top:	JSR clear_lcd
read:	JSR read_a
	BEQ top
	TAY
	AND #1
	BNE show_c
	TYA
	AND #2
	BNE show_b
	TYA
	AND #4
	BEQ read
	LDA #4
	JSR display_image
	JMP read
show_b:
	LDA #2
	JSR display_image
	JMP read
show_c:
	LDA #0
	JSR display_image
	JMP read
here:	JMP here