Function _mm512_mask_cvtsepi64_storeu_epi8
#[target_feature(enable = "avx512f")]
pub unsafe fn _mm512_mask_cvtsepi64_storeu_epi8(mem_addr: *mut i8, k: __mmask8, a: __m512i)Convert packed signed 64-bit integers in a to packed 8-bit integers with signed saturation, and store the active results (those with their respective bit set in writemask k) to unaligned memory at base_addr.