Question about access PCI controller registers

I’m a newbie to PCI and DDK. Now I need to read from the status register and
write into the control register of a PCI controller. These are the functions
in an application under Windows XP. I don’t need to write a driver and
actually the PCI controller does have driver. My question is, do I have to
follow the guidelines given in Microsoft KB Article - 253232 (;EN-US;Q253232& )? Is there
any easier way to do it?
Thank you very much!

Best wishes,