; Display charset bitmap data.

; Version 1.0

; $Id: charscan.a48 390 2003-07-19 12:41:28Z sgust $

; History:
; Version 1.0
;   first release

; This program prints one char and uses a sprite to scan for the bitmap
; of the char which is then printed. This is tricky, because the collision
; handling of the original console is really strange, collisions are mostly
; always triggered when the pixels are next to each other. So I use the
; higher pixel resolution of the sprite and only set a bit if both sub pixels
; are collided. This only works when using vdc_coll_char as collision target,
; checking with vdc_coll_spr0 fails when there is a one pixel hole in the char,
; like in $.

; Press "1" for next char or "0" for previous char.

; I have used this together with charset.a48 to check the o2em char bitmap
; data.

; Copyright (C) 2003 by Soeren Gust, sgust@ithh.informationstheater.de

; Permission is hereby granted, free of charge, to any person obtaining a copy
; of this software and associated documentation files (the "Software"), to deal
; in the Software without restriction, including without limitation the rights
; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
; copies of the Software, and to permit persons to whom the Software is
; furnished to do so, subject to the following conditions:

; The above copyright notice and this permission notice shall be included in
; all copies or substantial portions of the Software.

; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
; THE SOFTWARE.

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

; This is ugly, badly commented, unsupported code!

	cpu	8048

	org	400h
	
	include	"g7000.h"

iram_char	equ	020h
iram_bitmap	equ	021h

	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
	call	gfxoff
	mov	a,#col_grd_white
	mov	r0,#vdc_color
	movx	@r0,a

	section setshape
	mov	r0,#vdc_spr0_shape
	mov	a,#1
	movx	@r0,a
	inc	r0
	mov	r2,#7
	clr	a
.loop	movx	@r0,a
	inc	r0
	djnz	r2,.loop
	endsection setshape

	; set initial char
	mov	r0,#iram_char
	mov	a,#0
	mov	@r0,a

newchar
	; print char
	call	gfxoff
	mov	r0,#iram_char
	mov	a,@r0
	mov	r5,a
	mov	r0,#vdc_char0
	mov	r3,#20h		; x-position
	mov	r4,#20h		; y-position
	mov	r6,#col_chr_white
	call	printchar	; print it

	mov	r4,#020h
	mov	r1,#iram_bitmap
loop1	
	mov	r7,#0
	mov	r3,#01fh
loop2
	; set position, first subpixel
	call	gfxoff
	mov	r0,#vdc_spr0_ctrl
	mov	a,r4
	movx	@r0,a
	inc	r0
	mov	a,r3
	movx	@r0,a
	inc	r0
	mov	a,#col_spr_red+1
	movx	@r0,a
	mov	r0,#vdc_collision
	mov	a,#vdc_coll_char
	movx	@r0,a
	call	gfxon
	call	waitvsync
	mov	r0,#iram_collision
	mov	a,@r0
	anl	a,#001h
	mov	r6,a

	;;call	gfxoff
	;;mov	r0,#iram_collision
	;;mov	a,@r0
	;;mov	r0,#vdc_gridh0
	;;movx	@r0,a
	;;call	gfxon
	;;call	waitforkey

	; set position, second subpixel
	call	gfxoff
	mov	r0,#vdc_spr0_ctrl
	mov	a,r4
	movx	@r0,a
	inc	r0
	inc	r3
	mov	a,r3
	movx	@r0,a
	inc	r0
	mov	a,#col_spr_red
	movx	@r0,a
	mov	r0,#vdc_collision
	mov	a,#vdc_coll_char
	movx	@r0,a
	call	gfxon
	call	waitvsync
	mov	r0,#iram_collision
	mov	a,@r0
	anl	a,#001h
	anl	a,r6			; only set when both pixels are set
	mov	r6,a

	;;call	gfxoff
	;;mov	r0,#iram_collision
	;;mov	a,@r0
	;;mov	r0,#vdc_gridh0
	;;movx	@r0,a
	;;call	gfxon
	;;call	waitforkey

	; combine with other bits
	mov	a,r7
	rl	a
	orl	a,r6
	mov	r7,a
	mov	a,r3
	xrl	a,#027h			; max x
	jz	nextlin			; next line
	jmp	loop2

nextlin	; start new line
	mov	a,r7
	mov	@r1,a
	inc	r1
	inc	r4
	inc	r4
	mov	a,r4
	xrl	a,#02eh
	jz	finished
	jmp	loop1

finished
	; now print results, first 5 as chars
	call	gfxoff
	mov	r1,#iram_bitmap
	mov	r0,#vdc_char1
	mov	r3,#010h
	mov	r4,#040h
	mov	r6,#col_chr_white
loop3
	mov	a,@r1
	call	displayhex
	inc	r1
	mov	a,r3
	add	a,#8
	mov	r3,a
	mov	a,r1
	xrl	a,#iram_bitmap+5
	jnz	loop3

	; print spaces in q0/1
	mov	r0,#vdc_quad0
	mov	r3,#010h
	mov	r4,#060h
	mov	r2,#8
loop4
	mov	r6,#col_chr_white
	mov	r5,#00ch
	call	printchar
	djnz	r2,loop4

	; last 2 in quad0/1
	mov	r0,#vdc_quad0
	mov	r3,#010h
	mov	r4,#060h
	mov	r6,#col_chr_white
	mov	a,@r1
	swap	a
	anl	a,#0fh
	call	displayhexnibble
	mov	a,@r1
	anl	a,#0fh
	mov	r0,#vdc_quad1
	call	displayhexnibble

	inc	r1
	mov	r0,#vdc_quad1+4
	mov	a,@r1
	swap	a
	anl	a,#0fh
	call	displayhexnibble
	mov	a,@r1
	anl	a,#0fh
	mov	r0,#vdc_quad0+8
	call	displayhexnibble

	call	gfxon
	jmp	keyloop

	align	256

keyloop	call	waitforkey
	jz	.key0
	dec	a
	jz	.key1
	jmp	keyloop

.key0	mov	r0,#iram_char
	mov	a,@r0
	dec	a
	mov	@r0,a
	jmp	newchar

.key1	mov	r0,#iram_char
	mov	a,@r0
	inc	a
	mov	@r0,a
	jmp	newchar

	align 256

displayhex
; r0=charpointer r3=x, r4=y, r6=color a=number
; alters r7
	mov	r7,a
	swap	a
	anl	a,#00fh
	call	displayhexnibble
	mov	a,r7
	anl	a,#00fh
	call	displayhexnibble
	ret

displayhexnibble
; r0=charpointer r3=x, r4=y, r6=color, a=number
; alters r3, r5, a
	add	a,#hextable & 0ffh
	movp	a,@a
	mov	r5,a
	call	printchar
	ret

hextable
	db	0,1,2,3,4,5,6,7,8,9,020h,025h,023h,01ah,012h,01bh