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
|
-- 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_16_fg_16_14.vhd,v 1.2 2001-10-26 16:29:36 paw Exp $
-- $Revision: 1.2 $
--
-- ---------------------------------------------------------------------
-- not in book
entity example_entity is
end entity example_entity;
-- end not in book
architecture contrived of example_entity is
constant sig_width : positive := 16;
signal s1, s2, s3 : bit_vector (0 to sig_width - 1);
signal sel : bit;
-- . . .
begin
mux : block is
generic ( width : positive );
generic map ( width => sig_width );
port ( d0, d1 : in bit_vector(0 to width - 1);
y : out bit_vector(0 to width - 1);
sel : in bit);
port map ( d0 => s1, d1=> s2, y => s3, sel => sel );
constant zero : bit_vector(0 to width - 1) := ( others => '0' );
signal gated_d0, gated_d1 : bit_vector(0 to width - 1);
begin
gated_d0 <= d0 when sel = '0' else zero;
gated_d1 <= d1 when sel = '1' else zero;
y <= gated_d0 or gated_d1;
end block mux;
-- . . .
-- not in book
stimulus : process is
begin
s1 <= X"1111"; s2 <= X"2222"; sel <= '0'; wait for 10 ns;
s1 <= X"0101"; wait for 10 ns;
s2 <= X"0202"; wait for 10 ns;
sel <= '1'; wait for 10 ns;
s1 <= X"0001"; wait for 10 ns;
s2 <= X"0002"; wait for 10 ns;
wait;
end process stimulus;
-- end not in book
end architecture contrived;
|
