; ***********************************************************************
; *									*
; *        User Mode Code for the Flash Program, Second Version         *
; *									*
; ***********************************************************************

; Author:   John Zaitseff <J.Zaitseff@unsw.edu.au>
; Date:     28th May, 2003
; Version:  1.2

; This file contains the main program for the second version of Flash, as
; used in ELEC2041 Experiment 5.  This code runs in User mode.  The main
; feature of this program is that it uses an SWI instruction to set the
; LEDs on and off.


	.text			   ; Ordinary program code follows

	.include "header-v2-pub.s" ; Include various public definitions
	.global main		   ; Make this label visible to other modules


; -----------------------------------------------------------------------
; The main program, running in User mode.  Notice that the main program
; does NOT know how the SWI handler performs its duties beyond the public
; interface.  In other words, this code has been written in such a way
; that it only needs to know what a given SWI function does and what are
; that function's inputs and outputs.

main:				   ; Main program, running in User mode

main_loop:
	mov	r0, #swi_set_LEDs  ; Request the SWI handler to set the LEDs
	mov	r1, #value1	   ; R1 = value to turn the LEDs on
	swi			   ; Generate a software interrupt

	mov	r0, #swi_delay	   ; Request the SWI handler to delay program
	ldr	r1, =waitval	   ; R1 = number of delay loops
	swi			   ; Generate a software interrupt

	mov	r0, #swi_set_LEDs  ; Request the SWI handler to set the LEDs
	mov	r1, #value2	   ; R1 = value to turn the LEDs off
	swi			   ; Generate a software interrupt

	mov	r0, #swi_delay	   ; Request the SWI handler to delay program
	ldr	r1, =waitval	   ; R1 = number of delay loops
	swi			   ; Generate a software interrupt

	b	main_loop	   ; Repeat forever (or until stopped)


	.end