$2.$ Data Dependencies $(30$ points$)$

Here is a short MIPS assembly language loop. $($This is a simpler version of a very common

operation in scientific applications.$)$ Assume that we run this code on the $5-$stage pipelined

datapath.

Bilbo:

lw $t$1,0($$a$2)$

add $t$2,$ $t$1,$ $a$3$

lw $t$3,0($$a$1)$

sub $t$3,$ $t$3,$ $t$2$

sw $t$3,0($$a$1)$

subi $a$4,$ $a$4,1$

addi $a$2,$ $a$2,8$

addi $a$1,$ $a$1,8$

bne $a$4,$ $zero, Bilbo

Find all data dependencies and RAW hazards in the code. How many stalls do you need to

insert to solve RAW hazards? No forwarding or reordering!