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;
    else
        if (CLK'event and clk='1' and MODE_UP = '0') then
            cntval <= cntval-1;
        else
        end if;
    end if;
end process;