[FFmpeg-devel] [HACK] 50% faster H.264 decoding
Mon Aug 23 07:39:59 CEST 2010
On Sun, Aug 22, 2010 at 8:31 PM, Luca Barbato <lu_zero at gentoo.org> wrote:
> On 08/23/2010 01:26 AM, Jason Garrett-Glaser wrote:
>>> ASM optimizations are single target and could be outright wrong when
>>> recycled (e.g x86 vs amd64).
>> You have no idea how the yasm abstraction layer works and should stop
>> posting about things you aren't familiar with.
> Point me something, I'll be glad to learn. I'm not sure you are that
> familiar with link time optimizations as well.
> Having "abstration layers" (macro to rename registers and instruction
> alias?) still doesn't change the fact that asm is closer to the cpu and
> when you write it you expect it to behaves is a way that is right for
> the target cpu. If the instruction costs, load delay and such change a
> different implementation of the same arch, isn't just a matter of
> recompiling with a compiler aware of it: you have to rewrite at least
> part of your asm in order to have it perform equally well.
How in the world would instrinsics solve that problem? There is no
compiler in the world that will magically rewrite your algorithm to
use completely different instructions on a given architecture.
More information about the ffmpeg-devel