; ; Copperlist Example 2. ; ; Written for OZAmiga by Chris Leathley. ; ; Example of copper timing and how it can be used to split colours ; horizontaly ; ; ; Branch offsets into the Amiga's rom kernal librarys (exec) ; Forbid = -132 ; turn off Multitasking Permit = -138 ; turn it back on again CloseLibrary = -414 ; open a library (from ram or disk) OpenLibrary = -552 ; close an opened library ; -------------------------------------------------------------------------- ; a68k code SECTION code,CODE,CHIP ; make sure in chip memory ; devpac code ; SECTION code,CODE_C ; make sure in chip memory ; -------------------------------------------------------------------------- ; program starts here ; START: clr.l $0 ; clear address 0 move.l $4,a6 ; turn off multitasking jsr Forbid(a6) .wait_vb cmp.b #$FF,$00DFF006 ; wait for vb to change bne.s .wait_vb move.l #SECONDCOPPER,$00DFF080 ; insert new copperlist move.w #$8280,$00DFF096 ; use new control bits ; wait for user to press the left mouse button and then exit program ; MAIN_LOOP: cmp.b #$FF,$00DFF006 ; wait for vertical blank bne.s MAIN_LOOP btst #$06,$00BFE001 ; left mouse button ? bne.s MAIN_LOOP ; no? do it all again ; program finished, exit back to dos ; EXIT: move.l $4,a6 ; exec pointer lea GFX_NAME,a1 ; library name moveq #0,d0 ; library version jsr OpenLibrary(a6) ; open graphics library move.l d0,a1 ; d0 has pointer to library move.l $0026(a1),$00DFF080 ; restore original copperlist jsr CloseLibrary(a6) ; close graphics library jsr Permit(a6) ; turn back on multitasking moveq #0,d0 ; no errors rts ; return of amiga dos ; -------------------------------------------------------------------------- ; graphics library name ; GFX_NAME: dc.b 'graphics.library',0 EVEN ; ; our second copperlist program ; ; examples of spliting up the copper on the horizontal axis ; SECONDCOPPER: dc.w $0180,$0000 ; screen starts off black dc.w $0100,$0000 ; turn off bitplane display ; ; aswell as waiting for vertical positions, the copper can wait for ; horizontal positions as well. $8F is the middle of the screen. ; The horizontail copper wait register must be a odd number. ; If you wait for $8E or $90 then the copper will become corrupt and ; will most likely crash the machine. ; dc.w $9009,$FFFE,$0180,$0F00,$908F,$FFFE,$0180,$00F0 ; ; wait for line $90 and change colour to red, then wait for the middle of the ; same line and change to colour to green. ; dc.w $9109,$FFFE,$0180,$0F00,$918F,$FFFE,$0180,$00F0 dc.w $9209,$FFFE,$0180,$0F00,$928F,$FFFE,$0180,$00F0 dc.w $9309,$FFFE,$0180,$0F00,$938F,$FFFE,$0180,$00F0 dc.w $9409,$FFFE,$0180,$0F00,$948F,$FFFE,$0180,$00F0 dc.w $9509,$FFFE,$0180,$0F00,$958F,$FFFE,$0180,$00F0 dc.w $9609,$FFFE,$0180,$0F00,$968F,$FFFE,$0180,$00F0 dc.w $9709,$FFFE,$0180,$0F00,$978F,$FFFE,$0180,$00F0 dc.w $9809,$FFFE,$0180,$0F00,$988F,$FFFE,$0180,$00F0 dc.w $9909,$FFFE,$0180,$0F00,$998F,$FFFE,$0180,$00F0 dc.w $9A09,$FFFE,$0180,$0F00,$9A8F,$FFFE,$0180,$00F0 dc.w $9B09,$FFFE,$0180,$0F00,$9B8F,$FFFE,$0180,$00F0 