#---------------------------------
# Lab 5 Exercise 2: Pixel Conversion
#
# Name: <YOUR-NAME-HERE>
# Onyen: <YOUR-ONYEN-HERE>
#
# --------------------------------
# Below is the expected output.
# 
# Converting pixels to grayscale:
# 0
# 1
# 2
# 34
# 5
# 67
# 89
# Finished.
# -- program is finished running --
#---------------------------------

.data
	startString:	.asciiz	"Converting pixels to grayscale:\n"
	finishString:	.asciiz	"Finished."
	newline:		.asciiz	"\n"
	pixels:			.word 	0x00010000,	0x010101,	0x6,		0x3333, 
							0x030c,		0x700853,	0x294999,	-1

.text

main:
	li $v0, 4			#System call code for print_str
	la $a0, startString 		#address of string to print 
	syscall				#print the string

	li $t3, 3
	la $t0, pixels

loop:
	lw $t1, 0($t0)
	bltz $t1, exit
	andi $t4, $t1, 0x00ff
	srl $t1, $t1, 8
	andi $t5, $t1, 0x00ff
	srl $t1, $t1, 8
	andi $t6, $t1, 0x00ff 		#unnecessary, but to be safe

	add $t7, $t4, $t5
	add $t7, $t7, $t6

	div $t7, $t3 			#quotient is in "lo"

	li $v0, 1			#System call code for print_int
	mflo $a0 	 		#address of string to print 
	syscall				#print the string

	li $v0, 4			#System call code for print_str
	la $a0, newline		 	#address of string to print 
	syscall				#print the string

	addi $t0, $t0, 4

	j loop

exit:
	li $v0, 4			#System call code for print_str
	la $a0, finishString 		#address of string to print 
	syscall				#print the string

	li   $v0, 10			#System call code for exit
	syscall				#exit the program