VHDL for循环 - 如果分支不能正常工作

Question

我是vhdl的新手，但我正在尝试建立一个蛇游戏。在下面的循环中，eat ='1'和ate ='0'的约束似乎不起作用。就好像嵌套在if语句中的代码总是运行一样。

有问题的if语句

if(snake_body_ram(i)(14)='1' or (eating='1' and ate='0'))then

这是整个过程

process(move, direction, snake_head_reg, snake_body_ram, clk, head_coord, direction, eating)
        variable dir_next, tail_next_dir : std_logic_vector(1 downto 0);
        variable coord_next : std_logic_vector(13 downto 0);
        variable ate: std_logic := '0';
        variable value : unsigned(5 downto 0) := (others=>'0');
    begin
        if(clk'event and clk='1')then
            if(move='1')then
                dir_next := snake_head_reg(16 downto 15);
                coord_next := snake_head_reg(13 downto 0);
                snake_head_reg(16 downto 15) <= direction;
                snake_head_reg(13 downto 0) <= head_coord;
                ate:='0';
                --look here brian
                bodyLabel: 
                    for i in 0 to 35 loop
                        if(snake_body_ram(i)(14)='1' or (eating='1' and ate='0'))then
                            snake_body_ram(i)(16 downto 15) <= dir_next;    
                            snake_body_ram(i)(13 downto 0) <= coord_next;
                            snake_body_ram(i)(14) <= '1';
                            if(eating='1')then
                                ate:='1';
                            end if;
                            dir_next := snake_body_ram(i)(16 downto 15);
                            coord_next := snake_body_ram(i)(13 downto 0);
                            if(i > 1)then
                                tail_next_dir:=snake_body_ram(i-1)(16 downto 15);
                            end if;
                        end if;
                    end loop;   
                snake_tail_reg(13 downto 0) <= coord_next;
                snake_tail_reg(14)<='1';
                snake_tail_reg(16 downto 15) <= tail_next_dir;
            end if;
        end if;
    end process;

这是设置“吃”的过程

process(food_reg, snake_head_reg, clk, move, state, btn, snake_tail_reg, snake_body_ram)
        --variable ate : std_logic := '0';
    begin
        --if(clk'event and clk='1' and move='1' and state=play)then
        if(clk'event and clk='1')then
            eating <= '0';
            if(move='1' and state=play)then
                you_lose <= '0';
                --if()then
                    if(food_reg = snake_head_reg(13 downto 0))then
                        --ate food
                        food_eaten <= food_eaten_next;
                        eating <= '1';
                    elsif(snake_head_reg(13 downto 0) = snake_tail_reg(13 downto 0))then
                        --hit tail
                        you_lose <= '1';
                    elsif(unsigned(snake_head_reg(13 downto 7)) < 2 or unsigned(snake_head_reg(13 downto 7)) > 77 or unsigned(snake_head_reg(6 downto 0)) < 2 or unsigned(snake_head_reg(6 downto 0)) > 57)then
                        --hit a wall
                        you_lose <= '1';
                    else
                        --check for body
                        bodyLabel: 
                            for i in 0 to 35 loop
                                if(snake_body_ram(i)(14)='1' and you_lose = '0')then
                                    if(snake_head_reg(13 downto 0) = snake_body_ram(i)(13 downto 0)) then
                                        you_lose <= '1';
                                        exit;
                                    end if;
                                else
                                    exit;
                                end if;
                            end loop;
                    end if;
                --end if;
            end if;
        else
        end if;
    end process;

我试图将共享整个文件所需的信息包括在内。如果您需要更多信息，请告诉我。感谢您花时间阅读此内容。