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, and copy the upper 3 packed elements from a to the upper elements.
See Implementation
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, and copy the upper 3 packed elements from a to the upper elements.