--------------------------------------------------------------------------------
-- Copyright (c) 1995-2003 Xilinx, Inc.
-- All Right Reserved.
--------------------------------------------------------------------------------
--   ____  ____ 
--  /   /\/   / 
-- /___/  \  /    Vendor: Xilinx 
-- \   \   \/     Version : 8.2i
--  \   \         Application : ISE
--  /   /         Filename : ClockDiv_tbw.vhw
-- /___/   /\     Timestamp : Wed Jun 13 10:50:34 2007
-- \   \  /  \ 
--  \___\/\___\ 
--
--Command: 
--Design Name: ClockDiv_tbw
--Device: Xilinx
--

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
USE IEEE.STD_LOGIC_TEXTIO.ALL;
USE STD.TEXTIO.ALL;

ENTITY ClockDiv_tbw IS
END ClockDiv_tbw;

ARCHITECTURE testbench_arch OF ClockDiv_tbw IS
    FILE RESULTS: TEXT OPEN WRITE_MODE IS "results.txt";

    COMPONENT ClockDiv
        PORT (
            reset : In std_logic;
            clk : In std_logic;
            clkdiv : Out std_logic
        );
    END COMPONENT;

    SIGNAL reset : std_logic := '0';
    SIGNAL clk : std_logic := '0';
    SIGNAL clkdiv : std_logic := 'U';

    SHARED VARIABLE TX_ERROR : INTEGER := 0;
    SHARED VARIABLE TX_OUT : LINE;

    constant PERIOD : time := 100 ns;
    constant DUTY_CYCLE : real := 0.5;
    constant OFFSET : time := 0 ns;

    BEGIN
        UUT : ClockDiv
        PORT MAP (
            reset => reset,
            clk => clk,
            clkdiv => clkdiv
        );

        PROCESS    -- clock process for clk
        BEGIN
            WAIT for OFFSET;
            CLOCK_LOOP : LOOP
                clk <= '0';
                WAIT FOR (PERIOD - (PERIOD * DUTY_CYCLE));
                clk <= '1';
                WAIT FOR (PERIOD * DUTY_CYCLE);
            END LOOP CLOCK_LOOP;
        END PROCESS;

