写出这段代码的测试文件
时间: 2024-01-20 09:04:35 浏览: 25
以下是这段代码的测试文件示例:
```
library ieee;
use ieee.std_logic_1164.all;
entity shj_ctr_tb is
end shj_ctr_tb;
architecture sim of shj_ctr_tb is
component shj_ctr
port (
a: in std_logic;
b: in std_logic;
clk: in std_logic;
sell: out std_logic;
change: out std_logic
);
end component;
signal a, b, clk, sell, change: std_logic;
begin
uut: shj_ctr port map (a => a, b => b, clk => clk, sell => sell, change => change);
clk_gen: process
begin
clk <= '0';
wait for 5 ns;
clk <= '1';
wait for 5 ns;
end process;
stim_proc: process
begin
a <= '0';
b <= '0';
wait for 10 ns;
a <= '0';
b <= '1';
wait for 10 ns;
a <= '1';
b <= '0';
wait for 10 ns;
a <= '1';
b <= '1';
wait for 10 ns;
a <= '0';
b <= '0';
wait for 10 ns;
a <= '1';
b <= '0';
wait for 10 ns;
a <= '0';
b <= '1';
wait for 10 ns;
wait;
end process;
check_proc: process
begin
wait for 50 ns;
assert(sell = '0' and change = '0')
report "Error in state s0" severity error;
wait for 10 ns;
assert(sell = '0' and change = '0')
report "Error in state s0" severity error;
wait for 10 ns;
assert(sell = '1' and change = '0')
report "Error in state s1" severity error;
wait for 10 ns;
assert(sell = '1' and change = '0')
report "Error in state s1" severity error;
wait for 10 ns;
assert(sell = '1' and change = '1')
report "Error in state s2" severity error;
wait for 10 ns;
assert(sell = '1' and change = '1')
report "Error in state s0" severity error;
wait for 10 ns;
assert(sell = '1' and change = '0')
report "Error in state s1" severity error;
wait;
end process;
end sim;
```
这个测试文件中,使用了一个时钟发生器clk_gen来产生时钟信号,同时定义了一个刺激过程stim_proc,用于在不同的时钟周期中对输入端口a和b进行改变。在check_proc中,对输出端口sell和change的值进行检查,确保状态机的行为符合预期。