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| author | Ben Avison <bavison@riscosopen.org> | 2013-08-05 13:12:49 +0100 |
|---|---|---|
| committer | Martin Storsjö <martin@martin.st> | 2013-08-05 19:25:55 +0300 |
| commit | a22ae9f0c579793f411e2bd7a8db557091a3a4ae (patch) | |
| tree | 9c2c26d112c1860e0db7f915eec99214d950b342 /libavcodec/mathops.h | |
| parent | 43bacd5b7d3d265a77cd29d8abb131057796aecc (diff) | |
| download | ffmpeg-streaming-a22ae9f0c579793f411e2bd7a8db557091a3a4ae.zip ffmpeg-streaming-a22ae9f0c579793f411e2bd7a8db557091a3a4ae.tar.gz | |
mpegts: Remove one 64-bit integer modulus operation per packet
The common case of the pointer having increased by one packet (which results
in no change to the modulus) can be detected with a 64-bit subtraction,
which is far cheaper than a division on many platforms.
Before After
Mean StdDev Mean StdDev Change
Divisions 248.3 8.8 51.5 7.4 +381.7%
Overall 2773.2 25.6 2372.5 43.1 +16.9%
Signed-off-by: Martin Storsjö <martin@martin.st>
Diffstat (limited to 'libavcodec/mathops.h')
| -rw-r--r-- | libavcodec/mathops.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/libavcodec/mathops.h b/libavcodec/mathops.h index 551017e..8a2ce90 100644 --- a/libavcodec/mathops.h +++ b/libavcodec/mathops.h @@ -195,6 +195,15 @@ if ((y) < (x)) {\ # define FASTDIV(a,b) ((uint32_t)((((uint64_t)a) * ff_inverse[b]) >> 32)) #endif /* FASTDIV */ +#ifndef MOD_UNLIKELY +# define MOD_UNLIKELY(modulus, dividend, divisor, prev_dividend) \ + do { \ + if ((prev_dividend) == 0 || (dividend) - (prev_dividend) != (divisor)) \ + (modulus) = (dividend) % (divisor); \ + (prev_dividend) = (dividend); \ + } while (0) +#endif + static inline av_const unsigned int ff_sqrt(unsigned int a) { unsigned int b; |
