INT E0 - REAL/32 - "DEV_MAP" - GET/SET SERIAL/PARALLEL PORTIBM PC Portable (uses same BIOS as XT) MAPPINGS
	CL = B8h
	DS:DX -> Device Map Parameter Block (DEVPB) (see #04059)
Return: nothing???
	may destroy SI,DI,DS


Format of REAL/32 Device Map Parameter Block (DEVPB):
Offset	Size	Description	(Table 04059)
 00h	WORD	direction (00h = get current mapping, 01h = set new mapping)
 02h  4 BYTEs	physical device IDs which map into LPT1 - LPT4
 06h  4 BYTEs	physical device IDs which map into COM1 - COM4
Note:	LPT4 and COM3/COM4 are reserved on early versions of Multiuser DOS,
	  but are supported from at least CCI Multiuser DOS v7.22 onward