[FFmpeg-devel] [PATCH] h264_i386: Optimize decode_significance_8x8_x86 for 64 bit.

Michael Niedermayer michaelni at gmx.at
Mon Nov 17 13:41:13 CET 2014

On Mon, Nov 17, 2014 at 08:19:32AM +0100, Reimar Döffinger wrote:
> On 17.11.2014, at 02:37, Michael Niedermayer <michaelni at gmx.at> wrote:
> > On Sat, Nov 15, 2014 at 06:16:03PM +0100, Reimar Döffinger wrote:
> >> 11674 -> 10877 decicycles on my Phenom II.
> >> Overall speedup was unfortunately within measurement error.
> > 
> > here its  10153 ->10135
> I suspect it also depends a bit on the compiler and how it changes the surrounding code.
> Note that I also tested with PIC actually.
> > but ive a slightly odd feeling about the chnages to the asm code,
> > iam not sure if all assemblers will be happy about the changed
> > code
> Do you mean particularly the movzbl change?

yes and the k stuff

> I am also unsure about that, I think there was a reason for that %k6 mess...
> But this as well as movzx seemed to work for me...

it works here too i just have the feeling it might fail on some odd
assembler or platform. Thats not meant to keep you from pushing this
just that it might require to be reverted or fixed if such
problems actually occor

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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