sse

问题 I need to horizontally add a __m128i that is 16 x epi8 values. The XOP instructions would make this trivial, but I don't have those available. Current method is: hd = _mm_hadd_epi16(_mm_cvtepi8_epi16(sum), _mm_cvtepi8_epi16(_mm_shuffle_epi8(sum, swap))); hd = _mm_hadd_epi16(hd, hd); hd = _mm_hadd_epi16(hd, hd); Is there a better way with up to SSE4.1? 回答1: You can do it with SSE2's _mm_sad_epu8 (psadbw), e.g.: inline uint32_t _mm_sum_epu8(const __m128i v) { __m128i vsum = _mm_sad_epu8(v, _mm

问题 One of the purposes of the C1 bit in the x87 FPU status word is to show whether or not an inexact result was rounded up. Does SSE/AVX provide any such indication for scalar operations? I did not see a similar bit in the MXCSR register. Am I forced to use x87 instructions if I want this information? 回答1: SSE/AVX do not provide hardware support for detecting this, even for scalar instructions like addss . SSE was designed for SIMD, with 4 floats per XMM vector, and presumably Intel didn't want

来源： https://stackoverflow.com/questions/48971804/how-to-compute-sincos-fast-on-a-x64-cpu

来源： https://stackoverflow.com/questions/14014622/xmm-instructions-segmentation-fault-with-memory-source-operand

来源： https://stackoverflow.com/questions/57313195/inline-assembly-code-to-read-write-xmm-ymm-registers

来源： https://stackoverflow.com/questions/57313195/inline-assembly-code-to-read-write-xmm-ymm-registers

来源： https://stackoverflow.com/questions/31466848/avx-256-bit-code-performing-slightly-worse-than-equivalent-128-bit-ssse3-code

来源： https://stackoverflow.com/questions/31466848/avx-256-bit-code-performing-slightly-worse-than-equivalent-128-bit-ssse3-code

来源： https://stackoverflow.com/questions/63248047/how-to-optimise-this-8-bit-positional-popcount-using-assembly

来源： https://stackoverflow.com/questions/63248047/how-to-optimise-this-8-bit-positional-popcount-using-assembly