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At this point the 64K bytes of RAM in the Commodore 64 are accessible by the built-in 6510 central processor, OR 48K bytes of RAM are available for the Z-80 central processor. You can shift back and forth between these two processors, but you can NOT use them at the same time in a single program. This is possible because of your Commodore 64's sophisticated timing mechanism.

Below is the memory address translation that is performed on the Z-80 cartridge. You should notice that by adding 4096 bytes to the memory locations used in CP/M® $1000 (hex) you equal the memory addresses of the normal Commodore 64 operating system. The correspondence between Z-80 and 6510 memory addresses is as follows:

0000-4095 0000-0FFF 4096-8191 1000-1FFF
4096-8191 1000-1FFF 8192-12287 2000-2FFF
8192-12287 2000-2FFF 12288-16383 3000-3FFF
12288-16383 3000-3FFF 16384-20479 4000-4FFF
16384-20479 4000-4FFF 20480-24575 5000-5FFF
20480-24575 5000-5FFF 24576-28671 6000-6FFF
24576-28671 6000-6FFF 28672-32767 7000-7FFF
28672-32767 7000-7FFF 32768-36863 8000-SFFF
32768-36863 8000-8FFF 36864-40959 9000-9FFF
36864-40959 9000-9FFF 40960-45055 A000-AFFF
40960-45055 A000-AFFF 45056-49151 B000-BFFF
45056-49151 B000-BFFF 49152-53247 C000-CFFF
49152-53247 C000-CFFF 53248-57343 D000-DFFF
53248-57343 D000-DFFF 57344-61439 E000-EFFF
57344-61439 E000-EFFF 61440-65535 F000-FFFF
61440-65535 F000-FFFF 0000-4095 0000-0FFF

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This page has been created by Sami Rautiainen.
Read the small print. Last updated November 06, 1998.