How do I modify PFDATA?

So if I understand correctly, I can configure the PFDATA pins as either input or output via the memory mapped PFTYPE register.

Now, lets say I only map 1 pin (PF6) as an output pin.  When I want to set or clear PF6 do I need to read in PFDATA, manipulate the bit and rewrite PFDATA?  Or can I just write a word ignoring the other bit values since those pins are set to input only?

Also, I can't use setbit or clrbit directly on PFDATA correct (as its a memory mapped location and not a register).  I have to read it in, manipulate the bit and write it out (or simply write a new byte with my one bit corrected as I asked above)?

Paul