Set Descriptor


                 This function  copies an eight byte buffer into the LDT
                 entry for a specified descriptor.

            To Call

                 AX = 000Ch
                 BX = Selector
                 ES:(E)DI =  Pointer to  an 8 byte  buffer that contains
                      descriptor

            Returns

                 If function was successful:
                 Carry flag is clear.

                 If function was not successful:
                 Carry flag is set.

            Programmer's Notes

                 o    This function  will fail if the selector specified
                      in BX is invalid.
                 o    Your program  should only  modify descriptors that
                      were   allocated    through   the   Allocate   LDT
                      Descriptors function.
                 o    32-bit programs  must use  ES:EDI to  point to the
                      buffer.  16-bit programs should use ES:DI.
                 o    The type byte (byte 5) follows the same format and
                      restrictions as  the access  rights/type parameter
                      (in CL)  to Set  Descriptor Access  Rights.    The
                      extended type  byte  (byte  6)  follows  the  same
                      format and  restrictions as  the  extended  access
                      rights/type parameter  (in CH)  to Set  Descriptor
                      Access Rights, except the limit field may have any
                      value,  except   the  low  order  4  bits  (marked
                      "reserved") are  used to  set the  upper 4 bits of
                      the descriptor's limit.