function reads one byte from the configuration space of the PCI bus. The
bus can be specified with the
paramter determines which ? to use.
is set to the ?. After the call is made,
points to the value that was read.
The return value is taken from the PCI controller in a way that I'm
not quite sure of.
If the PCI system is unavailable, PCIBIOS_FUNC_NOT_SUPPORTED is