CS536 Homework 9 Solution

Question 1:

Assuming that the parameters are pushed onto the stack before the function is called. Parameter a is at 4($fp) and b at 8($fp). 

.text
func:
	# Prologue
	sw    $ra, 0($sp)	#PUSH
	subu  $sp, $sp, 4
	sw    $fp, 0($sp)	#PUSH
	subu  $sp, $sp, 4
	addu  $fp, $sp, 8

	# FUNCTION BODY
	## WHILESTMT
.L0:
	lw    $t0, 4($fp)
	sw    $t0, 0($sp)	#PUSH
	subu  $sp, $sp, 4
	lw    $t0, 8($fp)
	sw    $t0, 0($sp)	#PUSH
	subu  $sp, $sp, 4
	lw    $t1, 4($sp)	#POP
	addu  $sp, $sp, 4
	lw    $t0, 4($sp)	#POP
	addu  $sp, $sp, 4
	blt   $t0, $t1, .L2
	j     .L1
.L2:
	#ASSIGN
	lw    $t0, 4($fp)
	sw    $t0, 0($sp)	#PUSH
	subu  $sp, $sp, 4
	li    $t0, 2
	sw    $t0, 0($sp)	#PUSH
	subu  $sp, $sp, 4
	lw    $t1, 4($sp)	#POP
	addu  $sp, $sp, 4
	lw    $t0, 4($sp)	#POP
	addu  $sp, $sp, 4
	mult  $t0, $t1
	mflo  $t0
	sw    $t0, 0($sp)	#PUSH
	subu  $sp, $sp, 4
	la    $t0, 4($fp)
	sw    $t0, 0($sp)	#PUSH
	subu  $sp, $sp, 4
	lw    $t1, 4($sp)	#POP
	addu  $sp, $sp, 4
	lw    $t0, 4($sp)	#POP
	addu  $sp, $sp, 4
	sw    $t0, 0($t1)
	j     .L0
.L1:		# Loop successor
	#RETURN
	lw    $t0, 4($fp)
	sw    $t0, 0($sp)	#PUSH
	subu  $sp, $sp, 4
	lw    $v0, 4($sp)	#POP
	addu  $sp, $sp, 4
	j     _func_Exit

_func_Exit:
	# Epilogue
	lw    $ra, 0($fp)
	move  $t0, $fp		#save control link
	lw    $fp, -4($fp)	#restore FP
	move  $sp, $t0		#restore SP
	jr    $ra

Question 2:

if ((a * b) > (a + b)) {
	c = (a * b) / (a + b);
}
else {
	c = (a + b) / (a * b);
}