*
* Erik Plankton bit for KNOCK KNOCK
*
* Code does NOT use O/S (except for set super/user)
*
* All code ˝ Machine System Dataż of Persistence Of Vision
* Dec '91
*
*
	bsr	set_super
	movem.l	$ffff8240.w,d0-d7		;get old pal
	movem.l	d0-d7,old_pal
	move.l	$44e.w,org_screen_base		;get screen base
	clr.b	$ffff8260.w		;low rez
	move.b	#$12,$fffffc02.w	;no mouse

	bsr	set_up		;set up screen for flipping
	lea	screen_base,a6
	move.l	(a6),4(a6)
	move.l	(a6),8(a6)

******
****** Feardrop music from MUSICAL WONDER
****** Written by Big Alex from OFFBEAT
******

; only one tune
	moveq	#1,d0
	jsr	tune

	lea	old_wave_1,a0
	lea	old_wave_2,a1
	move.l	a0,d0
	move.l	a1,d1
	eor.l	d0,d1
	move.w	d1,old_wave_switch

	bsr	scroll

	bsr	show_pic

	bsr	start_interrupts

wait	bsr	vsync

	bsr	set_screen

	bsr	set_rasters

;	move.w	#$123,$ffff8240.w

	move.w	old_wave_switch,d0
	and.l	#$ff,d0
	eor.l	d0,old_wave_pointer

	bsr	clear_scroll

	bsr	bounce_logo

;	move.w	pic+2,$ffff8240.w

	cmp.b	#$39,key+1
	bne.s	wait

	move.w	sr,-(sp)
	or.w	#$700,sr
	move.l	old_118,$118.w
	move.l	old_70,$70.w
	move.l	old_120,$120.w
	move.b	a07_bak,$fffffa07.w
	move.b	a09_bak,$fffffa09.w
	move.b	a13_bak,$fffffa13.w
	move.b	a17_bak,$fffffa17.w
	clr.b	$fffffa1b.w
	move.w	(sp)+,sr

	move.l	#0,d0
	jsr	tune
stop_tune
	lea	$ffff8800.w,a0
	move.l	#$8080000,(a0)
	move.l	#$9090000,(a0)
	move.l	#$a0a0000,(a0)


	movem.l	old_pal,d0-d7
	movem.l	d0-d7,$ffff8240.w

	move.l	org_screen_base,d6
	lsr.l	#8,d6
	lea	$ffff8201.w,a5
	movep.w	d6,(a5)

	move.b	#1,$ffff8260.w

	move.b	#$8,$fffffc02.w
	bsr	set_user

	clr.w	-(sp)
	trap	#1


*******************
* CUSTOM ROUTINES *
*******************
clear_scroll
	move.l	old_wave_pointer,a1
	move.l	(a1),a1
	move.w	#40-1,d0
	moveq	#0,d2
	move.w	d2,d3
	move.w	d2,d4
.loop	move.l	screen_base,a0
	move.w	(a1)+,d1
	addq.w	#6,a0
	move.l	a0,a2
	add.w	d1,a0
	lea	(31-5)*160(a0),a3
	REPT	5
	move.b	d3,(a0,d2.w)
	move.b	d3,(a3,d2.w)
	lea	160(a0),a0
	lea	160(a3),a3
	ENDR

	not.w	d4
	bpl.s	.word
	addq.w	#1,d2
	bra.s	.la
.word	addq.w	#7,d2
.la	move.l	a2,a0
	dbf	d0,.loop

scroll	move.l	screen_base,a1
	addq.w	#6,a1
	cmp.l	#waves_end,wave_pointer
	blt.s	.no_reset
	move.l	#waves,wave_pointer
.no_reset
	move.l	wave_pointer,a6

	move.l	old_wave_pointer,a5
	move.l	a6,(a5)

	lea	font_offsets,a2
	lea	font,a3
	move.l	scroll_pointer,a4
	move.l	a4,a5

	moveq	#0,d4
	moveq	#40,d5
	move.w	char_offset,d6
next_char
	move.b	(a5),d7		;get a letter
	sub.b	#32,d7		;rid of ASCII
	ext.w	d7

	moveq	#0,d0
	move.l	a3,a0
	move.b	(a2,d7),d0
	mulu	#(31*4),d0
	add.w	d0,a0
	move.w	d6,d0
	mulu	#31,d0		;char depth 31 deep
	add.w	d0,a0

