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libavutil: add bmi2 optimized av_mod_uintp2 

Reviewed-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: James Almer <jamrial@gmail.com>
This commit is contained in:
James Almer 2015-03-18 22:43:33 -03:00
parent d13e521cc8
commit 60b9373dbd
1 changed files with 22 additions and 2 deletions
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24
libavutil/x86/intmath.h
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@ -24,15 +24,35 @@
#include <stdint.h>
#include "config.h"
#if defined(__GNUC__)
/* Our generic version of av_popcount is faster than GCC's built-in on
* CPUs that don't support the popcnt instruction.
*/
#if defined(__GNUC__) && defined(__POPCNT__)
#if defined(__POPCNT__)
#define av_popcount __builtin_popcount
#if ARCH_X86_64
#define av_popcount64 __builtin_popcountll
#endif
#endif /* defined(__GNUC__) && defined(__POPCNT__) */
#endif /* __POPCNT__ */
#if defined(__BMI2__)
#define av_mod_uintp2 av_mod_uintp2_bmi2
static av_always_inline av_const unsigned av_mod_uintp2_bmi2(unsigned a, unsigned p)
{
if (av_builtin_constant_p(p))
return a & ((1 << p) - 1);
else {
unsigned x;
__asm__ ("bzhi %2, %1, %0 \n\t" : "=r"(x) : "rm"(a), "r"(p));
return x;
}
}
#endif /* __BMI2__ */
#endif /* __GNUC__ */
#endif /* AVUTIL_X86_INTMATH_H */