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ALLOCATING MEMORY FOR BIT-PLANES
After you set the number of bit-planes and specify resolution modes, you are ready to
allocate memory. A bit-plane consists of an end-to-end sequence of words at consecutive
memory locations. When operating under the Amiga operating system, use a system call
such as AllocMem() to remove a block of memory from the free list and make it available
to the program. If the machine has been taken over, simply reserve an area of memory
for the bit-planes. Next, set the bit plane pointer registers (BPLxPTH/BPLxPTL) to point to
the starting memory address of each bitplane you are using. The starting address is the
memory word that contains the bits of the upper left-hand corner of the bit-plane.
Table 3-6 shows how much memory is needed for basic playfields. You may need to
balance your color and resolution requirements against the amount of available memory
you have.
Table 3-7: Playfield Memory Requirements, NTSC
Number of Bytes
Picture Size Modes per Bit-Plane
320 X 200 Low-resolution, 8,000
non-interlaced
320 X 400 Low-resolution, 16,000
interlaced
640 X 200 High-resolution, 16,000
non-interlaced
640 X 400 High-resolution, 32,000
interlaced
- 46 Playfield Hardware -
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...