Question: Write micro program to implement the solutions for Problems I, II, and III.
Problems I: Write register transfer sequences for the following new instructions on ASC. Subtract:
SUB MEM ACC ← ACC - M[MEM].
Load immediate:
LDI data ACC ← Data
Assume data are in bits 0 through 7 of the instruction.
Problem II: Write register transfer sequences for the following new instructions: JSR: Subroutine jump; use memory location 0 for storing the return address. RET: Return from subroutine.
Problem III: Write the register transfer sequence needed to implement a multiply instruction on ASC. That is:
MPY MEM ACC ← ACC*M[MEM].
Use the repeated addition of ACC to itself M[MEM] times. Assume that the product fits in one word. List the hardware changes needed (if any).