INT 2C P - Cloaking - ALLOCATE GDT SELECTOR                                     
	AX = 0000h
	EBX = base address
	CL = access mode byte
	CH = extended access mode byte (omit limit field)
	EDX = segment limit
Return: CF clear if successful
	    AX = selector
	CF set on error
	    AX = error code (see #02556)
Notes:	this INT 2C interface is used by Netroom's DPMIsee DOS Protected-Mode Interface.EXE v3.00
	to access extended memory, set the base address to the desired
	  physical address plus 400000h (4M)
	this function was first introduced with RM386 (RAM-MAN/386) v6.00, the
	  memory manager included in Helix Software's Netroom
SeeAlso: AX=0001h,AX=0002h,AX=0003h,AX=0004h,AX=0005h,INT 31/AH=57h,#00501


(Table 02556)
Values for Cloaking error code:
 0001h	no more selectors
 0002h	not a GDT ring 0 selector
 0003h	invalid selector (out of range, not user selector)
 0004h	selector not allocated