************************************************************************
* 4-Bitplane-Zoom-Routine     C) May 1991 by the WEAPONMASTER/CYTAX    *
* Release in I.C.E. Issue #5	                                       *
************************************************************************
* I programmed this routine after I saw Sanity's 'Elysium'-demo.       *
* It wasn't my original intention to publish this sourcecode, so I     *
* didn't comment the routines in the way as I would do, if the source- *
* code should be released. For this reason nearly all comments are in  *
* German, but I decided to publish it, because a lot of coders wanted  *
* a copy from me.  The important routines are partially optimised, but *
* not the routines for display-, start-initialization and main-loop.   *
* I didn't want to waste much time, so I used parts of my older        *
* productions for controlling the important routines.                  *
************************************************************************

* If you want to contact me for any reason write to the I.C.E. address
* but mark your sending, that the other Cytax-members will notice
* that they should give it to me.
* (e.g. add something like: 'to Weaponmaster' or 'to WPM.')

* For 'zooming' press left Mouse-Button, right MB for exit
* The sourcecode works with 'Seka V3.2'

>extern "testpic",origpic,32032	;Bild muß folgendes Format haben
				;4 Bitplanes (320*200), 8000 Bytes groß
				;+ 16 Farben (dahinter)

;Makrodefinition zum Warten auf Blitter
waitblit: macro
wblit?0:
 btst #14,(A5)
 bne.s wblit?0
endm

start:
move.l 4.w,a6
jsr -132(a6)			;Forbid (eigentlich nicht notwendig,
				;da IRQs später aus)
lea grname,a1
clr.l d0
jsr -552(a6)
move.l d0,graphicsbase
beq error

lea $dff002,a5
move.w $1a(a5),intenaold
move.w #$7fff,$98(a5)		;IRQs aus

move.w #$03f0,$94(a5)
move.w #$2c81,$8c(a5)
move.w #$f5c1,$8e(a5)
move.w #$38,$90(a5)
move.w #$d0,$92(a5)
move   #$4200,$fe(a5)
move.w #0,$100(a5)

move.w #$2c07,d0
move.w #$fffe,d1
move.l #$01080078,d2
move.l #$010a0078,d3
move.w #$100,d4
move.w #$f507,d5
lea cpl_mod-6,a0

cop_init1:
move.w d0,(a0)+
move.w d1,(a0)+
move.l d2,(a0)+
move.l d3,(a0)+
add.w  d4,d0
cmp.w d5,d0
blo.s cop_init1

lea col1,a0
lea $17e(a5),a1
move.w #$f,d0
cop_init2:
move.w (a0)+,(a1)+
dbf d0,cop_init2

move.l #cladr,$7e(a5)
move.w #0,$86(a5)

move.l #planes1,planeakt
move.l #planes2,planeverd
clr.w bildnr

move.l planeakt,d0
move.w d0,cladr+2
swap d0
move.w d0,cladr+6
swap d0
add.l #40,d0
move.w d0,cladr+10
swap d0
move.w d0,cladr+14
swap d0
add.l #40,d0
move.w d0,cladr+18
swap d0
move.w d0,cladr+22
swap d0
add.l #40,d0
move.w d0,cladr+26
swap d0
move.w d0,cladr+30

move.w #$87c0,$94(a5)

jsr tabinit
jsr hauptprogramm

move.w #$03f0,$94(a5)

move.w intenaold,d0
bset #15,d0
move.w d0,$98(a5)
move.l graphicsbase,a1
move.l 38(a1),$7e(a5)
move.w #0,$86(a5)
jsr -414(a6)
move.w #$83f0,$94(a5)
error:
jsr -138(a6)
clr.l d0
rts

intenaold: dc.w 0

hauptprogramm:
clr.w bildnr

ranzoomen:
btst #10,$14(a5)
beq ende
btst #6,$bfe001
bne.s ranzoomen

move.w bildnr,d0
move.l planeakt,a0
lea 160(a0),a0
move.l planeverd,a1
lea 160(a1),a1
lea origpic,a4
bsr vergroessern
bsr umschalten
addq.w #1,bildnr
cmpi.w #160,bildnr
blt.s ranzoomen

