Function _mm_move_ss

pub unsafe fn _mm_move_ss(a: __m128, b: __m128) -> __m128

Available on (x86 or x86-64) and target feature sse and x86 only.

Returns a __m128 with the first component from b and the remaining components from a.

In other words for any a and b:

_mm_move_ss(a, b) == a.replace(0, b.extract(0))

Intel’s documentation