Get Descriptor


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

            To Call

                 AX = 000Bh
                 BX = Selector
                 ES:(E)DI =  Pointer to an 8 byte buffer to receive copy
                      of descriptor

            Returns

                 If function was successful:
                 Carry flag is clear.
                 ES:(E)DI = Pointer to buffer that contains descriptor

                 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 or unallocated.
                 o    32-bit programs  must use  ES:EDI to  point to the
                      buffer.  16-bit programs should use ES:DI.