INT 67h,  57h  MOVE/EXCHANGE MEMORY REGION                           . 4.0

On entry:
        AH = 57h
        AL = subfunction
            00h move memory region
            01h exchange memory region
        DS:SI = pointer to structure describing source and destination

Return:
        AH = status
            00h successful
            80h internal error
            81h hardware failure
            83h invalid handle
            84h undefined function requested
            8Ah invalid logical page number encountered
            8Fh undefined subfunction
            92h successful, but a portion of the source region has been
                overwritten
            93h length of source or destination region exceeds length of
                region allocated to either source or destination handle
            94h conventional and expanded memory regions overlap
            95h offset within logical page exceeds size of logical page
            96h region length exceeds 1M
            97h source and destination EMS regions have same handle and
                overlap
            98h memory source or destination type undefined
            A2h attempted to wrap around 1M conventional address space