src/mem/cache/tags/compressed_tags.cc

/*
 * Copyright (c) 2018 Inria
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Authors: Daniel Carvalho
 */

/**
 * @file
 * Definitions of a base set associative compressed superblocks tag store.
 */

#include "mem/cache/tags/compressed_tags.hh"

#include "mem/cache/replacement_policies/base.hh"
#include "mem/cache/tags/indexing_policies/base.hh"
#include "mem/packet.hh"
#include "params/CompressedTags.hh"

CompressedTags::CompressedTags(const Params *p)
    : SectorTags(p)
{
}

void
CompressedTags::tagsInit()
{
    // Create blocks and superblocks
    blks = std::vector<CompressionBlk>(numBlocks);
    superBlks = std::vector<SuperBlk>(numSectors);

    // Initialize all blocks
    unsigned blk_index = 0;          // index into blks array
    for (unsigned superblock_index = 0; superblock_index < numSectors;
         superblock_index++)
    {
        // Locate next cache superblock
        SuperBlk* superblock = &superBlks[superblock_index];

        // Link block to indexing policy
        indexingPolicy->setEntry(superblock, superblock_index);

        // Associate a replacement data entry to the block
        superblock->replacementData = replacementPolicy->instantiateEntry();

        // Initialize all blocks in this superblock
        superblock->blks.resize(numBlocksPerSector, nullptr);
        for (unsigned k = 0; k < numBlocksPerSector; ++k){
            // Select block within the set to be linked
            SectorSubBlk*& blk = superblock->blks[k];

            // Locate next cache block
            blk = &blks[blk_index];

            // Associate a data chunk to the block
            blk->data = &dataBlks[blkSize*blk_index];

            // Associate superblock to this block
            blk->setSectorBlock(superblock);

            // Associate the superblock replacement data to this block
            blk->replacementData = superblock->replacementData;

            // Set its index and sector offset
            blk->setSectorOffset(k);

            // Update block index
            ++blk_index;
        }
    }
}

void
CompressedTags::insertBlock(const PacketPtr pkt, CacheBlk *blk)
{
    // Insert block
    SectorTags::insertBlock(pkt, blk);

    // @todo We always store compressed blocks when possible
    CompressionBlk* compression_blk = static_cast<CompressionBlk*>(blk);
    compression_blk->setUncompressed();
}

void
CompressedTags::forEachBlk(std::function<void(CacheBlk &)> visitor)
{
    for (CompressionBlk& blk : blks) {
        visitor(blk);
    }
}

bool
CompressedTags::anyBlk(std::function<bool(CacheBlk &)> visitor)
{
    for (CompressionBlk& blk : blks) {
        if (visitor(blk)) {
            return true;
        }
    }
    return false;
}

CompressedTags *
CompressedTagsParams::create()
{
    return new CompressedTags(this);
}