Adding gem5 source to svn.

git-svn-id: https://www4.informatik.uni-erlangen.de/i4svn/danceos/trunk/devel/fail@1819 8c4709b5-6ec9-48aa-a5cd-a96041d1645a

simulators/gem5/src/base/random.cc

@@ -0,0 +1,127 @@
+/*
+ * 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 <limits>
+#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;
+    if (max == std::numeric_limits<uint32_t>::max())
+        return genrand();
+
+    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;
+    if (max == std::numeric_limits<uint64_t>::max())
+        return genrand();
+
+    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 &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;