.column
	moveq	#0,d1
	move.w	(a6)+,d1
	move.l	a1,-(sp)
	add.w	d1,a1
OFF	set	0
	REPT	31
	move.b	(a0)+,OFF(a1)
OFF	set	OFF+160
	ENDR

	move.l	(sp)+,a1

	subq.w	#1,d5
	beq.s	.finish

	addq.w	#1,a1		;lower byte of word
	tst.w	d4
	beq.s	.skip		;if D4=0 then do next word
	addq.w	#6,a1		;else goto next word on screen
.skip	not.w	d4
	addq.w	#1,d6		;character offset
	and.w	#3,d6
	bne	.column

	addq.w	#1,a5		;scroll pointer
	tst.b	(a5)		;is end of text?
	bpl	next_char	;NO!
	lea	scroll_text,a5	;do reset scrolline
	bra	next_char

.finish
	addq.w	#1,char_offset
	and.w	#3,char_offset
	bne.s	.end
	addq.w	#1,a4
	tst.b	(a4)
	bpl.s	.end
	lea	scroll_text,a4
.end	move.l	a4,scroll_pointer
	addq.l	#4,wave_pointer
	rts






bounce_logo
; clear old bounce
	move.w	bounce_offset,d0
	sub.w	#1,d0
	and.w	#1023,d0
	lea	bounce_table,a1
	add.b	d0,d0
	move.w	0(a1,d0.w),d0
	mulu	#160,d0

	sub.w	#160*4,d0
	bpl.s	.se
	clr.l	d0

.se	move.l	screen_base,a2
	add.w	d0,a2
	lea	52*160(a2),a3
	moveq	#0,d1
OFF	set 0
	REPT	20*9		;clear 4 lines
	move.w	d1,OFF(a2)
	move.w	d1,OFF(a3)
OFF	set OFF+8
	ENDR


	move.w	bounce_offset,d0
	and.w	#1023,d0
	add.b	d0,d0			;double line offset
	move.w	0(a1,d0.w),d0
	mulu	#160,d0
	lea	pic+34,a0
	move.l	screen_base,a1
	add.w	d0,a1

;now print the fuckin' logo.
	move.w	#53-1,d0	;logo depth
.loop
OFF	set 0
	REPT	20
	move.w	OFF(a0),OFF(a1)
OFF	set OFF+8
	ENDR
	lea	160(a0),a0
	lea	160(a1),a1
	dbf	d0,.loop

	add.w	#1,bounce_offset

	rts




set_rasters
	lea	rast_colours,a0
	move.w	#200/2-1,d0
.lo	clr.l	(a0)+
	dbf	d0,.lo

	lea	colour_bar,a0
	lea	rast_colours,a1
	lea	raster_path,a2
	move.w	path_ptr,d2
	moveq	#30-1,d0		;number of rasterbars
.loop
	move.l	a0,a4
	move.l	a1,a3
	add.w	(a2,d2),a3

	move.w	(a4)+,(a3)+		;width of bar - 1 line =word


	add.w	#(2*3),d2		;gap between lines
	and.w	#(2*256)-1,d2
	add.w	#2,a0		;increase through colours
	dbf	d0,.loop
	add.w	#6,path_ptr
	and.w	#(2*256)-1,path_ptr
	rts


new_120
	move.w	$300.w,$ffff8240.w

	movem.l	d6/a6,-(sp)
	move.l	raster_pos,a6
	move.w	(a6)+,$300.w
	move.l	a6,raster_pos

	move.l	400(a6),d6

	move.w	800(a6),$ffff8240+2.w	;ERIK PLANKTON logo colour

	move.l	d6,$ffff8240+16.w	;scrollers colours
	move.l	d6,$ffff8240+20.w

	movem.l	(sp)+,d6/a6
null	rte


new_70	clr.w	vsync_flag
	clr.b	$fffffa1b.w
	move.l	#new_120,$120.w
	move.b	#1,$fffffa21.w
	move.b	#8,$fffffa1b.w
	movem.l	d0-d7/a6,-(sp)
	movem.l	pic+2,d0-d7
	movem.l	d0-d7,$ffff8240.w

