1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
|
/*
* Copyright (c) 2003 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.
*/
#ifndef __SAT_COUNTER_HH__
#define __SAT_COUNTER_HH__
#include <string>
#include "base/predictor.hh"
#include "base/statistics.hh"
#include "sim/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
Statistics::Scalar<> predicted_one; // Total predictions of one, preds_one
Statistics::Scalar<> predicted_zero; // Total predictions of zero, preds_zero
Statistics::Scalar<> correct_pred_one; // Total correct predictions of one, correct_one
Statistics::Scalar<> correct_pred_zero; // Total correct predictions of zero, correct_zero
Statistics::Scalar<> record_zero; //updates_zero
Statistics::Scalar<> record_one; //updates_one
Statistics::Formula preds_total;
Statistics::Formula pred_frac_zero;
Statistics::Formula pred_frac_one;
Statistics::Formula correct_total;
Statistics::Formula updates_total;
Statistics::Formula pred_rate;
Statistics::Formula frac_correct_zero;
Statistics::Formula frac_correct_one;
Statistics::Formula coverage_zero;
Statistics::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__
|
