# Program to read numbers until a zero, printing each in hexadecimal
	.data
	.align 2
ret:	.word	0	# space for return address
s:	.space 8
	.asciiz	"\n"
tr:	.ascii	"0123456789ABCDEF"
        .text                   # Code
        .align  2
        .globl  main
main:	sw	$ra,ret		# save return address
ml1:	li	$v0,5		# code to read number
	syscall			#
	beq	$v0,$0,exit	# if number is 0, exit
	move	$a0,$v0		# copy number to arg register
	jal	itohex		# convert to hex in s[]
	la	$a0,s		# prepare to print s[]
	li	$v0,4		# code to print string
	syscall			# print the string
	b	ml1		# repeat

exit:	move	$v0,$0		# zero exit status
	lw	$ra,ret		# restore return address
	jr	$ra		# return from main

itohex:	la	$t2,s		# $t2 = &s[0] (used as end test)
	add	$t0,$t2,7	# $t0 = &s[7] (k)
loop:	andi	$t1,$a0,0xF	# $t1 = I & 0xF
	lb	$t1,tr($t1)	# $t1 = tr[I&0xF]
	sb	$t1,0($t0)	# s[k] = $t1
	srl	$a0,$a0,4	# I = I >> 4
	addi	$t0,$t0,-1	# k--
	bge	$t0,$t2,loop	# -->loop if k>=0
	jr 	$ra		# return