LRUPolicy.hh revision 7008 
1/*
2 * Copyright (c) 2007 Mark D. Hill and David A. Wood
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
29#ifndef LRUPOLICY_H
30#define LRUPOLICY_H
31
32#include "mem/ruby/system/AbstractReplacementPolicy.hh"
33
34/* Simple true LRU replacement policy */
35
36class LRUPolicy : public AbstractReplacementPolicy {
37 public:
38
39  LRUPolicy(Index num_sets, Index assoc);
40  ~LRUPolicy();
41
42  void touch(Index set, Index way, Time time);
43  Index getVictim(Index set) const;
44};
45
46inline
47LRUPolicy::LRUPolicy(Index num_sets, Index assoc)
48  : AbstractReplacementPolicy(num_sets, assoc)
49{
50}
51
52inline
53LRUPolicy::~LRUPolicy()
54{
55}
56
57inline
58void LRUPolicy::touch(Index set, Index index, Time time){
59  assert(index >= 0 && index < m_assoc);
60  assert(set >= 0 && set < m_num_sets);
61
62  m_last_ref_ptr[set][index] = time;
63}
64
65inline
66Index LRUPolicy::getVictim(Index set) const {
67  //  assert(m_assoc != 0);
68  Time time, smallest_time;
69  Index smallest_index;
70
71  smallest_index = 0;
72  smallest_time = m_last_ref_ptr[set][0];
73
74  for (unsigned int i=0; i < m_assoc; i++) {
75    time = m_last_ref_ptr[set][i];
76    //assert(m_cache[cacheSet][i].m_Permission != AccessPermission_NotPresent);
77
78    if (time < smallest_time){
79      smallest_index = i;
80      smallest_time = time;
81    }
82  }
83
84  //  DEBUG_EXPR(CACHE_COMP, MedPrio, cacheSet);
85  //  DEBUG_EXPR(CACHE_COMP, MedPrio, smallest_index);
86  //  DEBUG_EXPR(CACHE_COMP, MedPrio, m_cache[cacheSet][smallest_index]);
87  //  DEBUG_EXPR(CACHE_COMP, MedPrio, *this);
88
89  return smallest_index;
90}
91
92#endif // PSEUDOLRUBITS_H
93