Function _mm512_extractf64x4_pd

#[target_feature(enable = "avx512f")]
pub const fn _mm512_extractf64x4_pd(a: __m512d, IMM8: i32) -> __m256d

Extract 256 bits (composed of 4 packed double-precision (64-bit) floating-point elements) from a, selected with imm8, and store the result in dst.

Intel's documentation