Question

我有一系列信号。当作为“选择器”的信号等于单元格编号时，我想写入数组中的适当单元格。为了节省写入和代码行，我在生成循环中生成赋值：

read_data_signals_gen: for i in 0 to (CAU_num -1) generate

    v_direction_sig(i)(0) <=  DATA_IN when (chosen_flow_sig = i) and (read_state = st_read_v_direction_0) else
                              v_direction_sig(i)(0);
    v_direction_sig(i)(1) <=  DATA_IN when (chosen_flow_sig = i) and (read_state = st_read_v_direction_1) else
                              v_direction_sig(i)(1);
    v_direction_sig(i)(2) <=  DATA_IN when (chosen_flow_sig = i) and (read_state = st_read_v_direction_2) else
                              v_direction_sig(i)
  ...
end generation read_data_signals_gen;

chosen_flow_sig是std_logic_vector (1 downto 0)，获取"00"，"01"，"10"或"11"来表示单元格的编号，CAU_num是integer常量等于4.如何在when语句中创建比较，以便整数等于其二进制转换？

还有一个相关的问题。有没有办法执行以下代码：

type  BitArray is array (natural range <>) of std_logic;

sel_sig : std_logic_vector(0 to 1);
bit_arr : BitArray(0 to 3)

sel_sig <= "00"
bit_arr(sel_sig) <= '1'  -- HOW TO PERFORM THIS?

Answer 1

您可能正在寻找

to_integer(unsigned(sel_sig))

e.g。

bit_arr(to_integer(unsigned(sel_sig))) <= '1'

或

if to_integer(unsigned(sel_sig))=12 then ...

Answer 2

如果chosen_flow_sig表示数字，请使用数字类型（例如unsigned或integer）。如果你使用std_logic_vector，你会给自己带来痛苦，而你却不需要！

http://parallelpoints.com/node/3

如何比较整数和std_logic向量

2 个答案: