ras.cc revision 6226 
1/*
2 * Copyright (c) 2004-2005 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Kevin Lim
29 */
30
31#include "cpu/pred/ras.hh"
32
33void
34ReturnAddrStack::init(unsigned _numEntries)
35{
36     numEntries  = _numEntries;
37     usedEntries = 0;
38     tos = 0;
39
40     addrStack.resize(numEntries);
41
42     for (int i = 0; i < numEntries; ++i)
43         addrStack[i] = 0;
44}
45
46void
47ReturnAddrStack::reset()
48{
49    usedEntries = 0;
50    tos = 0;
51    for (int i = 0; i < numEntries; ++i)
52        addrStack[i] = 0;
53}
54
55void
56ReturnAddrStack::push(const Addr &return_addr)
57{
58    incrTos();
59
60    addrStack[tos] = return_addr;
61
62    if (usedEntries != numEntries) {
63        ++usedEntries;
64    }
65}
66
67void
68ReturnAddrStack::pop()
69{
70    if (usedEntries > 0) {
71        --usedEntries;
72    }
73
74    decrTos();
75}
76
77void
78ReturnAddrStack::restore(unsigned top_entry_idx,
79                         const Addr &restored_target)
80{
81    tos = top_entry_idx;
82
83    addrStack[tos] = restored_target;
84}
85