Recursive Factorial of an integer in MIPS assembly

MIPSfactorial.asm

.data
	n: .word 5
	result: .asciiz "Fact(x) = "
	
.text
.globl main

	main:
		lw $a0, n		#$a0 = n
		jal verifier
			
		#print the result
		li $v0, 4
		la $a0, result  #prints the string: "Fact(x) = "
		syscall 
		
		li $v0, 1
		mflo $a0	#$a0 = $lo = result of the factorial
		syscall
		
		#return 0
		li $v0, 10
		syscall
	
	verifier:
		slti $t0, $a0, 1			#if($a0<1), then $t0=1 
		beq $t0, $zero, factorial	#if($a0 >= 1) goto factorial
		addi $v0, $zero, 1			#$v0 = 1
			jr $ra
	
	factorial:
		addi $sp, $sp, -8			#allocate space on stack
		sw $ra, 0($sp)
		sw $s0, 4($sp)
		
		add $s0, $a0, $zero 		#$s0 = $a0 = n
		addi $a0, $a0, -1			#$a0--
			jal verifier			# $v0 = factorial(n-1)
		mult $s0, $v0				#$lo = n*factorial(n-1)
		mflo $v0					#$v0 = $lo
		
		lw $s0, 4($sp)
		lw $ra, 0($sp)
		addi $sp, $sp, 8			#deallocate space on stack
			jr $ra