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Add compat for __builtin_ctz.

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Win32 seems to have __lzcnt, but not __tzcnt ... <_<
This commit is contained in:
Themaister 2014-02-22 13:29:05 +01:00
parent d896d0f6e4
commit 89cf3de78c
1 changed files with 23 additions and 1 deletions
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24
rewind.c
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@ -149,6 +149,28 @@ static void reassign_bottom(state_manager_t *state)
}
#if __SSE2__
#if defined(__GNUC__)
static inline unsigned compat_ctz(uint32_t v)
{
return __builtin_ctz(v);
}
#else
// Only checks at nibble granularity, because that's what we need.
static inline unsigned compat_ctz(uint32_t v)
{
if (v & 0x000f)
return 0;
if (v & 0x00f0)
return 4;
if (v & 0x0f00)
return 8;
if (v & 0xf000)
return 12;
return 16;
}
#endif
#include <emmintrin.h>
// There's no equivalent in libc, you'd think so ... std::mismatch exists, but it's not optimized at all. :(
static unsigned find_mismatch(const uint32_t *a, const uint32_t *b, unsigned samples)
@ -162,7 +184,7 @@ static unsigned find_mismatch(const uint32_t *a, const uint32_t *b, unsigned sam
__m128i c = _mm_cmpeq_epi32(v0, v1);
uint32_t mask = _mm_movemask_epi8(c);
if (mask != 0xffff) // Something has changed, figure out where.
return i + (__builtin_ctz(~mask) >> 2);
return i + (compat_ctz(~mask) >> 2);
}
for (; i < samples; i++)