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/*
* 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
* Steve Reinhardt
*/
/**
* @file
* GHB Prefetcher implementation.
*/
#include "base/trace.hh"
#include "debug/HWPrefetch.hh"
#include "mem/cache/prefetch/ghb.hh"
void
GHBPrefetcher::calculatePrefetch(PacketPtr &pkt, std::list<Addr> &addresses,
std::list<Tick> &delays)
{
if (useContextId && !pkt->req->hasContextId()) {
DPRINTF(HWPrefetch, "ignoring request with no context ID");
return;
}
Addr blk_addr = pkt->getAddr() & ~(Addr)(blkSize-1);
int ctx_id = useContextId ? pkt->req->contextId() : 0;
assert(ctx_id < Max_Contexts);
int new_stride = blk_addr - lastMissAddr[ctx_id];
int old_stride = lastMissAddr[ctx_id] - secondLastMissAddr[ctx_id];
secondLastMissAddr[ctx_id] = lastMissAddr[ctx_id];
lastMissAddr[ctx_id] = blk_addr;
if (new_stride == old_stride) {
for (int d = 1; d <= degree; d++) {
Addr new_addr = blk_addr + d * new_stride;
if (pageStop && !samePage(blk_addr, new_addr)) {
// Spanned the page, so now stop
pfSpanPage += degree - d + 1;
return;
} else {
addresses.push_back(new_addr);
delays.push_back(latency);
}
}
}
}
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