Function vshrn_n_s64 

pub fn vshrn_n_s64(a: int64x2_t, const N: i32) -> int32x2_t

Available on (AArch64 or ARM64EC) and (AArch64 or ARM64EC or target feature v7) and (ARM or AArch64 or ARM64EC) and target feature neon only.

Shift right narrow Arm’s documentation