Consider the following loop.

LOOP: LDUR X$10,[$X$1,$ #$0]$

LDUR X$11,[$X$1,$ #$8]$

ADD X$12,$ X$10,$ X$11$

STUR X$12,[$X$1,$ #$-8]$

SUBI X$1,$ X$1,$ #$16$

CBNZ X$12,$ LOOP

$($a$)$ Assume that data and control hazards are handled by simply stalling the pipeline $($i$.$e$.$ inserting NOP instructions where necessary$).$ Show the pipeline timing diagram of the code execution.

Cycle number:

$1$

$2$

$3$

$4$

$5$

$6$

$7$

$8$

$9$

$10$

$11$

$12$

$13$

$14$

$15$

$16$

$17$

$18$

$19$

$20$

LOOP: LDUR X$10,[$X$1,$ #$0]$

IF

ID

EX

ME

WB

LDUR X$11,[$X$1,$ #$8]$

IF

ADD X$12,$ X$10,$ X$11$

STUR X$12,[$X$1,$ #$-8]$

SUBI X$1,$ X$1,$ #$16$

CBNZ X$12,$ LOOP

$2$nd iteration: LDUR X$10,[$X$1,$ #$0]$

$($b$)$ Can you reorder the code to reduce the number of stalls? If yes, show the reordered code.

$($c$)$ Show the pipeline timing diagram of the code execution with data forwarding and assume that the branch is handled by predicting it as taken and the branch target address