Bitfields for Intel 82434LX/NX Host Read/Write Buffer Control:
Bit(s)	Description	)
 7-4	reserved
 3	enable read-around-write
 2	reserved
 1	enable CPU-to-PCI posted writes
 0	(LX only) enable CPU-to-memory posted writes
	(NX always posts memory writes)
SeeAlso: #01055,#01057