INT 67h,  4Fh  GET/SET PARTIAL PAGE MAP                              . 4.0

On entry:
        AH = 4Fh
        AL = subfunction
            00h get partial page map
               DS:SI = pointer to structure containing list of segments whose
                       mapping contexts are to be saved
               ES:DI = pointer to array to receive page map
            01h set partial page map
               DS:SI = pointer to structure containing saved partial page map
            02h get size of partial page map
               BX = number of mappable segments in the partial map to be saved

Return:
        AH = status
            00h successful
            80h internal error
            81h hardware malfunction
            84h undefined function requested
            8Bh one of specified segments is not mappable
            8Fh undefined subfunction parameter
            A3h contents of partial page map corrupted or count of mappable
                segments exceeds total number of mappable segments in system
        AL = size of partial page map for subfunction 02h