Returns a vector containing the results of performing a multiply-sum operation using the given vectors.
Elemental function
The result is a vector of the same type as ARG3.
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 in the following way: For p = mn to mn+m-1, multiply element p of ARG1 by element p of ARG2. Add the sum of these products to element n of ARG3. All additions are performed using 32-bit modular arithmetic.