# exam1ec.asm
# Chris Annis
# sum of even integers from 0 to N

	.text
	.globl	main
main:
	li	$v0,4		# output msg1
	la	$a0, msg1
	syscall
	li	$v0,5		# input N and save
	syscall	
	move	$t0,$v0
	add	$t3,$t0,1	# $t3 = N+1
	add	$t4,$t3,1	# $t4 = N+2

	li	$t1, 0		# initialize counter (i)
	li	$t2, 0		# initialize sum

loop:	add	$t2, $t2, $t1	# sum = sum + i
	addi	$t1, $t1, 2	# i = i + 2
	beq	$t3, $t1, exit  # if i = N+1 
	beq	$t4, $t1, exit	# if i = N+2
	j	loop

exit:	li	$v0, 4		# output msg2
	la	$a0, msg2
	syscall

	li	$v0,1		# output sum
	move	$a0, $t2
	syscall
	li	$v0,4		# output lf
	la	$a0, lf
	syscall
	li	$v0,10		# exit
	syscall
	.data
msg1:	.asciiz	"\nNumber of integers (N)?  "
msg2:	.asciiz	"\nSum  =   "
lf:     .asciiz	"\n"