Pip, pip, hurray!

It’s been a wild month in Mac land! MAME 0.289 should be out around the time I post this, and we’re already going strong with new features for 0.290.

On the Power Mac 6100 front, we left off with Mac OS up to 8.6 working. With some help from Claude Opus once again, I found a subtle bug in a couple of PowerPC instructions and fixing that got Mac OS 9.0 and 9.0.4 to boot to Finder. 9.1 required some additional tweaks, particularly to get the performance reasonable, but it worked out and made the MAMEception video possible.

After that I took a va-68K-tion from PowerPC and set two different bleeding-edge AI models (Claude Fable and GPT-5.6) loose on finding bugs in MAME’s 68K FPU support. There were known to be issues: Marathon wouldn’t launch on machines with an FPU, Speedometer would crash mid-benchmark, and probably other apps would also crash. An extensive rework of the code followed which made it much cleaner and far more accurate. This fixed Marathon and Speedometer, and it also fixed glitched polygons in Taito’s Side By Side arcade machine, which runs on a 68040.

Additional 68K fixes followed, including fixing issues with the MMU and some more FPU defects. While those were in progress, I was clued in that Apple hacker Plamen was doing some AI assisted debugging of his own and gotten A/UX to boot on a few Macs. I adapted his changes, made some of my own, and pretty soon A/UX 3.1.1 would boot and run on every Mac model that it supported. This was a major milestone for MAME, and another one soon followed: it was found that Linux-m68k will boot and run on some Quadras thanks to all of the fixes. That marked the first time Linux-m68k has booted on MAME for any architecture, and it means Linux should boot and run on non-Mac 68k machines that MAME supports too.

Since then more has happened: Apple’s MESH SCSI chip was implemented, which allowed the Pippin, Power Mac 7200, and Power Mac G3 to read and write to SCSI devices. Pippin now boots and runs discs. There’s still some work to do on it, notably the unique “AppleJack” controllers, the flash ROM for saving, and some other details, but many of the games already can be played with the keyboard and mouse.