AVR Stack Addition

stackadd.s

; Christian Hotz-Behofsits 2012
; Simple AVRASM Test - take all values from the Stack, add them and print to PORTA

.NOLIST
.INCLUDE "m1280def.inc"
.LIST

.section .text

.org 0x0000

Reset:
	rjmp main
	
add_stack:
	out PORTB, R17		;print old value

	pop R19
	add R17, R19
	out PORTA, R17		;print new value

	rjmp loop

main:
	clr R17			;R17 init
	
	;output init
	ser R21
	out DDRA, R21
	out DDRB, R21

	;init stack
	ldi R18, lo8(RAMEND)
	out SPL, R18
	ldi r18, hi8(RAMEND)
	out SPH, r18


	;push
	ldi R20, 0x01
	push R20
	
	ldi R20, 0x04
	push R20

	ldi R20, 0x01
	push R20


loop:
	ldi R18, lo8(RAMEND)
	in R16, SPL
	CP R18, R16
	ldi R18, hi8(RAMEND)
	in R16, SPH
	CPC R18, R16
	brne add_stack
	rjmp loop