[FFmpeg-devel] [RFC] snow SSE2 optimizations

[Luca Barbato]

Reimar Doeffinger wrote:
> Hello,
> On Tue, Aug 28, 2007 at 06:25:46PM +0200, Luca Barbato wrote:
>> Michael Niedermayer wrote:
>>> On Tue, Aug 28, 2007 at 05:10:18PM +0200, Luca Barbato wrote:
>>>> Start guessing why there is just one altivec (across 3 generations of
>>>> cpus) and SPU is still quite similar...
>>>>
>>>> The intel design for instructions set wasn't and isn't the smarter and
>>>> they keep adding irregular changes...
>>> true, but it also isnt the most stupid, sparc-vis beats them by quite a bit
>>> and i dont think a perfectly regular set is a good idea either, because
>>> 90% of the resulting instructions are never used by anyone, but the
>>> cpu must support them, it makes the cpu more complex and slower
>>>
>> Check altivec/vmx or SPU. The instruction set rarely gets annoing and it
>> isn't that big or underfeatured.
> 
> They only forgot to provide a useable way to detect if (or which parts
> of) it is available.
> 

cpuinfo/spufs presence/sigill trick/elf aux table/...

catching sigill is usable last time I checked.

lu

-- 

Luca Barbato

Gentoo/linux Gentoo/PPC
http://dev.gentoo.org/~lu_zero