src/base/random.cc

   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
  48 using namespace std;
  49
  50 class RandomContext : public ParamContext
  51 {
  52   public:
  53     RandomContext(const string &_iniSection)
  54         : ::ParamContext(_iniSection) {}
  55     ~RandomContext() {}
  56
  57     void checkParams();
  58 };
  59
  60 RandomContext paramContext("random");
  61
  62 Param<unsigned>
  63 seed(&paramContext, "seed", "seed to random number generator", 1);
  64
  65 void
  66 RandomContext::checkParams()
  67 {
  68     ::srand48(seed);
  69 }
  70
  71 long
  72 getLong()
  73 {
  74     return mrand48();
  75 }
  76
  77 double
  78 m5round(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
  91 int64_t
  92 getUniform(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
 100 uint64_t
 101 getUniformPos(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
 111 double
 112 getDouble()
 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 }