WinSTon: Emulation Problems

2005-01-02

We tested several ‘problematic disk images’ using the newly ‘enhanced’ WinSTon. It would seem that historically, WinSTon is plagued by three distinct problems.

1. Lack of any real FDC emulation.
2. Serious CPU bugs.
3. File handling not even close to suitable for use with proper disk images (so far we’ve been working with our own hacks to circumvent this problem for testing).

Since we’ve mainly been dealing with the FDC side of things, and a few timing/DMA related issues, we’re now finding the remaining problematic disk images (as listed in the WinSTon documentation as items to resolve) are still not working. We feel the new FDC emulation is accurate, and so these problems are almost certainly down to the CPU bugs.

Unfortunately the CPU core is written in assembler, which is nearly impossible to debug. It would require extensive amounts of reverse engineering to sort that out, and more work than say... re-writing a new core. Then, once all the parts of the emulator which are tied to it are re-written, we’d looking at the best part of a whole new emulator.