I would like to combine two __m128
values to one __m256
.
Something like this:
__m128 a = _mm_set_ps(1, 2, 3, 4);
__m128 b = _mm_set_ps(5, 6, 7, 8);
to something like:
__m256 c = { 1, 2, 3, 4, 5, 6, 7, 8 };
are there any intrinsics that I can use to do this?
This should do what you want:
__m128 a = _mm_set_ps(1,2,3,4);
__m128 b = _mm_set_ps(5,6,7,8);
__m256 c = _mm256_castps128_ps256(a);
c = _mm256_insertf128_ps(c,b,1);
If the order is reversed from what you want, then just switch a
and b
.
The intrinsic of interest is _mm256_insertf128_ps
which will let you insert a 128-bit register into either lower or upper half of a 256-bit AVX register:
The complete family of them is here: