Bitfields for AMD-640 PCI Buffer Control register:
Bit(s)	Description	)
 7	enable CPU-to-PCI posted writes
 6	enable PCI-to-DRAM posted writes
 5	enable PCI-to-DRAM prefetch
 4-2	reserved (0)
 1	disable PCI retry for processor QuadWord access
 0	CPU-to-PCI buffer flushing
	0 flushing has priority over bus grants
	1 bus-grant to another PCI initiator has priority over flushing
SeeAlso: #00983