to collect and manage performance data, and
+react to performance events. The collection of performance data
+requires no context switches. LWP runs in the context of a thread and
+so several counters can be used independently across multiple threads.
+LWP can be used in both 64-bit and legacy 32-bit modes.
+
+For detailed information on the LWP instruction set, see the
+@cite{AMD Lightweight Profiling Specification} available at
+@uref{http://developer.amd.com/cpu/LWP,Lightweight Profiling Specification}.
+
+@node i386-BMI
+@section Bit Manipulation Instructions
+
+@cindex BMI, i386
+@cindex BMI, x86-64
+
+@code{@value{AS}} supports the Bit Manipulation (BMI) instruction set.
+
+BMI instructions provide several instructions implementing individual
+bit manipulation operations such as isolation, masking, setting, or
+resetting.
+
+@c Need to add a specification citation here when available.
+
+@node i386-TBM
+@section AMD's Trailing Bit Manipulation Instructions
+
+@cindex TBM, i386
+@cindex TBM, x86-64
+
+@code{@value{AS}} supports AMD's Trailing Bit Manipulation (TBM)
+instruction set, available on AMD's BDVER2 processors (Trinity and
+Viperfish).
+
+TBM instructions provide instructions implementing individual bit
+manipulation operations such as isolating, masking, setting, resetting,
+complementing, and operations on trailing zeros and ones.
+
+@c Need to add a specification citation here when available.
+
@node i386-16bit
@section Writing 16-bit Code
it also supports writing code to run in real mode or in 16-bit protected
mode code segments. To do this, put a @samp{.code16} or
@samp{.code16gcc} directive before the assembly language instructions to
-be run in 16-bit mode. You can switch @code{@value{AS}} back to writing
-normal 32-bit code with the @samp{.code32} directive.
+be run in 16-bit mode. You can switch @code{@value{AS}} to writing
+32-bit code with the @samp{.code32} directive or 64-bit code with the
+@samp{.code64} directive.
@samp{.code16gcc} provides experimental support for generating 16-bit
code from gcc, and differs from @samp{.code16} in that @samp{call},
is correct since the processor default operand size is assumed to be 16
bits in a 16-bit code section.
-@node i386-Bugs
-@section AT&T Syntax bugs
-
-The UnixWare assembler, and probably other AT&T derived ix86 Unix
-assemblers, generate floating point instructions with reversed source
-and destination registers in certain cases. Unfortunately, gcc and
-possibly many other programs use this reversed syntax, so we're stuck
-with it.
-
-For example
-
-@smallexample
- fsub %st,%st(3)
-@end smallexample
-@noindent
-results in @samp{%st(3)} being updated to @samp{%st - %st(3)} rather
-than the expected @samp{%st(3) - %st}. This happens with all the
-non-commutative arithmetic floating point operations with two register
-operands where the source register is @samp{%st} and the destination
-register is @samp{%st(i)}.
-
@node i386-Arch
@section Specifying CPU Architecture
@item @samp{i486} @tab @samp{i586} @tab @samp{i686} @tab @samp{pentium}
@item @samp{pentiumpro} @tab @samp{pentiumii} @tab @samp{pentiumiii} @tab @samp{pentium4}
@item @samp{prescott} @tab @samp{nocona} @tab @samp{core} @tab @samp{core2}
+@item @samp{corei7} @tab @samp{l1om} @tab @samp{k1om}
@item @samp{k6} @tab @samp{k6_2} @tab @samp{athlon} @tab @samp{k8}
-@item @samp{amdfam10}
+@item @samp{amdfam10} @tab @samp{bdver1} @tab @samp{bdver2} @tab @samp{bdver3}
+@item @samp{bdver4} @tab @samp{znver1} @tab @samp{btver1} @tab @samp{btver2}
@item @samp{generic32} @tab @samp{generic64}
@item @samp{.mmx} @tab @samp{.sse} @tab @samp{.sse2} @tab @samp{.sse3}
@item @samp{.ssse3} @tab @samp{.sse4.1} @tab @samp{.sse4.2} @tab @samp{.sse4}
-@item @samp{.avx} @tab @samp{.vmx} @tab @samp{.smx} @tab @samp{.xsave}
-@item @samp{.aes} @tab @samp{.pclmul} @tab @samp{.fma} @tab @samp{.movbe}
-@item @samp{.ept}
+@item @samp{.avx} @tab @samp{.vmx} @tab @samp{.smx} @tab @samp{.ept}
+@item @samp{.clflush} @tab @samp{.movbe} @tab @samp{.xsave} @tab @samp{.xsaveopt}
+@item @samp{.aes} @tab @samp{.pclmul} @tab @samp{.fma} @tab @samp{.fsgsbase}
+@item @samp{.rdrnd} @tab @samp{.f16c} @tab @samp{.avx2} @tab @samp{.bmi2}
+@item @samp{.lzcnt} @tab @samp{.invpcid} @tab @samp{.vmfunc} @tab @samp{.hle}
+@item @samp{.rtm} @tab @samp{.adx} @tab @samp{.rdseed} @tab @samp{.prfchw}
+@item @samp{.smap} @tab @samp{.mpx} @tab @samp{.sha} @tab @samp{.prefetchwt1}
+@item @samp{.clflushopt} @tab @samp{.xsavec} @tab @samp{.xsaves} @tab @samp{.se1}
+@item @samp{.avx512f} @tab @samp{.avx512cd} @tab @samp{.avx512er} @tab @samp{.avx512pf}
+@item @samp{.avx512vl} @tab @samp{.avx512bw} @tab @samp{.avx512dq} @tab @samp{.avx512ifma}
+@item @samp{.avx512vbmi} @tab @samp{.clwb} @tab @samp{.pcommit}
@item @samp{.3dnow} @tab @samp{.3dnowa} @tab @samp{.sse4a} @tab @samp{.sse5}
-@item @samp{.svme} @tab @samp{.abm}
-@item @samp{.padlock}
+@item @samp{.syscall} @tab @samp{.rdtscp} @tab @samp{.svme} @tab @samp{.abm}
+@item @samp{.lwp} @tab @samp{.fma4} @tab @samp{.xop} @tab @samp{.cx16}
+@item @samp{.padlock} @tab @samp{.clzero}
@end multitable
Apart from the warning, there are only two other effects on
.arch i8086,nojumps
@end smallexample
+@node i386-Bugs
+@section AT&T Syntax bugs
+
+The UnixWare assembler, and probably other AT&T derived ix86 Unix
+assemblers, generate floating point instructions with reversed source
+and destination registers in certain cases. Unfortunately, gcc and
+possibly many other programs use this reversed syntax, so we're stuck
+with it.
+
+For example
+
+@smallexample
+ fsub %st,%st(3)
+@end smallexample
+@noindent
+results in @samp{%st(3)} being updated to @samp{%st - %st(3)} rather
+than the expected @samp{%st(3) - %st}. This happens with all the
+non-commutative arithmetic floating point operations with two register
+operands where the source register is @samp{%st} and the destination
+register is @samp{%st(i)}.
+
@node i386-Notes
@section Notes
projects / deliverable / binutils-gdb.git / blobdiff