USE 68K ASSEMBLY

The Russian Peasant method of multiplication computes the product of two unsigned numbers by doubling/halving of the factors. The algorithm is described through the example of multiplying 30 x 25. First, put the factors in two columns. On each iteration double the value in column 1 and divide the value in column 2 by 2. The process terminates when the quotient reaches 1. The product is formed by adding the terms in column 1 whose corresponding term in column 2 is odd. The product of 30 x 25 = 30 + 240 + 480 = 750.

(Apparently, real Russian peasants may have tracked their doublings with bowls of pebble instead of columns of numbers. The ancient Egyptians also invented a similar process thousands of years earlier, and computers are still using related methods today.)

Your task is to write a program that implements the Russian Peasant algorithm to perform unsigned multiplication. Assume the two factors (numbers to be multiplied) are 16-bit values stored in data registers D0 and D1, respectively. When implementing your algorithm do not use the 68000s multiplication or division instructions. Rather, use the (faster) shift instructions when performing multiplication and division by 2.