Computer Systems Architecture

Read register 1

Read register 2

Write register

Write data

Registers ALU Zero

Read data 1

Read data 2

Sign extend

16 32

Instruction [31–26]

Instruction [25–21]

Instruction [20–16]

Instruction [15–0]

ALU result

M u x

M u x

Shift left 2

Shift left 2

Instruction register

PC 0

1

M u x

0

1

M u x

0

1

M u x

0

1 A

B 0 1 2 3

M u x

0

1

2

ALUOut

Instruction [15–0]

Memory data

register

Address

Write data

Memory MemData

4

Instruction [15–11]

PCWriteCond

PCWrite

IorD

MemRead

MemWrite

MemtoReg

IRWrite

PCSource

ALUOp

ALUSrcB

ALUSrcA

RegWrite

RegDst

26 28

Outputs

Control

Op [5–0]

ALU control

PC [31–28]

Instruction [25-0]

Instruction [5–0]

Jump address [31–0]