Re: function implemtations
Sounds legit to me.
RobotC is not open source, and you are unlikely to find information on how things are done on it. But I suspect it is a lot like the others.
I have looked a few places. The NXT firmware is open source. At one time or another I had the link and downloaded it, but I can't find it at the moment (somewhere on the LEGO mindstorms download page I think), but check out http://nxtgcc.sourceforge.net/
- it probably has a link to it some where as well as lot of other links that you might find helpful.
Also, NXC is supposedly open source, but it requires a commercial environment you can no longer obtain legally (so its not really open source, just claims to be). You can eventually find links to older versions of it and can look into how things are done, but probably not rebuild or modify it, which is the definition of open source, unless you have borland's delphi. It generates Assembler code, which is then assembled into interpreted byte code, much like a virtual machine. A few hints in Robotc, cause me to believe it is very similar.
Finally, look into LeJOS. It included the Java Virtual machine, and also works as above. Truly open source, with current implementations fully available in source. http://lejos.sourceforge.net/
Its not for the casual user, but if you are an experienced developer, it is interesting (and in need of some modern alternative to Java). Have any real projects in mind? I've though about it a few times, but it is more than a one person effort.