1
2-- Copyright (C) 1996 Morgan Kaufmann Publishers, Inc
3
4-- This file is part of VESTs (Vhdl tESTs).
5
6-- VESTs is free software; you can redistribute it and/or modify it
7-- under the terms of the GNU General Public License as published by the
8-- Free Software Foundation; either version 2 of the License, or (at
9-- your option) any later version.
10
11-- VESTs is distributed in the hope that it will be useful, but WITHOUT
12-- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13-- FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14-- for more details.
15
16-- You should have received a copy of the GNU General Public License
17-- along with VESTs; if not, write to the Free Software Foundation,
18-- Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19
20-- ---------------------------------------------------------------------
21--
22-- $Id: ch_17_fg_17_07.vhd,v 1.2 2001-10-26 16:29:36 paw Exp $
23-- $Revision: 1.2 $
24--
25-- ---------------------------------------------------------------------
26
27entity fg_17_07 is
28
29end entity fg_17_07;
30
31
32----------------------------------------------------------------
33
34
35architecture test of fg_17_07 is
36
37  signal s : bit_vector(0 to 3);
38
39begin
40
41  process is
42
43            type value_cell;
44
45          type value_ptr is access value_cell;
46
47          type value_cell is record
48                               value : bit_vector(0 to 3);
49                               next_cell : value_ptr;
50                             end record value_cell;
51
52          variable value_list, current_cell : value_ptr;
53          variable search_value : bit_vector(0 to 3);
54
55  begin
56    value_list := new value_cell'( B"1000", value_list );
57    value_list := new value_cell'( B"0010", value_list );
58    value_list := new value_cell'( B"0000", value_list );
59
60    search_value := B"0010";
61
62    -- code from book:
63
64    current_cell := value_list;
65    while current_cell /= null
66      and current_cell.value /= search_value loop
67      current_cell := current_cell.next_cell;
68    end loop;
69    assert current_cell /= null
70      report "search for value failed";
71
72    -- end of code from book
73
74    search_value := B"1111";
75
76    current_cell := value_list;
77    while current_cell /= null
78      and current_cell.value /= search_value loop
79      current_cell := current_cell.next_cell;
80    end loop;
81    assert current_cell /= null
82      report "search for value failed";
83
84    wait;
85  end process;
86
87end architecture test;
88