2006-06-28 17:02:14 +02:00
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/*
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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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* Dave Greene
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*/
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/**
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* @file
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* Miss Status and Handling Register (MSHR) definitions.
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*/
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#include <assert.h>
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#include <string>
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#include <vector>
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2007-06-25 15:47:05 +02:00
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#include <algorithm>
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2006-06-28 17:02:14 +02:00
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#include "mem/cache/miss/mshr.hh"
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2007-03-06 20:13:43 +01:00
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#include "sim/core.hh" // for curTick
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2006-06-28 17:02:14 +02:00
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#include "sim/host.hh"
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#include "base/misc.hh"
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#include "mem/cache/cache.hh"
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using namespace std;
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MSHR::MSHR()
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{
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inService = false;
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ntargets = 0;
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2006-06-29 22:07:19 +02:00
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threadNum = -1;
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2007-07-22 03:18:42 +02:00
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targets = new TargetList();
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deferredTargets = new TargetList();
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2006-06-28 17:02:14 +02:00
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}
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2007-07-22 03:18:42 +02:00
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MSHR::TargetList::TargetList()
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: needsExclusive(false), hasUpgrade(false)
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{}
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inline void
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2007-07-23 06:43:38 +02:00
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MSHR::TargetList::add(PacketPtr pkt, Tick readyTime,
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Counter order, bool cpuSide)
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2007-07-22 03:18:42 +02:00
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{
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if (cpuSide) {
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if (pkt->needsExclusive()) {
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needsExclusive = true;
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}
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if (pkt->cmd == MemCmd::UpgradeReq) {
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hasUpgrade = true;
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}
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2007-07-23 06:43:38 +02:00
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MSHR *mshr = dynamic_cast<MSHR*>(pkt->senderState);
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if (mshr != NULL) {
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assert(!mshr->downstreamPending);
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mshr->downstreamPending = true;
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}
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2007-07-22 03:18:42 +02:00
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}
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push_back(Target(pkt, readyTime, order, cpuSide));
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}
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void
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MSHR::TargetList::replaceUpgrades()
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{
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if (!hasUpgrade)
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return;
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Iterator end_i = end();
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for (Iterator i = begin(); i != end_i; ++i) {
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if (i->pkt->cmd == MemCmd::UpgradeReq) {
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i->pkt->cmd = MemCmd::ReadExReq;
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DPRINTF(Cache, "Replacing UpgradeReq with ReadExReq\n");
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}
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}
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hasUpgrade = false;
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}
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2007-07-23 06:43:38 +02:00
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void
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MSHR::TargetList::clearDownstreamPending()
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{
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Iterator end_i = end();
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for (Iterator i = begin(); i != end_i; ++i) {
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MSHR *mshr = dynamic_cast<MSHR*>(i->pkt->senderState);
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if (mshr != NULL) {
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assert(mshr->downstreamPending);
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mshr->downstreamPending = false;
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}
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}
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}
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2006-06-28 17:02:14 +02:00
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void
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2007-06-25 15:47:05 +02:00
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MSHR::allocate(Addr _addr, int _size, PacketPtr target,
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2007-06-30 22:34:16 +02:00
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Tick whenReady, Counter _order)
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2006-06-28 17:02:14 +02:00
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{
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2006-07-10 23:16:15 +02:00
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addr = _addr;
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2007-06-18 02:27:53 +02:00
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size = _size;
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2007-06-30 22:34:16 +02:00
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readyTime = whenReady;
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2007-06-25 15:47:05 +02:00
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order = _order;
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2007-06-18 02:27:53 +02:00
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assert(target);
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2007-06-21 20:59:17 +02:00
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isCacheFill = false;
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2007-06-18 02:27:53 +02:00
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_isUncacheable = target->req->isUncacheable();
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inService = false;
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2007-07-23 06:43:38 +02:00
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downstreamPending = false;
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2007-06-18 02:27:53 +02:00
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threadNum = 0;
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ntargets = 1;
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// Don't know of a case where we would allocate a new MSHR for a
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2007-06-25 15:47:05 +02:00
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// snoop (mem-side request), so set cpuSide to true here.