subq.w #1,bildnr

move.l #$30000,d0
verz:
subq.l #1,d0
bne.s verz

wegzoomen:
btst #10,$14(a5)
beq ende
btst #6,$bfe001
bne.s wegzoomen

move.w bildnr,d0
move.l planeakt,a0
lea 160(a0),a0
move.l planeverd,a1
lea 160(a1),a1
bsr verkleinern
bsr umschalten
subq.w #1,bildnr
bpl.s wegzoomen
bra hauptprogramm

ende:
rts

bildnr: dc.w 0

****************************************************************************

umschalten:
move.l planeakt,d0
move.l planeverd,d1
exg d0,d1
move.l d0,planeakt
move.l d1,planeverd

waitrast:
move.w 4(a5),d1
and.w #$ff00,d1
cmp.w #$f600,d1
blo.s waitrast

move.w d0,cladr+2
swap d0
move.w d0,cladr+6
swap d0
add.l #40,d0
move.w d0,cladr+10
swap d0
move.w d0,cladr+14
swap d0
add.l #40,d0
move.w d0,cladr+18
swap d0
move.w d0,cladr+22
swap d0
add.l #40,d0
move.w d0,cladr+26
swap d0
move.w d0,cladr+30

move.l #cpl_mod,d0
waitblit
move.l d0,$52(a5)		;DPT
move.w #-40,$72(a5)		;ADAT
move.w #10,$64(a5)		;DMOD
move.l #$ffffffff,$42(a5)	;Masken
move.l #$01f00000,$3E(a5)	;CON0
move.w #$3241,$56(a5)		;SIZE

move.w bildnr,d1
add.w d1,d1
add.w d1,d1
lea ModTabZeiger,a0
move.l (a0,d1.w),a0

move.w (a0)+,d1			;Offset
move.w (a0)+,d2			;Anzahl = Blt-Height
beq.s um_next

lsl.w #6,d2
addq.w #1,d2			;Bltsize

ext.l d1
add.l d0,d1			;Startadresse.

waitblit
move.l a0,$4e(a5)		;APT
move.l d1,$52(a5)		;DPT
move.w #$09f0,$3e(a5)		;CON0
move.w #0,$62(a5)		;AMOD
move.w d2,$56(a5)		;Size

um_next:
waitblit

move.l d0,$4e(a5)		;APT
addq.l #4,d0
move.l d0,$52(a5)		;DPT
move.w #10,$62(a5)		;AMOD
move.w #$09f0,$3E(a5)		;CON
move.w #$3241,$56(a5)		;SIZE

waitblit
rts

**********************************************************************
* Startinitialisierungen der Zoom-Routine                            *
**********************************************************************

TabInit:
lea ZeilenTab(PC),a0
lea BitTab(PC),a1

moveq #15,d0

 ti_loop1:
 lea WortTab(PC),a2
 move.w (a1)+,d1
 move.w #9,d2

  ti_loop2:
  move.w (a2)+,d3
  asl.w #4,d3
  add.w d1,d3
  move.w d3,(a0)+
  dbf d2,ti_loop2

 dbf d0,ti_loop1

lea ArbeitsTab(pc),a0
move.w #159,d0
move.w #2000,d1
 ti_loop3:
 move.w d1,(a0)+
 dbf d0,ti_loop3

lea ZeilenTab(pc),a0
lea Einftab(pc),a1
lea ArbeitsTab(pc),a2
clr.w d0

 ti_loop4:
 move.w (a0,d0.w),d1
 moveq #-2,d2

  ti_loop5:
  addq.w #2,d2
  cmp.w (a2,d2.w),d1
  bgt.s ti_loop5

 lea 318(a2),a3
 lea (a2,d2.w),a4

  ti_loop6:
  move.w -(a3),2(a3)
  cmpa.l a4,a3
  bhi.s ti_loop6

 move.w d1,(a4)

 lsr.w #1,d2
 move.w d2,(a1)+
 addq.w #2,d0
 cmp.w #160*2,d0
 blo.s ti_loop4

lea VielfachenTab,a2
clr.w (a2)+

move.w #120,d0
move.w #160,d1
move.w #200,d2

ti_loop10:
move.w d0,(a2)+
add.w d1,d0
dbf d2,ti_loop10

;Modulotabelle aufbauen

lea modulotab,a0
lea ModTabZeiger,a1
lea Vielfachentab,a2
moveq #1,d7			;n = Breite /2

move.l a0,(a1)+			;Offset auf Daten in ModTab für
move.l #0,(a0)+			;Bildnr. 0 (nichts sichtbar)