        PROCESS
            PROCEDURE CHECK_clkdiv(
                next_clkdiv : std_logic;
                TX_TIME : INTEGER
            ) IS
                VARIABLE TX_STR : String(1 to 4096);
                VARIABLE TX_LOC : LINE;
                BEGIN
                IF (clkdiv /= next_clkdiv) THEN
                    STD.TEXTIO.write(TX_LOC, string'("Error at time="));
                    STD.TEXTIO.write(TX_LOC, TX_TIME);
                    STD.TEXTIO.write(TX_LOC, string'("ns clkdiv="));
                    IEEE.STD_LOGIC_TEXTIO.write(TX_LOC, clkdiv);
                    STD.TEXTIO.write(TX_LOC, string'(", Expected = "));
                    IEEE.STD_LOGIC_TEXTIO.write(TX_LOC, next_clkdiv);
                    STD.TEXTIO.write(TX_LOC, string'(" "));
                    TX_STR(TX_LOC.all'range) := TX_LOC.all;
                    STD.TEXTIO.writeline(RESULTS, TX_LOC);
                    STD.TEXTIO.Deallocate(TX_LOC);
                    ASSERT (FALSE) REPORT TX_STR SEVERITY ERROR;
                    TX_ERROR := TX_ERROR + 1;
                END IF;
            END;
            BEGIN
                -- -------------  Current Time:  60ns
                WAIT FOR 60 ns;
                CHECK_clkdiv('0', 60);
                -- -------------------------------------
                -- -------------  Current Time:  240ns
                WAIT FOR 180 ns;
                reset <= '1';
                -- -------------------------------------
                -- -------------  Current Time:  340ns
                WAIT FOR 100 ns;
                reset <= '0';
                -- -------------------------------------
                -- -------------  Current Time:  1260ns
                WAIT FOR 920 ns;
                CHECK_clkdiv('1', 1260);
                -- -------------------------------------
                -- -------------  Current Time:  1360ns
                WAIT FOR 100 ns;
                CHECK_clkdiv('0', 1360);
                -- -------------------------------------
                -- -------------  Current Time:  2260ns
                WAIT FOR 900 ns;
                CHECK_clkdiv('1', 2260);
                -- -------------------------------------
                -- -------------  Current Time:  2360ns
                WAIT FOR 100 ns;
                CHECK_clkdiv('0', 2360);
                -- -------------------------------------
                -- -------------  Current Time:  3260ns
                WAIT FOR 900 ns;
                CHECK_clkdiv('1', 3260);
                -- -------------------------------------
                -- -------------  Current Time:  3360ns
                WAIT FOR 100 ns;
                CHECK_clkdiv('0', 3360);
                -- -------------------------------------
                -- -------------  Current Time:  4260ns
                WAIT FOR 900 ns;
                CHECK_clkdiv('1', 4260);
                -- -------------------------------------
                -- -------------  Current Time:  4360ns
                WAIT FOR 100 ns;
                CHECK_clkdiv('0', 4360);
                -- -------------------------------------
                -- -------------  Current Time:  5260ns
                WAIT FOR 900 ns;
                CHECK_clkdiv('1', 5260);
                -- -------------------------------------
                -- -------------  Current Time:  5360ns
                WAIT FOR 100 ns;
                CHECK_clkdiv('0', 5360);
                -- -------------------------------------
                -- -------------  Current Time:  6260ns
                WAIT FOR 900 ns;
                CHECK_clkdiv('1', 6260);
                -- -------------------------------------
                -- -------------  Current Time:  6360ns
                WAIT FOR 100 ns;
                CHECK_clkdiv('0', 6360);
                -- -------------------------------------
                -- -------------  Current Time:  7260ns
                WAIT FOR 900 ns;
                CHECK_clkdiv('1', 7260);
                -- -------------------------------------
                -- -------------  Current Time:  7360ns
                WAIT FOR 100 ns;
                CHECK_clkdiv('0', 7360);
                -- -------------------------------------
                -- -------------  Current Time:  8260ns
                WAIT FOR 900 ns;
                CHECK_clkdiv('1', 8260);
                -- -------------------------------------
                -- -------------  Current Time:  8360ns
                WAIT FOR 100 ns;
                CHECK_clkdiv('0', 8360);
                -- -------------------------------------
                -- -------------  Current Time:  9260ns
                WAIT FOR 900 ns;
                CHECK_clkdiv('1', 9260);
                -- -------------------------------------
                -- -------------  Current Time:  9360ns
                WAIT FOR 100 ns;
                CHECK_clkdiv('0', 9360);
                -- -------------------------------------
                -- -------------  Current Time:  10260ns
                WAIT FOR 900 ns;
                CHECK_clkdiv('1', 10260);
                -- -------------------------------------
                -- -------------  Current Time:  10360ns
                WAIT FOR 100 ns;
                CHECK_clkdiv('0', 10360);
                -- -------------------------------------
                -- -------------  Current Time:  11260ns
                WAIT FOR 900 ns;
                CHECK_clkdiv('1', 11260);
                -- -------------------------------------
                -- -------------  Current Time:  11360ns
                WAIT FOR 100 ns;
                CHECK_clkdiv('0', 11360);
                -- -------------------------------------
                WAIT FOR 740 ns;

                IF (TX_ERROR = 0) THEN
                    STD.TEXTIO.write(TX_OUT, string'("No errors or warnings"));
                    STD.TEXTIO.writeline(RESULTS, TX_OUT);
                    ASSERT (FALSE) REPORT
                      "Simulation successful (not a failure).  No problems detected."
                      SEVERITY FAILURE;
                ELSE
                    STD.TEXTIO.write(TX_OUT, TX_ERROR);
                    STD.TEXTIO.write(TX_OUT,
                        string'(" errors found in simulation"));
                    STD.TEXTIO.writeline(RESULTS, TX_OUT);
                    ASSERT (FALSE) REPORT "Errors found during simulation"
                         SEVERITY FAILURE;
                END IF;
            END PROCESS;

    END testbench_arch;