All BIOS functions are supported by the current C-setup. The naming convention is that of Bruce Tomlin. To use BIOS functions (and/or variables) include <vectrex.h> to your C-programs.
The standard include path defines its location at:
"...Vide/C/PeerC/vectrex/include/vectrex.h"
Looking at the above file (and its following include hierarchy) you will see how Peer implemented all BIOS calls with inlined "C" functions.
Also when you generate a new "C" project, the doc directory as a quick access also lists the most important includes in a very well himan readable form.
Also all RAM/VIA locations are defined in a ways that makes them easily accessable.
Examples:
TODO