Well, the replies to my original post have made it pretty clear why this isn't 'newsworthy', and after the fact I have found bunch of simulators out there. Only not open-sourced.

Anyway, the latest version of my simulator, at version 0.6, covers most of 8051. I've also played around with actual hardware for a bit, and found some interesting things that are somewhat difficult to simulate on this level.. and I agree that a sub-cpuclock simulation would be useful.

The primary goal for the simulator has, however, been covered now, and it is possible to use it as a tool to help develop assembler (and c) programs for a 8051-style hardware. There's still some things to do, such as configuration through commandline options, but from my point of view it's basically done.

Some things, like serial communication, are missing. On the other hand, there's some extra bits that may help software development (or, for instance, doing school lab assignments), such as exceptions on doing bad things on exception handlers, and some widgets on a 'logic board' mode such as 7-seg displays. The whole point of open-sourcing the thing is that people can, if the want, write custom 'widgets' to play with.

I also apologise for the use of the 'emulator' term, which apparently isn't appropriate from hardware development point of view, although it is largely in use in software development (see MAME for instance).

I haven't tried any of the commercial tools (such as Keil), so I don't know if I'm missing some crucial bit on my shiny reinvented wheel =). Anyway, thanks for the interest, hostile or not. I'm aiming at releasing 1.0, along with source code, in a month or so.