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Files
AmigaExamples/017.dual_playfield/init.s
2016-03-20 21:11:56 +11:00

44 lines
1.4 KiB
ArmAsm

include "../include/bplconbits.i"
;; custom chip base globally in a6
init:
movem.l d0-a6,-(sp)
move #$7ff,DMACON(a6) ; disable all dma
move #$7fff,INTENA(a6) ; disable all interrupts
;; set up default palette
bsr installColorPalette
;; poke playfield 1 bitplane pointers
lea pf1_bitplanepointers(pc),a0
lea pf1_bitplanes(pc),a1
bsr pokeBitplanePointers
;; poke playfield 2 bitplane pointers
lea pf2_bitplanepointers(pc),a0
lea pf2_bitplanes(pc),a1
bsr pokeBitplanePointers
;; set up playfield
move.w #(RASTER_Y_START<<8)|RASTER_X_START,DIWSTRT(a6)
move.w #((RASTER_Y_STOP-256)<<8)|(RASTER_X_STOP-256),DIWSTOP(a6)
move.w #(RASTER_X_START/2-SCREEN_RES),DDFSTRT(a6)
move.w #(RASTER_X_START/2-SCREEN_RES)+(8*((SCREEN_WIDTH/16)-1)),DDFSTOP(a6)
;; enabled 2x the bitplanes as 2x playfields
move.w #((SCREEN_BIT_DEPTH*2)<<12)|COLOR_ON|DBLPF,BPLCON0(a6)
;; set playfield2 to have priority
move.w #PF2PRI,BPLCON2(a6)
move.w #SCREEN_WIDTH_BYTES*SCREEN_BIT_DEPTH-SCREEN_WIDTH_BYTES,BPL1MOD(a6)
move.w #SCREEN_WIDTH_BYTES*SCREEN_BIT_DEPTH-SCREEN_WIDTH_BYTES,BPL2MOD(a6)
;; install copper list, then enable dma and selected interrupts
lea copper(pc),a0
move.l a0,COP1LC(a6)
move.w COPJMP1(a6),d0
move.w #(DMAF_BLITTER|DMAF_SETCLR!DMAF_COPPER!DMAF_RASTER!DMAF_MASTER),DMACON(a6)
;; move.w #(INTF_SETCLR|INTF_VERTB|INTF_INTEN),INTENA(a6)
movem.l (sp)+,d0-a6
rts