I would like to look at the source code - preferably in C/C++ - for some built in functions,
as well as the general register initialization and set-up for the Arduino environment,
in order to see the implementation details.
Where is this available?
Look in your folders \arduino\hardware\arduino\cores\arduino
At least some of them are there by name - main.cpp - to start with.
While that's a generally useful response it can't be completed without knowing the platform of the original poster.
My platform is Windows. Your responses have been helpful. Thanks.
All the Arduino source files are in the distrubution you installed. Built in shown below, supplied libraries in a different folder. You just need to look around.
C:\Documents and Settings\Primary Windows User\My Documents\My Programs\Arduino\arduino-0022\hardware\arduino\cores\arduino
The source code is available at