random.cc revision 1296
1/* 2 * Copyright (c) 2003 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 29#include <cstdlib> 30#include <cmath> 31 32#include "sim/param.hh" 33#include "base/random.hh" 34 35using namespace std; 36 37class RandomContext : public ParamContext 38{ 39 public: 40 RandomContext(const string &_iniSection) 41 : ::ParamContext(_iniSection) {} 42 ~RandomContext() {} 43 44 void checkParams(); 45}; 46 47RandomContext paramContext("random"); 48 49Param<unsigned> 50seed(¶mContext, "seed", "seed to random number generator", 1); 51 52void 53RandomContext::checkParams() 54{ 55 ::srandom(seed); 56} 57 58long 59getLong() 60{ 61 return random(); 62} 63 64// idea for generating a double from erand48 65double 66getDouble() 67{ 68 union { 69 uint32_t _long[2]; 70 uint16_t _short[4]; 71 }; 72 73 _long[0] = random(); 74 _long[1] = random(); 75 76 return ldexp((double) _short[0], -48) + 77 ldexp((double) _short[1], -32) + 78 ldexp((double) _short[2], -16); 79} 80