Bitfields for PCI configuration address port: Bit(s) Description (Table P0944)

Bitfields for PCI configuration address port:
Bit(s)	Description	(Table P0944)
 1-0	reserved (00)
 7-2	configuration register number (see #00878)
 10-8	function
 15-11	device number
 23-16	bus number
 30-24	reserved (0)
 31	enable configuration space mapping
Note:	configuration registers are considered DWORDs, so the number in bits 7-2 is the configuration space address shifted right two bits

Ральф Браун.