replaceable_entry.hh revision 14131:f0529ae28f97 
1/**
2 * Copyright (c) 2018 Inria
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: Daniel Carvalho
29 */
30
31#ifndef __MEM_CACHE_REPLACEMENT_POLICIES_REPLACEABLE_ENTRY_HH__
32#define __MEM_CACHE_REPLACEMENT_POLICIES_REPLACEABLE_ENTRY_HH__
33
34#include <cstdint>
35#include <memory>
36
37/**
38 * The replacement data needed by replacement policies. Each replacement policy
39 * should have its own implementation of replacement data.
40 */
41struct ReplacementData {};
42
43/**
44 * A replaceable entry is a basic entry in a 2d table-like structure that needs
45 * to have replacement functionality. This entry is located in a specific row
46 * and column of the table (set and way in cache nomenclature), which are
47 * stored within the entry itself.
48 *
49 * It contains the replacement data pointer, which must be instantiated by the
50 * replacement policy before being used.
51 * @sa Replacement Policies
52 */
53class ReplaceableEntry
54{
55  private:
56    /**
57     * Set to which this entry belongs.
58     */
59    uint32_t _set;
60
61    /**
62     * Way (relative position within the set) to which this entry belongs.
63     */
64    uint32_t _way;
65
66  public:
67    ReplaceableEntry() = default;
68    virtual ~ReplaceableEntry() = default;
69
70    /**
71     * Replacement data associated to this entry.
72     * It must be instantiated by the replacement policy before being used.
73     */
74    std::shared_ptr<ReplacementData> replacementData;
75
76    /**
77     * Set both the set and way. Should be called only once.
78     *
79     * @param set The set of this entry.
80     * @param way The way of this entry.
81     */
82    virtual void
83    setPosition(const uint32_t set, const uint32_t way)
84    {
85        _set = set;
86        _way = way;
87    }
88
89    /**
90     * Get set number.
91     *
92     * @return The set to which this entry belongs.
93     */
94    uint32_t getSet() const { return _set; }
95
96    /**
97     * Get way number.
98     *
99     * @return The way to which this entry belongs.
100     */
101    uint32_t getWay() const { return _way; }
102};
103
104#endif // __MEM_CACHE_REPLACEMENT_POLICIES_REPLACEABLE_ENTRY_HH_
105