ti_loop9:
move.l a0,(a1)+			;Offset auf Daten in ModTab für
				;jeweilige Bildnr.
moveq #0,d6			;Register für Coplistoffsets

move.w d7,d0			;n
move.w d7,d2
mulu #$a000,d0
move.l #$640000,d1
sub.l d0,d1
swap d1				;= erste Zeile, in der Modulos
				;aus Tab geschrieben werden
add.w d1,d1
add.w d1,d1			;4*
add.w d1,d6			;+
add.w d1,d1			;8*
add.w d1,d6			;=12* (da Move Mod1; Mod2; Wait =
				;(3 CopperBefehle)
add.l d0,d0
swap d0				;= 2n* 200/320 = Höhe

move.l #$a000,d1
divu d2,d1
swap d1
clr.w d1
lsr.l #8,d1			;$a000/n * $100  als $10000er-Bruch

moveq #0,d2
moveq #0,d4

;in d0: Anzahl (eigentlich Anzahl-1 wegen Zeile 0) -> Schleifenvar.
;in d1: Zähler zum Aufaddieren
;d2: Aufaddierungsregister
;d3:
;d4: Jeweils letzte Zeile
;d6: Coplistoffset
;a0: ModTab
;a1: ModZeiger
;a2: VielfachenTab

move.w d6,(a0)+			;Coplistoffset schreiben
move.w d0,(a0)+			;Anzahl-1 schreiben
addq.w #1,-2(a0)		;+1 = Anzahl (Bltsize-Höhe)

bra.s ti_loop7

ti_loop8:
add.l d1,d2			;Zähler aufaddieren
swap d2				;= i-te Zeile
move.w d2,d3			;darzustellende OrigZeile

sub.w d4,d3			;- letzte OrigZeile = Zeilendifferenz
add.w d3,d3			;*2 = VielfachenOffset

;move.w  d3,(a0)+
move.w (a2,d3.w),(a0)+		;Mod aus VfTab nach ModTab schreiben
move.w d2,d4
swap d2
ti_loop7:
dbf d0, ti_loop8

move.w #201,d3			;Von letzter Zeile (d4) auf OrgZeile 201
sub.w d4,d3			;Zeilendifferenz
add.w d3,d3
move.w (a2,d3.w),(a0)+
;move.w  d3,(a0)+
addq.w #1,d7
cmp.w #160,d7
bls.s ti_loop9
rts

****************************************************************************
verkleinern:
****************************************************************************

;A0 Quellpuffer
;A1 Zielpuffer
;Bildnr. in d0

;lea $dff002,a5

add.w d0,d0
lea EinfTab(pc),a2
move.w #$9f,d6
sub.w (a2,d0.w),d6

move.l a0,a2			;Pufferadr. kopieren
move.l a1,a3

move.w d6,d7
not.w d7
and.w #$f,d7			;Bitnr. links in   d7
lsr.w #4,d6			;Breite-1 in W. in d6
move.w d6,d5
add.w d5,d5			;Breite-2 in B. in d5

*** LINKER TEIL

moveq #38,d0
sub.w d5,d0
move.w d6,d1
add.w #$c801,d1

waitblit
move.l #$fffffffe,$42(a5)	;FWM,LWM
movem.l a0/A1,$4E(a5)		;APT,DPT
move.w d0,$62(a5)		;AMOD
move.w d0,$64(a5)		;DMOD
move.l #$19f00000,$3e(a5)	;CON0,CON1
move.w d1,$56(a5)		;SIZE

*** LINKER TEIL RECHTES WORT

adda.w d5,a0
adda.w d5,a1
clr.w d4
bset d7,d4
subq.w #1,d4
;beq nächste Blitteroperation
moveq #38,d2
waitblit
movem.l a0/a1,$4E(a5)		;APT,DPT
move.l a1,$4a(a5)		;BPT
move.w d2,$60(a5)		;BMOD
move.w d2,$62(a5)		;AMOD
move.w d2,$64(a5)		;DMOD
move.w #$ffff,$44(a5)		;LWM
move.w d4,$6e(a5)		;CDAT
move.w #$0de4,$3e(a5)		;CON0
move.w #$c801,$56(a5)		;SIZE