	bsr	tune+4

	move.l	raster_pos,a6
	move.w	(a6)+,$300.w
	move.l	a6,raster_pos

	movem.l	(sp)+,d0-d7/a6
	move.l	#rast_colours,raster_pos
	rte

new_118	movem.l	d0,-(sp)
	move.b	$fffffc02.w,d0
	cmp.b	#$1d,d0
	bne.s	.k1
	bset	#2,key
.k1	cmp.b	#$9d,d0
	bne.s	.k2
	bclr	#2,key
.k2	cmp.b	#$38,d0
	bne.s	.k3
	bset	#3,key
.k3	cmp.b	#$b8,d0
	bne.s	.k4
	bclr	#3,key
.k4	move.b	d0,key+1
	bclr	#6,$fffffa11.w
	movem.l	(sp)+,d0
	rte


vsync	move.w	#-1,vsync_flag
aa	tst.w	vsync_flag
	bne.s	aa
	rts


***********************
* SUBROUTINES SECTION *
***********************
set_up	move.l	#screens,d0
	clr.b	d0
	move.l	d0,screen_base
	move.l	d0,d1
	add.l	#32000,d1
	eor.l	d0,d1
	move.l	d1,scr_xor
	rts

start_interrupts
	move.w	sr,-(sp)		;set for interrupts
	or.w	#$700,sr
	move.l	$70.w,old_70
	move.l	$120.w,old_120
	move.l	$118.w,old_118
	move.l	#new_70,$70.w
	move.l	#null,120.w
	move.l	#new_118,$118.w
	move.b	$fffffa07.w,a07_bak
	move.b	$fffffa09.w,a09_bak
	move.b	$fffffa13.w,a13_bak
	move.b	$fffffa17.w,a17_bak
	clr.b	$fffffa1b.w
	move.b	#1,$fffffa07.w
	move.b	#$40,$fffffa09.w
	move.b	#1,$fffffa13.w
	bclr.b	#3,$fffffa17.w
	move.w	(sp)+,sr
	rts

set_screen
	lea	screen_base,a6
	move.l	4(a6),8(a6)
	move.l	(a6),d6
	move.l	d6,4(a6)
	move.l	scr_xor,d7
	eor.l	d7,d6
	move.l	d6,screen_base
	lsr.l	#8,d6
	lea	$ffff8201.w,a5
	movep.w	d6,(a5)
	rts






set_super
	clr.l	-(sp)		;Set super stack equal
	move.w	#$20,-(sp)	; to user stack before call
	trap	#1
	addq.l	#6,sp		;correct stack
	move.l	d0,stack_save	;save old supervisor stack value
	rts
set_user
	move.l	stack_save,-(sp)
	move.w	#$20,-(sp)
	trap	#1		;back to user
	addq.l	#6,sp		;correct stack
	rts


show_pic
	lea	pic+34,a0
	move.l	screen_base,a1
	lea	32000(a1),a2
	move.w	#32000/4-1,d0
.loop	move.l	(a0),(a1)+
	move.l	(a0)+,(a2)+
	dbf	d0,.loop
	rts

