;	Altirra - Atari 800/800XL/5200 emulator
;	Modular Kernel ROM - Boot Screen
;	Copyright (C) 2008-2016 Avery Lee
;
;	Copying and distribution of this file, with or without modification,
;	are permitted in any medium without royalty provided the copyright
;	notice and this notice are preserved.  This file is offered as-is,
;	without any warranty.

		opt		o-f-l-
		org		$80

chardt1	dta		0
chardt2	dta		0
charpos	dta		0
charadr	dta		a(0)
charmsk	dta		0
charodd	dta		0
char_x	dta		0
char_y	dta		0
scrnad1	dta		a(0)
scrnad2	dta		a(0)
msgadr	dta		a(0)

spracl	dta		0
sprach	dta		0
spricl	dta		0
sprich	dta		0

sysvbi	dta		a(0)
sysirq	dta		a(0)

rtcsav	dta		0,0,0
rtctmp	dta		0,0,0

phase	dta		0
		opt		l+

		org		$5000,$d000
		opt		o+f+
		
.proc BootScreen
		jsr		clear_ram
		
		;copy down display list
		ldx		#dlistdata_end-dlistdata
		mva:rne	dlistdata-1,x dlist-1,x-
		
		;copy down bitmap graphics
		mwa		#playfield3+19 scrnad2
		mwa		#drivedat scrnad1
		ldx		#40
blit_loop:
		ldy		#12
		mva:rpl	(scrnad1),y (scrnad2),y-
		clc
		lda		scrnad2
		adc		#$20
		sta		scrnad2
		scc:inc	scrnad2+1
		lda		scrnad1
		clc
		adc		#13
		sta		scrnad1
		scc:inc	scrnad1+1
		dex
		bne		blit_loop
		

		sei
		mva		#$3d sdmctl
		mva		#0 nmien
		mwa		vvblki sysvbi
		mwa		#vbi vvblki
		mwa		#dli vdslst
		mwa		vimirq sysirq
		mwa		#irq vimirq
		ldx		#8
		mva:rpl	color_table,x pcolr0,x-
		mwa		#dlist sdlstl
		mva		#$c0 nmien
		mva		#>player0 pmbase
		mva		#$40 hposp0
		mva		#$60 hposp1
		mva		#$a4 hposp2
		mva		#$98 hposp3
		mva		#$00 hposm3
		mva		#$00 hposm2
		mva		#$60 hposm1
		mva		#$68 hposm0
		mva		#$03 gractl
		mva		#$01 gprior
		lda		#$03
		sta		sizep0
		sta		sizep1
		sta		sizep3
		lda		#$00
		sta		sizep2
		lda		#$0f
		sta		sizem
		cli
		
		;init sprites 0,1
		ldx		#0
		ldy		#32
sprinit:
		mva		spr0dat,x player0,y
		mva		spr1dat,x player1,y+
		tya
		and		#$0f
		bne		sprinit
		inx
		cpx		#8
		bne		sprinit
		
		lda		#0
		sta		char_x
		sta		char_y
		jsr		Imprint
		
		;		  0123456789012345678901234567890123456789012345678901234567890123
		dta		d"AltirraOS"
		_KERNELSTR_BIOS_NAME_INTERNAL
		dta		d" "
		_VERSIONSTR_INTERNAL
		
		;need space here for HLE to shift
		dta		" ",$9b
		dta		d"Copyright (C) 2012-2016 Avery Lee",$9b
		dta		d"All Rights Reserved",$9b
		dta		d"This is a substitute for the standard OS ROM. See the help file",$9b
		dta		d"for how to use real Atari ROM images for higher compatibility."
		dta		$ff
		
		lda		#0
		sta		phase
loop1:
		ldx		#0
		txa
sprclr:
		sta		player2,x
		sta		player3,x
		dex
		bne		sprclr
		
		;save off the current RTCLOK
		lda:rne	vcount
		ldx		#2
		mva:rpl	rtclok,x rtcsav,x-
		
