Returns a vector containing the results of performing a sum across 1/2 vector operation on the given vectors.
Elemental function
The result is of the same type as ARG1.
The first and third element of the result are 0. The second element of the result contains the saturated sum of the first and second elements of ARG1 and the second element of ARG2. The fourth element of the result contains the saturated sum of the third and fourth elements of ARG1 and the fourth element of ARG2.