157 lines
4.6 KiB
ArmAsm
157 lines
4.6 KiB
ArmAsm
include "../include/registers.i"
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include "hardware/dmabits.i"
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include "hardware/intbits.i"
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LVL3_INT_VECTOR equ $6c
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SCREEN_WIDTH equ 320
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SCREEN_HEIGHT equ 256
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SCREEN_WIDTH_BYTES equ (SCREEN_WIDTH/8)
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SCREEN_BIT_DEPTH equ 5
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SCREEN_RES equ 8 ; 8=lo resolution, 4=hi resolution
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RASTER_X_START equ $81 ; hard coded coordinates from hardware manual
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RASTER_Y_START equ $2c
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RASTER_X_STOP equ RASTER_X_START+SCREEN_WIDTH
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RASTER_Y_STOP equ RASTER_Y_START+SCREEN_HEIGHT
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BOB_WIDTH equ 64+16 ; Must blit extra word to allow shifting
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BOB_HEIGHT equ 64
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BOB_WIDTH_BYTES equ BOB_WIDTH/8
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BOB_WIDTH_WORDS equ BOB_WIDTH/16
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BOB_XPOS equ 16
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BOB_YPOS equ 16
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BOB_XPOS_BYTES equ (BOB_XPOS)/8
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entry:
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;; custom chip base globally in a6
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lea CUSTOM,a6
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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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include "out/image-palette.s"
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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),DDFSTRT(a6)
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move.w #(RASTER_X_START/2-SCREEN_RES)+(8*((SCREEN_WIDTH/16)-1)),DDFSTOP(a6)
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move.w #(SCREEN_BIT_DEPTH<<12)|$200,BPLCON0(a6)
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move.w #SCREEN_WIDTH_BYTES*SCREEN_BIT_DEPTH-SCREEN_WIDTH_BYTES,BPL1MOD(a6)
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move.w #SCREEN_WIDTH_BYTES*SCREEN_BIT_DEPTH-SCREEN_WIDTH_BYTES,BPL2MOD(a6)
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;; poke bitplane pointers
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lea bitplanes(pc),a1
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lea copper(pc),a2
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moveq #SCREEN_BIT_DEPTH-1,d0
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.bitplaneloop:
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move.l a1,d1
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move.w d1,2(a2)
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swap d1
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move.w d1,6(a2)
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lea SCREEN_WIDTH_BYTES(a1),a1 ; bit plane data is interleaved
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addq #8,a2
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dbra d0,.bitplaneloop
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;; install copper list, then enable dma and selected interrupts
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lea copper(pc),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 #(INTF_SETCLR|INTF_INTEN|INTF_EXTER),INTENA(a6)
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bsr.s doblit
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.mainLoop:
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move.w #$02a,d0 ;wait for EOFrame
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bsr.s waitRaster
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bra.s .mainLoop
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waitRaster: ;wait for rasterline d0.w. Modifies d0-d2/a0.
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move.l #$1ff00,d2
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lsl.l #8,d0
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and.l d2,d0
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lea $dff004,a0
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.wr: move.l (a0),d1
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and.l d2,d1
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cmp.l d1,d0
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bne.s .wr
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rts
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blitWait:
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tst DMACONR(a6) ;for compatibility
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.waitblit:
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btst #6,DMACONR(a6)
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bne.s .waitblit
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rts
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;; BLTCON? configuration
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;; http://amigadev.elowar.com/read/ADCD_2.1/Hardware_Manual_guide/node011C.html
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;; blitter logic function minterm truth table
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;; fill in D column for desired function
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;; A(mask) B(bob) C(bg) D(dest)
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;; - - - -
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;; 0 0 0 0
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;; 0 0 1 1
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;; 0 1 0 0
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;; 0 1 1 1
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;; 1 0 0 0
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;; 1 0 1 0
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;; 1 1 0 1
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;; 1 1 1 1
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;; read D column from bottom up = 11001010 = $ca
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;; this is used in the LF? bits
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BLIT_LF_MINTERM equ $ca
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BLIT_A_SOURCE_SHIFT equ 8 ; number of pixels from BOB_XPOS to move the bob right
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BLIT_B_SOURCE_SHIFT equ 8 ; number of pixels from BOB_XPOS to move the bob right
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BLIT_DEST equ $100
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BLIT_SRCC equ $200
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BLIT_SRCB equ $400
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BLIT_SRCA equ $800
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BLIT_ASHIFTSHIFT equ 12 ;Bit index of ASH? bits
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BLIT_BLTCON1 equ BLIT_B_SOURCE_SHIFT<<BLIT_ASHIFTSHIFT
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doblit:
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movem.l d0-a6,-(sp)
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bsr blitWait
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move.w #(BLIT_SRCA|BLIT_SRCB|BLIT_SRCC|BLIT_DEST|BLIT_LF_MINTERM|BLIT_A_SOURCE_SHIFT<<BLIT_ASHIFTSHIFT),BLTCON0(A6)
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move.w #BLIT_BLTCON1,BLTCON1(a6)
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move.w #$ffff,BLTAFWM(a6) ; no mask for first word
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move.w #$0000,BLTALWM(a6) ; mask out last word
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move.w #-2,BLTAMOD(a6) ; negative 2 byte modulo to account for extra blitted word
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move.w #-2,BLTBMOD(a6) ; negative 2 byte modulo to account for extra blitted word
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move.w #SCREEN_WIDTH_BYTES-BOB_WIDTH_BYTES,BLTCMOD(a6) ;C modulo
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move.w #SCREEN_WIDTH_BYTES-BOB_WIDTH_BYTES,BLTDMOD(a6) ;D modulo
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move.l #emojiMask,BLTAPTH(a6) ; mask bitplane
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move.l #emoji,BLTBPTH(a6) ; bob bitplane
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move.l #bitplanes+BOB_XPOS_BYTES+(SCREEN_WIDTH_BYTES*SCREEN_BIT_DEPTH*BOB_YPOS),BLTCPTH(a6) ;background top left corner
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move.l #bitplanes+BOB_XPOS_BYTES+(SCREEN_WIDTH_BYTES*SCREEN_BIT_DEPTH*BOB_YPOS),BLTDPTH(a6) ;destination top left corner
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move.w #(BOB_HEIGHT*SCREEN_BIT_DEPTH)<<6|(BOB_WIDTH_WORDS),BLTSIZE(a6) ;rectangle size, starts blit
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movem.l (sp)+,d0-a6
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rts
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copper:
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;; bitplane pointers must be first else poking addresses will be incorrect
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dc.w BPL1PTL,0
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dc.w BPL1PTH,0
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dc.w BPL2PTL,0
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dc.w BPL2PTH,0
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dc.w BPL3PTL,0
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dc.w BPL3PTH,0
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dc.w BPL4PTL,0
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dc.w BPL4PTH,0
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dc.w BPL5PTL,0
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dc.w BPL5PTH,0
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dc.l $fffffffe
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bitplanes:
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incbin "out/image.bin"
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emoji:
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incbin "out/emoji.bin"
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emojiMask:
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incbin "out/emoji-mask.bin" |