base_set_assoc.cc revision 13217:725b1701b4ee 
1/*
2 * Copyright (c) 2012-2014 ARM Limited
3 * All rights reserved.
4 *
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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
78void
79BaseSetAssoc::init(BaseCache* cache)
80{
81    // Set parent cache
82    setCache(cache);
83
84    // Initialize blocks
85    unsigned blkIndex = 0;       // index into blks array
86    for (unsigned i = 0; i < numSets; ++i) {
87        sets[i].resize(assoc);
88
89        // link in the data blocks
90        for (unsigned j = 0; j < assoc; ++j) {
91            // Select block within the set to be linked
92            BlkType*& blk = sets[i][j];
93
94            // Locate next cache block
95            blk = &blks[blkIndex];
96
97            // Associate a data chunk to the block
98            blk->data = &dataBlks[blkSize*blkIndex];
99
100            // Associate a replacement data entry to the block
101            blk->replacementData = replacementPolicy->instantiateEntry();
102
103            // Setting the tag to j is just to prevent long chains in the
104            // hash table; won't matter because the block is invalid
105            blk->tag = j;
106
107            // Set its set and way
108            blk->set = i;
109            blk->way = j;
110
111            // Update block index
112            ++blkIndex;
113        }
114    }
115}
116
117void
118BaseSetAssoc::invalidate(CacheBlk *blk)
119{
120    BaseTags::invalidate(blk);
121
122    // Decrease the number of tags in use
123    tagsInUse--;
124
125    // Invalidate replacement data
126    replacementPolicy->invalidate(blk->replacementData);
127}
128
129ReplaceableEntry*
130BaseSetAssoc::findBlockBySetAndWay(int set, int way) const
131{
132    return sets[set][way];
133}
134
135BaseSetAssoc *
136BaseSetAssocParams::create()
137{
138    return new BaseSetAssoc(this);
139}
140