coherence_protocol.cc

linux下基于c++的处理器仿真平台。具有处理器流水线

	// on response to given request: specify new state
	transitionTable[Invalid][Read].onResponse(Shared);
	transitionTable[Invalid][ReadEx].onResponse(Modified);
	transitionTable[Shared][writeToSharedCmd].onResponse(Modified);

	// bus snoop transition functions
	transitionTable[Invalid][Read].onSnoop(nullTransition);
	transitionTable[Invalid][ReadEx].onSnoop(nullTransition);
	transitionTable[Shared][Read].onSnoop(nullTransition);
	transitionTable[Shared][ReadEx].onSnoop(invalidateTrans);
	transitionTable[Modified][ReadEx].onSnoop(supplyAndInvalidateTrans);
	transitionTable[Modified][Read].onSnoop(supplyAndGotoSharedTrans);
	//Tansitions on seeing a DMA (writeInv(samelevel) or DMAInv)
	transitionTable[Invalid][Invalidate].onSnoop(invalidateTrans);
	transitionTable[Shared][Invalidate].onSnoop(invalidateTrans);
	transitionTable[Modified][Invalidate].onSnoop(invalidateTrans);
	transitionTable[Invalid][WriteInvalidate].onSnoop(invalidateTrans);
	transitionTable[Shared][WriteInvalidate].onSnoop(invalidateTrans);
	transitionTable[Modified][WriteInvalidate].onSnoop(invalidateTrans);

	if (doUpgrades) {
	    transitionTable[Invalid][Upgrade].onSnoop(nullTransition);
	    transitionTable[Shared][Upgrade].onSnoop(invalidateTrans);
	}
    }

    else if(protocol == "mesi") {
	// incoming requests: specify outgoing bus request
	transitionTable[Invalid][Read].onRequest(Read);
	transitionTable[Invalid][Write].onRequest(ReadEx);
	transitionTable[Shared][Write].onRequest(writeToSharedCmd);
	//Prefetching causes a read
	transitionTable[Invalid][Soft_Prefetch].onRequest(Read);
      	transitionTable[Invalid][Hard_Prefetch].onRequest(Read);

	// on response to given request: specify new state
	transitionTable[Invalid][Read].onResponse(Exclusive); 
	//It will move into shared if the shared line is asserted in the
	//getNewState function
	transitionTable[Invalid][ReadEx].onResponse(Modified);
	transitionTable[Shared][writeToSharedCmd].onResponse(Modified);

	// bus snoop transition functions
	transitionTable[Invalid][Read].onSnoop(nullTransition);
	transitionTable[Invalid][ReadEx].onSnoop(nullTransition);
	transitionTable[Shared][Read].onSnoop(assertShared);
	transitionTable[Shared][ReadEx].onSnoop(invalidateTrans);
	transitionTable[Exclusive][Read].onSnoop(assertShared);
	transitionTable[Exclusive][ReadEx].onSnoop(invalidateTrans);
	transitionTable[Modified][ReadEx].onSnoop(supplyAndInvalidateTrans);
	transitionTable[Modified][Read].onSnoop(supplyAndGotoSharedTrans);
	//Tansitions on seeing a DMA (writeInv(samelevel) or DMAInv)
	transitionTable[Invalid][Invalidate].onSnoop(invalidateTrans);
	transitionTable[Shared][Invalidate].onSnoop(invalidateTrans);
	transitionTable[Modified][Invalidate].onSnoop(invalidateTrans);
	transitionTable[Exclusive][Invalidate].onSnoop(invalidateTrans);
	transitionTable[Invalid][WriteInvalidate].onSnoop(invalidateTrans);
	transitionTable[Shared][WriteInvalidate].onSnoop(invalidateTrans);
	transitionTable[Modified][WriteInvalidate].onSnoop(invalidateTrans);
	transitionTable[Exclusive][WriteInvalidate].onSnoop(invalidateTrans);

	if (doUpgrades) {
	    transitionTable[Invalid][Upgrade].onSnoop(nullTransition);
	    transitionTable[Shared][Upgrade].onSnoop(invalidateTrans);
	}
    }

    else if(protocol == "mosi") {
	// incoming requests: specify outgoing bus request
	transitionTable[Invalid][Read].onRequest(Read);
	transitionTable[Invalid][Write].onRequest(ReadEx);
	transitionTable[Shared][Write].onRequest(writeToSharedCmd);
	transitionTable[Owned][Write].onRequest(writeToSharedCmd);
	//Prefetching causes a read
	transitionTable[Invalid][Soft_Prefetch].onRequest(Read);
	transitionTable[Invalid][Hard_Prefetch].onRequest(Read);

