stride.hh

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/*
 * Copyright (c) 2018 Inria
 * Copyright (c) 2012-2013, 2015 ARM Limited
 * All rights reserved
 *
 * The license below extends only to copyright in the software and shall
 * not be construed as granting a license to any other intellectual
 * property including but not limited to intellectual property relating
 * to a hardware implementation of the functionality of the software
 * licensed hereunder.  You may use the software subject to the license
 * terms below provided that you ensure that this notice is replicated
 * unmodified and in its entirety in all distributions of the software,
 * modified or unmodified, in source code or in binary form.
 *
 * Copyright (c) 2005 The Regents of The University of Michigan
 * All rights reserved.
 *
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 * 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
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 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * Authors: Ron Dreslinski
 *          Daniel Carvalho
 */

#ifndef __MEM_CACHE_PREFETCH_STRIDE_HH__
#define __MEM_CACHE_PREFETCH_STRIDE_HH__

#include <string>
#include <unordered_map>
#include <vector>

#include "base/types.hh"
#include "mem/cache/prefetch/queued.hh"
#include "mem/cache/replacement_policies/replaceable_entry.hh"
#include "mem/packet.hh"

class BaseReplacementPolicy;
struct StridePrefetcherParams;

class StridePrefetcher : public QueuedPrefetcher
{
  protected:
    const int maxConf;
    const int threshConf;
    const int minConf;
    const int startConf;

    const int pcTableAssoc;
    const int pcTableSets;

    const bool useMasterId;

    const int degree;

    BaseReplacementPolicy* replacementPolicy;

    struct StrideEntry : public ReplaceableEntry
    {
        StrideEntry();

        void invalidate();

        Addr instAddr;
        Addr lastAddr;
        bool isSecure;
        int stride;
        int confidence;
    };

    class PCTable
    {
      public:
        PCTable(int assoc, int sets, const std::string name,
                BaseReplacementPolicy* replacementPolicy);

        ~PCTable();

        StrideEntry* findEntry(Addr pc, bool is_secure);

        StrideEntry* findVictim(Addr pc);

      private:
        const std::string name() {return _name; }
        const int pcTableSets;
        const std::string _name;
        std::vector<std::vector<StrideEntry>> entries;

        BaseReplacementPolicy* replacementPolicy;

        Addr pcHash(Addr pc) const;
    };
    std::unordered_map<int, PCTable> pcTables;

    PCTable* findTable(int context);

    PCTable* allocateNewContext(int context);

  public:
    StridePrefetcher(const StridePrefetcherParams *p);

    void calculatePrefetch(const PrefetchInfo &pfi,
                           std::vector<AddrPriority> &addresses) override;
};

#endif // __MEM_CACHE_PREFETCH_STRIDE_HH__