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MJoergen / C64MEGA65

Commodore 64 core for the MEGA65 based on the MiSTer FPGA C64 core
GNU General Public License v3.0
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Investigate JaffyDOS (low priority, but append docs) #149

Closed Kugelblitz360 closed 1 month ago

Kugelblitz360 commented 1 month ago

JaffyDOS is a patched version of JiffyDOS with some enhancements for SD2IEC devices and a Kernal filebrowser.

In Core 5.1 you can run this by just giving it the Jiffy-name as in the readme.

When JaffyDOS 1.3 is active, cartridges (in the port, not in software) do not work correctly. "Super Snapshot" fails to run both on KFF and EF3 hardware, other freezers misbehave, RESET sometimes does not work. Users with real C64 hardware claim that it works.

The first fix would be to discourage use of JaffyDOS with the currently released Core. Using original JiffyDOS kernal works without the observed problems with cartridges.

It would be interesting to investigate whether the startup code inside JaffyDOS (skips for example Memcheck) is incompatible with the current Core and whether either Jaffy or the Core can be patched.

Kugelblitz360 commented 1 month ago

The developer of JaffyDOS has confirmed that Super Snapshot jumps into Kernal at an odd address. He has provided me with a patched Super Snapshot ROM that works, so we can close this issue too.