sub CLxsub {
       $x = 0;
       $dis->delete( '0.0', 'end' );
   }
                                                                                
   sub xsysub {
       $x = $y;
       $y = $dis->get;
       $dis->delete( '0.0', 'end' );
       $dis->insert( 'end', $x );
       $res = 's';
   }
                                                                                
   sub Rssub {
       my $aj = $dis->get;
       $dis->delete( '0.0', 'end' );
       $dis->insert( 'end', $y );
       $x   = $y;
       $y   = $z;
       $z   = $t;
       $t   = $aj;
       $res = 's';
   }