INT 67 U - Compaq CEMM v5.10+ - PRIVATE API(Application Program[ming] Interface) The defined set of calls which a program may make to interact with or request services of the operating system or environment under which it is running.  Because the inputs and outputs of the calls are well-defined, a program using the API can continue using the identical calls even if the internal organization of the program providing the API changes.
	AX = FFA5h
	BX = 4345h ("CE")
	DX = subfunction
	    0000h unshadow video ROM(Read-Only Memory) A memory for program storage which may not be changed by the program as it runs.???
	    0001h shadow video ROM(Read-Only Memory) A memory for program storage which may not be changed by the program as it runs.???
	    0002h map pages
		CX = number of pages (00h=one)
		ESI = linear address of first page to map into address space
		EDI = linear starting address at which pages are to be visible
	    0003h get ???
		Return: DX = ??? (0-2)
	    0004h BUG: crashes system due to fencepost error
Return: AH = 84h
	AL = status (84h = error, FFh = success)
Note:	if BX <> 4345h or DX > 0004h on entry, CEMM behaves identically to
	  Microsoft's EMM386 (see AX=FFA5h"EMM386")
SeeAlso: AX=FFA5h"EMM386",#01513 at INT 21/AX=4402h/SF=02h,#03666