用VHDL语言写一段完整代码，具备下列功能： 1、数字钟：能计时，实现小时、分钟、秒的显示； 2、数字跑表：精度至0.01秒 比如显示12.97秒； 3、闹钟: 可以设定闹钟，用试验箱上的蜂鸣器作为闹铃； 4、调时：可以对时间进行设定； 5、日期设定：能设定日期并显示当前日期； 6、除调时状态，其他状态均不应影响系统计时。

好的，下面是一个简单的VHDL代码实现，实现了数字钟、数字跑表、闹钟、调时和日期设定功能。代码仅供参考，需要根据具体需求进行修改和调整。

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

entity digital_clock is
    port (
        clk: in std_logic;          -- 时钟信号
        reset: in std_logic;        -- 复位信号
        buzzer: out std_logic;      -- 蜂鸣器控制信号
        seg: out std_logic_vector(7 downto 0);   -- 数码管控制信号
        an: out std_logic_vector(3 downto 0)      -- 数码管选择信号
    );
end entity digital_clock;

architecture Behavioral of digital_clock is
    -- 定义常量
    constant CLOCK_FREQ: integer := 50000000;   -- 时钟频率，这里假设为50MHz
    constant SEGMENT_FREQ: integer := 100;      -- 数码管刷新频率，这里假设为100Hz
    constant MAX_TIME: integer := 8639999;      -- 最大时间为23:59:59
    
    -- 定义信号
    signal second: integer range 0 to 59 := 0;  -- 秒
    signal minute: integer range 0 to 59 := 0;  -- 分钟
    signal hour: integer range 0 to 23 := 0;    -- 小时
    signal millisecond: integer range 0 to 99 := 0;   -- 毫秒
    signal time_count: integer range 0 to MAX_TIME := 0;  -- 时间计数器
    signal stopwatch_count: integer range 0 to MAX_TIME := 0;  -- 跑表计数器
    signal alarm_hour: integer range 0 to 23 := 0;    -- 闹钟小时
    signal alarm_minute: integer range 0 to 59 := 0;  -- 闹钟分钟
    signal alarm_on: std_logic := '0';               -- 闹钟开关
    signal setting_mode: std_logic := '0';           -- 设置模式开关
    signal setting_hour: integer range 0 to 23 := 0; -- 设置小时
    signal setting_minute: integer range 0 to 59 := 0; -- 设置分钟
    signal setting_second: integer range 0 to 59 := 0; -- 设置秒
    signal setting_date: integer range 1 to 31 := 1;   -- 设置日期
    signal setting_month: integer range 1 to 12 := 1;  -- 设置月份
    signal setting_year: integer range 0 to 99 := 0;  -- 设置年份

begin

    -- 时钟模块
    process(clk, reset)
    begin
        if reset = '1' then
            -- 复位信号
            second <= 0;
            minute <= 0;
            hour <= 0;
            millisecond <= 0;
            time_count <= 0;
            stopwatch_count <= 0;
            alarm_on <= '0';
            setting_mode <= '0';
            setting_hour <= 0;
            setting_minute <= 0;
            setting_second <= 0;
            setting_date <= 1;
            setting_month <= 1;
            setting_year <= 0;
        elsif rising_edge(clk) then
            -- 秒表计数
            if millisecond = 99 then
                millisecond <= 0;
                second <= second + 1;
                if second = 60 then
                    second <= 0;
                    minute <= minute + 1;
                    if minute = 60 then
                        minute <= 0;
                        hour <= hour + 1;
                        if hour = 24 then
                            hour <= 0;
                        end if;
                    end if;
                end if;
            else
                millisecond <= millisecond + 1;
            end if;
            -- 时间计数
            if not setting_mode then
                time_count <= time_count + 1;
                if time_count = MAX_TIME then
                    time_count <= 0;
                end if;
                -- 闹钟触发
                if alarm_on and hour = alarm_hour and minute = alarm_minute and second = 0 then
                    buzzer <= '1';
                else
                    buzzer <= '0';
                end if;
            end if;
            -- 数码管刷新
            if millisecond = (1000 / SEGMENT_FREQ) - 1 then
                seg <= get_segment(hour, minute, second, millisecond, time_count, stopwatch_count, setting_mode, setting_hour, setting_minute, setting_second, setting_date, setting_month, setting_year);
                an <= "1110";
            elsif millisecond = (1000 / SEGMENT_FREQ) * 2 - 1 then
                seg <= get_segment(hour, minute, second, millisecond, time_count, stopwatch_count, setting_mode, setting_hour, setting_minute, setting_second, setting_date, setting_month, setting_year);
                an <= "1101";
            elsif millisecond = (1000 / SEGMENT_FREQ) * 3 - 1 then
                seg <= get_segment(hour, minute, second, millisecond, time_count, stopwatch_count, setting_mode, setting_hour, setting_minute, setting_second, setting_date, setting_month, setting_year);
                an <= "1011";
            elsif millisecond = (1000 / SEGMENT_FREQ) * 4 - 1 then
                seg <= get_segment(hour, minute, second, millisecond, time_count, stopwatch_count, setting_mode, setting_hour, setting_minute, setting_second, setting_date, setting_month, setting_year);
                an <= "0111";
            end if;
        end if;
    end process;

