1. Keyboard Reg Addr LD1 M1 OpCode Reg File 4-bit Reg M U X enable enable WR ER A L U WM 4-bit Reg M U X Mem Unit Mem Addr EM LD2 M2 Enhancing Data Path • We can add a memory and a register file to data path as shown • Data from ALU can be written in reg file, memory, and registers • Data from reg file and mem unit can be selected for register input

2. M- Reg LDM Input Reg Addr LD1 M1 OpCode Reg File 4-bit Reg M U X enable enable enable WR ER A L U WM 4-bit Reg M U X Mem Unit Mem Addr EM LD2 M2 Addition for multiply • For multiplication, we add a shift unit and and M-reg • M-reg can be loaded with output of ALU and copied on bus • Shift unit can shift operand one bit left or right with or without M-register contents

3. M- Reg LDM Input Reg Addr LD1 M1 OpCode Reg File 4-bit Reg M U X enable enable enable WR ER A L U WM 4-bit Reg M U X Mem Unit Mem Addr EM LD2 M2 Complete Block diagram