[Ffmpeg-cvslog] r6602 - trunk/libavcodec/cabac.h

Uoti Urpala uoti.urpala
Mon Oct 9 17:20:32 CEST 2006

On Mon, 2006-10-09 at 16:15 +0200, michael wrote:
> first try of a handwritten get_cabac() for x86, this is 10-20% faster on P3 depening on if you try to subtract the START/STOP_TIMER overhead

With -O3, new asm gives about same speed as the C version with redundant
state setting removed. With -O2 it gives about 2% faster overall speed.

Timer results with default -O4:
420 dezicycles in get_cabac, 134149491 runs, 68237 skips

with -O2:
322 dezicycles in get_cabac, 67101846 runs, 7018 skips

The inlined versions with -O4 have extra instructions between rdtsc and
get_cabac asm. The C versions didn't have such differences in timer
results depending on -O2 / -O3.

More information about the ffmpeg-cvslog mailing list