edf9092fee
- A new abstract BTB class is created to enable different BTB implementations. The new BTB class gets its own parameter and stats. - An enum is added to differentiate branch instruction types. This enum is used to enhance statistics and BPU management. - The existing BTB is moved into `simple_btb` as default. - An additional function is added to store the static instruction in the BTB. This function is used for the decoupled front-end. - Update configs to match new BTB parameters. Change-Id: I99b29a19a1b57e59ea2b188ed7d62a8b79426529 Signed-off-by: David Schall <david.schall@ed.ac.uk>
100 lines
3.8 KiB
C++
100 lines
3.8 KiB
C++
/*
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* Copyright (c) 2022-2023 The University of Edinburgh
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* All rights reserved
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*
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* The license below extends only to copyright in the software and shall
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* not be construed as granting a license to any other intellectual
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* property including but not limited to intellectual property relating
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* to a hardware implementation of the functionality of the software
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* licensed hereunder. You may use the software subject to the license
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* terms below provided that you ensure that this notice is replicated
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* unmodified and in its entirety in all distributions of the software,
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* modified or unmodified, in source code or in binary form.
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*
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* Copyright (c) 2004-2005 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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#include "cpu/pred/btb.hh"
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namespace gem5
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{
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namespace branch_prediction
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{
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BranchTargetBuffer::BranchTargetBuffer(const Params ¶ms)
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: ClockedObject(params),
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numThreads(params.numThreads),
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stats(this)
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{
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}
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BranchTargetBuffer::BranchTargetBufferStats::BranchTargetBufferStats(
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statistics::Group *parent)
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: statistics::Group(parent),
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ADD_STAT(lookups, statistics::units::Count::get(),
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"Number of BTB lookups"),
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ADD_STAT(misses, statistics::units::Count::get(),
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"Number of BTB misses"),
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ADD_STAT(updates, statistics::units::Count::get(),
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"Number of BTB updates"),
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ADD_STAT(mispredict, statistics::units::Count::get(),
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"Number of BTB mispredictions. "
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"No target found or target wrong."),
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ADD_STAT(evictions, statistics::units::Count::get(),
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"Number of BTB evictions")
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{
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using namespace statistics;
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lookups
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.init(enums::Num_BranchType)
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.flags(total | pdf);
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misses
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.init(enums::Num_BranchType)
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.flags(total | pdf);
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updates
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.init(enums::Num_BranchType)
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.flags(total | pdf);
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mispredict
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.init(enums::Num_BranchType)
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.flags(total | pdf);
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evictions.flags(nozero);
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for (int i = 0; i < enums::Num_BranchType; i++) {
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lookups.subname(i, enums::BranchTypeStrings[i]);
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misses.subname(i, enums::BranchTypeStrings[i]);
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updates.subname(i, enums::BranchTypeStrings[i]);
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mispredict.subname(i, enums::BranchTypeStrings[i]);
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}
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}
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} // namespace branch_prediction
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} // namespace gem5
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