EWM Update: Apple 1 Progress & Booting the Apple ][+ ROM

Nov 16, 2016 · 1 min read

Here is some more progress with my 6502 / Apple1 emulator.

Lots of fixes and features .. I forgot to implement some instructions, SEC, SED, SEI. Oopsie. Now I can load ROMs from disk, detect invalid instructions. I implemented APIs to register memory (RAM, ROM, IO) regions. There is now basic interrupt support, although the Apple 1 does not use those at all.

The screenshot shows the emulator with the KRUSADER ROM loaded. (Which is an assembler for the Apple 1 / Replica 1).

KRUSADER

And big news, I booted up an Apple ][+ ROM succesfully! I have no display emulation yet, but in a CPU trace I can see it boot and then correctly poll the keyboard in a loop. So that is a start of something.

If you are interested in playing around with my emulator, you can find the project at github.com/st3fan/ewm.

Most of my professional and personal work is Open Source. You can find many projects at github.com/st3fan - feel free to leave a bug report or open a feature request.