Posted By
IstvanV
on 2007-06-10
12:30:04
|  Re: plus4emu 1.1.1 release
I found something that looks like a bug in the kernal, and could easily be worked around in the emulator, but I am not sure if that should be done. The problem is that the routine at $eda9 - which checks if there is a serial or parallel (1551) floppy drive - is not very reliable, and can incorrectly report a parallel device, particularly if there are many $55 bitmaps on the screen (because it writes that value to the parallel interface area, and tries to read it back; if there is no device, the value read will most likely be what was read/written most recently on the data bus - a behavior that plus4emu does reproduce). This seems to be why I get random crashes occasionally while loading some demos. Adding a workaround would be quite simple, but since the problem can be reproduced on the real machine, I do not know if "bug compatible" emulation or reliable disk I/O is more important. Any opinions ?
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