Question

1.Please use 5-stage pipeline to describe following MIPS assembly code in non-forwarding pipeline.

lw         $s0,      0($t0)

add        $s1,      $s0, $s0

mul       $s2,      $s1, $s0

. 2.Please use 5-stage pipeline to describe following MIPS assembly code in forwarding pipeline.

lw         $s0,      0($t0)

add        $s1,      $s0, $s0

mul       $s2,      $s1, $s0

sw         $s2,      4($t0)

Answer 1

1.

	1	2	3	4	5	6	7	8	9	10	11
Inst 1	IF	ID	EX	MEM	WB
Inst 2		IF	ID	STALL	STALL	EX	MEM	WB
inst 3			IF	STALL	STALL	ID	STALL	STALL	EX	MEM	WB

2.

	1	2	3	4	5	6	7	8
Inst 1	IF	ID	EX	MEM	WB
Inst 2		IF	ID	EX	MEM	WB
Inst 3			IF	ID	EX	MEM	WB
Inst 4				IF	ID	EX	MEM	WB