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; Start DMA
;
MOVE.W #(DMAF_SETCLR!DMAF_RASTER!DMAF_MASTER),DMACON(a0)
; Enable bit-plane DMA only, no Copper
; Because this example has no Copper list, it sits in a
; loop waiting for the vertical blanking interval. When it
; comes, you check the LOF ( long frame bit in VPOSR. If
; LOF = 0, this is a short frame and the bit-plane pointers
; are set to point to S20050. If LOF = 1, then this is a
; long frame and the bit-plane pointers are set to point to
; $20000. This keeps the long and short frames in the
; right relationship to each other.
VLOOP:
MOVE.W INTREQR(a0),d0 ; Read interrupt requests
AND.W #$0020,d0 ; Mask off all but vertical blank
BEQ VLOOP ; Loop until vertical blank comes
MOVE.W #$0020,INTREQ(a0) ; Reset vertical interrupt
MOVE.W VPOSR(a0),d0 ; Read LOF bit into d0 bit 15
BPL VL1 ; If LOF = 0, jump
MOVE.L #$20000,BPL1PTH(a0) ; LOF = 1, point to $20000
BRA VLOOP ; Back to top
VL1:
MOVE.L #$20050,BPL1PTH(a0) ; LOF = 0, point to $20050
BRA VLOOP ; Back to top
;
; Character list
;
CHARLIST:
DC.L $18FC3DF0,$3C6666D8,$3C66C0CC,$667CC0CC
DC.L $7E66C0CC,$C36666D8,$C3FC3DF0,$00000000
DC.L $FFFFFFFF
- 61 Playfield Hardware -
Summary of Contents for Amiga A1000
Page 1: ...AMIGA HARDWARE REFERENCE MANUAL 1992 Commodore Business Machines Amiga 1200 PAL...
Page 20: ...Figure 1 1 Block Diagram for the Amiga Computer Family Introduction 11...
Page 21: ...12 Introduction...
Page 72: ...Figure 3 12 A dual Playfield display Playfield Hardware 63...
Page 87: ...Figure 3 24 Horizontal Scrolling 78 playfield hardware...
Page 101: ...92 Playfield Hardware...
Page 199: ...Figure 6 9 DMA time slot allocation 190 Blitter hardware...
Page 203: ...Figure 6 13 Blitter Block Diagram 194 Blitter Hardware...
Page 229: ...220 System Control Hardware...
Page 246: ...Figure 8 8 Chinon Timing diagram cont Interface Hardware 237...
Page 265: ...256 Interface Hardware...
Page 289: ...280 Appendix A...
Page 297: ...288 Appendix B...
Page 298: ...APPENDIX C CUSTOM CHIP PIN ALLOCATION LIST NOTE Means an active low signal Appendix C 289...
Page 302: ...APPENDIX D SYSTEM MEMORY MAP Appendix D 293...
Page 343: ...334 Appendix F...
Page 351: ...342 Appendix G...
Page 361: ...352 Appendix H...
Page 367: ...358 Appendix I...