# Function core::arch::x86::_mm256_mask_gf2p8affineinv_epi64_epi8 [−][src]

`pub unsafe fn _mm256_mask_gf2p8affineinv_epi64_epi8<const B: i32>(`

src: __m256i,

k: __mmask32,

x: __m256i,

a: __m256i

) -> __m256i

This is supported on

**x86 and target feature**only.`avx512gfni,avx512bw,avx512vl`

## 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.

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.