Bitfields for Intel 82378/82379 PCI Control:
Bit(s)	Description	)
 7	reserved (0)
 6	DMA Reserved Page Register Aliasing Control
	=0 alias PORT 80h-8Fh to PORT 90h-9Fh
 5	Interrupt Acknowledge Enable
	=0 ignore INTA cycles on the PCI bus, but still allow 8259 register
	  access and poll-mode functions
 4-3	Subtractive Decoding Sample Point
	00 slow sample point
	01 typical
	10 fast sample point
	11 reserved
 2	PCI Posted Write Buffer Enable
 1	ISA Master Line Buffer Configuration
	=0 single-transaction mode
	=1 eight-byte mode for ISA bus master transfers
 0	DMA Line Buffer Configuration
	=0 single-transaction mode
	=1 eight-byte mode
SeeAlso: #01064,#01066