create or replace procedure p( p_string in varchar2 )
   is
      l_string long default p_string;
   begin
      loop
        exit when l_string is null;
        dbms_output.put_line( substr( l_string, 1, 250 ) );
        l_string := substr( l_string, 251 );
      end loop;
   end;
/

begin
 p(lpad('>', 1000, 'x'));
end;
/