Re: Diagnostic ROM
Alex Evans via Coco <coco-uNHYcr1XS/wmlAP/[email protected]> Tue, 16 Dec 2025 10:51:09 -0500
| Newsgroups | gmane.comp.hardware.tandy.coco |
|---|---|
| Message-ID | <CAD7WSBT7oPfrhiy=u6bLHQkeoeaiQUZtxA9Jhov=tAs-2BbQsg@mail.gmail.com> |
There is a major shortcoming I should address. The data in ROMS that are overlaid by the diagnostic pak. For the CoCo3, this is relatively easy to accomplish. I can copy some code into RAM and switch the ROM mode to 32k internal. Run the code and switch back. For the CoCo 1/2 and Dragon 32, this isn't an issue as the program pak doesn't overlay any of the ROMS. However for the Dragon 64, this is actually an issue. As I understand it the Dragon 64 has two BASIC ROMs, one in the Usual location that is for running in 32k RAM mode and another that is copied to upper RAM to allow for more space in BASIC in all RAM mode. This ROM is (IIRC) mapped from $C000 to $FFEF and is normally disabled when there is a program pak inserted. -- Coco mailing list Coco-uNHYcr1XS/wmlAP/[email protected] https://pairlist5.pair.net/mailman/listinfo/coco