Relock Real Mode Region


                 This function  is used  to relock  memory regions  that
                 were marked as pageable by the previous function.

            To Call

                 AX = 0603h
                 BX:CX = Starting linear address of memory to relock
                 SI:DI = Size of region to page in bytes

            Returns

                 If function was successful:
                 Carry flag is clear.

                 If function was not successful:
                 Carry flag is set.

            Programmer's Notes

                 o    If this  function fails  then none  of the  memory
                      will be relocked.
                 o    If the specified region overlaps part of a page at
                      the beginning  or end  of the  region, the page(s)
                      will be not be relocked.