Divide the lower single-precision (32-bit) floating-point element in a by the lower
single-precision (32-bit) floating-point element in b, store the result in the lower
element of result, and copy the upper 3 packed elements from a to the upper elements of result.
Divide the lower single-precision (32-bit) floating-point element in a by the lower single-precision (32-bit) floating-point element in b, store the result in the lower element of result, and copy the upper 3 packed elements from a to the upper elements of result.