random.hh

来自「M5,一个功能强大的多处理器系统模拟器.很多针对处理器架构,性能的研究都使用它作」· HH 代码 · 共 243 行

/*
 * Copyright (c) 2003, 2004, 2005
 * The Regents of The University of Michigan
 * All Rights Reserved
 *
 * This code is part of the M5 simulator.
 *
 * Permission is granted to use, copy, create derivative works and
 * redistribute this software and such derivative works for any
 * purpose, so long as the copyright notice above, this grant of
 * permission, and the disclaimer below appear in all copies made; and
 * so long as the name of The University of Michigan is not used in
 * any advertising or publicity pertaining to the use or distribution
 * of this software without specific, written prior authorization.
 *
 * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION FROM THE
 * UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY PURPOSE, AND
 * WITHOUT WARRANTY BY THE UNIVERSITY OF MICHIGAN OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE. THE REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE
 * LIABLE FOR ANY DAMAGES, INCLUDING DIRECT, SPECIAL, INDIRECT,
 * INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM
 * ARISING OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
 * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGES.
 *
 * Authors: Nathan L. Binkert
 *          Ali G. Saidi
 */

#ifndef __BASE_RANDOM_HH__
#define __BASE_RANDOM_HH__

#include <ios>
#include <string>

#include "base/range.hh"
#include "sim/host.hh"

class Checkpoint;

class Random
{
  protected:
    static const int N = 624;
    static const int M = 397;
    static const uint32_t MATRIX_A = (uint32_t)0x9908b0df;
    static const uint32_t UPPER_MASK = (uint32_t)0x80000000;
    static const uint32_t LOWER_MASK = (uint32_t)0x7fffffff;

    uint32_t mt[N];
    int mti;

    uint32_t genrand();
    uint32_t genrand(uint32_t max);
    uint64_t genrand(uint64_t max);

    void
    _random(int8_t &value)
    {
        value = genrand() & (int8_t)-1;
    }

    void
    _random(int16_t &value)
    {
        value = genrand() & (int16_t)-1;
    }

    void
    _random(int32_t &value)
    {
        value = (int32_t)genrand();
    }

    void
    _random(int64_t &value)
    {
        value = (int64_t)genrand() << 32 | (int64_t)genrand();
    }

    void
    _random(uint8_t &value)
    {
        value = genrand() & (uint8_t)-1;
    }

    void
    _random(uint16_t &value)
    {
        value = genrand() & (uint16_t)-1;
    }

    void
    _random(uint32_t &value)
    {
        value = genrand();
    }

    void
    _random(uint64_t &value)
    {
        value = (uint64_t)genrand() << 32 | (uint64_t)genrand();
    }

    // [0,1]
    void
    _random(float &value)
    {
        // ieee floats have 23 bits of mantissa
        value = (genrand() >> 9) / 8388608.0;
    }

    // [0,1]
    void
    _random(double &value)
    {
        double number = genrand() * 2097152.0 + (genrand() >> 11);
        value = number / 9007199254740992.0;
    }


    // Range based versions of the random number generator
    int8_t
    _random(int8_t min, int8_t max)
    {
        uint32_t diff = max - min;
        return static_cast<int8_t>(min + genrand(diff));
    }

    int16_t
    _random(int16_t min, int16_t max)
    {
        uint32_t diff = max - min;
        return static_cast<int16_t>(min + genrand(diff));
    }

    int32_t
    _random(int32_t min, int32_t max)
    {
        uint32_t diff = max - min;
        return static_cast<int32_t>(min + genrand(diff));
    }

    int64_t
    _random(int64_t min, int64_t max)
    {
        uint64_t diff = max - min;
        return static_cast<int64_t>(min + genrand(diff));
    }

    uint8_t
    _random(uint8_t min, uint8_t max)
    {
        uint32_t diff = max - min;
        return static_cast<uint8_t>(min + genrand(diff));
    }

    uint16_t
    _random(uint16_t min, uint16_t max)
    {
        uint32_t diff = max - min;
        return static_cast<uint16_t>(min + genrand(diff));
    }

    uint32_t
    _random(uint32_t min, uint32_t max)
    {
        uint32_t diff = max - min;
        return static_cast<uint32_t>(min + genrand(diff));
    }

    uint64_t
    _random(uint64_t min, uint64_t max)
    {
        uint64_t diff = max - min;
        return static_cast<uint64_t>(min + genrand(diff));
    }

  public:
    Random();
    Random(uint32_t s);
    Random(uint32_t init_key[], int key_length);
    ~Random();

    void init(uint32_t s);
    void init(uint32_t init_key[], int key_length);

    template <typename T>
    T
    random()
    {
        T value;
        _random(value);
        return value;
    }

    template <typename T>
    T
    random(T min, T max)
    {
        return _random(min, max);
    }

    template <typename T>
    T
    random(const Range<T> &range)
    {
        return _random(range.start, range.end);
    }

    // [0,1]
    double
    gen_real1()
    {
        return genrand() / 4294967296.0;
    }

    // [0,1)
    double
    gen_real2()
    {
        return genrand() / 4294967295.0;
    }

    // (0,1)
    double
    gen_real3()
    {
        return ((double)genrand() + 0.5) / 4294967296.0;
    }

  public:
    void serialize(const std::string &base, std::ostream &os);
    void unserialize(const std::string &base, Checkpoint *cp,
                     const std::string &section);
};

extern Random random_mt;

#endif // __BASE_RANDOM_HH__