	// on response to given request: specify new state
	transitionTable[Invalid][Read].onResponse(Shared);
	transitionTable[Invalid][ReadEx].onResponse(Modified);
	transitionTable[Shared][writeToSharedCmd].onResponse(Modified);
	transitionTable[Owned][writeToSharedCmd].onResponse(Modified);

	// bus snoop transition functions
	transitionTable[Invalid][Read].onSnoop(nullTransition);
	transitionTable[Invalid][ReadEx].onSnoop(nullTransition);
	transitionTable[Invalid][Upgrade].onSnoop(nullTransition);
	transitionTable[Shared][Read].onSnoop(assertShared);
	transitionTable[Shared][ReadEx].onSnoop(invalidateTrans);
	transitionTable[Shared][Upgrade].onSnoop(invalidateTrans);
	transitionTable[Modified][ReadEx].onSnoop(supplyAndInvalidateTrans);
	transitionTable[Modified][Read].onSnoop(supplyAndGotoOwnedTrans);
	transitionTable[Owned][Read].onSnoop(supplyAndGotoOwnedTrans);
	transitionTable[Owned][ReadEx].onSnoop(supplyAndInvalidateTrans);
	transitionTable[Owned][Upgrade].onSnoop(invalidateTrans);
	//Tansitions on seeing a DMA (writeInv(samelevel) or DMAInv)
	transitionTable[Invalid][Invalidate].onSnoop(invalidateTrans);
	transitionTable[Shared][Invalidate].onSnoop(invalidateTrans);
	transitionTable[Modified][Invalidate].onSnoop(invalidateTrans);
	transitionTable[Owned][Invalidate].onSnoop(invalidateTrans);
	transitionTable[Invalid][WriteInvalidate].onSnoop(invalidateTrans);
	transitionTable[Shared][WriteInvalidate].onSnoop(invalidateTrans);
	transitionTable[Modified][WriteInvalidate].onSnoop(invalidateTrans);
	transitionTable[Owned][WriteInvalidate].onSnoop(invalidateTrans);
    }

    else if(protocol == "moesi") {
	// incoming requests: specify outgoing bus request
	transitionTable[Invalid][Read].onRequest(Read);
	transitionTable[Invalid][Write].onRequest(ReadEx);
	transitionTable[Shared][Write].onRequest(writeToSharedCmd);
	transitionTable[Owned][Write].onRequest(writeToSharedCmd);
	//Prefetching causes a read
	transitionTable[Invalid][Soft_Prefetch].onRequest(Read);
	transitionTable[Invalid][Hard_Prefetch].onRequest(Read);

	// on response to given request: specify new state
	transitionTable[Invalid][Read].onResponse(Exclusive); 
	//It will move into shared if the shared line is asserted in the
	//getNewState function
	transitionTable[Invalid][ReadEx].onResponse(Modified);
	transitionTable[Shared][writeToSharedCmd].onResponse(Modified);
	transitionTable[Owned][writeToSharedCmd].onResponse(Modified);
	
	// bus snoop transition functions
	transitionTable[Invalid][Read].onSnoop(nullTransition);
	transitionTable[Invalid][ReadEx].onSnoop(nullTransition);
	transitionTable[Invalid][Upgrade].onSnoop(nullTransition);
	transitionTable[Shared][Read].onSnoop(assertShared);
	transitionTable[Shared][ReadEx].onSnoop(invalidateTrans);
	transitionTable[Shared][Upgrade].onSnoop(invalidateTrans);
	transitionTable[Exclusive][Read].onSnoop(assertShared);
	transitionTable[Exclusive][ReadEx].onSnoop(invalidateTrans);
	transitionTable[Modified][Read].onSnoop(supplyAndGotoOwnedTrans);
	transitionTable[Modified][ReadEx].onSnoop(supplyAndInvalidateTrans);
	transitionTable[Owned][Read].onSnoop(supplyAndGotoOwnedTrans);
	transitionTable[Owned][ReadEx].onSnoop(supplyAndInvalidateTrans);
	transitionTable[Owned][Upgrade].onSnoop(invalidateTrans);
	//Transitions on seeing a DMA (writeInv(samelevel) or DMAInv)
	transitionTable[Invalid][Invalidate].onSnoop(invalidateTrans);
	transitionTable[Shared][Invalidate].onSnoop(invalidateTrans);
	transitionTable[Exclusive][Invalidate].onSnoop(invalidateTrans);
	transitionTable[Modified][Invalidate].onSnoop(invalidateTrans);
	transitionTable[Owned][Invalidate].onSnoop(invalidateTrans);
	transitionTable[Invalid][WriteInvalidate].onSnoop(invalidateTrans);
	transitionTable[Shared][WriteInvalidate].onSnoop(invalidateTrans);
	transitionTable[Exclusive][WriteInvalidate].onSnoop(invalidateTrans);
	transitionTable[Modified][WriteInvalidate].onSnoop(invalidateTrans);
	transitionTable[Owned][WriteInvalidate].onSnoop(invalidateTrans);
    }

