[FFmpeg-devel] Inline ASM vs. Intrinsics

Michael Niedermayer michaelni
Fri May 11 15:44:47 CEST 2007


On Fri, May 11, 2007 at 02:07:38PM +0200, Luca Barbato wrote:
> Michael Niedermayer wrote:
> > 
> > just curious, how would asm make that more difficult?
> altivec intrinsics:
> #include <vmx2spu.h>
> [spu specific way to get data]
> [former altivec code here, unchanged]
> [spu specific way to push data]
> The altivec code would just build for spu thanks to the altivec/vmx ->
> spu mapping header.
> asm :
> reread what you wrote
> rewrite it
> Obviously you could refactor the code to use some spu-only constructs
> you may deem useful, BUT most of the code would remain the very same.

if every altivec instruction has a equivalent SPU instruction then its
more a matter of search and replace then reread and rewrite
if not then the altivec instrinsic code wont work on SPU either at least
not optimally with current gcc

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

it is not once nor twice but times without number that the same ideas make
their appearance in the world. -- Aristotle
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