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/*
* Copyright (c) 2003-2005 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.
*
* Authors: Nathan Binkert
* Ali Saidi
*/
#include "base/fenv.hh"
#include "base/intmath.hh"
#include "base/misc.hh"
#include "base/random.hh"
#include "sim/serialize.hh"
using namespace std;
Random::Random()
{
// default random seed taken from original source
init(5489);
}
Random::Random(uint32_t s)
{
init(s);
}
Random::Random(uint32_t init_key[], int key_length)
{
init(init_key, key_length);
}
Random::~Random()
{
}
// To preserve the uniform random distribution between min and max,
// and allow all numbers to be represented, we generate a uniform
// random number to the nearest power of two greater than max. If
// this number doesn't fall between 0 and max, we try again. Anything
// else would skew the distribution.
uint32_t
Random::genrand(uint32_t max)
{
if (max == 0)
return 0;
int log = ceilLog2(max) + 1;
int shift = (sizeof(uint32_t) * 8 - log);
uint32_t random;
do {
random = genrand() >> shift;
} while (random > max);
return random;
}
uint64_t
Random::genrand(uint64_t max)
{
if (max == 0)
return 0;
int log = ceilLog2(max) + 1;
int shift = (sizeof(uint64_t) * 8 - log);
uint64_t random;
do {
random = (uint64_t)genrand() << 32 | (uint64_t)genrand();
random = random >> shift;
} while (random > max);
return random;
}
void
Random::serialize(const string &base, ostream &os)
{
int length = N;
paramOut(os, base + ".mti", mti);
paramOut(os, base + ".length", length);
arrayParamOut(os, base + ".data", mt, length);
}
void
Random::unserialize(const string &base, Checkpoint *cp, const string §ion)
{
int length;
paramIn(cp, section, base + ".mti", mti);
paramIn(cp, section, base + ".length", length);
if (length != N)
panic("cant unserialize random number data. length != %d\n", length);
arrayParamIn(cp, section, base + ".data", mt, length);
}
Random random_mt;
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