base.hh

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 * Copyright (c) 2018-2020 Inria
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#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;
 
namespace Compressor {
 
class Base : public SimObject
{
  public:
    class CompressionData;
 
  protected:
    typedef uint64_t Chunk;
 
    friend class Multi;
 
    const std::size_t blkSize;
 
    const unsigned chunkSizeBits;
 
    const std::size_t sizeThreshold;
 
    struct BaseStats : public Stats::Group
    {
        const Base& compressor;
 
        BaseStats(Base& compressor);
 
        void regStats() override;
 
        Stats::Scalar compressions;
 
        Stats::Scalar failedCompressions;
 
        Stats::Vector compressionSize;
 
        Stats::Scalar compressionSizeBits;
 
        Stats::Formula avgCompressionSizeBits;
 
        Stats::Scalar decompressions;
    } stats;
 
    std::vector<Chunk> toChunks(const uint64_t* data) const;
 
    void fromChunks(const std::vector<Chunk>& chunks, uint64_t* data) const;
 
    virtual std::unique_ptr<CompressionData> compress(
        const std::vector<Chunk>& chunks, Cycles& comp_lat,
        Cycles& decomp_lat) = 0;
 
    virtual void decompress(const CompressionData* comp_data,
                              uint64_t* cache_line) = 0;
 
  public:
    typedef BaseCacheCompressorParams Params;
    Base(const Params *p);
    virtual ~Base() = default;
 
    std::unique_ptr<CompressionData>
    compress(const uint64_t* data, Cycles& comp_lat, Cycles& decomp_lat);
 
    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 Base::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;
};
 
} // namespace Compressor
 
#endif //__MEM_CACHE_COMPRESSORS_BASE_HH__