microwatt/plru_tb.vhdl

library vunit_lib;
context vunit_lib.vunit_context;

library ieee;
use ieee.std_logic_1164.all;

library work;
use work.common.all;
use work.wishbone_types.all;

entity plru_tb is
    generic (runner_cfg : string := runner_cfg_default);
end plru_tb;

architecture behave of plru_tb is
    signal clk          : std_ulogic;
    signal rst          : std_ulogic;

    constant clk_period : time := 10 ns;

    signal acc_en : std_ulogic;
    signal acc : std_ulogic_vector(2 downto 0);
    signal lru : std_ulogic_vector(2 downto 0);

begin
    plru0: entity work.plru
        generic map(
            BITS => 3
            )
        port map(
            clk => clk,
            rst => rst,

            acc => acc,
            acc_en => acc_en,
            lru => lru
            );

    clk_process: process
    begin
        clk <= '0';
        wait for clk_period/2;
        clk <= '1';
        wait for clk_period/2;
    end process;

    rst_process: process
    begin
        rst <= '1';
        wait for 2*clk_period;
        rst <= '0';
        wait;
    end process;

    stim: process
    begin
        test_runner_setup(runner, runner_cfg);

        wait for 8*clk_period;

        info("reset state:" & to_hstring(lru));
        check_equal(lru, 0, result("LRU"));

        info("accessing 1:");
        acc <= "001";
        acc_en <= '1';
        wait for clk_period;
        info("lru:" & to_hstring(lru));
        check_equal(lru, 4, result("LRU"));

        info("accessing 2:");
        acc <= "010";
        wait for clk_period;
        info("lru:" & to_hstring(lru));
        check_equal(lru, 4, result("LRU"));

        info("accessing 7:");
        acc <= "111";
        wait for clk_period;
        info("lru:" & to_hstring(lru));
        check_equal(lru, 0, result("LRU"));

        info("accessing 4:");
        acc <= "100";
        wait for clk_period;
        info("lru:" & to_hstring(lru));
        check_equal(lru, 0, result("LRU"));

        info("accessing 3:");
        acc <= "011";
        wait for clk_period;
        info("lru:" & to_hstring(lru));
        check_equal(lru, 6, result("LRU"));

        info("accessing 5:");
        acc <= "101";
        wait for clk_period;
        info("lru:" & to_hstring(lru));
        check_equal(lru, 0, result("LRU"));

        info("accessing 3:");
        acc <= "011";
        wait for clk_period;
        info("lru:" & to_hstring(lru));
        check_equal(lru, 6, result("LRU"));

        info("accessing 5:");
        acc <= "101";
        wait for clk_period;
        info("lru:" & to_hstring(lru));
        check_equal(lru, 0, result("LRU"));

        info("accessing 6:");
        acc <= "110";
        wait for clk_period;
        info("lru:" & to_hstring(lru));
        check_equal(lru, 0, result("LRU"));

        info("accessing 0:");
        acc <= "000";
        wait for clk_period;
        info("lru:" & to_hstring(lru));
        check_equal(lru, 4, result("LRU"));

        wait for clk_period;
        wait for clk_period;
        
        test_runner_cleanup(runner);
    end process;
end;