diff options
Diffstat (limited to 'src/base/hybrid_pred.hh')
| -rw-r--r-- | src/base/hybrid_pred.hh | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/src/base/hybrid_pred.hh b/src/base/hybrid_pred.hh new file mode 100644 index 000000000..ea4a9d04c --- /dev/null +++ b/src/base/hybrid_pred.hh @@ -0,0 +1,201 @@ +/* + * 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. + */ + +//========================================================================== +// +// This predictor takes the AND of a "local" and a "global" predictor +// in order to determine its prediction. +// +// +// +// + +#ifndef __HYBRID_PRED_HH__ +#define __HYBRID_PRED_HH__ + +#include <string> + +#include "base/sat_counter.hh" +#include "base/statistics.hh" + +class HybridPredictor : public GenericPredictor +{ + private: + std::string pred_name; + std::string one_name; + std::string zero_name; + bool reg_individual_stats; + + SaturatingCounterPred *local; + SaturatingCounterPred *global; + + unsigned long max_index; + + // + // Stats + // + Stats::Scalar<> pred_one; //num_one_preds + Stats::Scalar<> pred_zero; //num_zero_preds + Stats::Scalar<> correct_pred_one; //num_one_correct + Stats::Scalar<> correct_pred_zero; //num_zero_correct + Stats::Scalar<> record_one; //num_one_updates + Stats::Scalar<> record_zero; //num_zero_updates + + Stats::Formula total_preds; + Stats::Formula frac_preds_zero; + Stats::Formula frac_preds_one; + Stats::Formula total_correct; + Stats::Formula total_accuracy; + Stats::Formula zero_accuracy; + Stats::Formula one_accuracy; + Stats::Formula zero_coverage; + Stats::Formula one_coverage; + + public: + HybridPredictor(const char *_p_name, const char *_z_name, + const char *_o_name, + unsigned _index_bits, unsigned _counter_bits, + unsigned _zero_change, unsigned _one_change, + unsigned _thresh, + unsigned _global_bits, unsigned _global_thresh, + bool _reg_individual_stats = false); + + void clear() { + global->clear(); + local->clear(); + } + + unsigned peek(unsigned long _index) { + unsigned l = local->peek(_index); + unsigned g = global->peek(_index); + + if (l && g) + return 1; + + return 0; + } + + unsigned value(unsigned long _index) { + unsigned l = local->peek(_index); + unsigned g = global->peek(_index); + + l = l & 0xFFFF; + g = g & 0xFFFF; + + return (l << 16) | g; + + } + + unsigned predict(unsigned long _index) { + unsigned l = local->predict(_index); + unsigned g = global->predict(_index); + + if (l && g) { + ++pred_one; + return 1; + } + + ++pred_zero; + return 0; + } + + + // + // This version need only be used if local/global statistics + // will be maintained + // + unsigned predict(unsigned long _index, unsigned &_pdata) { + unsigned l = local->predict(_index); + unsigned g = global->predict(_index); + + // + // bit 0 => local predictor result + // bit 1 => global predictor result + // + _pdata = 0; + if (l) + _pdata |= 1; + if (g) + _pdata |= 2; + if (l && g) { + ++pred_one; + return 1; + } + + ++pred_zero; + return 0; + } + + void record(unsigned long _index, unsigned _val, unsigned _predicted) { + + if (_val) { + local->record(_index, _val, 0); + global->record(_index, _val, 0); + ++record_one; + + if (_val == _predicted) { + ++correct_pred_one; + } + } else { + local->record(_index, _val, 0); + global->record(_index, _val, 0); + ++record_zero; + + if (_val == _predicted) + ++correct_pred_zero; + } + } + + void record(unsigned long _index, unsigned _val, unsigned _predicted, + unsigned _pdata) + { + + local->record(_index, _val, (_pdata & 1)); + global->record(_index, _val, ((_pdata & 2) ? 1 : 0)); + + + if (_val) { + ++record_one; + + if (_val == _predicted) + ++correct_pred_one; + } else { + ++record_zero; + + if (_val == _predicted) + ++correct_pred_zero; + } + } + + void regStats(); + void regFormulas(); +}; + + +#endif // _HYBRID_PRED_HH__ + |