34 lines
1.2 KiB
ArmAsm
34 lines
1.2 KiB
ArmAsm
include "includes.i"
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xdef Init
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;; custom chip base globally in a6
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Init:
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movem.l d0-a6,-(sp)
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;; move #$7ff,DMACON(a6) ; disable all dma
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;; move #$7fff,INTENA(a6) ; disable all interrupts
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;; lea Level3InterruptHandler,a3
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;; move.l a3,LVL3_INT_VECTOR
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;; set up playfield
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move.w #(RASTER_Y_START<<8)|RASTER_X_START,DIWSTRT(a6)
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move.w #((RASTER_Y_STOP-256)<<8)|(RASTER_X_STOP-256),DIWSTOP(a6)
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move.w #(RASTER_X_START/2-SCREEN_RES)-8,DDFSTRT(a6) ; -8 for extra scrolling word
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move.w #(RASTER_X_START/2-SCREEN_RES)+(8*((SCREEN_WIDTH/16)-1)),DDFSTOP(a6)
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;; enabled 2x the bitplanes as 2x playfields
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move.w #(SCREEN_BIT_DEPTH*2<<12)|COLOR_ON|DBLPF,BPLCON0(a6)
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move.w #BITPLANE_WIDTH_BYTES*SCREEN_BIT_DEPTH-SCREEN_WIDTH_BYTES-2,BPL1MOD(a6) ; -2 for extra scrolling word
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move.w #BITPLANE_WIDTH_BYTES*SCREEN_BIT_DEPTH-SCREEN_WIDTH_BYTES-2,BPL2MOD(a6)
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;; install copper list, then enable dma and selected interrupts
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lea copperList,a0
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move.l a0,COP1LC(a6)
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move.w COPJMP1(a6),d0
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move.w #(DMAF_BLITTER|DMAF_SETCLR!DMAF_COPPER!DMAF_RASTER!DMAF_MASTER),DMACON(a6)
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;; move.w #PF2PRI,BPLCON2(a6)
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;; move.w #(INTF_SETCLR|INTF_VERTB|INTF_INTEN),INTENA(a6)
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movem.l (sp)+,d0-a6
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rts |