****************
  SECTION DATA
****************


pic	incbin	plankton.pi1

tune	incbin	feardrop.mus
	even



scroll_pointer	dc.l	init_scroll_text+7

init_scroll_text
	dcb.b	100," "
scroll_text
 dc.b "   HELLO DUDES, WELCOME TO ANOTHER EXCELLENT DEMO STARING ERIK "
 DC.B "PLANKTON.   YOU MAY HAVE NOTICED THAT I'VE BEEN JOINED BY ANOTHER "
 DC.B "CODER ON THIS DEMO, HIS NAME IS BLIND BASTARD.      IF YOU WANT "
 DC.B "TO KNOW WHY HE'S CALLED THAT WELL, HE SPENT SO MUCH TIME "
 DC.B "WANKING OVER MY FIRST DEMO THAT HE HAD TO SEE AN OPTICIAN FOR HIS "
 DC.B "EYE SIGHT     (AND A DOCTOR FOR THE BLISTERS ON HIS PALMS!!!)      "
 DC.B "      IT'S BEEN A LONG TIME SINCE MY FIRST DEMO, IT WENT DOWN "
 DC.B "SO WELL THAT I FELT I HAD TO WRITE ANOTHER.      THE SAMPLING "
 DC.B "AND SOME GRAFIX WERE DONE BY ME, OTHER GRAFIX WERE BY OZYMANDIAS "
 DC.B "OF 'PERSISTENCE OF VISION'.   I MUST SEND MEGA THANKS TO "
 DC.B "MAC SYS DATA FOR ALL HIS HELP ON THE CODING,    BORIS FOR THE "
 DC.B "PACKING TECHNIQUE AND HELPING PUT IT ALL TOGETHER    AND   OZYMANDIAS WHO IS "
 DC.B "ONE OF THE BEST GRAFIX ARTISTS ON THE ST.         I THINK "
 DC.B "THAT IS ENOUGH BOTTOM LICKING FOR NOW!       "
 DC.B "THERE ARE OTHER GREETING AND CREDITS ELSE WHERE IN THIS DEMO SO "
 DC.B "I WON'T DO ANY MORE.        WELL AFTER 16 YEARS OF GROWING UP "
 DC.B "I FINALLY FIGURED OUT THAT GIRLS ARE WEIRD...     I MEAN, JUST "
 DC.B "'CAUSE I GOT A LITTLE DRUNK AND JUMPED ON ONE DIDN'T MEAN SHE "
 DC.B "HAD TO SMASH MY FACE IN DID IT?     OH, I FEEL ILL.        "
 DC.B "WHY CAN'T THEY MAKE BEER THAT DOESN'T MAKE YOUR HEAD HURT "
 DC.B "IN THE MORNING?     I WAS TOLD TO DRINK A PINT OF WATER "
 DC.B "BEFORE I WENT TO BED BUT I COULDN'T FUCKIN' FIND A PINT GLASS "
 DC.B "IN THE HOUSE SO I DRANK ABOUT 4 MOUTH FULLS THEN SPEWED UP IN THE "
 DC.B "SINK...   URRGGGHH  CARROTS!                                     "
 dc.b $ff
	even
char_offset	dc.w	0
font	dcb.b	31*4,0
	incbin	1plane.fnt
	even
old_wave_switch	dc.w	0
old_wave_pointer
	dc.l	old_wave_1
old_wave_1	dc.l	waves
old_wave_2	dc.l	waves
wave_pointer	dc.l	waves
waves		incbin	sine1.dat"
waves_end	incbin	sine1.dat"
	even
font_offsets
;          !  "  #  $  %  &  '  (  )  *  +  ,  -  .  /
 dc.b	0,41,43,00,00,00,00,46,44,45,00,00,38,42,39,48

;        0  1  2  3  4  5  6  7  8  9  :  ;  <  =  >  ?  @
 dc.b	27,28,29,30,31,32,33,34,35,36,40,00,00,00,00,47,00

;        A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q
 dc.b	01,02,03,04,05,06,07,08,09,10,11,12,13,14,15,16,17

;        R  S  T  U  V  W  X  Y  Z  [  \  ]  ^  _  `  a  b  c
 dc.b	18,19,20,21,22,23,24,25,26,40,00,41,00,00,00,00,00,00

;        d  e  f  g  h  i  j  k  l  m  n  o  p  q  r  s  t  u
 dc.b	50,00,00,00,00,00,00,00,00,48,00,00,00,00,00,49,00,00





colour_bar
 dc.w	$0ff,$07f,$06f,$05f,$04f,$03f,$02f,$01f
 dc.w	$00f,$107,$206,$305,$405,$503,$602,$701
 dc.w	$f00,$f80,$f10,$f90,$f20,$fa0,$f30,$fb0
 dc.w	$f40,$fc0,$f50,$fd0,$f60,$fe0

path_ptr	dc.w	0

raster_path	incbin	RASTER.PTH

rast_colours
	dcb.w	200,0

	dc.w	0000		;null byte due to the way I did it

	dcb.w	42,$000		;don't do no rasters in logo

; Holy shit loads of raster colour like things for the scroller.
	dc.w	$800,$100,$900
	dc.w	$200,$a00,$300,$b00,$480,$c10,$590
	dc.w	$d20,$6a0,$e30,$7b0,$f40,$7c0,$650
	dc.w	$5d0,$468,$3e1,$279,$1f2,$0fa,$0f3
	dc.w	$0fb,$074,$0ec,$065,$0dd,$056,$0ce
	dc.w	$047,$0bf,$83e

