procedure sort( var r : ArrayToSort; lo, up : integer );

     var  i : integer;
          tempr : ArrayEntry;
     begin
     {*** construct heap ***}
     for i := (up div 2) downto 2 do    siftup(r,i,up);
     {*** repeatedly extract maximum ***}
     for i := up downto 2 do begin
          siftup(r,1,i);
          tempr := r[1];
          r[1] := r[i];
          r[i] := tempr
          end
     end;