diff options
| author | Ganesh Ajjanagadde <gajjanagadde@gmail.com> | 2017-02-22 12:53:33 -0500 |
|---|---|---|
| committer | Vittorio Giovara <vittorio.giovara@gmail.com> | 2017-03-01 11:23:19 -0500 |
| commit | 7bfda7d157eb6f7a2df908addd60221a7a6f5eb0 (patch) | |
| tree | db02192c17a61a82f3948c200090d51c899cb42d /libavutil | |
| parent | 5ff3b5cafcc685b6936d16602b0f80aa09a95870 (diff) | |
intmath: add faster clz support
Diffstat (limited to 'libavutil')
| -rw-r--r-- | libavutil/intmath.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/libavutil/intmath.h b/libavutil/intmath.h index a5ee6525ee..780bbab039 100644 --- a/libavutil/intmath.h +++ b/libavutil/intmath.h @@ -44,6 +44,10 @@ # endif #endif /* ff_log2 */ +#ifndef ff_clz +# define ff_clz(v) __builtin_clz(v) +#endif /* ff_clz */ + #endif /* AV_GCC_VERSION_AT_LEAST(3,4) */ extern const uint8_t ff_log2_tab[256]; @@ -132,6 +136,21 @@ static av_always_inline av_const int ff_ctz_c(int v) } #endif +#ifndef ff_clz +#define ff_clz ff_clz_c +static av_always_inline av_const unsigned ff_clz_c(unsigned x) +{ + unsigned i = sizeof(x) * 8; + + while (x) { + x >>= 1; + i--; + } + + return i; +} +#endif + /** * Trailing zero bit count. * |