; get some chip specific definitions like the special names for ports

.include "C:\Program Files\Atmel\AVR Tools\AvrAssembler\Appnotes\m16def.inc"



.CSEG

.org 0



main:

	push 	r16 ; just a dummy to fix a bug in the simulator





	; initialize the registers prior to use

	; and explain what they'll be used for.



	; setup the ports for output



mainLoop:

	; figure out what you're going to display and then display

	; it.  Note that in here would be a good place for a function

	; call to your decode table.  Remember, when you access your 

	; jump table, you'll need to pass parameters via registers

	

	; now we need to delay, you'll probably need to use several

	; nested loops

	

	jmp mainLoop



	



;; Jump Table

.cseg

.org [base adress for jump table]

	; insert instructions

	jmp whereToReturnFromJumpTable

	; insert instructions

	jmp whereToReturnFromJumpTable

	; insert instructions

	jmp whereToReturnFromJumpTable

	; etc

;______________________________________
; Sample function call from class:
;______________________________________
decodeValue:
	;;  takes the nibble that's in r16 and outputs the
	;;  decoded value back in r16. 

	; we're going to use the Z register (r31:r30) so we need
	; to save the value there in case the caller is expecting
	; it to be saved
	push 	r31
	push 	r30

	andi 	r16, 0x0f 	; mask off just the bits I want from r16 to make sure I don't
						; jump to somewhere that's not in the table
;	lsl		r16			; I need to multiply the value by 2 (if icall)

	ldi		r31, 04		; load the jump adress into the Z register (r31:r30)
	mov		r30, r16    

	icall				; make the jump into the jump table
	;**OR**:
	lpm		r16,Z       ; Load constant from program

	; at this point, I should have the return value in r16 so all that is left 
	; to do is restore the values in the Z register and return
	pop		r30
	pop		r31
	ret

;; the jump table starts here.  Note that the offset is hardcoded at 1024.

.cseg

.org 1024
	;***THIS (icall):    OR THIS (lpm):***
	ldi r16, 0x81		.db 0x81
	ret					.db 0xf3

	ldi r16, 0xf3		.db 0x49
	ret
	
	ldi r16, 0x49
	ret
	; etc.