replaceable_entry.hh revision 13225 
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     /**
68      * Replacement data associated to this entry.
69      * It must be instantiated by the replacement policy before being used.
70      */
71     std::shared_ptr<ReplacementData> replacementData;
72
73    /**
74     * Set both the set and way. Should be called only once.
75     *
76     * @param set The set of this entry.
77     * @param way The way of this entry.
78     */
79    void setPosition(const uint32_t set, const uint32_t way) {
80        _set = set;
81        _way = way;
82    }
83
84    /**
85     * Get set number.
86     *
87     * @return The set to which this entry belongs.
88     */
89    uint32_t getSet() const { return _set; }
90
91    /**
92     * Get way number.
93     *
94     * @return The way to which this entry belongs.
95     */
96    uint32_t getWay() const { return _way; }
97};
98
99#endif // __MEM_CACHE_REPLACEMENT_POLICIES_REPLACEABLE_ENTRY_HH_
100