abc76f20cb
creation and initialization now happens in python. Parameter objects are generated and initialized by python. The .ini file is now solely for debugging purposes and is not used in construction of the objects in any way. --HG-- extra : convert_revision : 7e722873e417cb3d696f2e34c35ff488b7bff4ed
259 lines
8.1 KiB
C++
259 lines
8.1 KiB
C++
/*
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* Copyright (c) 2002-2005 The Regents of The University of Michigan
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Erik Hallnor
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* Ron Dreslinski
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* Steve Reinhardt
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*/
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/**
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* @file
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* Declaration of CoherenceProcotol a basic coherence policy.
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*/
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#ifndef __COHERENCE_PROTOCOL_HH__
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#define __COHERENCE_PROTOCOL_HH__
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#include <string>
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#include "base/statistics.hh"
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#include "enums/Coherence.hh"
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#include "mem/cache/cache_blk.hh"
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#include "mem/packet.hh"
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#include "sim/sim_object.hh"
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class BaseCache;
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class MSHR;
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/**
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* A simple coherence policy for the memory hierarchy. Currently implements
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* MSI, MESI, and MOESI protocols.
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*/
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class CoherenceProtocol : public SimObject
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{
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public:
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/**
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* Contruct and initialize this policy.
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* @param name The name of this policy.
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* @param protocol The string representation of the protocol to use.
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* @param doUpgrades True if bus upgrades should be used.
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*/
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CoherenceProtocol(const std::string &name, Enums::Coherence protocol,
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const bool doUpgrades);
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/**
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* Destructor.
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*/
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virtual ~CoherenceProtocol() {};
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/**
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* Register statistics
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*/
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virtual void regStats();
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/**
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* Get the proper bus command for the given command and status.
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* @param cmd The request's command.
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* @param status The current state of the cache block.
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* @param mshr The MSHR matching the request.
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* @return The proper bus command, as determined by the protocol.
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*/
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MemCmd getBusCmd(MemCmd cmd, CacheBlk::State status,
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MSHR *mshr = NULL);
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/**
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* Return the proper state given the current state and the bus response.
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* @param pkt The bus response.
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* @param oldState The current block state.
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* @return The new state.
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*/
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CacheBlk::State getNewState(PacketPtr &pkt,
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CacheBlk::State oldState);
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/**
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* Handle snooped bus requests.
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* @param cache The cache that snooped the request.
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* @param pkt The snooped bus request.
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* @param blk The cache block corresponding to the request, if any.
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* @param mshr The MSHR corresponding to the request, if any.
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* @param new_state The new coherence state of the block.
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* @return True if the request should be satisfied locally.
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*/
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bool handleBusRequest(BaseCache *cache, PacketPtr &pkt, CacheBlk *blk,
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MSHR *mshr, CacheBlk::State &new_state);
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protected:
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/** Snoop function type. */
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typedef bool (*SnoopFuncType)(BaseCache *, PacketPtr &, CacheBlk *,
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MSHR *, CacheBlk::State&);
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//
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// Standard snoop transition functions
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//
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/**
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* Do nothing transition.
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*/
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static bool nullTransition(BaseCache *, PacketPtr &, CacheBlk *,
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MSHR *, CacheBlk::State&);
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/**
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* Invalid transition, basically panic.
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*/
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static bool invalidTransition(BaseCache *, PacketPtr &, CacheBlk *,
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MSHR *, CacheBlk::State&);
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/**
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* Invalidate block, move to Invalid state.
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*/
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static bool invalidateTrans(BaseCache *, PacketPtr &, CacheBlk *,
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MSHR *, CacheBlk::State&);
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/**
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* Supply data, no state transition.
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*/
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static bool supplyTrans(BaseCache *, PacketPtr &, CacheBlk *,
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MSHR *, CacheBlk::State&);
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/**
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* Supply data and go to Shared state.
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*/
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static bool supplyAndGotoSharedTrans(BaseCache *, PacketPtr &, CacheBlk *,
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MSHR *, CacheBlk::State&);
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/**
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* Supply data and go to Owned state.
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*/
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static bool supplyAndGotoOwnedTrans(BaseCache *, PacketPtr &, CacheBlk *,
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MSHR *, CacheBlk::State&);
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/**
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* Invalidate block, supply data, and go to Invalid state.
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*/
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static bool supplyAndInvalidateTrans(BaseCache *, PacketPtr &, CacheBlk *,
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MSHR *, CacheBlk::State&);
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/**
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* Assert the shared line for a block that is shared/exclusive.
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*/
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static bool assertShared(BaseCache *, PacketPtr &, CacheBlk *,
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MSHR *, CacheBlk::State&);
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/**
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* Definition of protocol state transitions.
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*/
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class StateTransition
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{
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friend class CoherenceProtocol;
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/** The bus command of this transition. */
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Packet::Command busCmd;
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/** The state to transition to. */
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int newState;
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/** The snoop function for this transition. */
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SnoopFuncType snoopFunc;
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/**
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* Constructor, defaults to invalid transition.
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*/
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StateTransition();
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/**
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* Initialize bus command.
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* @param cmd The bus command to use.
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*/
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void onRequest(Packet::Command cmd)
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{
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busCmd = cmd;
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}
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/**
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* Set the transition state.
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* @param s The new state.
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*/
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void onResponse(CacheBlk::State s)
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{
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newState = s;
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}
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/**
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* Initialize the snoop function.
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* @param f The new snoop function.
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*/
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void onSnoop(SnoopFuncType f)
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{
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snoopFunc = f;
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}
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};
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friend class CoherenceProtocol::StateTransition;
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/** Mask to select status bits relevant to coherence protocol. */
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static const int stateMask = BlkValid | BlkWritable | BlkDirty;
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/** The Modified (M) state. */
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static const int Modified = BlkValid | BlkWritable | BlkDirty;
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/** The Owned (O) state. */
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static const int Owned = BlkValid | BlkDirty;
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/** The Exclusive (E) state. */
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static const int Exclusive = BlkValid | BlkWritable;
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/** The Shared (S) state. */
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static const int Shared = BlkValid;
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/** The Invalid (I) state. */
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static const int Invalid = 0;
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/**
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* Maximum state encoding value (used to size transition lookup
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* table). Could be more than number of states, depends on
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* encoding of status bits.
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*/
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static const int stateMax = stateMask;
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/**
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* The table of all possible transitions, organized by starting state and
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* request command.
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*/
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StateTransition transitionTable[stateMax+1][MemCmd::NUM_MEM_CMDS];
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/**
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* @addtogroup CoherenceStatistics
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* @{
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*/
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/**
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* State accesses from parent cache.
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*/
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Stats::Scalar<> requestCount[stateMax+1][MemCmd::NUM_MEM_CMDS];
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/**
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* State accesses from snooped requests.
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*/
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Stats::Scalar<> snoopCount[stateMax+1][MemCmd::NUM_MEM_CMDS];
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/**
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* @}
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*/
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};
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#endif // __COHERENCE_PROTOCOL_HH__
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