-------------------------------------------------------------------------------
-- Project  ELE8304 : Circuits intégrés à très grande échelle
-------------------------------------------------------------------------------
-- File     riscv_pc_tb.vhd
-- Authors  Titouan Luard <luardtitouan@gmail.com> 
--          Yann Roberge <yann.roberge@polymtl.ca> 
-- Lab      GRM - Polytechnique Montreal
-- Date     2021-11-19
-------------------------------------------------------------------------------
-- Brief    Full adder, supports sign-extension, addition-subtraction,
--          signed and unsigned.
-------------------------------------------------------------------------------
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use ieee.math_real.all;

library work;
use work.riscv_pkg.all;

entity riscv_pc_tb is
end riscv_pc_tb;

architecture tb of riscv_pc_tb is

    constant XLEN   : positive := 32;

    signal target    : std_logic_vector(XLEN-1 downto 0);
    signal clk       : std_logic;
    signal stall     : std_logic;
    signal transfert : std_logic;
    signal rstn      : std_logic;
    signal pc        : std_logic_vector(XLEN-1 downto 0);
    
    signal expected_result : std_logic_vector(XLEN-1 downto 0);
    constant PERIOD   : time := 10 ns;

begin

  -- DUT
  dut: entity work.riscv_pc
    generic map (
      RESET_VECTOR => (others => '0')
    )
    port map (
      i_target    => target,
      i_clk   => clk,
      i_stall => stall,
      i_transfert  => transfert,
      i_rstn  => rstn,
      o_pc => pc
    );

  drive_clk : process
  begin
    clk <= '0';
    wait for PERIOD/2;
    clk <= '1';
    wait for PERIOD/2;
  end process drive_clk;

  -- Main TB process
  p_main : process
  begin
    -- Vecteurs de tests

    report "BEGIN SIMULATION";

    report "initialisation";
    rstn <= '0' ;
    expected_result<=(others => '0');
    wait for PERIOD;
    assert pc = expected_result
      report "init error" severity error;
    wait for PERIOD;

    report "pasage dans l'adder";
    rstn <= '1';
    wait for PERIOD; 
    transfert<= '0';
    expected_result<=(2 downto 0 => "100",others => '0');
    assert pc = expected_result
      report "adder error" severity error;
    wait for PERIOD;

    report "target";
    transfert <= '1';
    target <= (0 downto 0 =>'1', others => '0' );
    expected_result<=(0 downto 0 =>'1', others => '0');
    assert pc =  expected_result
      report "target error" severity error;
    wait for PERIOD;
    report "reset";
    rstn <= '0' ;
    expected_result<=(others => '0');
    wait for PERIOD;
    assert pc = expected_result
      report "reset error" severity error;
    wait for PERIOD;

    report "SIMULATION DONE";
    wait;
  end process p_main;

end architecture tb;