1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
|
-- Copyright (C) 2002 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
-- 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
|
