Posted By
Gaia
on 2017-01-07
17:02:31
|  Re: Porting to Commodore Plus 4 of my game Genius, memory/bitmap mode questions..
Running the program did some random lockups at times. I have also seen some ORA $AF00,Y -like assembly code starting from $A696 that is ultimately responsible for overwriting the correct $FF12 value with $FF (or actually: whatever startup or leftover pattern is there in the memory). This commands the TED to read bitmap data from ROM (not that it makes much sense for bitmap graphics - the character set is also using this bit). I suggest you fill this memory with zeroes and ones only or change the code.
Trust me, the timer1 runs and generates IRQ at the same pace in the emulators  so in case you see some different values that could rather be a debugger/monitor issue.
EDIT: Drag'n'drop crash: in YAPE, "blitz" loading of PRG files directly from the D64 image is enabled by default. Make sure to turn it off in the Advanced settings. Then it loads fine.
|
