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4. Platform specific header files

Programs containing PET specific code may use the pet.h or cbm.h header files. Using the later may be an option when writing code for more than one CBM platform, since it includes pet.h and declares several functions common to all CBM platforms.

4.1 PET specific functions

There are currently no special PET functions.

4.2 CBM specific functions

Some functions are available for all (or at least most) of the Commodore machines. See the function reference for declaration and usage.

4.3 Hardware access

The following pseudo variables declared in the pet.h header file do allow access to hardware located in the address space. Some variables are structures, accessing the struct fields will access the chip registers.


Access to the two PIA (peripheral interface adapter) chips is available via the PIA1 and PIA2 variables. The structure behind these variables is explained in _pia.h.


The VIA structure allows access to the VIA (versatile interface adapter). See the _6522.h header file located in the include directory for the declaration of the structure.

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