Bitfields for Intel 82437,82439HX/TX DRAM control register:
Bit(s)	Description	)
 7-6	DRAM Hole Enable
	00 none
	01 512K-640K
	10 15M-16M (82437FX/MX/VX only)
	11 14M-16M (82437VX,82439TX only)
 5	reserved
 4	(82437MX only) refresh type during Suspend
	=1 self-refreshing DRAMs in system
	=0 CAS-before-RAS refresh
	(82439TX only) Enhanced Paging disabled
 3	EDO Detect Mode enable
	(used to detect whether memory is EDO bank-by-bank)
 2-0	DRAM refresh rate
	     FX/VX/HX	 MX	     TX
	000  disabled	 15.6 us     disabled
	001  50 MHz	 31.2 us     15.6 us
	010  60 MHz	 62.4 us     31.2 us
	011  66 MHz	 125 us	     64.4 us
	100  reserved	 250 us	     125 us
	101  reserved	 reserved    256 us
	1xx  reserved	 reserved    reserved
SeeAlso: #01099,#01108,#01098,#01115,#01106