*** MITTE

moveq #18,d2
sub.w d5,d2			;Breite Mitte in W.
beq.s vk_nextBlit		;falls 0, nächste Operation
moveq #40,d3
sub.w d2,d3
sub.w d2,d3
add.w #$c800,d2
addq.w #2,a0
addq.w #2,a1

waitblit
movem.l a0/a1,$4e(a5)		;APT,DPT
move.w d3,$62(a5)		;AMOD
move.w d3,$64(a5)		;DMOD
move.w #$09f0,$3e(a5)		;CON0
move.w d2,$56(a5)		;SIZE

*** RECHTER TEIL

vk_nextblit:
lea $7d00-2(a2),a2
lea $7d00-2(a3),a3
waitblit
movem.l a2/a3,$4E(a5)		;APT,DPT
move.w #$7fff,$44(a5)		;LWM
move.w d0,$62(a5)		;AMOD
move.w d0,$64(a5)		;DMOD
move.l #$19f00002,$3e(a5)	;CON0,CON1
move.w d1,$56(a5)		;SIZE

*** RECHTER TEIL LINKES WORT

eori.w #$f,d7
addq.w #1,d7
clr.w d4
bset d7,d4
;subq.w #1,d7
subq.w #1,d4
not.w d4
;beq Ende (==> RTS)

moveq #38,d2
suba.w d5,a2
suba.w d5,a3

waitblit
movem.l a2/a3,$4E(a5)		;APT,DPT
move.l a3,$4a(a5)		;BPT
move.w d2,$60(a5)		;BMOD
move.w d2,$62(a5)		;AMOD
move.w d2,$64(a5)		;DMOD
move.w #$ffff,$44(a5)		;LWM
move.w d4,$6e(a5)		;CDAT
move.w #$0DE4,$3e(a5)		;CON0
move.w #$c801,$56(a5)		;SIZE
rts

****************************************************************************
vergroessern:
****************************************************************************

;A0 Quellpuffer
;A1 Zielpuffer
;Bildnr. in d0
;A4 Zeiger auf OriginalBild

lea $dff002,a5

lea einftab(pc),a2
add.w d0,d0
move.w d0,-(a7)                 ;Tabellenoffset auf Stack retten
move.w #$9f,d6
sub.w (a2,d0.w),d6

move.l a0,a2			;Pufferadr. kopieren
move.l a1,a3

move.w d6,d7
and.w #$f,d7			;Bitpos rechts in d7
lsr.w #4,d6			;Breite-1 in W. d6
move.w d6,d5
add.w d5,d5			;Breite-2 in B. in d5

*** RECHTER TEIL

lea 38(a0),a0
lea 38(a1),a1
suba.w d5,a0			;Startadr.
suba.w d5,a1

moveq #38,d0
sub.w d5,d0			;Modulo
move.w d6,d1
add.w #$c801,d1			;Size

waitblit
move.l #$ffffffff,$42(a5)       ;FWM,LWM
movem.l a0/a1,$4e(a5)		;APT,DPT
move.w d0,$62(a5)               ;AMOD
move.w d0,$64(a5)		;DMOD
move.l #$19f00000,$3e(a5)       ;CON0,CON1
move.w d1,$56(a5)		;SIZE

*** RECHTER TEIL LINKES WORT

lea $7d00-4(a2),a0
lea $7d00-2(a3),a1		;Startadr.
suba.w d5,a0
suba.w d5,a1

clr.w d4
addq.w #1,d7
bset d7,d4
subq.w #1,d7
subq.w #1,d4			;Maske
not.w d4
;beq next_Blit_OP

moveq #38,d2			;Modulo

waitblit

move.l a1,$4a(a5)		;BPT
move.l a1,$4e(a5)		;APT
move.l a1,$52(a5)		;DPT
move.w d2,$60(a5)		;BMOD
move.w d2,$62(a5)		;AMOD
move.w d2,$64(a5)		;DMOD
move.w d4,$6e(a5)		;CDAT
move.l #$1de40002,$3e(a5)       ;CON0,CON1
move.w #$c801,$56(a5)		;SIZE

;next_Blit_O:P
subq.w #2,a1

*** MITTE

moveq #18,d2
sub.w d5,d2                     ;Breite Mitte in W.
beq.s vgr_nextblit		;falls 0, nächste Operation
moveq #40,d3
sub.w d2,d3
sub.w d2,d3			;Modulo

waitblit

movem.l a0/a1,$4e(a5)		;APT,DPT
move.w d3,$62(a5)		;AMOD
move.w d3,$64(a5)               ;DMOD
move.w d2,d3
add.w #$c800,d2
move.w #$09f0,$3e(a5)		;CON0
move.w d2,$56(a5)		;SIZE

add.w d3,d3
suba.w d3,a0
suba.w d3,a1

*** LINKER TEIL

vgr_nextblit:

waitblit

movem.l a0/a1,$4e(a5)		;APT,DPT
move.w d0,$62(a5)		;AMOD
move.w d0,$64(a5)		;DMOD
move.w #$19f0,$3e(a5)		;CON0
move.w d1,$56(a5)		;SIZE

