src/mem/cache/tags/base_set_assoc.cc

   1 /*
   2  * Copyright (c) 2012-2014 ARM Limited
   3  * All rights reserved.
   4  *
   5  * The license below extends only to copyright in the software and shall
   6  * not be construed as granting a license to any other intellectual
   7  * property including but not limited to intellectual property relating
   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  *
  17  * Redistribution and use in source and binary forms, with or without
  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
  22  * notice, this list of conditions and the following disclaimer in the
  23  * documentation and/or other materials provided with the distribution;
  24  * neither the name of the copyright holders nor the names of its
  25  * contributors may be used to endorse or promote products derived from
  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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  38  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  39  */
  40
  41 /**
  42  * @file
  43  * Definitions of a conventional tag store.
  44  */
  45
  46 #include "mem/cache/tags/base_set_assoc.hh"
  47
  48 #include <string>
  49
  50 #include "base/intmath.hh"
  51
  52 BaseSetAssoc::BaseSetAssoc(const Params &p)
  53     :BaseTags(p), allocAssoc(p.assoc), blks(p.size / p.block_size),
  54      sequentialAccess(p.sequential_access),
  55      replacementPolicy(p.replacement_policy)
  56 {
  57     // There must be a indexing policy
  58     fatal_if(!p.indexing_policy, "An indexing policy is required");
  59
  60     // Check parameters
  61     if (blkSize < 4 || !isPowerOf2(blkSize)) {
  62         fatal("Block size must be at least 4 and a power of 2");
  63     }
  64 }
  65
  66 void
  67 BaseSetAssoc::tagsInit()
  68 {
  69     // Initialize all blocks
  70     for (unsigned blk_index = 0; blk_index < numBlocks; blk_index++) {
  71         // Locate next cache block
  72         CacheBlk* blk = &blks[blk_index];
  73
  74         // Link block to indexing policy
  75         indexingPolicy->setEntry(blk, blk_index);
  76
  77         // Associate a data chunk to the block
  78         blk->data = &dataBlks[blkSize*blk_index];
  79
  80         // Associate a replacement data entry to the block
  81         blk->replacementData = replacementPolicy->instantiateEntry();
  82     }
  83 }
  84
  85 void
  86 BaseSetAssoc::invalidate(CacheBlk *blk)
  87 {
  88     BaseTags::invalidate(blk);
  89
  90     // Decrease the number of tags in use
  91     stats.tagsInUse--;
  92
  93     // Invalidate replacement data
  94     replacementPolicy->invalidate(blk->replacementData);
  95 }
  96
  97 void
  98 BaseSetAssoc::moveBlock(CacheBlk *src_blk, CacheBlk *dest_blk)
  99 {
 100     BaseTags::moveBlock(src_blk, dest_blk);
 101
 102     // Since the blocks were using different replacement data pointers,
 103     // we must touch the replacement data of the new entry, and invalidate
 104     // the one that is being moved.
 105     replacementPolicy->invalidate(src_blk->replacementData);
 106     replacementPolicy->reset(dest_blk->replacementData);
 107 }