Over the last few weeks I have been working intensively with the C65 ROM and at some point I had the idea of somehow getting the C65 to work on the C128. The background is that I don't have the money for a real C65 and the MEGA65 is unfortunately not yet available. But the C128 is here and have not much to do.
So I set about trying to find out how I can incorporate the limitations of the C128 into the C65 ROM in a reasonably acceptable way.
The most important thing was to redirect all the explicit 65CE02 commands used by the C65 into corresponding 8502 code sequences. Of course, the running time is noticeably slower, but in the end it is better than I expected. Even more so, since the C128 does not have the 3.5 MHz of the C65.
The BASIC 10 benchmarks I wrote for the C65 and MEGA65 all run, although noticeably slower. But at least the work!
Download the attached D71 image and start the C128 or C128 emulator in the 80 character mode.
Then load the boot programm with DLOAD "*",8 and start it with RUN.
This will then start the main programm. The C65-ROM modified for this purpose is on the diskette ("c65-system.rom").
Be aware: This ROM is adapted for this application and does not run on the MEGA65!
If you want to try it out, have fun with it!