CristalCaveGem » LustreC » Lustrec-Tests

-- Copyright (C) 1996 Morgan Kaufmann Publishers, Inc

-- This file is part of VESTs (Vhdl tESTs).

-- VESTs is free software; you can redistribute it and/or modify it

-- under the terms of the GNU General Public License as published by the

-- Free Software Foundation; either version 2 of the License, or (at

-- your option) any later version. 

-- VESTs is distributed in the hope that it will be useful, but WITHOUT

-- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

-- FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

-- for more details. 

-- You should have received a copy of the GNU General Public License

-- along with VESTs; if not, write to the Free Software Foundation,

-- Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 

-- ---------------------------------------------------------------------

--

-- $Id: ch_21_fg_21_03.vhd,v 1.2 2001-10-26 16:29:37 paw Exp $

-- $Revision: 1.2 $

--

-- ---------------------------------------------------------------------

-- code from book (in text)

entity random_source is

  generic ( min, max : natural;

            seed : natural;

            interval : delay_length );

  port ( number : out natural );

end entity random_source;

-- end code from book

architecture fudged of random_source is

begin

  process is

            variable next_number : natural := seed;

  begin

    if next_number > max then

      next_number := min;

    end if;

    number <= next_number;

    next_number := next_number + 1;

    wait for interval;

  end process;

end architecture fudged;

entity test_bench is

end entity test_bench;

-- code from book

architecture random_test of test_bench is

  subtype bv11 is bit_vector(10 downto 0);

  function natural_to_bv11 ( n : natural ) return bv11 is

    variable result : bv11 := (others => '0');

    variable remaining_digits : natural := n;

  begin

    for index in result'reverse_range loop

      result(index) := bit'val(remaining_digits mod 2);

      remaining_digits := remaining_digits / 2;

      exit when remaining_digits = 0;

    end loop;

    return result;

  end function natural_to_bv11;

  signal stimulus_vector : bv11;

  -- . . .

begin

  stimulus_generator : entity work.random_source

    generic map ( min => 0, max => 2**10 - 1, seed => 0,

                  interval => 100 ns )

    port map ( natural_to_bv11(number) => stimulus_vector );

  -- . . .

end architecture random_test;

-- end code from book