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Added idea for SSE2 implementation of findMSB

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This commit is contained in:
Christophe Riccio 2012-09-13 02:14:41 +02:00
parent 69dd0d26b5
commit 56738ee5cb
1 changed files with 18 additions and 0 deletions
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18
glm/core/func_integer.inl
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@ -563,6 +563,24 @@ namespace glm
}
#else
*/
/* SSE implementation idea
__m128i const Zero = _mm_set_epi32( 0, 0, 0, 0);
__m128i const One = _mm_set_epi32( 1, 1, 1, 1);
__m128i Bit = _mm_set_epi32(-1, -1, -1, -1);
__m128i Tmp = _mm_set_epi32(Value, Value, Value, Value);
__m128i Mmi = Zero;
for(int i = 0; i < 32; ++i)
{
__m128i Shilt = _mm_and_si128(_mm_cmpgt_epi32(Tmp, One), One);
Tmp = _mm_srai_epi32(Tmp, One);
Bit = _mm_add_epi32(Bit, _mm_and_si128(Shilt, i));
Mmi = _mm_and_si128(Mmi, One);
}
return Bit;
*/
template <typename genIUType>
GLM_FUNC_QUALIFIER int findMSB
(