Lock Linear Region


                 This function locks a specified linear address range.

            To Call

                 AX = 0600h
                 BX:CX = Starting linear address of memory to lock
                 SI:DI = Size of region to lock 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 locked.
                 o    If the specified region overlaps part of a page at
                      the beginning  or end  of the  region, the page(s)
                      will be locked.