INT 67 - LIM EMS 4.0 - MAP/UNMAP MULTIPLE HANDLE PAGES
        AH = 50h
        AL = subfunction
            00h use physical page numbers
            01h use segment addresses
        DX = handle
        CX = number of entries in array
        DS:SI -> mapping array (see below)
Return: AH = status
            00h successful
            80h internal error
            81h hardware malfunction
            83h invalid handle
            84h undefined function requested
            8Ah one or more logical pages are invalid
            8Bh one or more physical pages are invalid
            8Fh invalid subfunction

Format of mapping array entry:
Offset  Size    Description
 00h    WORD    logical page number or FFFFh to unmap physical page
 02h    WORD    physical page number or segment address