Function _mm_floor_ss

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

Available on (x86 or x86-64) and target feature sse4.1 and x86 only.

Round the lower single-precision (32-bit) floating-point element in b down to an integer value, store the result as a single-precision floating-point element in the lower element of the intrinsic result, and copies the upper 3 packed elements from a to the upper elements of the intrinsic result.

Intel’s documentation