[Ffmpeg-devel] Re: [PATCH] SIMD accelected SNOW decoding

Guillaume POIRIER poirierg
Sun Nov 27 23:11:31 CET 2005


Hi,

On 11/27/05, Guillaume POIRIER <poirierg at gmail.com> wrote:
> Hi there,
>
> I long time ago (6month), yartrebo wrote some 2 routines to speed-up
> SNOW decoding (30-40% faster). It never got committed because neither
> of the 2 were working on AMD64.
>
> 6 month later, I suspect more talented people can look at it.
>
> Find in attachment the work-in-progress patch yartrebo sent me before
> going in summer break (never to return again it seems).
>
> See below for the gdb backtrace of one of the routine (both trigger a
> segfault). Unfortunately, that doesn't give the very line number the
> fails on the ASM (maybe because the program never actually reaches the
> asm be fails to call it?).

Hum, a closer look at the asm shows a series of IA32 style registers,
rather than the use REG_xx which are used throughout the rest of
ffmpeg code. No wonder it could not work! :)

I'll fix that and see what happens.

Guillaume
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