Returns a vector containing the results of performing a sum across 1/4 vector operation on the given vectors.
Elemental function
The result is a vector of the same type as ARG2.
Assume that the elements of each vector are numbered beginning with 0. If ARG1 is an INTEGER(1) vector or an UNSIGNED(1) vector, then let m be 4. Otherwise, let m be 2. For each element n of the result vector, the value is obtained by adding elements mn through mn+m-1 of ARG1 and element n of ARG2 using saturated addition.