		;try to read sector #1 on D1:
		ldx		#0
		lda		#$31
		sta		ddevic
		lda		#1
		sta		dunit
		mva		#$52 dcomnd
		mwa		#$0400 dbuflo
		mwa		#1 daux1
		jsr		dskinv
		bmi		loop2
		jmp		do_boot
loop2:
		lda		rtclok+2
		cmp:req	rtclok+2
		lda		rtclok+2
		cmp:req	rtclok+2
		
		ldx		phase
		mwa		phasetab+1,x spricl
		
		ldy		phasetab,x
		lda		#0
		sta		spracl
		sta		sprach
clloop:
		sta		missiles,y
		sta		player2,y
		sta		player3,y
		dey
		bmi		clloop
		
		ldy		phasetab,x
		lda		#$ff
blitloop:
		ldx		sprach
		lda		sprdat2,x
		sta		player2,y
		lda		sprdat3,x
		sta		player3,y
		
		iny
		adw		spracl spricl spracl
		lda		sprach
		cmp		#$20
		bcc		blitloop
		lda		#0
blitloop2:
		sta		missiles,y
		sta		player2,y
		sta		player3,y
		iny
		cpy		#$40
		bne		blitloop2

		;if this is the first animation frame, wait a bit after it
		lda		phase
		bne		no_wait
		
		ldx		#25
waitloop:
		lda		rtclok+2
		cmp:req	rtclok+2
		dex
		bne		waitloop
		txa
		
no_wait:
		clc
		adc		#3
		sta		phase
		cmp		#phasetab_end-phasetab
		scs:jmp	loop2
		
		lda		#0
		sta		phase		
		jmp		loop1

phasetab:
		:48 dta	$7a+[48-#]/3, a([$200+#*#*3]/3)
phasetab_end:

;==========================================================================	
do_boot:
		sei
		lda		#0
		sta		nmien
		sta		dmactl

		;reset GTIA
		sta:rpl	$d000,x+
		
		;invoke cold start
		jmp		coldsv

;==========================================================================
clear_ram:
		lda		#$20
		sta		charadr+1
		lda		#0
		sta		charadr
		tay
		ldx		#$20
clear_loop:
		sta:rne	(charadr),y+
		inc		charadr+1
		dex
		bne		clear_loop
		rts

;==========================================================================
vbi:
		lda		pfadr+1
		eor		#$05
		sta		pfadr+1
		lda		color_table+5
		sta		colpf1
		lda		color_table+6
		sta		colpf2
		jmp		(sysvbi)

irq:
		bit		nmist
		bpl		do_irq
dli:
		pha
		txa
		pha
		lda		vcount
		cmp		#72
		bcs		split
		lsr
		lsr
		tax
		lda		coltab-5,x
		sta		wsync
		sta		colpm0
		sta		colpm1
xit:
		sta		nmires
		pla
		tax
		pla
		rti
do_irq:
		jmp		(sysirq)
split:
		lda		#$50
		ldx		#$5c
		sta		wsync
		sta		colpf2
		stx		colpf1

		jmp		xit

;==========================================================================			
imprint:
		pla
		sta		msgadr
		pla
		sta		msgadr+1
imloop:
		inw		msgadr
		ldy		#0
		lda		(msgadr),y
		cmp		#$ff
		beq		imdone
		jsr		PlotChar
		jmp		imloop
imdone:
		lda		msgadr+1
		pha
		lda		msgadr
		pha
		rts
.endp

;==========================================================================	
plotchar:
		cmp		#$9b
		bne		not_eol
		mva		#0 char_x
		inc		char_y
		rts
not_eol:
		sta		charadr

		lda		#0
		sta		scrnad1
		sta		scrnad2
		lda		char_y
		ora		#>playfield
		sta		scrnad1+1
		clc
		adc		#$05
		sta		scrnad2+1

		lda		char_x
		lsr
		sta		charpos
		ror
		sta		charodd

		lda		#$e0/8
		ldx		#3
shlloop:
		asl		charadr
		rol
		dex
		bne		shlloop
		sta		charadr+1
		
		clc
rowloop:
		ldx		#4
		ldy		#0
		lda		(charadr),y
		lsr
bitloop:
		lsr
		ror		chardt1
		lsr
		ror		chardt2
		dex
		bne		bitloop

		ldy		charpos
		bit		charodd
		bmi		odd
		lda		chardt2
		eor		(scrnad2),y
		and		#$0f
		eor		chardt2
		sta		(scrnad2),y

		lda		chardt1
		eor		(scrnad1),y
		and		#$0f
		
		bpl		even
odd:
		lda		chardt1
		lsr
		lsr
		lsr
		lsr
		sta		chardt1
		lda		chardt2
		lsr
		lsr
		lsr
		lsr
		sta		chardt2
		eor		(scrnad2),y
		and		#$f0
		eor		chardt2
		sta		(scrnad2),y
		lda		chardt1
		eor		(scrnad1),y
		and		#$f0
even:
		eor		chardt1
		sta		(scrnad1),y
		inc		charadr
		tya
		clc
		adc		#$20
		sta		charpos
		bcc		rowloop
		
