Assume that the following code is executed on a five stage pipeline data path: add $5, $2, $1
lw $3, 4($5)
lw $2, 0($2)
or $3, $5, $3
sw $3, 0($5)
and $7, $7, $2

Required:
a. If there is no forwarding and hazard detection unit, insert NOPs in the code to ensure correct operation. How many clock cycles are needed to finish this set of instructions?
b. Repeat part (a) with this assumption that you can change or rearrange the instructions, and the only register that you can use in addition to the above registers is $6. How many clock cycles will you need in this case? What is the speed up compared to part (a).