Function vdup_lane_s16 

pub fn vdup_lane_s16(a: int16x4_t, const N: i32) -> int16x4_t

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

Set all vector lanes to the same value Arm’s documentation