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/*
* Copyright (c) 2002-2005 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: Erik Hallnor
* Dave Greene
*/
/**
* @file
* Miss Status and Handling Register (MSHR) definitions.
*/
#include <assert.h>
#include <string>
#include <vector>
#include <algorithm>
#include "mem/cache/miss/mshr.hh"
#include "sim/core.hh" // for curTick
#include "sim/host.hh"
#include "base/misc.hh"
#include "mem/cache/cache.hh"
using namespace std;
MSHR::MSHR()
{
inService = false;
ntargets = 0;
threadNum = -1;
}
void
MSHR::allocate(Addr _addr, int _size, PacketPtr target,
Tick whenReady, Counter _order)
{
addr = _addr;
size = _size;
readyTime = whenReady;
order = _order;
assert(target);
isCacheFill = false;
needsExclusive = target->needsExclusive();
_isUncacheable = target->req->isUncacheable();
inService = false;
threadNum = 0;
ntargets = 1;
// Don't know of a case where we would allocate a new MSHR for a
// snoop (mem-side request), so set cpuSide to true here.
targets.push_back(Target(target, whenReady, _order, true));
assert(deferredTargets.empty());
deferredNeedsExclusive = false;
pendingInvalidate = false;
pendingShared = false;
data = NULL;
}
void
MSHR::deallocate()
{
assert(targets.empty());
assert(deferredTargets.empty());
assert(ntargets == 0);
inService = false;
//allocIter = NULL;
//readyIter = NULL;
}
/*
* Adds a target to an MSHR
*/
void
MSHR::allocateTarget(PacketPtr target, Tick whenReady, Counter _order)
{
if (inService) {
if (!deferredTargets.empty() || pendingInvalidate ||
(!needsExclusive && target->needsExclusive())) {
// need to put on deferred list
deferredTargets.push_back(Target(target, whenReady, _order, true));
if (target->needsExclusive()) {
deferredNeedsExclusive = true;
}
} else {
// still OK to append to outstanding request
targets.push_back(Target(target, whenReady, _order, true));
}
} else {
if (target->needsExclusive()) {
needsExclusive = true;
}
targets.push_back(Target(target, whenReady, _order, true));
}
++ntargets;
}
void
MSHR::allocateSnoopTarget(PacketPtr pkt, Tick whenReady, Counter _order)
{
assert(inService); // don't bother to call otherwise
if (pendingInvalidate) {
// a prior snoop has already appended an invalidation, so
// logically we don't have the block anymore...
return;
}
DPRINTF(Cache, "deferred snoop on %x: %s %s\n", addr,
needsExclusive ? "needsExclusive" : "",
pkt->needsExclusive() ? "pkt->needsExclusive()" : "");
if (needsExclusive || pkt->needsExclusive()) {
// actual target device (typ. PhysicalMemory) will delete the
// packet on reception, so we need to save a copy here
targets.push_back(Target(new Packet(pkt), whenReady, _order, false));
++ntargets;
if (needsExclusive) {
// We're awaiting an exclusive copy, so ownership is pending.
// It's up to us to respond once the data arrives.
pkt->assertMemInhibit();
}
if (pkt->needsExclusive()) {
// This transaction will take away our pending copy
pendingInvalidate = true;
}
} else {
// Read to a read: no conflict, so no need to record as
// target, but make sure neither reader thinks he's getting an
// exclusive copy
pendingShared = true;
pkt->assertShared();
}
}
bool
MSHR::promoteDeferredTargets()
{
if (deferredTargets.empty()) {
return false;
}
assert(targets.empty());
targets = deferredTargets;
deferredTargets.clear();
assert(targets.size() == ntargets);
needsExclusive = deferredNeedsExclusive;
pendingInvalidate = false;
pendingShared = false;
deferredNeedsExclusive = false;
order = targets.front().order;
readyTime = std::max(curTick, targets.front().readyTime);
return true;
}
void
MSHR::handleFill(Packet *pkt, CacheBlk *blk)
{
if (pendingShared) {
// we snooped another read while this read was in
// service... assert shared line on its behalf
pkt->assertShared();
}
}
void
MSHR::dump()
{
ccprintf(cerr,
"inService: %d thread: %d\n"
"Addr: %x ntargets %d\n"
"Targets:\n",
inService, threadNum, addr, ntargets);
TargetListIterator tar_it = targets.begin();
for (int i = 0; i < ntargets; i++) {
assert(tar_it != targets.end());
ccprintf(cerr, "\t%d: Addr: %x cmd: %s\n",
i, tar_it->pkt->getAddr(), tar_it->pkt->cmdString());
tar_it++;
}
ccprintf(cerr, "\n");
}
MSHR::~MSHR()
{
}
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