THIS SOURCE FILE HAS BEEN PACKED USING POWERPACKER 2. TO USE IT YOU WILL NEED TO DEPACK IT! ; 'core.s' source , see accompaning text in the May 1994 issue ; of Amiga computing . Written by Mark Jackson using Devpac 3.02 ; what this basically does is take over the system and set up our ; own screen . When the 'ESC' key is pressed the system will be restored ; this can be used as the core of any program section core,code_c ; put in CHIP memory opt c-,o+ ; not case-sensitive ; optimisation on move.l 4.w,a6 ; execbase jsr forbid(a6) ; turn off multitasking! lea $dff000,a5 ; a5 always points to ; register's base address move.l #40*256*5,d0 ; number of bytes we require = ; 40 bytes * 256 lines * 5 bitplanes moveq.l #2,d1 ; chip memory please move.l 4.w,a6 ; execbase jsr allocmem(a6) ; allocate us some memory , please tst.l d0 ; is there enough spare memory? beq error ; no - exit program! move.l d0,screen ; save address of our memory move.l screen,a0 ; address to start clearing move.w #40*256*5,d0 ; number of bytes to clear bsr clear_memory ; clear memory lea gfxlib,a1 ; name of library to open moveq #0,d0 ; version number unimportant move.l 4.w,a6 ; execbase jsr openlib(a6) ; open graphics-library move.l d0,gfxbase ; save base address move.l screen,d0 ; address of first bitplane move.l d0,d1 move.w d1,pl1l ; set pointer low word swap d1 move.w d1,pl1h ; and high word add.l #40*256,d0 ; point to next bitplane move.l d0,d1 move.w d1,pl2l swap d1 move.w d1,pl2h add.l #40*256,d0 move.l d0,d1 move.w d1,pl3l swap d1 move.w d1,pl3h add.l #40*256,d0 move.l d0,d1 move.w d1,pl4l swap d1 move.w d1,pl4h add.l #40*256,d0 move.l d0,d1 move.w d1,pl5l swap d1 move.w d1,pl5h move.l gfxbase,a6 ; graphics-library base address move.w #$80,dmacon(a5) ; turn copper dma off move.l $32(a6),oldcpr ; save address of old copper-list move.l #newcpr,$32(a6) ; insert our new copper-list move.w #$8080,dmacon(a5) ; and turn copper dma back on! main_loop: move.b vhposr(a5),d0 ; get scanline cmp.b #$ff,d0 ; reached line $ff? bne.s main_loop ; not yet ; this is where our routines ; are called from move.b $bfec01,d0 ; read keyboard (raw keycode) eor.b #$ff,d0 ; decode byte ror.b #1,d0 cmp.b #$45,d0 ; escape key pressed? bne.s main_loop ; nope! - loop back until it is move.l gfxbase,a6 ; graphics-library base address move.w #$80,dmacon(a5) ; copper dma off move.l oldcpr,$32(a6) ; restore system copper-list move.w #$8080,dmacon(a5) ; copper dma on move.l 4.w,a6 ; execbase move.l screen,a1 ; address of screen memory move.l #40*256*5,d0 ; number of bytes we took jsr freemem(a6) ; free the memory move.l gfxbase,a1 ; graphics-library base address move.l 4.w,a6 ; execbase jsr closelib(a6) ; close library error: move.l 4.w,a6 ; execbase jsr permit(a6) ; multitasking on moveq #0,d0 ; no errors , please! rts ; and return to CLI oldcpr: ; space to store address of dc.l 0 ; system copper-list newcpr: ; our new copper-list dc.w bplcon0,$5200 ; 5 bitplane (32 colour) screen dc.w bpl1mod,0 ; bitplane modulo (odd bitplanes) dc.w bpl2mod,0 ; bitplane modulo (even bitplanes) dc.w ddfstrt,$38 ; left edge of screen dc.w ddfstop,$d0 ; right edge of screen dc.w