Bitfields for AMD-640 Shadow RAM Control Register 2:
Bit(s)	Description	)
 7-6	segment DC00h-DFFFh shadow RAM control
	00 shadowing disabled
	01 write enabled
	10 read enabled
	11 both read and write enabled
 5-4	segment D800h-DBFFh shadow RAM control
 3-2	segment D400h-D7FFh shadow RAM control
 1-0	segment D000h-D3FFh shadow RAM control
SeeAlso: #00983,#00992,#00994