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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.
*
* 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: Ron Dreslinski
* Daniel Carvalho
*/
/**
* @file
* Describes a strided prefetcher.
*/
#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;
/** Replacement policy used in the PC tables. */
BaseReplacementPolicy* replacementPolicy;
struct StrideEntry : public ReplaceableEntry
{
/** Default constructor */
StrideEntry();
/** Invalidate the entry */
void invalidate();
Addr instAddr;
Addr lastAddr;
bool isSecure;
int stride;
int confidence;
};
class PCTable
{
public:
/**
* Default constructor. Create a table with given parameters.
*
* @param assoc Associativity of the table.
* @param sets Number of sets in the table.
* @param name Name of the prefetcher.
* @param replacementPolicy Replacement policy used by the table.
*/
PCTable(int assoc, int sets, const std::string name,
BaseReplacementPolicy* replacementPolicy);
/**
* Default destructor.
*/
~PCTable();
/**
* Search for an entry in the pc table.
*
* @param pc The PC to look for.
* @param is_secure True if the target memory space is secure.
* @return Pointer to the entry.
*/
StrideEntry* findEntry(Addr pc, bool is_secure);
/**
* Find a replacement victim to make room for given PC.
*
* @param pc The PC value.
* @return The victimized entry.
*/
StrideEntry* findVictim(Addr pc);
private:
const std::string name() {return _name; }
const int pcTableSets;
const std::string _name;
std::vector<std::vector<StrideEntry>> entries;
/**
* Replacement policy used by StridePrefetcher.
*/
BaseReplacementPolicy* replacementPolicy;
/**
* PC hashing function to index sets in the table.
*
* @param pc The PC value.
* @return The set to which this PC maps.
*/
Addr pcHash(Addr pc) const;
};
std::unordered_map<int, PCTable> pcTables;
/**
* Try to find a table of entries for the given context. If none is
* found, a new table is created.
*
* @param context The context to be searched for.
* @return The table corresponding to the given context.
*/
PCTable* findTable(int context);
/**
* Create a PC table for the given context.
*
* @param context The context of the new PC table.
* @return The new PC table
*/
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__
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