official gnu as reference for x86 instructions - specifically cmpxchg

[Segher Boessenkool]

On Wed, May 15, 2024 at 12:15:39PM +0100, Jonathan Wakely via Gcc-help wrote:
> On Wed, 15 May 2024 at 10:12, anand akhare via Gcc-help
> <gcc-help@gcc.gnu.org> wrote:
> > Pls provide any link reference which is official reference gnu assembler instruction for x86,
> 
> Gas doesn't define the x86 instructions, Intel does.

The source code of GAS (well, libopcodes) is the ultimate reference to
what instruction syntax is accepted by GAS.  See
https://sourceware.org/git/?p=binutils-gdb.git;a=blob&f=opcodes/i386-opc.tbl
and files around that.


Segher