SSE loading ints into __m128

问题:

What are the gcc's intrinsic for loading 4 ints into __m128 and 8 ints into __m256 (aligned/unaligned)? What about unsigned ints?

回答1:

Using Intel's SSE intrnisics, the ones you're looking for are:

• _mm_load_si128()
• _mm_loadu_si128()
• _mm256_load_si256()
• _mm256_loadu_si256()

Documentation:

• https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_mm_load_si128
• https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_mm256_load_si256

There's no distinction between signed or unsigned. You'll need to cast the pointer to __m128i* or __m256i*.

---

Note that these are Intel's SSE intrinsics and will work in GCC, Clang, MSVC, and ICC.
The GCC intrinsics work only in, well, GCC AFAIK of.