WinDriver fully supports backward compatibility with the standard PCI features on PCI Express boards. The wide support provided by WinDriver for the standard PCI bus - including a rich set of APIs, code samples and the graphical DriverWizard for hardware debugging and driver code generation - is also applicable to PCI Express devices, which by design are backward compatible with the legacy PCI bus.
You can also use WinDriver's PCI API to easily communicate with PCI devices connected to the PC via PCI Express-to-PCI bridges and switches (e.g. the PLX 8111/8114 bridges or the PLX 8532 switch, respectively).
In addition, on Windows and Linux WinDriver provides you with a set of APIs for easy access to the PCI Express extended configuration space - see the description of the WDC_PciReadCfgXXX() and WDC_PciWriteCfgXXX() functions in sections B.3.26 - B.3.33 of the present manual, or the description of the lower-level WD_PciConfigDump() function in the WinDriver PCI Manual.
Additional enhanced support for the PCI Express bus, in the form of specific PCI Express WinDriver libraries and special features, are expected to be added in future versions of WinDriver.