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COPINS (cont.) MOVE WAIT UNTIL SKIP IF
BIT IR1 IR2 IR1 IR2 IR1 IR2
15 X RD15 VP7 BFD * VP7 BFD *
14 X RD14 VP6 VE6 VP6 VE6
13 X RD13 VP5 VE5 VP5 VES
12 X RD12 VP4 VE4 VP4 VE4
11 X RD11 VP3 VE3 VP3 VE3
10 X RD10 VP2 VE2 VP2 VE2
09 X RD09 VP1 VE1 VP1 VE1
08 DA8 RD08 VP0 VE0 VP0 VE0
07 DA7 RD07 HP8 HE8 HP8 HE8
06 DA6 RD06 HP7 HE7 HP7 HE7
05 DAS RD05 HP6 HE6 HP6 HE6
04 DA4 RD04 HP5 HE5 HPS HES
03 DA3 RD03 HP4 HE4 HP4 HE4
02 DA2 RD02 HP3 HE3 HP3 HE3
01 DA1 RD01 HP2 HE2 HP2 HE2
00 0 RD00 1 0 1 1
IR1 =First instruction register
IR2 =Second instruction register
DA =Destination address for MOVE instruction. Fetched
during IR1 time, used during IR2 time on RGA bus.
RD =RAM data moved by MOVE instruction at IR2 time
directly from RAM to the address given by the
DA field.
VP =Vertical beam position comparison bit.
HP =Horizontal beam position comparison bit.
VE =Enable comparison (mask bit).
HE =Enable comparison (mask bit).
* NOTE BFD-Blitter finished disable. When this bit is true, the Blitter
Finished flag will have no effect on the Copper. When this
bit is zero, the Blitter Finished flag must be true (in addition to the
rest of the bit comparison) before the Copper can exit from its wait
state or skip over an instruction. Note that the V7 comparison cannot be
masked.
The Copper is basically a two-cycle machine that requests the bus only
during odd memory cycles (4 memory cycles per instruction). This prevents
collisions with display, audio, disk, refresh, and sprites, all of which
use only even cycles. It therefore needs (and has) priority over only the
blitter and micro-processor.
There are only three types of instructions: MOVE immediate, WAIT until,
and SKIP if. All instructions (except for WAIT) require two bus cycles
(and two instruction words). Since only the odd bus cycles are requested,
four memory cycle times are required per instruction (memory cycles are
280 ns.)
- Appendix A 269 -
Содержание Amiga A1000
Страница 1: ...AMIGA HARDWARE REFERENCE MANUAL 1992 Commodore Business Machines Amiga 1200 PAL...
Страница 20: ...Figure 1 1 Block Diagram for the Amiga Computer Family Introduction 11...
Страница 21: ...12 Introduction...
Страница 72: ...Figure 3 12 A dual Playfield display Playfield Hardware 63...
Страница 87: ...Figure 3 24 Horizontal Scrolling 78 playfield hardware...
Страница 101: ...92 Playfield Hardware...
Страница 199: ...Figure 6 9 DMA time slot allocation 190 Blitter hardware...
Страница 203: ...Figure 6 13 Blitter Block Diagram 194 Blitter Hardware...
Страница 229: ...220 System Control Hardware...
Страница 246: ...Figure 8 8 Chinon Timing diagram cont Interface Hardware 237...
Страница 265: ...256 Interface Hardware...
Страница 289: ...280 Appendix A...
Страница 297: ...288 Appendix B...
Страница 298: ...APPENDIX C CUSTOM CHIP PIN ALLOCATION LIST NOTE Means an active low signal Appendix C 289...
Страница 302: ...APPENDIX D SYSTEM MEMORY MAP Appendix D 293...
Страница 343: ...334 Appendix F...
Страница 351: ...342 Appendix G...
Страница 361: ...352 Appendix H...
Страница 367: ...358 Appendix I...