random.cc revision 3483 
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#include <cstdlib>
33#include <cmath>
34
35#if defined(__sun__)
36#include <ieeefp.h>
37#endif
38
39#include "sim/param.hh"
40#include "base/random.hh"
41#include "base/trace.hh"
42
43using namespace std;
44
45class RandomContext : public ParamContext
46{
47  public:
48    RandomContext(const string &_iniSection)
49        : ::ParamContext(_iniSection) {}
50    ~RandomContext() {}
51
52    void checkParams();
53};
54
55RandomContext paramContext("random");
56
57Param<unsigned>
58seed(&paramContext, "seed", "seed to random number generator", 1);
59
60void
61RandomContext::checkParams()
62{
63    ::srand48(seed);
64}
65
66long
67getLong()
68{
69    return mrand48();
70}
71
72double
73m5round(double r)
74{
75#if defined(__sun__)
76    double val;
77    fp_rnd oldrnd = fpsetround(FP_RN);
78    val = rint(r);
79    fpsetround(oldrnd);
80    return val;
81#else
82    return round(r);
83#endif
84}
85
86int64_t
87getUniform(int64_t min, int64_t max)
88{
89    double r;
90    r = drand48() * (max-min) + min;
91
92    return (int64_t)m5round(r);
93}
94
95uint64_t
96getUniformPos(uint64_t min, uint64_t max)
97{
98    double r;
99    r = drand48() * (max-min) + min;
100
101    return (uint64_t)m5round(r);
102}
103
104
105// idea for generating a double from erand48
106double
107getDouble()
108{
109    union {
110        uint32_t _long[2];
111        uint16_t _short[4];
112    };
113
114    _long[0] = mrand48();
115    _long[1] = mrand48();
116
117    return ldexp((double) _short[0], -48) +
118        ldexp((double) _short[1], -32) +
119        ldexp((double) _short[2], -16);
120}
121