Question

Assume the processor executes the following instruction sequence.

and $t1, $t4, $t5

and $t4, $t1, $t3

add $t1, $t1, $t4

beq $t1, $t3, BranchTo

Assume there is full forwarding (from EX/MEM register and from MEM/WB register). Indicate remaining hazards and insert nop instructions to eliminate them.

Answer 1

using Full Forwarding .

I1:and $t1, $t4, $t5
I2:and $t4, $t1, $t3
I3:add $t1, $t1, $t4
I4:beq $t1, $t3, BranchTo

value of register $t1 is forwarded from instruction I1 to I2 (Resolving hazard using Forwarding)
value of register $t1 is forwarded from instruction I1 to I3 and value of register $t4 is forwarded from instruction I2 to I3(Resolving hazards using Forwarding)
value of register $t1 is forwarded from instruction I3 to I4 (Resolving hazard using Forwarding)

There is No any remaining Hazard.
No nop instruction needed