random.cc revision 3918 
1/*
2 * Copyright (c) 2003-2005 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Nathan Binkert
29 *          Ali Saidi
30 */
31
32#if defined(__sun)
33#include <ieeefp.h>
34#endif
35#ifdef __SUNPRO_CC
36#include <stdlib.h>
37#include <math.h>
38#endif
39
40#include <cstdlib>
41#include <cmath>
42
43
44#include "sim/param.hh"
45#include "base/random.hh"
46#include "base/trace.hh"
47
48using namespace std;
49
50class RandomContext : public ParamContext
51{
52  public:
53    RandomContext(const string &_iniSection)
54        : ::ParamContext(_iniSection) {}
55    ~RandomContext() {}
56
57    void checkParams();
58};
59
60RandomContext paramContext("random");
61
62Param<unsigned>
63seed(&paramContext, "seed", "seed to random number generator", 1);
64
65void
66RandomContext::checkParams()
67{
68    ::srand48(seed);
69}
70
71long
72getLong()
73{
74    return mrand48();
75}
76
77double
78m5round(double r)
79{
80#if defined(__sun)
81    double val;
82    fp_rnd oldrnd = fpsetround(FP_RN);
83    val = rint(r);
84    fpsetround(oldrnd);
85    return val;
86#else
87    return round(r);
88#endif
89}
90
91int64_t
92getUniform(int64_t min, int64_t max)
93{
94    double r;
95    r = drand48() * (max-min) + min;
96
97    return (int64_t)m5round(r);
98}
99
100uint64_t
101getUniformPos(uint64_t min, uint64_t max)
102{
103    double r;
104    r = drand48() * (max-min) + min;
105
106    return (uint64_t)m5round(r);
107}
108
109
110// idea for generating a double from erand48
111double
112getDouble()
113{
114    union {
115        uint32_t _long[2];
116        uint16_t _short[4];
117    };
118
119    _long[0] = mrand48();
120    _long[1] = mrand48();
121
122    return ldexp((double) _short[0], -48) +
123        ldexp((double) _short[1], -32) +
124        ldexp((double) _short[2], -16);
125}
126