.text
	# do fact(3)	
	li	$a0,3
	jal	fact

	# print the return value (the result of factorial)	
	add	$a0,$v0,$0
	li	$v0,1
	syscall
	
	# exit the program
	li	$v0,10
	syscall

fact:
	# push activation frame
	addi	$sp,$sp,-8	
	sw	$s0,0($sp)
	sw	$ra,4($sp)
	# set $v0 to 1 in case we have N==0
	li	$v0,1
	# save copy of argument N
	add	$s0,$a0,$0
	
	# test for fact(0)
	beq	$a0,$0,fact_exit
	
	# call fact(N-1)
	addi	$a0,$a0,-1
	jal	fact
	# multiply fact(N-1)*N
	mul	$v0,$s0,$v0
	
fact_exit:
	# pop activation frame
	lw	$s0,0($sp)
	lw	$ra,4($sp)
	addi	$sp,$sp,8
	jr	$ra