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我想写一个网点位select
功能打包SSE2双打:优化网点条件选择包装双打
#include <iostream>
#include <emmintrin.h>
inline __m128d select(bool expression, const __m128d& x, const __m128d& y)
{
const int conditional_mask = expression ? -1 : 0;
const auto mask = _mm_castsi128_pd(_mm_set_epi64x(conditional_mask, conditional_mask));
return _mm_or_pd(_mm_and_pd(mask, x), _mm_andnot_pd(mask, y));
}
int main()
{
auto r1 = _mm_setr_pd(1, 2);
auto r2 = _mm_setr_pd(5, 6);
auto result = select(true, r1, r2);
auto packed = reinterpret_cast<double*>(&result);
std::cout << "result = " << packed[0] << ", " << packed[1] << std::endl;
std::getchar();
return EXIT_SUCCESS;
}
是否有SSE2和SSE4一个简单的方法,这将是更优化64?
我可以证实这个作品,好电话:-) – keith