Bitfields for Intel 82378/82379 ISA Address Decoder Control Register:
Bit(s)	Description	)
 7-4	ISA memory cycle forwarding to PCI
	0000-1111 = 1M-16M top of ISA memory; any accesses above programmed
		  limit are forwarded to PCI bus
 3-0	ISA/DMA memory cycle to PCI bus enables
	bit 3: 896K-960K (E000h-EFFFh)
	bit 2: 640K-768K (A000h-BFFFh)
	bit 1: 512K-640K (8000h-9FFFh)
	bit 0: 0K-512K	 (0000h-7FFFh)
SeeAlso: #01064,#01070