# main.asm.rb

$gp0 = 0x1F801810
$gp1 = 0x1F801814

# TODO:
# FIND OUT WHAT WE HAVE TO DO TO REGISTER A VSYNC INTERRUPT

jmp l_start
nop

label :hello_world
	string "ello wrld!\n"

label :printf
	addiu r0, 0xa0, at # address of bios func
	jr at
	addiu r0, 0x3f, t1 # printf number

label :draw_line
	# todo: draw line function, take args in a0 - a3
	# tood: implement shift left so we can use that to combine x and y co-ords
	li t0, $gp0

	li t1, 0x40_ffffff # monochrome line, color ffffff
	sw t1, 0, t0

	# lwi st, t1 # line vert 1
	sw t1, 0, t0

	# lwi en, t1 # line vert 2
	sw t1, 0, t0

label :start
	nop ; nop ; nop ; nop

	# THIS IS NEEDED
	li t0, $gp1
	li t1, 0x03_00_00_00 # display enable
	sw t1, 0, t0

	li t0, $gp0

	li t1, 0xe1_000000 + 0b0_0_0_1_0_01_00_0_0000
	sw t1, 0, t0

	# THIS IS NEEDED
	li t1, 0xe4_000000 + (640) + (480 << 10) # Drawing Area bottom right
	sw t1, 0, t0

	def line(st, en)
		li t1, 0x40_ffffff # monochrome line, color ffffff
		sw t1, 0, t0

		li t1, st  # line vert 1
		sw t1, 0, t0

		li t1, en # line vert 2
		sw t1, 0, t0
	end

	line 0x0010_0010, 0x0030_0030
	line 0x0030_0030, 0x0060_0000
	line 0x0060_000a, 0x00f0_0060

	li a0, l_hello_world
	jal l_printf
	addiu sp, -16, sp # delay slot
	addiu sp, 16, sp

label :end_loop
	li t9, l_end_loop
	jr t9
	nop