[FFmpeg-devel] [PATCH 4/7] x86: sbrdsp: implement SSE hf_apply_noise

Michael Niedermayer michaelni at gmx.at
Sun Apr 7 13:53:18 CEST 2013


On Sun, Apr 07, 2013 at 12:25:13PM +0200, Christophe Gisquet wrote:
> 2013/4/6 Michael Niedermayer <michaelni at gmx.at>:
[...]
> > it might make sense to do something in some header with a macro
> > maybe so that punpckl/dq get turned into unpck* on SSE1
> 
> Like mova/movh for instance, as the isns are indeed completely similar.
> 
> Jason and Loren suggest using and upgrading SBUTTERFLY. But:
> 1) There may be cases where we still want to use those unpck for something else
> 2) pxor/xorps  could also to be considered (pshufd/shufps are very
> similar but probably not enough to go through this
> 
> Regarding SBUTTERFLY, the AVX1 _f128 version would need to be integrated.
> 
> But here the noise table addressing wraps around so I think, to use
> ymm, it would require unrolling the function to handle this. There I'd

iam not sure i understand the problem you describe but the noise table
can just be extended by a few elements copied from the begin to avoid
having to deal with wrap around where its inconvenient


> prefer to focus on xmm versions and leave ymm to someone that really
> wants to write an avx version and test it (eg for gsoc/whatever).
> 
> --
> Christophe
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-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

There will always be a question for which you do not know the correct answer.
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