Re: [patch 13/17] Immediate Values - x86 Optimization

[H. Peter Anvin]

Mathieu Desnoyers wrote:
> * H. Peter Anvin (hpa@xxxxxxxxx) wrote:
> > Mathieu Desnoyers wrote:
> > > Ok, so the most flexible solution that I see, that should fit for both
> > > x86 and x86_64 would be :
> > > 1 byte  :       "=q" : "a", "b", "c", or "d" register for the i386.  For
> > >                        x86-64 it is equivalent to "r" class (for 8-bit
> > >                        instructions that do not use upper halves).
> > > 2, 4, 8 bytes : "=r" : A register operand is allowed provided that it is 
> > > in a
> > >                        general register.
> > Any reason to keep carrying this completely misleading comment chunk still?
> >
> > 	-hpa
>
> This comment explains why I use the =q constraint for the 1 bytes
> immediate value. It makes sure we use an instruction with 1-byte opcode,
> without REX.R prefix, on x86_64.

No, it doesn't.  That would be "=Q".

	-hpa
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