Function vrsubhn_s64 

pub fn vrsubhn_s64(a: int64x2_t, b: int64x2_t) -> int32x2_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.

Rounding subtract returning high narrow Arm’s documentation