Right now it's not usable, stepping sometimes fails if debugger tries to step inside a CRT functions like sprintf, it doesn't work properly with multi-threaded code, and expression evaluation system has lots of bugs. However after I finish writing instruction decoder, I'll start to tackle those bugs.
At this point debugger has a sloppy architecture, and I think that adding more people will only make it worse. But anyway thanks.
That's really cool! I am also working on a debugger (for Linux), and it's nice to see a real working design for this. I had some thoughts along the same lines but I'm quite far from implementing anything like that yet.