[Ffmpeg-devel] mmx/sse optimizations

[Guillaume POIRIER]

Hi,

On 12/22/05, Rich Felker <dalias at aerifal.cx> wrote:
> On Thu, Dec 22, 2005 at 10:17:32AM -0800, Mike Melanson wrote:

> >       SIMD code is a different beast than normal ASM. I think this tool
> >       has its place. Perhaps another idea would be a tool that enables the user
> > to describe some kind of general algorithm with a set of SIMD-like
> > primitives. Then the tool decides what the equivalent code would look
> > like using different SIMD sets (MMX, SSE2, AltiVec) AND can output the
> > correct ASM syntax for use in gcc and MSVC.
>
> Hmm, sounds a lot like vector intrinsics. IMO they're a trap that lead
> to people making simd code that's 5-25% slower than handwritten asm.

Well, just like when using high level languages, it's all a matter of
how much dev time your are willing to trade against code speed (and
platform-independent). It's sometimes not worth spending so much time
writing Da Best asm code...

Guillaume
--
Life is pleasant. Death is peaceful. It's the transition that's troublesome.
    Isaac Asimov (1920 - 1992)

MPlayer's doc is offline. Find some fresh one here:
http://tuxrip.free.fr//MPlayer-DOCS-HTML/en/
http://tuxrip.free.fr//MPlayer-DOCS-HTML/fr/