*** LINKER TEIL RECHTES WORT

lea (a3,d5.w),a1
moveq #38,d2
clr.w d4
eori.w #$f,d7
bset d7,d4
subq.w #1,d4
;beq nextOp

waitblit
move.l a1,$4a(a5)		;BPT
move.l a1,$4e(a5)		;APT
move.l a1,$52(a5)		;DPT
move.w d2,$60(a5)		;BMOD
move.w d2,$62(a5)		;AMOD
move.w d2,$64(a5)		;DMOD
move.w d4,$6e(a5)		;CDAT
move.l #$1de40000,$3e(a5)	;CON0,CON1
move.w #$c801,$56(a5)		;SIZE

;Daten, die jetzt noch benötigt werden:
;d5 (Breite-2) in Bytes
;a3 Zielpuffer
;a4 Zeiger auf OriginalBild
;d7 Bitnummer Einfügstelle links

move.w (a7)+,d0			;Bildnr.

*** Zeile links einfügen

lea ZeilenTab(pc),a2
move.w (a2,d0.w),d6		;Origzeile Zeilentab
move.w #$9f,d1
sub.w d6,d1			;Origzeile $9f-Zeilentab
move.w d1,d2
not.w d2
and.w #$f,d2			;Bitpos Origzeile links
lsr.w #4,d1
add.w d1,d1                     ;Offset in OrigBild in Bytes

lea (a4,d1.w),a0		;Quelle OrigBild
lea (a3,d5.w),a1		;Ziel A/D
bsr einfuegen

*** Zeile rechts einfügen

neg.w d1
lea 38(a4,d1.w),a0
neg.w d5
lea 38(a3,d5.w),a1
eor #$f,d7
eor #$f,d2
bsr einfuegen
rts

einfuegen:
clr.w   d4
bset d7,d4

move.w d2,d3
sub.w d7,d3
bmi ef_desc

;ascending

ror.w #4,d3			;Barrelshifter-Bits positionieren
or.w  #$0de4,d3

waitblit

movem.l a0/a1,$4e(a5)		;APT,DPT
move.l  a1,$4a(a5)		;BPT
move.w  d3,$3e(a5)		;CON0
move.w  #0,$40(a5)		;CON1
move.w  d4,$6e(a5)              ;CDAT
move.w  #$c801,$56(a5)		;SIZE
rts

ef_desc:
neg.w d3
ror.w #4,d3
or.w #$0de4,d3

lea 799*40(a0),a0
lea 799*40(a1),a1

waitblit

movem.l a0/a1,$4e(a5)		;APT,DPT
move.l  a1,$4a(a5)		;BPT
move.w d3,$3e(a5)		;CON0
move.w #2,$40(a5)		;CON1
move.w d4,$6e(a5)		;CDAT
move.w #$c801,$56(a5)		;SIZE
rts

ZeilenTab:	blk.w 160,0
EinfTab: 	blk.w 160,0
ArbeitsTab:	blk.w 160,0

WortTab: dc.w 0,5,7,3,9,1,6,4,8,2
BitTab: dc.w 8,12,4,14,2,10,6,15,0,3,13,5,11,9,7,1

grname: dc.b "graphics.library",0,0
graphicsbase: dc.l 0

cladr:
dc.w $e2,0,$e0,0, $e6,0,$e4,0, $ea,0, $e8,0, $ee,0, $ec,0
dc.w 0,0,0
cpl_mod:
blk.b 6,0
blk.b 200*12
dc.w $ffff,$fffe

planeAkt:  dc.l planes1
planeVerd: dc.l planes2

VielfachenTab: blk.w 202,0
ModTabZeiger:  blk.l 161,0
ModuloTab:     blk.b 33044 	;Format dc.w Coplistoffset,Anzahl,
                           	;            Wert1, Wert2, ...
planes1:  blk.b 32320,0
planes2:  blk.b 32320,0
origpic:  blk.b 32000,0
col1: blk.w 16,0