Spring 2002 CSCI 255 Project 2

This assignment is due Friday, 3 May.

The GCD, greatest common divisor, of two positive numbers N and M is the largest number that divides both N and M. Over 2000 years ago, Euclid described an algorithm for computing the GCD which is similar to the following recursive C function:

int GCD(int N, int M) {
  if (N < M)
    return GCD(M, N) ;
  else if (N == M) 
    return N ;
  else /* N > M */
    return GCD(N-M, M) ;

Your assignment is to write this recursive function in LC/2 using the run-time stack conventions described in Section 14.5 of the textbook. To relieve you of the burden of writing a "driver" function for this routine, a copy of a main routine that (1), inputs two numbers; (2), constructs a run-time stack; (3), calls your function which must be located at instruction at x3000; and (4) prints the result of this call is stored in the file /usr/local/csci/255/proj2/proj2main.asm.

Turning in this assignment

This assignment is to be turned in by copying it to your Computer Science Unix directory. First create a protected directory csci/255/proj2 as shown below:

Then save your completed assembly program in the file proj2.asm within your csci/255/proj2 directory.