There are, however, several huge issues still.
Firstly, Bus Error is not working properly.
Now, I don't know enough about Musashi nor actual exception handling to know what's going wrong, but whilst it'll correctly report an occasional bus error and follow the exception handler, if there are a few of them in a row, chaos ensues and the core gets stuck in some kind of bus error hell loop.
This is a big problem as no 'stock' OS will boot. My custom EmuTOS image has bus error detection disabled and everything is specifically coded. Any problems that then rely on detecting hardware with bus errors will be 50/50.
Secondly, reliability. Every now and again a bus error, or other issue will appear out of the blue. Sometimes it's really frequently, sometimes it'll run for half an hour. This feels like a breakdown in the protocol and the bursty nature of the failures has the smell of a beating issue when you have two independent clocks. Probably the lowest priority issue ATM, but certainly a biggie when its turn comes around.
Thirdly, there's something amiss with sound. No music from Frontier, one of the other games I tried out crashed around the start of the music and the diagnostic cartridge fails with testing exceptions on the screen, but with a low tone stuck on the audio out. This could very well be an indirect Bus Error issue. If the YM chip were properly detected and set up maybe it would work? Not sure. Don't think it's the now infamous YM chip DTACK issue as this is being tested on an STE.
Fourthly, the ST-RAM speed. I've not got to the bottom of this yet as it's also fairly low down the food chain. I'm not 100% sure I like the state machine model used in the firmware and hacking that might improve things, but my gut feeling is that this is a time-between-bus-cycles issue rather than a bus-cycle-length issue. This manifests most obviously in Frontier where, despite the frame count looking good when I run it from AltRAM, the screen flickers like mad as the palette switching code does its thing.
Anyone who can proffer something on the Musashi code for handling bus errors please tap me up as this is the biggest hurdle to progress ATM.
Open source 50MHz 030 and TT-RAM accelerator for the Falcon
Open source 16Mhz 68k and AltRAM accelerator for the ST
ST-optimised USB mouse adapter based on SmallyMouse2
The Frontier: Elite 2 intro as a benchmark