Base: Rework the way M5 provides and creates random numbers.

--HG--
extra : convert_revision : 10ec3484647b3acb8e821f8520f97d535e41e861

5 files changed, 416 insertions, 127 deletions

diff --git a/src/base/SConscript b/src/base/SConscript
index ca68bfb60..393cf57ec 100644
--- a/src/base/SConscript
+++ b/src/base/SConscript
@@ -70,6 +70,7 @@ Source('misc.cc')
 Source('output.cc')
 Source('pollevent.cc')
 Source('random.cc')
+Source('random_mt.cc')
 Source('range.cc')
 Source('remote_gdb.cc')
 Source('sat_counter.cc')
diff --git a/src/base/random.cc b/src/base/random.cc
index 8a2e3c1c0..7daa90b9c 100644
--- a/src/base/random.cc
+++ b/src/base/random.cc
@@ -29,60 +29,88 @@
  *          Ali Saidi
  */
 
-#ifdef __SUNPRO_CC
-#include <stdlib.h>
-#include <math.h>
-#endif
-
-#include <cstdlib>
-#include <cmath>
-
 #include "base/fenv.hh"
+#include "base/intmath.hh"
+#include "base/misc.hh"
 #include "base/random.hh"
+#include "sim/serialize.hh"
 
 using namespace std;
 
-uint32_t
-getInt32()
+Random::Random()
 {
-    return mrand48() & 0xffffffff;
+    // default random seed taken from original source
+    init(5489);
 }
 
-double
-getDouble()
+Random::Random(uint32_t s)
 {
-    return drand48();
+    init(s);
 }
 
-double
-m5round(double r)
+Random::Random(uint32_t init_key[], int key_length)
 {
-#if defined(__sun)
-    double val;
-    int oldrnd = m5_fegetround();
-    m5_fesetround(M5_FE_TONEAREST);
-    val = rint(r);
-    m5_fesetround(oldrnd);
-    return val;
-#else
-    return round(r);
-#endif
+    init(init_key, key_length);
 }
 
-int64_t
-getUniform(int64_t min, int64_t max)
+Random::~Random()
 {
-    double r;
-    r = drand48() * (max-min) + min;
+}
 
-    return (int64_t)m5round(r);
+// 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)
+{
+    int log = ceilLog2(max);
+    int shift = (sizeof(uint32_t) * 8 - log);
+    uint32_t random;
+
+    do {
+        random = genrand() >> shift;
+    } while (random > max);
+
+    return random;
 }
 
 uint64_t
-getUniformPos(uint64_t min, uint64_t max)
+Random::genrand(uint64_t max)
+{
+    int log = ceilLog2(max);
+    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)
 {
-    double r;
-    r = drand48() * (max-min) + min;
+    int length = N;
+    paramOut(os, base + ".mti", mti);
+    paramOut(os, base + ".length", length);
+    arrayParamOut(os, base + ".data", mt, length);
+}
 
-    return (uint64_t)m5round(r);
+void
+Random::unserialize(const string &base, Checkpoint *cp, const string &section)
+{
+    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;
diff --git a/src/base/random.hh b/src/base/random.hh
index 0cd88728d..401ba086f 100644
--- a/src/base/random.hh
+++ b/src/base/random.hh
@@ -32,99 +32,211 @@
 #ifndef __BASE_RANDOM_HH__
 #define __BASE_RANDOM_HH__
 
-#include "sim/host.hh"
-
-uint32_t getUInt32();
-double getDouble();
-double m5random(double r);
-uint64_t getUniformPos(uint64_t min, uint64_t max);
-int64_t getUniform(int64_t min, int64_t max);
-
-template <typename T>
-struct Random;
-
-template<> struct Random<int8_t>
-{
-    static int8_t get()
-    { return getUInt32() & (int8_t)-1; }
-
-    static int8_t uniform(int8_t min, int8_t max)
-    { return getUniform(min, max); }
-};
-
-template<> struct Random<uint8_t>
-{
-    static uint8_t get()
-    { return getUInt32() & (uint8_t)-1; }
-
-    static uint8_t uniform(uint8_t min, uint8_t max)
-    { return getUniformPos(min, max); }
-};
-
-template<> struct Random<int16_t>
-{
-    static int16_t get()
-    { return getUInt32() & (int16_t)-1; }
-
-    static int16_t uniform(int16_t min, int16_t max)
-    { return getUniform(min, max); }
-};
-
-template<> struct Random<uint16_t>
-{
-    static uint16_t get()
-    { return getUInt32() & (uint16_t)-1; }
-
-    static uint16_t uniform(uint16_t min, uint16_t max)
-    { return getUniformPos(min, max); }
-};
-
-template<> struct Random<int32_t>
-{
-    static int32_t get()
-    { return (int32_t)getUInt32(); }
-
-    static int32_t uniform(int32_t min, int32_t max)
-    { return getUniform(min, max); }
-};
-
-template<> struct Random<uint32_t>
-{
-    static uint32_t get()
-    { return (uint32_t)getUInt32(); }
-
-    static uint32_t uniform(uint32_t min, uint32_t max)
-    { return getUniformPos(min, max); }
-};
+#include <ios>
+#include <string>
 
-template<> struct Random<int64_t>
-{
-    static int64_t get()
-    { return (int64_t)getUInt32() << 32 || (uint64_t)getUInt32(); }
-
-    static int64_t uniform(int64_t min, int64_t max)
-    { return getUniform(min, max); }
-};
-
-template<> struct Random<uint64_t>
-{
-    static uint64_t get()
-    { return (uint64_t)getUInt32() << 32 || (uint64_t)getUInt32(); }
+#include "base/range.hh"
+#include "sim/host.hh"
 