    else {
	cerr << "CoherenceProtocol: unrecognized protocol " << protocol
	     <<  endl;
	fatal("");
    }
}


MemCmd
CoherenceProtocol::getBusCmd(MemCmd cmdIn, CacheBlk::State state,
			     MSHR *mshr)
{
    state &= stateMask;
    int cmd_idx = cmdIn.toIndex();

    assert(0 <= state && state <= stateMax);
    assert(0 <= cmd_idx && cmd_idx < NUM_MEM_CMDS);

    MemCmd cmdOut = transitionTable[state][cmd_idx].busCmd;

    assert(cmdOut != InvalidCmd);

    ++requestCount[state][cmd_idx];

    return cmdOut;
}


CacheBlk::State
CoherenceProtocol::getNewState(const MemReqPtr &req, CacheBlk::State oldState)
{
    CacheBlk::State state = oldState & stateMask;
    int cmd_idx = req->cmd.toIndex();

    assert(0 <= state && state <= stateMax);
    assert(0 <= cmd_idx && cmd_idx < NUM_MEM_CMDS);

    CacheBlk::State newState = transitionTable[state][cmd_idx].newState;

    //Check if it's exclusive and the shared line was asserted, 
    //then  goto shared instead
    if (newState == Exclusive && (req->flags & SHARED_LINE)) {
	newState = Shared;
    }

    assert(newState != -1);

    //Make sure not to loose any other state information
    newState = (oldState & ~stateMask) | newState;
    return newState;
}


bool
CoherenceProtocol::handleBusRequest(BaseCache *cache, MemReqPtr &req,
				    CacheBlk *blk,
				    MSHR *mshr, 
				    CacheBlk::State & new_state)
{
    if (blk == NULL) {
	// nothing to do if we don't have a block
	return false;
    }

    CacheBlk::State state = blk->status & stateMask;
    int cmd_idx = req->cmd.toIndex();

    assert(0 <= state && state <= stateMax);
    assert(0 <= cmd_idx && cmd_idx < NUM_MEM_CMDS);

//    assert(mshr == NULL); // can't currently handle outstanding requests
    //Check first if MSHR, and also insure, if there is one, that it is not in service
    assert(!mshr || mshr->inService == 0);
    ++snoopCount[state][cmd_idx];

    bool ret = transitionTable[state][cmd_idx].snoopFunc(cache, req, blk, mshr,
						     new_state);


    
    return ret;
}

bool
CoherenceProtocol::nullTransition(BaseCache *cache, MemReqPtr &req,
				  CacheBlk *blk, MSHR *mshr, 
				  CacheBlk::State & new_state)
{
    // do nothing
    if (blk)
	new_state = blk->status;
    return false;
}


bool
CoherenceProtocol::invalidTransition(BaseCache *cache, MemReqPtr &req,
				     CacheBlk *blk, MSHR *mshr, 
				     CacheBlk::State & new_state)
{
    panic("Invalid transition");
    return false;
}

#ifndef DOXYGEN_SHOULD_SKIP_THIS

BEGIN_DECLARE_SIM_OBJECT_PARAMS(CoherenceProtocol)

    Param<string> protocol;
    Param<bool> do_upgrades;

END_DECLARE_SIM_OBJECT_PARAMS(CoherenceProtocol)


BEGIN_INIT_SIM_OBJECT_PARAMS(CoherenceProtocol)

    INIT_PARAM(protocol, "name of coherence protocol"),
    INIT_PARAM_DFLT(do_upgrades, "use upgrade transactions?", true)

END_INIT_SIM_OBJECT_PARAMS(CoherenceProtocol)


CREATE_SIM_OBJECT(CoherenceProtocol)
{
    return new CoherenceProtocol(getInstanceName(), protocol,
				 do_upgrades);
}

REGISTER_SIM_OBJECT("CoherenceProtocol", CoherenceProtocol)

#endif // DOXYGEN_SHOULD_SKIP_THIS