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Move ff_sqrt() to libavutil/intmath.h

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Originally committed as revision 22345 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Måns Rullgård
2010-03-08 21:19:56 +00:00
parent d73a458f27
commit 94ca624fbc
9 changed files with 29 additions and 22 deletions
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22
libavutil/intmath.h
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@@ -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 */