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| author | Lili Cui <lili.cui@intel.com> | 2019-06-26 15:12:58 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2019-06-26 15:13:55 -0700 |
| commit | aa108c0c462e43ab77a1f178d8c8d2277ac73a57 (patch) | |
| tree | 9ef0b21434fdc7e6e8cd3006922ea9cce4e841eb /gas/doc | |
| parent | a68aa5d3020948564ef99d704d27e458ba22ad9d (diff) | |
| download | gdb-aa108c0c462e43ab77a1f178d8c8d2277ac73a57.zip gdb-aa108c0c462e43ab77a1f178d8c8d2277ac73a57.tar.gz gdb-aa108c0c462e43ab77a1f178d8c8d2277ac73a57.tar.bz2 | |
i386: Document memory size reference in assembler
* doc/c-i386.texi: Document x/y/z instruction sufffixes in AT&T
syntax and xmmword/ymmword/zmmword/fword/tbyte/oword ptr in
Intel syntax.
Diffstat (limited to 'gas/doc')
| -rw-r--r-- | gas/doc/c-i386.texi | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/gas/doc/c-i386.texi b/gas/doc/c-i386.texi index 908c6ca..80bbcbe 100644 --- a/gas/doc/c-i386.texi +++ b/gas/doc/c-i386.texi @@ -590,11 +590,16 @@ instruction, do @emph{not} have reversed order. @ref{i386-Bugs}. In AT&T syntax the size of memory operands is determined from the last character of the instruction mnemonic. Mnemonic suffixes of @samp{b}, @samp{w}, @samp{l} and @samp{q} specify byte (8-bit), word (16-bit), long -(32-bit) and quadruple word (64-bit) memory references. Intel syntax accomplishes -this by prefixing memory operands (@emph{not} the instruction mnemonics) with -@samp{byte ptr}, @samp{word ptr}, @samp{dword ptr} and @samp{qword ptr}. Thus, -Intel @samp{mov al, byte ptr @var{foo}} is @samp{movb @var{foo}, %al} in AT&T -syntax. +(32-bit) and quadruple word (64-bit) memory references. Mnemonic suffixes +of @samp{x}, @samp{y} and @samp{z} specify xmm (128-bit vector), ymm +(256-bit vector) and zmm (512-bit vector) memory references, only when there's +no other way to disambiguate an instruction. Intel syntax accomplishes this by +prefixing memory operands (@emph{not} the instruction mnemonics) with +@samp{byte ptr}, @samp{word ptr}, @samp{dword ptr}, @samp{qword ptr}, +@samp{xmmword ptr}, @samp{ymmword ptr} and @samp{zmmword ptr}. Thus, Intel +syntax @samp{mov al, byte ptr @var{foo}} is @samp{movb @var{foo}, %al} in AT&T +syntax. In Intel syntax, @samp{fword ptr}, @samp{tbyte ptr} and +@samp{oword ptr} specify 48-bit, 80-bit and 128-bit memory references. In 64-bit code, @samp{movabs} can be used to encode the @samp{mov} instruction with the 64-bit displacement or immediate operand. |