--------------------------------------------------------------------------------
--
-- FIFO Generator Core Demo Testbench 
--
--------------------------------------------------------------------------------
--
-- (c) Copyright 2009 - 2010 Xilinx, Inc. All rights reserved.
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--------------------------------------------------------------------------------
--
-- Filename: q16_tb.vhd
--
-- Description:
--   This is the demo testbench top file for fifo_generator core.
--
--------------------------------------------------------------------------------
-- Library Declarations
--------------------------------------------------------------------------------
LIBRARY ieee;
LIBRARY std;
USE ieee.std_logic_1164.ALL;
USE ieee.std_logic_unsigned.ALL;
USE IEEE.std_logic_arith.ALL;
USE IEEE.std_logic_misc.ALL;
USE ieee.numeric_std.ALL;
USE ieee.std_logic_textio.ALL;
USE std.textio.ALL;

LIBRARY work;
USE work.q16_pkg.ALL;

ENTITY q16_tb IS
END ENTITY;


ARCHITECTURE q16_arch OF q16_tb IS
 SIGNAL  status              : STD_LOGIC_VECTOR(7 DOWNTO 0) := "00000000";
 SIGNAL  wr_clk              : STD_LOGIC;
 SIGNAL  rd_clk              : STD_LOGIC;
 SIGNAL  reset 	             : STD_LOGIC;
 SIGNAL  sim_done            : STD_LOGIC := '0';
 SIGNAL  end_of_sim          : STD_LOGIC_VECTOR(4 DOWNTO 0) := (OTHERS => '0');
 -- Write and Read clock periods
 CONSTANT wr_clk_period_by_2 : TIME := 200 ns;
 CONSTANT rd_clk_period_by_2 : TIME := 100 ns;
 -- Procedures to display strings
 PROCEDURE disp_str(CONSTANT str:IN STRING) IS
    variable dp_l : line := null;   
 BEGIN
  write(dp_l,str);
  writeline(output,dp_l);
 END PROCEDURE;
 
 PROCEDURE disp_hex(signal hex:IN STD_LOGIC_VECTOR(7 DOWNTO 0)) IS
    variable dp_lx : line := null;   
 BEGIN
  hwrite(dp_lx,hex);
  writeline(output,dp_lx);
 END PROCEDURE;

BEGIN
  
  -- Generation of clock

  PROCESS BEGIN
    WAIT FOR 400 ns; -- Wait for global reset
    WHILE 1 = 1 LOOP
      wr_clk <= '0';
      WAIT FOR wr_clk_period_by_2;
      wr_clk <= '1'; 
      WAIT FOR wr_clk_period_by_2;
    END LOOP;
  END PROCESS;

  PROCESS BEGIN
    WAIT FOR 200 ns;-- Wait for global reset
    WHILE 1 = 1 LOOP
      rd_clk <= '0';
      WAIT FOR rd_clk_period_by_2;
      rd_clk <= '1'; 
      WAIT FOR rd_clk_period_by_2;
    END LOOP;
  END PROCESS;
  
  -- Generation of Reset
  
  PROCESS BEGIN
    reset <= '1';
    WAIT FOR 4200 ns;
    reset <= '0';
    WAIT;
  END PROCESS;
  
  
  -- Error message printing based on STATUS signal from q16_synth

  PROCESS(status)
  BEGIN
    IF(status /= "0" AND status /= "1") THEN
      disp_str("STATUS:");
      disp_hex(status);
    END IF;

    IF(status(7) = '1') THEN
      assert false
       report "Data mismatch found"
       severity error;
    END IF;

    IF(status(1) = '1') THEN
    END IF;
    
    IF(status(5) = '1') THEN
      assert false
       report "Empty flag Mismatch/timeout"
       severity error;
    END IF;

    IF(status(6) = '1') THEN
      assert false
       report "Full Flag Mismatch/timeout"
       severity error;
    END IF;
  END PROCESS;


  PROCESS 
  BEGIN
    wait until sim_done = '1';
    IF(status /= "0" AND status /= "1") THEN
      assert false
      report "Simulation failed"
      severity failure;
    ELSE
      assert false
      report "Test Completed Successfully"
      severity failure;
    END IF;
  END PROCESS;
  
  PROCESS
  BEGIN
    wait for 400 ms;
    assert false
    report "Test bench timed out"
    severity failure;
  END PROCESS;

  -- Instance of q16_synth
  
  q16_synth_inst:q16_synth
   GENERIC MAP(
              FREEZEON_ERROR => 0,
 	      TB_STOP_CNT    => 2,
 	      TB_SEED        => 26 
 	      )
  PORT MAP(
	   WR_CLK        => wr_clk,
	   RD_CLK        => rd_clk,
	   RESET         => reset,
	   SIM_DONE      => sim_done,
           STATUS        => status
	  );

END ARCHITECTURE;