dc.w $9C09,$FFFE,$0180,$0F00,$9C8F,$FFFE,$0180,$00F0 dc.w $9D09,$FFFE,$0180,$0F00,$9D8F,$FFFE,$0180,$00F0 dc.w $9E09,$FFFE,$0180,$0F00,$9E8F,$FFFE,$0180,$00F0 dc.w $9F09,$FFFE,$0180,$0000 ; screen back to black ; ; This section creates and white and blue jaggie line. The copper has ; a "waiting" resolution of about 4 lo-res pixels. ; dc.w $B009,$FFFE,$0180,$0FFF,$B081,$FFFE,$0180,$000F dc.w $B109,$FFFE,$0180,$0FFF,$B183,$FFFE,$0180,$000F dc.w $B209,$FFFE,$0180,$0FFF,$B285,$FFFE,$0180,$000F dc.w $B309,$FFFE,$0180,$0FFF,$B387,$FFFE,$0180,$000F dc.w $B409,$FFFE,$0180,$0FFF,$B489,$FFFE,$0180,$000F dc.w $B509,$FFFE,$0180,$0FFF,$B58B,$FFFE,$0180,$000F dc.w $B609,$FFFE,$0180,$0FFF,$B68D,$FFFE,$0180,$000F dc.w $B709,$FFFE,$0180,$0FFF,$B78F,$FFFE,$0180,$000F dc.w $B809,$FFFE,$0180,$0FFF,$B891,$FFFE,$0180,$000F dc.w $B909,$FFFE,$0180,$0FFF,$B993,$FFFE,$0180,$000F dc.w $BA09,$FFFE,$0180,$0FFF,$BA95,$FFFE,$0180,$000F dc.w $BB09,$FFFE,$0180,$0FFF,$BB97,$FFFE,$0180,$000F dc.w $BC09,$FFFE,$0180,$0FFF,$BC99,$FFFE,$0180,$000F dc.w $BD09,$FFFE,$0180,$0FFF,$BD9B,$FFFE,$0180,$000F dc.w $BE09,$FFFE,$0180,$0FFF,$BE9D,$FFFE,$0180,$000F dc.w $BF09,$FFFE,$0180,$0000 ; screen back to black ; ; this section creates the red and white dotted line across the screen. ; what it does is wait for the start of the line and then changes the ; background colour as fast as it can. ; ; after running this program you will notice that the space between the ; colours is about 8 pixels. Each copperlist entry takes 2 machine ; cycles to execute. It is not possible to modify the complete 32 ; colour registers in the "horizontal blank" (the area between the end ; of a line and the start of the next line). ; ; most games constantly modify the colour palette as it goes down the ; screen. A more current example is LIONHEART. the back parallax scroll ; only uses 3 colours. The copperlist changes the colours for the ; clouds and the mountains. The end effect is that the screen looks like ; it has a lot of colours on it. ; dc.w $D009,$FFFE dc.w $0180,$0FFF,$0180,$0F00,$0180,$0FFF,$0180,$0F00 dc.w $0180,$0FFF,$0180,$0F00,$0180,$0FFF,$0180,$0F00 dc.w $0180,$0FFF,$0180,$0F00,$0180,$0FFF,$0180,$0F00 dc.w $0180,$0FFF,$0180,$0F00,$0180,$0FFF,$0180,$0F00 dc.w $0180,$0FFF,$0180,$0F00,$0180,$0FFF,$0180,$0F00 dc.w $0180,$0FFF,$0180,$0F00,$0180,$0FFF,$0180,$0F00 dc.w $0180,$0FFF,$0180,$0F00,$0180,$0FFF,$0180,$0F00 dc.w $0180,$0FFF,$0180,$0F00,$0180,$0FFF,$0180,$0F00 dc.w $0180,$0FFF,$0180,$0F00,$0180,$0FFF,$0180,$0F00 dc.w $0180,$0FFF,$0180,$0F00,$0180,$0FFF,$0180,$0F00 dc.w $0180,$0FFF,$0180,$0F00,$0180,$0FFF,$0180,$0F00 dc.w $0180,$0FFF,$0180,$0F00,$0180,$0FFF,$0180,$0F00 dc.w $0180,$0FFF,$0180,$0F00,$0180,$0FFF,$0180,$0F00 dc.w $0180,$0FFF,$0180,$0F00,$0180,$0FFF,$0180,$0F00 dc.w $D109,$FFFE,$0180,$0000 ; screen back to black dc.w $FFFF,$FFFE ; end of copper list ; start vertical blank ; -------------------------------------------------------------------------- END ; end of program