base_set_assoc.cc revision 12745:e28c117a9806 
1/*
2 * Copyright (c) 2012-2014 ARM Limited
3 * All rights reserved.
4 *
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6 * not be construed as granting a license to any other intellectual
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8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder.  You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Copyright (c) 2003-2005,2014 The Regents of The University of Michigan
15 * All rights reserved.
16 *
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18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer;
21 * redistributions in binary form must reproduce the above copyright
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26 * this software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 *
40 * Authors: Erik Hallnor
41 */
42
43/**
44 * @file
45 * Definitions of a base set associative tag store.
46 */
47
48#include "mem/cache/tags/base_set_assoc.hh"
49
50#include <string>
51
52#include "base/intmath.hh"
53
54BaseSetAssoc::BaseSetAssoc(const Params *p)
55    :BaseTags(p), assoc(p->assoc), allocAssoc(p->assoc),
56     blks(p->size / p->block_size),
57     numSets(p->size / (p->block_size * p->assoc)),
58     sequentialAccess(p->sequential_access),
59     sets(p->size / (p->block_size * p->assoc)),
60     replacementPolicy(p->replacement_policy)
61{
62    // Check parameters
63    if (blkSize < 4 || !isPowerOf2(blkSize)) {
64        fatal("Block size must be at least 4 and a power of 2");
65    }
66    if (!isPowerOf2(numSets)) {
67        fatal("# of sets must be non-zero and a power of 2");
68    }
69    if (assoc <= 0) {
70        fatal("associativity must be greater than zero");
71    }
72
73    setShift = floorLog2(blkSize);
74    setMask = numSets - 1;
75    tagShift = setShift + floorLog2(numSets);
76
77    unsigned blkIndex = 0;       // index into blks array
78    for (unsigned i = 0; i < numSets; ++i) {
79        sets[i].assoc = assoc;
80
81        sets[i].blks.resize(assoc);
82
83        // link in the data blocks
84        for (unsigned j = 0; j < assoc; ++j) {
85            // Select block within the set to be linked
86            BlkType*& blk = sets[i].blks[j];
87
88            // Locate next cache block
89            blk = &blks[blkIndex];
90
91            // Associate a data chunk to the block
92            blk->data = &dataBlks[blkSize*blkIndex];
93
94            // Associate a replacement data entry to the block
95            blk->replacementData = replacementPolicy->instantiateEntry();
96
97            // Setting the tag to j is just to prevent long chains in the
98            // hash table; won't matter because the block is invalid
99            blk->tag = j;
100
101            // Set its set and way
102            blk->set = i;
103            blk->way = j;
104
105            // Update block index
106            ++blkIndex;
107        }
108    }
109}
110
111void
112BaseSetAssoc::invalidate(CacheBlk *blk)
113{
114    BaseTags::invalidate(blk);
115
116    // Decrease the number of tags in use
117    tagsInUse--;
118
119    // Invalidate replacement data
120    replacementPolicy->invalidate(blk->replacementData);
121}
122
123CacheBlk*
124BaseSetAssoc::findBlock(Addr addr, bool is_secure) const
125{
126    Addr tag = extractTag(addr);
127    unsigned set = extractSet(addr);
128    BlkType *blk = sets[set].findBlk(tag, is_secure);
129    return blk;
130}
131
132ReplaceableEntry*
133BaseSetAssoc::findBlockBySetAndWay(int set, int way) const
134{
135    return sets[set].blks[way];
136}
137
138BaseSetAssoc *
139BaseSetAssocParams::create()
140{
141    return new BaseSetAssoc(this);
142}
143