# sort for SPIM based on the code in the text.
	
	.data
	.align 0
space:	.asciiz " "
lf:	.asciiz "\n"
before:	.asciiz "Before: "
after:	.asciiz "After: "
prompt:	.asciiz "Enter Number: "
	
	.align 2	
array:	.word 1,2,5,6,9,0,7,8,3,4
		
	.text		# this is program code
	.align 2	# instructions must be on word boundaries
	.globl main	# main is a global label
	
main:	
	la $a0,array	# set up to read in an array of 10 ints
	li $a1,10	# and put them at label array
	jal readarray
	
	li $v0,4	# print a "Before:"
	la $a0,before
	syscall	
	
	la $a0,array	# print out the original array
	li $a1,10
	jal parray
	
	la $a0,array	# set up for call to sort
	li $a1,10
	jal sort	# go sort em

	li $v0,4	# print "After:	"	
	la $a0,after
	syscall

	la $a0,array	# print the array again (now sorted) 
	li $a1,10
	jal parray

	jr $ra
	
	# call the exit system call
	li $v0,10
	syscall


# printarray prints an array of integers
# called with:	
#   $a0 the address of the array
#   $a1 the number of elements in the array
	
parray:
	li $t0,0		# i=0;
	move $t1,$a0		# t1 is pointer to array
pa_loop:	
	beq $t0,$a1,done	# done if i==n

	lw $a0,0($t1)		# get a[i]
	li $v0,1
	syscall			# print one int

	li $v0,4
	la $a0,space
	syscall			# print a space

	addi $t1,$t1,4		# update pointer
	addi $t0,$t0,1		# and count
	j pa_loop
done:
	li $v0,4
	la $a0,lf
	syscall			# print a message

	addi $sp,$sp,4
	jr $ra

#-------------------------------

# readarray reads in an array of integers
# called with:	
#   $a0 the address of the array
#   $a1 the number of elements in the array
	
readarray:
	li $t0,0		# i=0;
	move $t1,$a0		# t1 is pointer to array
ra_loop:	
	beq $t0,$a1,ra_done	# done if i==n

	li $v0,4
	la $a0,prompt
	syscall			# print one int

	li $v0,5
	syscall
	sw $v0,0($t1)

	addi $t1,$t1,4		# update pointer
	addi $t0,$t0,1		# and count
	j ra_loop
ra_done:
	li $v0,4
	la $a0,lf
	syscall			# print a message

	addi $sp,$sp,4
	jr $ra

#-------------------------------


sort:
	addi $sp,$sp,-20
	sw $ra, 16($sp)
	sw $s3, 12($sp)
	sw $s2, 8($sp)
	sw $s1, 4($sp)
	sw $s0, 0($sp)
	
	move $s2,$a0
	move $s3,$a1
	
	move $s0,$zero

for1tst: 
#	move $a0,$s2
#	li $a1,10
#	jal parray
	
	slt $t0,$s0,$s3
	beq $t0,$zero,exit1
	
	addi $s1,$s0,-1
	
for2tst:	
	slti $t0,$s1,0
	bne $t0,$zero,exit2
	
	add $t1,$s1,$s1
	add $t1,$t1,$t1
	add $t2,$s2,$t1
	lw $t3,0($t2)
	lw $t2,4($t2)
	slt $t0,$t2,$t3
	beq $t0,$zero,exit2
	
	move $a0,$s2
	move $a1,$s1
	jal swap
	
	addi $s1,$s1,-1
	j for2tst
exit2:
	addi $s0,$s0,1
	j for1tst

exit1:
	lw $s0, 0($sp)
	lw $s1, 4($sp)	
	lw $s2, 8($sp)
	lw $s3, 12($sp)
	lw $ra, 16($sp)
	addi $sp,$sp,20

	jr $ra



swap:
	add $t1,$a1,$a1
	add $t1,$t1,$t1
	add $t1,$a0,$t1

	lw $t0,0($t1)
	lw $t2,4($t1)

	sw $t2,0($t1)
	sw $t0,4($t1)

	jr $ra