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slight optimization of SSE base integer mul (thanks to Rohit Garg)

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This commit is contained in:
Gael Guennebaud
2009-03-08 10:14:07 +00:00
parent f9790a649c
commit 7718a8ed83
2 changed files with 26 additions and 18 deletions
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27
Eigen/src/Core/arch/SSE/PacketMath.h
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@@ -29,6 +29,18 @@
#define EIGEN_CACHEFRIENDLY_PRODUCT_THRESHOLD 16
#endif
#define ei_vec4f_swizzle1(v,p,q,r,s) \
(_mm_castsi128_ps(_mm_shuffle_epi32( _mm_castps_si128(v), ((s)<<6|(r)<<4|(q)<<2|(p)))))
#define ei_vec4i_swizzle1(v,p,q,r,s) \
(_mm_shuffle_epi32( v, ((s)<<6|(r)<<4|(q)<<2|(p))))
#define ei_vec4f_swizzle2(a,b,p,q,r,s) \
(_mm_shuffle_ps( (a), (b), ((s)<<6|(r)<<4|(q)<<2|(p))))
#define ei_vec4i_swizzle2(a,b,p,q,r,s) \
(_mm_castps_si128( (_mm_shuffle_ps( _mm_castsi128_ps(a), _mm_castsi128_ps(b), ((s)<<6|(r)<<4|(q)<<2|(p))))))
template<> struct ei_packet_traits<float> { typedef __m128 type; enum {size=4}; };
template<> struct ei_packet_traits<double> { typedef __m128d type; enum {size=2}; };
template<> struct ei_packet_traits<int> { typedef __m128i type; enum {size=4}; };
@@ -54,14 +66,13 @@ template<> EIGEN_STRONG_INLINE __m128d ei_pmul<__m128d>(const __m128d& a, const
template<> EIGEN_STRONG_INLINE __m128i ei_pmul<__m128i>(const __m128i& a, const __m128i& b)
{
// this version is very slightly faster than 4 scalar products
return _mm_or_si128(
_mm_and_si128(
_mm_mul_epu32(a,b),
_mm_setr_epi32(0xffffffff,0,0xffffffff,0)),
_mm_slli_si128(
_mm_and_si128(
_mm_mul_epu32(_mm_srli_si128(a,4),_mm_srli_si128(b,4)),
_mm_setr_epi32(0xffffffff,0,0xffffffff,0)), 4));
return ei_vec4i_swizzle1(
ei_vec4i_swizzle2(
_mm_mul_epu32(a,b),
_mm_mul_epu32(ei_vec4i_swizzle1(a,1,0,3,2),
ei_vec4i_swizzle1(b,1,0,3,2)),
0,2,0,2),
0,2,1,3);
}
template<> EIGEN_STRONG_INLINE __m128 ei_pdiv<__m128>(const __m128& a, const __m128& b) { return _mm_div_ps(a,b); }