		;update position
		inc		char_x
		ldx		char_x
		cpx		#64
		bcc		done
		mva		#0 char_x
		inc		char_y
done:
		rts

;==========================================================================	
spr0dat:
		dta		%00000000
		dta		%00000011
		dta		%00001111
		dta		%00111100
		dta		%00111100
		dta		%00111111
		dta		%00111100
		dta		%00000000

spr1dat:
		dta		%00000000
		dta		%11000000
		dta		%11110000
		dta		%00111100
		dta		%00111100
		dta		%11111100
		dta		%00111100
		dta		%00000000

sprdat2:
		dta		%00000000
		dta		%00000000
		dta		%00011000
		dta		%00111100
		dta		%00111100
		dta		%00111100
		dta		%00111100
		dta		%00111100
		dta		%00111100
		dta		%00011000
		dta		%00000000
		dta		%00000000
		dta		%11100111
		dta		%10000001
		dta		%10000001
		dta		%00000000
		dta		%00000000
		dta		%10000001
		dta		%10000001
		dta		%11100111
		dta		%00000000
		dta		%00000000
		dta		%00000000
		dta		%00000000
		dta		%00000000
		dta		%00000000
		dta		%00000000
		dta		%00000000
		dta		%00000000
		dta		%00000000
		dta		%00000000
		dta		%00000000
		
sprdat3:
		dta		%11111111
		dta		%11111111
		dta		%11111111
		dta		%11111111
		dta		%11111111
		dta		%11111111
		dta		%11111111
		dta		%11111111
		dta		%11111111
		dta		%11111111
		dta		%11111111
		dta		%11111111
		dta		%11100111
		dta		%11100111
		dta		%11100111
		dta		%11100111
		dta		%11100111
		dta		%11100111
		dta		%11100111
		dta		%11100111
		dta		%11111111
		dta		%11111111
		dta		%11111111
		dta		%11111111
		dta		%11111111
		dta		%11111111
		dta		%01111111
		dta		%11111111
		dta		%11111111
		dta		%11111111
		dta		%11111111
		dta		%11111111

;==========================================================================	
color_table:
		dta		$00
		dta		$00
		dta		$02
		dta		$00
		dta		$08
		dta		$0C
		dta		$02
		dta		$14
		dta		$50
		
;==========================================================================	
coltab:
		dta		$1a
		dta		$fa
		dta		$ea
		dta		$da
		dta		$ca
		dta		$ba
		dta		$aa
		dta		$9a
		dta		$8a
		dta		$7a
		dta		$6a
		dta		$5a
		
		dta		$0E,$50

;==========================================================================	
drivedat:
		icl		'driveimage.inc'
		
;==========================================================================	
		
dlistdata:
		:4 dta	$70
		:8 dta	$F0
		dta		$4E,a(playfield3)
		:6 dta	$0E
		dta		$8E
		:4 dta	$0E,$0E,$0E,$0E,$0E,$0E,$0E,$8E
		
		dta		$F0
		dta		$70
		
		dta		$4F,a(playfield)
pfadr = dlist+(*-dlistdata)-2
		:7 dta	$0F
		:8 dta	$0F
		:8 dta	$0F
		dta		$70
		:8 dta	$0F
		:8 dta	$0F
		dta		$41,a(dlist)
dlistdata_end:

		org		$d7ff
		dta		$ff

		opt		l-f-
		
		org		$2000
playfield:
		org		$2500
playfield2:

		org		$2b00
missiles:
		org		$2c00
player0:
		org		$2d00
player1:
		org		$2e00
player2:
		org		$2f00
player3:

		org		$3000
playfield3:
		org		$3f00
dlist:

		opt		l+
		org		$d800
