Create Code Segment Alias Descriptor


                 This function  will create  a data  descriptor that has
                 the same  base and  limit as the specified code segment
                 descriptor.

            To Call

                 AX = 000Ah
                 BX = Code segment selector

            Returns

                 If function was successful:
                 Carry flag is clear.
                 AX = New data selector

                 If function was not successful:
                 Carry flag is set.

            Programmer's Notes

                 o    This function  will fail if the selector specified
                      in BX is not a code segment or is invalid.
                 o    Use the Free LDT Descriptor function to deallocate
                      the alias descriptor.
                 o    The code  segment alias  descriptor will not track
                      changes to  the code  descriptor.  In other words,
                      if an  alias descriptor  is created,  and then the
                      base or  limit of the code segment is changed, the
                      alias descriptor's base or limit would not change.