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2007-07-22 03:18:42 +02:00
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assert(targets->isReset());
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targets->add(target, whenReady, _order, true);
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assert(deferredTargets->isReset());
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2007-06-25 02:32:31 +02:00
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pendingInvalidate = false;
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2007-06-27 07:23:10 +02:00
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pendingShared = false;
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2007-06-26 23:53:15 +02:00
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data = NULL;
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2006-06-28 17:02:14 +02:00
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}
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2007-07-23 06:43:38 +02:00
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bool
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MSHR::markInService()
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{
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assert(!inService);
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if (isSimpleForward()) {
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// we just forwarded the request packet & don't expect a
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// response, so get rid of it
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assert(getNumTargets() == 1);
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popTarget();
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return true;
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}
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inService = true;
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if (!downstreamPending) {
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// let upstream caches know that the request has made it to a
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// level where it's going to get a response
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targets->clearDownstreamPending();
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}
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return false;
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}
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2006-06-28 17:02:14 +02:00
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void
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MSHR::deallocate()
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{
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2007-07-22 03:18:42 +02:00
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assert(targets->empty());
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targets->resetFlags();
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assert(deferredTargets->isReset());
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2006-06-28 17:02:14 +02:00
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assert(ntargets == 0);
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inService = false;
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2006-08-15 23:41:22 +02:00
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//allocIter = NULL;
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//readyIter = NULL;
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2006-06-28 17:02:14 +02:00
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}
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/*
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* Adds a target to an MSHR
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*/
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void
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2007-07-22 03:18:42 +02:00
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MSHR::allocateTarget(PacketPtr pkt, Tick whenReady, Counter _order)
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2006-06-28 17:02:14 +02:00
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{
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2007-07-22 03:18:42 +02:00
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// if there's a request already in service for this MSHR, we will
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// have to defer the new target until after the response if any of
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// the following are true:
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// - there are other targets already deferred
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// - there's a pending invalidate to be applied after the response
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// comes back (but before this target is processed)
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// - the outstanding request is for a non-exclusive block and this
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// target requires an exclusive block
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if (inService &&
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(!deferredTargets->empty() || pendingInvalidate ||
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(!targets->needsExclusive && pkt->needsExclusive()))) {
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// need to put on deferred list
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deferredTargets->add(pkt, whenReady, _order, true);
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2007-06-25 02:32:31 +02:00
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} else {
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2007-07-22 03:18:42 +02:00
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// no request outstanding, or still OK to append to
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// outstanding request
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targets->add(pkt, whenReady, _order, true);
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2007-06-25 02:32:31 +02:00
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}
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2006-06-28 17:02:14 +02:00
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2007-06-25 02:32:31 +02:00
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++ntargets;
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}
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2007-07-21 22:45:17 +02:00
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bool
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MSHR::handleSnoop(PacketPtr pkt, Counter _order)
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2007-06-25 02:32:31 +02:00
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{
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2007-07-24 07:28:40 +02:00
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if (!inService || (pkt->isExpressSnoop() && downstreamPending)) {
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2007-07-22 03:18:42 +02:00
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// Request has not been issued yet, or it's been issued
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// locally but is buffered unissued at some downstream cache
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// which is forwarding us this snoop. Either way, the packet
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// we're snooping logically precedes this MSHR's request, so
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// the snoop has no impact on the MSHR, but must be processed
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// in the standard way by the cache. The only exception is
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// that if we're an L2+ cache buffering an UpgradeReq from a
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// higher-level cache, and the snoop is invalidating, then our
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// buffered upgrades must be converted to read exclusives,
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// since the upper-level cache no longer has a valid copy.
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// That is, even though the upper-level cache got out on its
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// local bus first, some other invalidating transaction
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// reached the global bus before the upgrade did.
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if (pkt->needsExclusive()) {
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targets->replaceUpgrades();
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deferredTargets->replaceUpgrades();
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}
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2007-07-21 22:45:17 +02:00
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return false;
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}
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2007-06-25 02:32:31 +02:00
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2007-07-22 03:18:42 +02:00
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// From here on down, the request issued by this MSHR logically
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// precedes the request we're snooping.
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if (pkt->needsExclusive()) {
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// snooped request still precedes the re-request we'll have to
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// issue for deferred targets, if any...
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deferredTargets->replaceUpgrades();
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}
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2007-06-25 02:32:31 +02:00
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if (pendingInvalidate) {
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// a prior snoop has already appended an invalidation, so
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2007-07-22 03:18:42 +02:00
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// logically we don't have the block anymore; no need for
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// further snooping.
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2007-07-21 22:45:17 +02:00
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return true;
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2006-06-28 17:02:14 +02:00
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}
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2007-06-25 02:32:31 +02:00
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2007-07-22 03:18:42 +02:00
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if (targets->needsExclusive || pkt->needsExclusive()) {
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2007-06-27 07:23:10 +02:00
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// actual target device (typ. PhysicalMemory) will delete the
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// packet on reception, so we need to save a copy here
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2007-07-24 07:28:40 +02:00
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PacketPtr cp_pkt = new Packet(pkt);
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targets->add(cp_pkt, curTick, _order, false);
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2007-06-27 07:23:10 +02:00
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++ntargets;
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2007-07-22 03:18:42 +02:00
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if (targets->needsExclusive) {
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2007-06-27 07:23:10 +02:00
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// We're awaiting an exclusive copy, so ownership is pending.
