190 lines
5.6 KiB
C++
190 lines
5.6 KiB
C++
/*
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* Copyright (c) 2003 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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#ifndef __SAT_COUNTER_HH__
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#define __SAT_COUNTER_HH__
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#include <string>
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#include "base/predictor.hh"
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#include "base/statistics.hh"
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#include "sim/stats.hh"
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//
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//
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// A simple saturating counter predictor
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//
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//
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class SaturatingCounterPred : public GenericPredictor
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{
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private:
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std::string pred_name;
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std::string zero_name;
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std::string one_name;
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unsigned index_bits;
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unsigned counter_bits;
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unsigned zero_change;
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unsigned one_change;
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unsigned thresh;
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unsigned init_value;
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unsigned max_value; // maximum counter value
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unsigned long max_index; // also the index mask value
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unsigned *table;
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// Statistics
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Stats::Scalar<> predicted_one; // Total predictions of one, preds_one
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Stats::Scalar<> predicted_zero; // Total predictions of zero, preds_zero
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Stats::Scalar<> correct_pred_one; // Total correct predictions of one, correct_one
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Stats::Scalar<> correct_pred_zero; // Total correct predictions of zero, correct_zero
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Stats::Scalar<> record_zero; //updates_zero
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Stats::Scalar<> record_one; //updates_one
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Stats::Formula preds_total;
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Stats::Formula pred_frac_zero;
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Stats::Formula pred_frac_one;
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Stats::Formula correct_total;
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Stats::Formula updates_total;
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Stats::Formula pred_rate;
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Stats::Formula frac_correct_zero;
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Stats::Formula frac_correct_one;
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Stats::Formula coverage_zero;
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Stats::Formula coverage_one;
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private:
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bool pred_one(unsigned &counter) { return counter > thresh; }
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bool pred_zero(unsigned &counter) { return counter <= thresh; }
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void update_one(unsigned &counter) {
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if (one_change)
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counter += one_change;
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else
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counter = 0;
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// check for wrap
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if (counter > max_value)
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counter = max_value;
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}
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void update_zero(unsigned &counter) {
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if (zero_change) {
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// check for wrap
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if (counter < zero_change)
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counter = 0;
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else
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counter -= zero_change;
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} else
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counter = 0;
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}
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public:
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SaturatingCounterPred(std::string p_name,
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std::string z_name, std::string o_name,
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unsigned _index_bits, unsigned _counter_bits = 2,
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unsigned _zero_change = 1, unsigned _one_change = 1,
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unsigned _thresh = 1, unsigned _init_value = 0);
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void clear() {
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for (int i = 0; i <= max_index; ++i)
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table[i] = init_value;
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}
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// Record the ACTUAL result... and indicate whether the prediction
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// corresponding to this event was correct
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void record(unsigned long _index, unsigned _val, unsigned _predicted,
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unsigned _pdata)
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{
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record(_index, _val, _predicted);
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}
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void record(unsigned long _index, unsigned _val, unsigned _predicted) {
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unsigned long index = _index & max_index;
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if (_val) {
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update_one(table[index]);
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++record_one;
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if (_predicted)
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++correct_pred_one;
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} else {
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update_zero(table[index]);
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++record_zero;
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if (!_predicted)
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++correct_pred_zero;
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}
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}
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unsigned value(unsigned long _index) {
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unsigned long index = _index & max_index;
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return table[index];
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}
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unsigned predict(unsigned long _index, unsigned &pdata) {
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return predict(_index);
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}
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unsigned predict(unsigned long _index) {
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unsigned long index = _index & max_index;
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if (pred_one(table[index])) {
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++predicted_one;
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return 1;
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}
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++predicted_zero;
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return 0;
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}
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// No internal state is changed here
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unsigned peek(unsigned long _index) {
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unsigned long index = _index & max_index;
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if (pred_one(table[index]))
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return 1;
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return 0;
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}
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//=======================================================
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void regStats();
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void regFormulas();
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};
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#endif // __SAT_COUNTER_HH__
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