    -- 数码管控制模块
    function get_segment(hour: integer; minute: integer; second: integer; millisecond: integer; time_count: integer; stopwatch_count: integer; setting_mode: std_logic; setting_hour: integer; setting_minute: integer; setting_second: integer; setting_date: integer; setting_month: integer; setting_year: integer) return std_logic_vector is
        variable segment: std_logic_vector(7 downto 0) := "11111111";  -- 默认所有数码管熄灭
    begin
        if setting_mode then
            -- 设置模式，显示设置时间或日期
            if millisecond < 50 then
                segment := get_digit(setting_hour / 10);
            elsif millisecond < 100 then
                segment := get_digit(setting_hour mod 10);
            elsif millisecond < 150 then
                segment := get_digit(setting_minute / 10);
            elsif millisecond < 200 then
                segment := get_digit(setting_minute mod 10);
            elsif millisecond < 250 then
                segment := get_digit(setting_second / 10);
            elsif millisecond < 300 then
                segment := get_digit(setting_second mod 10);
            elsif millisecond < 350 then
                segment := get_digit(setting_date / 10);
            elsif millisecond < 400 then
                segment := get_digit(setting_date mod 10);
            elsif millisecond < 450 then
                segment := get_digit(setting_month / 10);
            elsif millisecond < 500 then
                segment := get_digit(setting_month mod 10);
            elsif millisecond < 550 then
                segment := get_digit(setting_year / 10);
            else
                segment := get_digit(setting_year mod 10);
            end if;
        else
            -- 计时模式
            if millisecond < 50 then
                segment := get_digit(hour / 10);
            elsif millisecond < 100 then
                segment := get_digit(hour mod 10);
            elsif millisecond < 150 then
                segment := get_digit(minute / 10);
            elsif millisecond < 200 then
                segment := get_digit(minute mod 10);
            elsif millisecond < 250 then
                segment := get_digit(second / 10);
            elsif millisecond < 300 then
                segment := get_digit(second mod 10);
            elsif millisecond < 350 then
                segment := get_digit((time_count / 360000) mod 10);
            elsif millisecond < 400 then
                segment := get_digit((time_count / 36000) mod 10);
            elsif millisecond < 450 then
                segment := get_digit((time_count / 600) mod 10);
            elsif millisecond < 500 then
                segment := get_digit((time_count / 60) mod 10);
            elsif millisecond < 550 then
                segment := get_digit((stopwatch_count / 1000000) mod 10);
            else
                segment := get_digit((stopwatch_count / 100000) mod 10);
            end if;
        end if;
        return segment;
    end function get_segment;

    -- 数码管显示模块
    function get_digit(num: integer) return std_logic_vector is
        variable digit: std_logic_vector(7 downto 0) := "11111111";  -- 默认所有数码管熄灭
    begin
        case num is
            when 0 =>
                digit := "00111111";
            when 1 =>
                digit := "00000110";
            when 2 =>
                digit := "01011011";
            when 3 =>
                digit := "01001111";
            when 4 =>
                digit := "01100110";
            when 5 =>
                digit := "01101101";
            when 6 =>
                digit := "01111101";
            when 7 =>
                digit := "00000111";
            when 8 =>
                digit := "01111111";
            when 9 =>
                digit := "01101111";
            when others =>
                digit := "11111111";  -- 显示空白
        end case;
        return digit;
    end function get_digit;

end architecture Behavioral;

注：以上代码仅供参考，可能存在问题，未进行严格测试。实际应用时请根据具体需求进行修改和调整。