Function _mm256_mask_roundscale_pd 

pub fn _mm256_mask_roundscale_pd(
    src: __m256d,
    k: __mmask8,
    a: __m256d,
    const IMM8: i32,
) -> __m256d

Available on x86 and target feature avx512f and target feature avx512vl only.

Round packed double-precision (64-bit) floating-point elements in a to the number of fraction bits specified by imm8, and store the results in dst using writemask k (elements are copied from src when the corresponding mask bit is not set).
Rounding is done according to the imm8[2:0] parameter, which can be one of:\

• _MM_FROUND_TO_NEAREST_INT : round to nearest
• _MM_FROUND_TO_NEG_INF : round down
• _MM_FROUND_TO_POS_INF : round up
• _MM_FROUND_TO_ZERO : truncate
• _MM_FROUND_CUR_DIRECTION : use MXCSR.RC - see _MM_SET_ROUNDING_MODE

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