Function vshr_n_s64 

pub fn vshr_n_s64(a: int64x1_t, const N: i32) -> int64x1_t

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

Shift right Arm’s documentation