On 24/11/11 12:03, Robert Nagy wrote:
Just scrolling through the prores code. And found a possible minor
optimization. Don't have a setup for compiling right now so I can't measure
the perf diff.
In static inline int decode_vlc_codeword(GetBitContext *gb, uint8_t
codebook)
Replace:
log = 31 - av_log2(buf) /* count prefix bits (zeroes) */
with something like:
#ifdef X86
#define NLZ(x) // use BSR instruction
#else
#define NLZ(x) 31 - av_log2_c(x)
#endif
log = NLZ(buf); /* count prefix bits (zeroes) */
If the compiler doesn't do that for us, might be useful adding a mathop
for it.
lu
--
Luca Barbato
Gentoo/linux
http://dev.gentoo.org/~lu_zero
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