/* Midterm practice #1.  Implement the following function according to
 * the specification.  Follow the C-assembly interface conventions of
 * the lab's compiler and assembler.
 *
 * In:  summands - an array of long signed numbers
 *      n - the number of elements in summands
 *      sump - a pointer to where the sum should be stored
 * Out: -1 - indicates that an overflow occurred
 *       0 - indicates that the operation completed successfully
 * Computes the sum of the n summands and stores it at the address
 * pointed to by sump.
 */
short sum(long * summands, unsigned short n, long * sump);