Platform-independent functions for FastPWM?
It is highly unlikely there would be direct 1:1 functions that implement such discrete operations. Simply because such operations are pretty unique to a single family of microcontrollers. They are too low-level for an API to even consider wanting them.

Instead, there are higher level functions which may, if the chip requires it, include those operations. 

The operations you list are all related to PWM, so the higher level function that would encompass them would be analogWrite().