; how to use the clock routines
; Version 1.0
;
; History:
; Version 1.0
;   first release
;
; This demoprogram displays a clock. It can be controlled with the
; joystick. Moving left stops the clock, moving right restarts it.
; The direction can be changed with moving up and down. On PAL Systems
; the clock is too slow, for the BIOS are 60 frames = 1 second.
; At every full minute the program plays a sound.

; Copyright (C) 1997 by Soeren Gust, sgust@ithh.informationstheater.de

; This program is free software; you can redistribute it and/or modify
; it under the terms of the GNU General Public License as published by
; the Free Software Foundation; either version 2 of the License, or
; (at your option) any later version.
;
; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
; GNU General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program; if not, write to the Free Software
; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

; You can always get the latest version at http://soeren.informationstheater.de

	cpu	8048
	
	org	400h

	include	"g7000.h"

	jmp	selectgame	; RESET
	jmp	irq		; interrupt
	jmp	timer		; timer
	jmp	vsyncirq	; VSYNC-interrupt
	jmp	start		; after selectgame
	jmp	soundirq	; sound-interrupt

timer	retr			; we don't need timer

start
	; need to initialise quad0/1
	call	gfxoff

	; set the start time = 01:00
	call	extramenable
	mov	r0,#eram_minutes
	mov	a,#01h		; BCD
	movx	@r0,a		; 1 minutes
	mov	r0,#eram_seconds
	mov	a,#01h		; BCD
	movx	@r0,a		; 1 second, will roll over immediatly

	; initialise the display
	call	vdcenable
	mov	r3,#020h	; x position
	mov	r4,#040h	; y position
	mov	r6,#col_chr_white
	call	initclock

	; activate the clock
	call	waitvsync	; make sure there is no roll
				; over before we want it
	mov	r0,#iram_clock
	mov	a,#03ah
	mov	@r0,a		; start clock backwards
				; rolls over at first vsync
				; and initialises display in
				; first doclock
	call	gfxon

loop
	call	waitvsync	; once per frame

	mov	r4,#040h	; y position, same as above !!
	mov	r6,#col_chr_white
	call	doclock		; update clock, if necessary

	; test the time and play sound every minute
	call	extramenable
	mov	r0,#eram_seconds
	movx	a,@r0
	jnz	nosound

	; only play sound, if count=0 and still counting
	mov	r0,#iram_clock
	mov	a,@r0
	anl	a,#0ffh-clock_forward
	jnz	nosound

	; now play the sound
	mov	a,#tune_select2
	call	playsound

nosound
	; test the joystick
	mov	r1,#0
	call	getjoystick

	; get value to manipulate
	mov	r0,#iram_clock
	mov	a,@r0
	mov	r7,a

	; test left/right
	mov	a,r2			; x offset
	inc	a
	jnz	joy_noleft
	; left=stop clock
	mov	a,#clock_stop
	orl	a,r7			; set clock_stop
	mov	r7,a
	jmp	joy_noright		; left = not right
joy_noleft
	dec	a
	dec	a
	jnz	joy_noright
	; right=start clock
	mov	a,#0ffh-clock_stop
	anl	a,r7			; clear clock_stop
	mov	r7,a
joy_noright
	mov	a,r3			; y offset	
	inc	a
	jnz	joy_noup
	; up=count forwards
	mov	a,#clock_forward
	orl	a,r7			; set clock_forward
	mov	r7,a
	jmp	joy_end			; up = not down
joy_noup
	dec	a
	dec	a
	jnz	joy_end
	; down=count backwards
	mov	a,#0ffh-clock_forward
	anl	a,r7			; clear clock_forward
	mov	r7,a
joy_end
	; put new value back into iram_clock
	mov	a,r7
	mov	@r0,a

	jmp	loop			; next frame

	end