Function _mm_mask_gf2p8affine_epi64_epi8 

pub fn _mm_mask_gf2p8affine_epi64_epi8(
    src: __m128i,
    k: __mmask16,
    x: __m128i,
    a: __m128i,
    const B: i32,
) -> __m128i

Available on x86 and target feature gfni and target feature avx512bw and target feature avx512vl only.

Performs 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.

Uses the writemask in k - elements are copied from src if the corresponding mask bit is not set. Otherwise the computation result is written into the result.

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