Function vext_f16 

pub fn vext_f16(a: float16x4_t, b: float16x4_t, const N: i32) -> float16x4_t

Available on (AArch64 or target_arch=arm64ec) and non-target_arch=arm64ec and target feature neon and target feature fp16 only.

Extract vector from pair of vectors Arm’s documentation