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Diffstat (limited to 'src/base/sat_counter.hh')
| -rw-r--r-- | src/base/sat_counter.hh | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/src/base/sat_counter.hh b/src/base/sat_counter.hh new file mode 100644 index 000000000..79de11156 --- /dev/null +++ b/src/base/sat_counter.hh @@ -0,0 +1,193 @@ +/* + * Copyright (c) 2001-2005 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: Steve Raasch + * Steve Reinhardt + */ + +#ifndef __SAT_COUNTER_HH__ +#define __SAT_COUNTER_HH__ + +#include <string> + +#include "base/predictor.hh" + +#include "base/statistics.hh" +#include "sim/stats.hh" + +// +// +// A simple saturating counter predictor +// +// +class SaturatingCounterPred : public GenericPredictor +{ + private: + std::string pred_name; + std::string zero_name; + std::string one_name; + + unsigned index_bits; + unsigned counter_bits; + unsigned zero_change; + unsigned one_change; + unsigned thresh; + unsigned init_value; + + unsigned max_value; // maximum counter value + + unsigned long max_index; // also the index mask value + unsigned *table; + + // Statistics + Stats::Scalar<> predicted_one; // Total predictions of one, preds_one + Stats::Scalar<> predicted_zero; // Total predictions of zero, preds_zero + Stats::Scalar<> correct_pred_one; // Total correct predictions of one, correct_one + Stats::Scalar<> correct_pred_zero; // Total correct predictions of zero, correct_zero + + Stats::Scalar<> record_zero; //updates_zero + Stats::Scalar<> record_one; //updates_one + + Stats::Formula preds_total; + Stats::Formula pred_frac_zero; + Stats::Formula pred_frac_one; + Stats::Formula correct_total; + Stats::Formula updates_total; + Stats::Formula pred_rate; + Stats::Formula frac_correct_zero; + Stats::Formula frac_correct_one; + Stats::Formula coverage_zero; + Stats::Formula coverage_one; + + private: + bool pred_one(unsigned &counter) { return counter > thresh; } + bool pred_zero(unsigned &counter) { return counter <= thresh; } + + void update_one(unsigned &counter) { + + if (one_change) + counter += one_change; + else + counter = 0; + + // check for wrap + if (counter > max_value) + counter = max_value; + } + + void update_zero(unsigned &counter) { + if (zero_change) { + // check for wrap + if (counter < zero_change) + counter = 0; + else + counter -= zero_change; + } else + counter = 0; + } + + + public: + + SaturatingCounterPred(std::string p_name, + std::string z_name, std::string o_name, + unsigned _index_bits, unsigned _counter_bits = 2, + unsigned _zero_change = 1, unsigned _one_change = 1, + unsigned _thresh = 1, unsigned _init_value = 0); + + void clear() { + for (int i = 0; i <= max_index; ++i) + table[i] = init_value; + } + + // Record the ACTUAL result... and indicate whether the prediction + // corresponding to this event was correct + void record(unsigned long _index, unsigned _val, unsigned _predicted, + unsigned _pdata) + { + record(_index, _val, _predicted); + } + + void record(unsigned long _index, unsigned _val, unsigned _predicted) { + unsigned long index = _index & max_index; + + if (_val) { + update_one(table[index]); + ++record_one; + + if (_predicted) + ++correct_pred_one; + } else { + update_zero(table[index]); + ++record_zero; + + if (!_predicted) + ++correct_pred_zero; + } + } + + unsigned value(unsigned long _index) { + unsigned long index = _index & max_index; + + return table[index]; + } + + + unsigned predict(unsigned long _index, unsigned &pdata) { + return predict(_index); + } + + unsigned predict(unsigned long _index) { + unsigned long index = _index & max_index; + + if (pred_one(table[index])) { + ++predicted_one; + return 1; + } + + ++predicted_zero; + return 0; + } + + // No internal state is changed here + unsigned peek(unsigned long _index) { + unsigned long index = _index & max_index; + + if (pred_one(table[index])) + return 1; + + return 0; + } + + + //======================================================= + void regStats(); + void regFormulas(); +}; + + +#endif // __SAT_COUNTER_HH__ |