a) Write an MC68000 subroutine MUL_SUB and a macro MUL_MAC that implement unsigned multiplication of two 16 bit numbers without using the mulu or muls instruction (for example, use multiple additions to implement multiplication). For the subroutine, pass parameters using data registers.

b) Write an MC68000 assembly program that reads two 16-bit numbers stored at memory locations X and Y, calls MUL_SUB and MUL_MAC and compares both results, then based on the outcome of the comparison displays a message: CORRECT or INCORRECT on the screen.