68K Assembly Language Problem

Thanks in advance :)

Write a 68000 assembly subroutine (not a main program!!) that will scan memory locations from the address in A2 through the address in A3 and count how many bytes contain the number $4A. You can use data registers and address registers as needed, but your subroutine should finish by placing the total number of bytes containing the number $4A into register DO as a longword, then returning to the main program. Assume that the contents of A3 is a larger number than the contents of A2