68K ASSEMBLY LANGUAGE PROBLEM: please help!

3. Write a subroutine, NOT A PROGRAM, in 68K Assembly language, which will fill a block of memory with a pattern of bytes. The following parameters define the interface to the subroutine: The fill pattern is passed in in register DO The beginning address in memory is passed in register AO The ending address is passed in register Al It is assumed that A0, Aland DO may be modified by the subroutine, but any other register that is needed must be saved and restored. It is assumed that the addresses will be supplied in longword format and that the value in Al is at least 1 byte larger than the value in A. No values are returned by the subroutine 3. Write a subroutine, NOT A PROGRAM, in 68K Assembly language, which will fill a block of memory with a pattern of bytes. The following parameters define the interface to the subroutine: The fill pattern is passed in in register DO The beginning address in memory is passed in register AO The ending address is passed in register Al It is assumed that A0, Aland DO may be modified by the subroutine, but any other register that is needed must be saved and restored. It is assumed that the addresses will be supplied in longword format and that the value in Al is at least 1 byte larger than the value in A. No values are returned by the subroutine