base.hh

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/*
 * 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
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Authors: Daniel Carvalho
 */

#ifndef __MEM_CACHE_COMPRESSORS_BASE_HH__
#define __MEM_CACHE_COMPRESSORS_BASE_HH__

#include <cstdint>

#include "base/statistics.hh"
#include "base/types.hh"
#include "sim/sim_object.hh"

class CacheBlk;
struct BaseCacheCompressorParams;

class BaseCacheCompressor : public SimObject
{
  protected:
    friend class MultiCompressor;

    class CompressionData;

    const std::size_t blkSize;

    const std::size_t sizeThreshold;

    struct BaseCacheCompressorStats : public Stats::Group
    {
        const BaseCacheCompressor& compressor;

        BaseCacheCompressorStats(BaseCacheCompressor& compressor);

        void regStats() override;

        Stats::Scalar compressions;

        Stats::Vector compressionSize;

        Stats::Scalar compressionSizeBits;

        Stats::Formula avgCompressionSizeBits;

        Stats::Scalar decompressions;
    } stats;

    virtual std::unique_ptr<CompressionData> compress(
        const uint64_t* cache_line, Cycles& comp_lat, Cycles& decomp_lat) = 0;

    virtual void decompress(const CompressionData* comp_data,
                              uint64_t* cache_line) = 0;

  public:
     typedef BaseCacheCompressorParams Params;

    BaseCacheCompressor(const Params *p);

    virtual ~BaseCacheCompressor() {};

    void compress(const uint64_t* data, Cycles& comp_lat,
                  Cycles& decomp_lat, std::size_t& comp_size_bits);

    Cycles getDecompressionLatency(const CacheBlk* blk);

    static void setDecompressionLatency(CacheBlk* blk, const Cycles lat);

    static void setSizeBits(CacheBlk* blk, const std::size_t size_bits);
};

class BaseCacheCompressor::CompressionData {
  private:
    std::size_t _size;

  public:
    CompressionData();

    virtual ~CompressionData();

    void setSizeBits(std::size_t size);

    std::size_t getSizeBits() const;

    std::size_t getSize() const;
};

#endif //__MEM_CACHE_COMPRESSORS_BASE_HH__