process (CLK, RES_IN, MODE_UP)
            begin
                if RES_IN = '1' then cntval <= "000000000000000000000000000";
                end if;
            if (CLK'event and clk='1' and MODE_UP = '1') then
                        cntval <= cntval+1;
                    elsif (CLK'event and clk='1' and MODE_UP = '0') then
                        cntval <= cntval-1;
                    else
                end if;
        end process;