Re: [gentoo-dev] Review: desc/cpu_flags_x86.desc

[Michał Górny]

Dnia 2015-01-18, o godz. 15:15:22
Matt Turner <mattst88@g.o> napisał(a):

> On Sun, Jan 18, 2015 at 12:44 PM, Michał Górny <mgorny@g.o> wrote:
> > Hello,
> >
> > I would like to commit the following flags as cpu_flags_x86_desc.
> > The list combines global USE flags with some local USE flags I've been
> > able to find.
> >
> >
> > 3dnow - Use the 3DNow! instruction set
> > 3dnowext - Use the Enhanced 3DNow! instruction set
> > aes-ni - Enable support for Intel's AES instruction set (aes in cpuinfo)
> > avx - Adds support for Advanced Vector Extensions instructions
> > avx2 - Adds support for Advanced Vector Extensions 2 instructions
> > fma - Use the Fused Multiply Add instruction set
>
> There are fma3 and fma4 instruction sets. We need to determine which
> one the packages that have this flag are actually using and name the
> flag appropriately.

Ok then:

fma3 - Use the Fused Multiply Add v3 instruction set
fma4 - Use the Fused Multiply Add v4 instruction set

> > mmx - Use the MMX instruction set
> > mmxext - Use the Extended MMX instruction set (intersection of Enhanced 3DNow! and SSE instruction sets) (3dnowext or sse in cpuinfo)
> > padlock - Use VIA padlock instructions
> > popcnt - Enable popcnt instruction support
> > sse - Use the SSE instruction set
> > sse2 - Use the SSE2 instruction set
> > sse3 - Use the SSE3 instruction set (pni in cpuinfo)
> > sse4 - Enable SSE4 instruction support
>
> We shouldn't have an sse4 USE flag. It's either one of the three
> below, but SSE4 by itself isn't a thing.

Ok. dev-libs/marisa has --enable for all *four* of them :). And some
totally crazy, broken --enable magic which looks very mismatched...

> > sse4_1 - Enable SSE4.1 instruction support
> > sse4_2 - Enable SSE4.2 instruction support
> > sse4a - Enable SSE4a instruction support
> > ssse3 - Use the SSSE3 instruction set

-- 
Best regards,
Michał Górny