Function create_code_segment_alias_descriptor (seg : Word) : Word;
Creates a new descriptor that has the same base and limit as the specified descriptor.
Parameters:
Return values: Data selector (alias)
Notes: In effect, the function returns a copy of the descriptor. The descriptor alias returned by this function will not track changes to the original descriptor. In other words, if an alias is created with this function, and the base or limit of the original segment is then changed, the two descriptors will no longer map the same memory.
Check int31error variable
allocate_ldt_descriptors, set_segment_limit, set_segment_base_address