pub unsafe fn _mm_mask_cmp_epu64_mask(
    k1: __mmask8,
    a: __m128i,
    b: __m128i,
    const IMM3: _MM_CMPINT_ENUM
) -> __mmask8
🔬 This is a nightly-only experimental API. (stdsimd #48556)
Available on x86 and target feature avx512f,avx512vl only.
Expand description

Compare packed unsigned 64-bit integers in a and b based on the comparison operand specified by imm8, and store the results in mask vector k using zeromask k1 (elements are zeroed out when the corresponding mask bit is not set).

Intel’s documentation