	dc.w	$1a6,$92d,$295,$a1c,$304,$b0b,$483
	dc.w	$c1a,$592,$d29,$6a1,$e38,$7b0,$f48
	dc.w	$6c1,$559,$4d2,$36a,$2e3,$17b,$0f4
	dc.w	$16c,$255,$34d,$436,$52e,$617,$70f
	dc.w	$706,$705,$604,$503,$402,$301
	dc.w	$300,$b80,$410,$c90,$520,$da0,$630
	dc.w	$eb0,$740,$fc0,$f50,$fd0,$f60,$fe0
	dc.w	$f70,$ff0,$770,$ee0,$660,$dd0,$550
	dc.w	$cc0,$440,$bb0,$338,$aa1,$229,$992
	dc.w	$11a,$883,$00b,$004,$00c,$005,$00d
	dc.w	$006,$00e,$007,$00f
	dc.w	$01f,$02f,$03f,$04f,$05f,$06f
	dc.w	$16f,$25f,$34f,$43f,$52f,$61f,$70f
	dc.w	$f87,$f1e,$f96,$f2d,$fa5,$f3c,$fb4
	dc.w	$f4b,$fc3,$f5a,$fd2,$f6a,$fe1,$f78
	dc.w	$ff0,$f70,$fe0,$f60,$fd0,$f50,$fc0
	dc.w	$f40,$fb0,$f30,$fa0,$f20,$f90,$f10
	dc.w	$f80,$f00,$f00



	dc.w	$fff,$fff,$fff,$fff,$fff,$fff,$fff
;colours for ERIK LOGO
	dc.w	$800,$800,$100,$100,$900,$900,$200,$200,$a00,$a00
	dc.w	$300,$300,$b00,$b00,$400,$400,$c00,$c00,$500,$500
	dc.w	$d00,$d00,$600,$600,$e00,$e00,$700,$700,$f00,$f00

	dc.w	$f80,$f80,$f10,$f10,$f90,$f90,$f20,$f20,$fa0,$fa0
	dc.w	$f30,$f30,$fb0,$fb0,$f40,$f40,$fc0,$fc0,$f50,$f50
	dc.w	$fd0,$fd0,$f60,$f60,$fe0,$fe0,$f70,$f70,$ff0,$ff0

	dc.w	$ff8,$ff8,$ff1,$ff1,$ff9,$ff9,$ff2,$ff2,$ffa,$ffa
	dc.w	$ff3,$ff3,$ffb,$ffb,$ff4,$ff4,$ffc,$ffc,$ff5,$ff5
	dc.w	$ffd,$ffd,$ff6,$ff6,$ffe,$ffe,$ff7,$ff7,$fff,$fff

	dc.w	$7ff,$7ff,$eff,$eff,$6ff,$6ff,$dff,$dff,$5ff,$5ff
	dc.w	$cff,$cff,$4ff,$4ff,$bff,$bff,$3ff,$3ff,$aff,$aff
	dc.w	$2ff,$2ff,$9ff,$9ff,$1ff,$1ff,$8ff,$8ff,$0ff,$0ff

	dc.w	$07f,$07f,$0ef,$0ef,$06f,$06f,$0df,$0df,$05f,$05f
	dc.w	$0cf,$0cf,$04f,$04f,$0bf,$0bf,$03f,$03f,$0af,$0af
	dc.w	$02f,$02f,$09f,$09f,$01f,$01f,$08f,$08f,$00f,$00f

	dc.w	$087,$087,$01e,$01e,$096,$096,$02d,$02d,$0a5,$0a5
	dc.w	$03c,$03c,$0b4,$0b4,$04b,$04b,$0c3,$0c3,$05a,$05a
	dc.w	$0d2,$0d2,$069,$069,$0e1,$0e1,$078,$078,$0f0,$0f0

	dc.w	$070,$070,$0e0,$0e0,$060,$060,$0d0,$0d0,$050,$050
	dc.w	$0c0,$0c0,$040,$040,$0b0,$0b0,$030,$030,$0a0,$0a0
	dc.w	$020,$020,$090,$090,$010,$010,$080,$080,$000,$000



bounce_offset	dc.w	0
bounce_table	incbin	bounce.pth


****************
 SECTION BSS
****************
screen_base	ds.l	1
		ds.l	1
		ds.l	1
scr_xor		ds.l	1
org_screen_base	ds.l	1
old_pal		ds.w	16
stack_save	ds.l	1

vsync_flag	ds.w	1
old_70		ds.l	1
old_120		ds.l	1
old_118		ds.l	1
a07_bak		ds.w	1
a09_bak		ds.w	1
a13_bak		ds.w	1
a17_bak		ds.w	1
key		ds.w	1

raster_pos	ds.l	1

	ds.b	256
screens	ds.b	32000
	ds.b	32000