MEM 0040h:00D6h	- EHD floppy - AND-BITS TO ADJUST PORTIBM PC Portable (uses same BIOS as XT) ADDRESS
Size:	BYTE
Note:	this byte contains FFh if controller at 03Fxh and 7Fh if at 037xh; the
	  value is ANDed with DL prior to using IN A?,DX or OUT DX,A?
	  instructions