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