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// It's up to us to respond once the data arrives.
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pkt->assertMemInhibit();
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2007-07-24 07:28:40 +02:00
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} else {
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// Someone else may respond before we get around to
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// processing this snoop, which means the copied request
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// pointer will no longer be valid
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cp_pkt->req = NULL;
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2007-06-27 07:23:10 +02:00
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}
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2007-06-26 07:23:29 +02:00
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2007-06-27 07:23:10 +02:00
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if (pkt->needsExclusive()) {
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// This transaction will take away our pending copy
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pendingInvalidate = true;
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}
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2007-06-25 02:32:31 +02:00
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} else {
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2007-06-27 07:23:10 +02:00
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// Read to a read: no conflict, so no need to record as
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// target, but make sure neither reader thinks he's getting an
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// exclusive copy
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pendingShared = true;
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pkt->assertShared();
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2006-06-28 17:02:14 +02:00
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}
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2007-07-21 22:45:17 +02:00
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return true;
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2007-06-25 02:32:31 +02:00
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}
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bool
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MSHR::promoteDeferredTargets()
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{
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2007-07-22 03:18:42 +02:00
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assert(targets->empty());
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if (deferredTargets->empty()) {
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2007-06-25 02:32:31 +02:00
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return false;
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}
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2007-07-22 03:18:42 +02:00
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// swap targets & deferredTargets lists
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TargetList *tmp = targets;
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2007-06-25 02:32:31 +02:00
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targets = deferredTargets;
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2007-07-22 03:18:42 +02:00
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deferredTargets = tmp;
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assert(targets->size() == ntargets);
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// clear deferredTargets flags
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deferredTargets->resetFlags();
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2006-06-28 17:02:14 +02:00
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2007-06-25 02:32:31 +02:00
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pendingInvalidate = false;
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2007-06-27 07:23:10 +02:00
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pendingShared = false;
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2007-07-22 03:18:42 +02:00
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order = targets->front().order;
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readyTime = std::max(curTick, targets->front().readyTime);
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2007-06-25 02:32:31 +02:00
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return true;
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2006-06-28 17:02:14 +02:00
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}
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2007-06-26 23:53:15 +02:00
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void
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2007-06-27 07:23:10 +02:00
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MSHR::handleFill(Packet *pkt, CacheBlk *blk)
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2007-06-26 23:53:15 +02:00
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{
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2007-06-27 08:30:30 +02:00
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if (pendingShared) {
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2007-06-27 07:23:10 +02:00
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// we snooped another read while this read was in
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// service... assert shared line on its behalf
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pkt->assertShared();
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2007-06-26 23:53:15 +02:00
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}
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}
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2006-06-28 17:02:14 +02:00
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void
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MSHR::dump()
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{
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ccprintf(cerr,
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"inService: %d thread: %d\n"
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2006-08-15 22:21:46 +02:00
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"Addr: %x ntargets %d\n"
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2006-06-28 17:02:14 +02:00
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"Targets:\n",
|
2006-08-15 22:21:46 +02:00
|
|
|
inService, threadNum, addr, ntargets);
|
2007-07-22 03:18:42 +02:00
|
|
|
#if 0
|
|
|
|
TargetListIterator tar_it = targets->begin();
|
2006-06-28 17:02:14 +02:00
|
|
|
for (int i = 0; i < ntargets; i++) {
|
2007-07-22 03:18:42 +02:00
|
|
|
assert(tar_it != targets->end());
|
2006-06-28 17:02:14 +02:00
|
|
|
|
2007-06-18 02:27:53 +02:00
|
|
|
ccprintf(cerr, "\t%d: Addr: %x cmd: %s\n",
|
|
|
|
i, tar_it->pkt->getAddr(), tar_it->pkt->cmdString());
|
2006-06-28 17:02:14 +02:00
|
|
|
|
|
|
|
tar_it++;
|
|
|
|
}
|
2007-07-22 03:18:42 +02:00
|
|
|
#endif
|
2006-06-28 17:02:14 +02:00
|
|
|
ccprintf(cerr, "\n");
|
|
|
|
}
|
|
|
|
|
|
|
|
MSHR::~MSHR()
|
|
|
|
{
|
|
|
|
}
|