-    static uint64_t uniform(uint64_t min, uint64_t max)
-    { return getUniformPos(min, max); }
-};
+class Checkpoint;
 
-template<> struct Random<float>
+class Random
 {
-    static float get()
-    { return getDouble(); }
+  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);
 };
 
-template<> struct Random<double>
-{
-    static double get()
-    { return getDouble(); }
-};
+extern Random random_mt;
 
 #endif // __BASE_RANDOM_HH__
diff --git a/src/base/random_mt.cc b/src/base/random_mt.cc
new file mode 100644
index 000000000..1492240ee
--- /dev/null
+++ b/src/base/random_mt.cc
@@ -0,0 +1,149 @@
+/*
+ * A C-program for MT19937, with initialization improved 2002/1/26.
+ * Coded by Takuji Nishimura and Makoto Matsumoto.
+ *
+ * Before using, initialize the state by using init_genrand(seed)
+ * or init_by_array(init_key, key_length).
+ *
+ * Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ *   2. 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.
+ *
+ *   3. The names of its contributors may not 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.
+ *
+ *
+ * Any feedback is very welcome.
+ * http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
+ * email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)
+ */
+
+#include "base/random.hh"
+
+/* initializes mt[N] with a seed */
+void
+Random::init(uint32_t s)
+{
+    mti = N + 1;
+    mt[0] = s & (uint32_t)0xffffffff;
+
+    for (mti = 1; mti < N; mti++) {
+        mt[mti] = 1812433253UL * (mt[mti-1] ^ (mt[mti-1] >> 30)) + mti;
+        /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
+        /* In the previous versions, MSBs of the seed affect   */
+        /* only MSBs of the array mt[].                        */
+        /* 2002/01/09 modified by Makoto Matsumoto             */
+        mt[mti] &= (uint32_t)0xffffffff;
+        /* for >32 bit machines */
+    }
+}
+
+/* initialize by an array with array-length */
+/* init_key is the array for initializing keys */
+/* key_length is its length */
+/* slight change for C++, 2004/2/26 */
+void
+Random::init(uint32_t init_key[], int key_length)
+{
+    int i = 1;
+    int j = 0;
+    int k = (N > key_length) ? N : key_length;
+
+    init(19650218);
+
+    for (; k; k--) {
+        mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * (uint32_t)1664525))
+          + init_key[j] + j; /* non linear */
+
+        mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
+
+        i++;
+        j++;
+
+        if (i >= N) {
+            mt[0] = mt[N - 1];
+            i = 1;
+        }
+
+        if (j >= key_length)
+            j = 0;
+    }
+
+    for (k = N - 1; k; k--) {
+        /* non linear */
+        mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >> 30)) * 1566083941UL)) - i;
+
+        /* for WORDSIZE > 32 machines */
+        mt[i] &= (uint32_t)0xffffffff;
+        i++;
+
+        if (i >= N) {
+            mt[0] = mt[N - 1];
+            i = 1;
+        }
+    }
+
+    /* MSB is 1; assuring non-zero initial array */
+    mt[0] = (uint32_t)0x80000000;
+}
+
+/* generates a random number on [0,0xffffffff]-interval */
+uint32_t
+Random::genrand()
+{
+    uint32_t y;
+    static uint32_t mag01[2] = { 0, MATRIX_A};
+
+    if (mti >= N) { /* generate N words at one time */
+        int kk;
+
+        for (kk = 0; kk < N - M; kk++) {
+            y = mt[kk] & UPPER_MASK | mt[kk+1] & LOWER_MASK;
+            mt[kk] = mt[kk + M] ^ (y >> 1) ^ mag01[y & 0x1UL];
+        }
+        for (; kk < N - 1; kk++) {
+            y = mt[kk] & UPPER_MASK | mt[kk+1] & LOWER_MASK;
+            mt[kk] = mt[kk + (M - N)] ^ (y >> 1) ^ mag01[y & 0x1UL];
+        }
+
+        y = mt[N - 1] & UPPER_MASK | mt[0] & LOWER_MASK;
+        mt[N - 1] = mt[M - 1] ^ (y >> 1) ^ mag01[y & 0x1UL];
+
+        mti = 0;
+    }
+
+    y = mt[mti++];
+
+    /* Tempering */
+    y ^= (y >> 11);
+    y ^= (y << 7) & (uint32_t)0x9d2c5680;
+    y ^= (y << 15) & (uint32_t)0xefc60000;
+    y ^= (y >> 18);
+
+    return y;
+}
diff --git a/src/dev/etherlink.cc b/src/dev/etherlink.cc
index 4130a7b3f..b1266000b 100644
--- a/src/dev/etherlink.cc
+++ b/src/dev/etherlink.cc
@@ -177,10 +177,9 @@ EtherLink::Link::transmit(EthPacketPtr pkt)
 
     packet = pkt;
     Tick delay = (Tick)ceil(((double)pkt->length * ticksPerByte) + 1.0);
-    if (delayVar != 0) {
-        Random<Tick> var;
-        delay +=  var.uniform(0, delayVar);
-    }
+    if (delayVar != 0)
+        delay += random_mt.random<Tick>(0, delayVar);
+
     DPRINTF(Ethernet, "scheduling packet: delay=%d, (rate=%f)\n",
             delay, ticksPerByte);
     doneEvent.schedule(curTick + delay);