# euclids.asm
# A MIPS implementation of the Euclidean algorithm
#

	.data
larger:		.word 0
smaller:	.word 0
gcd:		.word 0

	.text
	.globl main
main:
	li	$v0, 5			# Ask the user for the first number (can be smaller/larger)
	syscall

	add	$t0, $zero, $v0

	li	$v0, 5			# than the second number here.
	syscall

	add	$t1, $zero, $v0
	bgt	$t0, $t1, euclids	# If $t0 is greater than $t1, euclids!

	add	$t2, $zero, $t1		# The second number was larger
	add	$t1, $zero, $t0		# so we'll swap them
	add	$t0, $zero, $t2		# but we need another register.

	add	$t2, $zero, $zero	# Reset for cleanliness

	sw	$t0, larger		# I was going to print these numbers at the
	sw	$t1, smaller		# end but I'm.... lazy?

euclids:
	div	$t3, $t0, $t1		# We divide the larger by the smaller
	add	$t0, $zero, $t1		# ... copy the value to $t0
	mfhi 	$t4			# ... store the quotient in $t4
	mflo	$t5			# ... and the remainder in $t5

	add	$t1, $zero, $t4		# $t1 now holds $t4

	beqz	$t4, exit		# This value we just calculate was zero
	sw	$t4, gcd			# we only save here when the value isn't zero

	j	euclids			# repeat Euclid

exit:
	li	$v0, 1			# Print the GCD of (larger,smaller)
	lw	$a0, gcd
	syscall

	li	$v0, 10			# exit()
	syscall