# Function core::arch::x86::_mm256_gf2p8affineinv_epi64_epi8

source ·

    pub unsafe fn _mm256_gf2p8affineinv_epi64_epi8(
        x: __m256i,
        a: __m256i,
        const B: i32,
    ) -> __m256i

🔬This is a nightly-only experimental API. (`stdarch_x86_avx512` #111137)
Available on (x86 or x86-64) and target feature `gfni,avx` and x86 only.
Expand description

Performs an affine transformation on the inverted packed bytes in x. That is computes a*inv(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. The inverse of a byte is defined with respect to the reduction polynomial x^8+x^4+x^3+x+1. The inverse of 0 is 0. Each pack of 8 bytes in x is paired with the 64-bit word at the same position in a.

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