diwstrt,$2c81 ; top left corner of screen dc.w diwstop,$2cc1 ; bottom right corner of screen dc.w bpl1pth ; bitplane pointers pl1h: dc.w 0,bpl1ptl pl1l: dc.w 0,bpl2pth pl2h: dc.w 0,bpl2ptl pl2l: dc.w 0,bpl3pth pl3h: dc.w 0,bpl3ptl pl3l: dc.w 0,bpl4pth pl4h: dc.w 0,bpl4ptl pl4l: dc.w 0,bpl5pth pl5h: dc.w 0,bpl5ptl pl5l: dc.w 0 dc.w spr0pth ; sprite pointers sp0h: dc.w 0,spr0ptl sp0l: dc.w 0,spr1pth sp1h: dc.w 0,spr1ptl sp1l: dc.w 0,spr2pth sp2h: dc.w 0,spr2ptl sp2l: dc.w 0,spr3pth sp3h: dc.w 0,spr3ptl sp3l: dc.w 0,spr4pth sp4h: dc.w 0,spr4ptl sp4l: dc.w 0,spr5pth sp5h: dc.w 0,spr5ptl sp5l: dc.w 0,spr6pth sp6h: dc.w 0,spr6ptl sp6l: dc.w 0,spr7pth sp7h: dc.w 0,spr7ptl sp7l: dc.w 0 dc.w colour0,$000 ; colours (red $0-$f , green $0-$f dc.w colour1,$fff ; blue $0-$f) e.g. $f00 = bright red dc.w colour2,$fff ; $ff0 = yellow , etc. dc.w colour3,$fff dc.w colour4,$fff dc.w colour5,$fff dc.w colour6,$fff dc.w colour7,$fff dc.w colour8,$fff dc.w colour9,$fff dc.w colour10,$fff dc.w colour11,$fff dc.w colour12,$fff dc.w colour13,$fff dc.w colour14,$fff dc.w colour15,$fff dc.w colour16,$fff dc.w colour17,$fff dc.w colour18,$fff dc.w colour19,$fff dc.w colour20,$fff dc.w colour21,$fff dc.w colour22,$fff dc.w colour23,$fff dc.w colour24,$fff dc.w colour25,$fff dc.w colour26,$fff dc.w colour27,$fff dc.w colour28,$fff dc.w colour29,$fff dc.w colour30,$fff dc.w colour31,$fff dc.w $ffff,$fffe ; end of copper-list ************ clear memory ************ clear_memory: subq.w #1,d0 ; subtract one for dbra moveq.b #0,d1 ; value to fill memory with (zero) clear_loop: move.b d1,(a0)+ ; clear first byte , point to next dbra d0,clear_loop ; do this for every byte rts ; and that's it folks! ************ data ************ gfxlib: dc.b 'graphics.library',0 even gfxbase: dc.l 0 screen: dc.l 0 ; longword to store address of screen ************ equates ************ ** exec library offsets forbid equ -132 permit equ -138 openlib equ -552 closelib equ -414 allocmem equ -198 freemem equ -210 ** register offsets bplcon0 equ $100 bpl1mod equ $108 bpl2mod equ $10a bpl1pth equ $e0 bpl1ptl equ $e2 bpl2pth equ $e4 bpl2ptl equ $e6 bpl3pth equ $e8 bpl3ptl equ $ea bpl4pth equ $ec bpl4ptl equ $ee bpl5pth equ $f0 bpl5ptl equ $f2 diwstrt equ $8e diwstop equ $90 ddfstrt equ $92 ddfstop equ $94 dmacon equ $96 vhposr equ $6 spr0pth equ $120 spr0ptl equ $122 spr1pth equ $124 spr1ptl equ $126 spr2pth equ $128 spr2ptl equ $12a spr3pth equ $12c spr3ptl equ $12e spr4pth equ $130 spr4ptl equ $132 spr5pth equ $134 spr5ptl equ $136 spr6pth equ $138 spr6ptl equ $13a spr7pth equ $13c spr7ptl equ $13e colour0 equ $180 colour1 equ $182 colour2 equ $184 colour3 equ $186 colour4 equ $188 colour5 equ $18a colour6 equ $18c colour7 equ $18e colour8 equ $190 colour9 equ $192 colour10 equ $194 colour11 equ $196 colour12 equ $198 colour13 equ $19a colour14 equ $19c colour15 equ $19e colour16 equ $1a0 colour17 equ $1a2 colour18 equ $1a4 colour19 equ $1a6 colour20 equ $1a8 colour21 equ $1aa colour22 equ $1ac colour23 equ $1ae colour24 equ $1b0 colour25 equ $1b2 colour26 equ $1b4 colour27 equ $1b6 colour28 equ $1b8 colour29 equ $1ba colour30 equ $1bc colour31 equ $1be end