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| author | Måns Rullgård <mans@mansr.com> | 2010-03-08 21:19:56 +0000 |
|---|---|---|
| committer | Måns Rullgård <mans@mansr.com> | 2010-03-08 21:19:56 +0000 |
| commit | 94ca624fbcaf0cd3e03ff3529453fd7a8af2c5ed (patch) | |
| tree | ed6f445cfc0be488f83891b337292c01821b914c /libavutil/intmath.h | |
| parent | d73a458f279f1918a08d06b0dd43a798a71b2f74 (diff) | |
| download | ffmpeg-94ca624fbcaf0cd3e03ff3529453fd7a8af2c5ed.tar.gz | |
Move ff_sqrt() to libavutil/intmath.h
Originally committed as revision 22345 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavutil/intmath.h')
| -rw-r--r-- | libavutil/intmath.h | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/libavutil/intmath.h b/libavutil/intmath.h index 7aff78ceb1..02870cb282 100644 --- a/libavutil/intmath.h +++ b/libavutil/intmath.h @@ -56,4 +56,26 @@ extern const uint32_t ff_inverse[257]; #endif /* FASTDIV */ +extern const uint8_t ff_sqrt_tab[256]; + +static inline av_const unsigned int ff_sqrt(unsigned int a) +{ + unsigned int b; + + if (a < 255) return (ff_sqrt_tab[a + 1] - 1) >> 4; + else if (a < (1 << 12)) b = ff_sqrt_tab[a >> 4] >> 2; +#if !CONFIG_SMALL + else if (a < (1 << 14)) b = ff_sqrt_tab[a >> 6] >> 1; + else if (a < (1 << 16)) b = ff_sqrt_tab[a >> 8] ; +#endif + else { + int s = av_log2_16bit(a >> 16) >> 1; + unsigned int c = a >> (s + 2); + b = ff_sqrt_tab[c >> (s + 8)]; + b = FASTDIV(c,b) + (b << s); + } + + return b - (a < b * b); +} + #endif /* AVUTIL_INTMATH_H */ |