Function _mm256_gf2p8affine_epi64_epi8
#[target_feature(enable = "gfni", enable = "avx")]
pub fn _mm256_gf2p8affine_epi64_epi8(x: __m256i, a: __m256i, B: i32) -> __m256iPerforms an affine transformation on the packed bytes in x. That is computes a*x+b over the Galois Field 2^8 for each packed byte with a being a 8x8 bit matrix and b being a constant 8-bit immediate value. Each pack of 8 bytes in x is paired with the 64-bit word at the same position in a.