trunk/src/rng_mt.c

/* 
   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)

   $Id$
*/

#include "rng_mt.h"

/* Period parameters */  
#define N 624
#define M 397
#define MATRIX_A 0x9908b0dfUL   /* constant vector a         */
#define UPPER_MASK 0x80000000UL /* most significant w-r bits */
#define LOWER_MASK 0x7fffffffUL /* least significant r bits  */

static unsigned long mt[N]; /* the array for the state vector  */
static int mti = N + 1; /* mti==N+1 means mt[N] is not initialized */

/* initializes mt[N] with a seed */
void
init_genrand(unsigned long s)
{
  mt[0] = s & 0xffffffffUL;

  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] &= 0xffffffffUL;
    /* 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
init_by_array(unsigned long init_key[], int key_length)
{
  int i, j, k;

  init_genrand(19650218UL);

  i = 1; j = 0;
  k = (N > key_length ? N : key_length);

  for (; k; k--)
  {
    mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >> 30)) * 1664525UL))
          + 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--)
  {
    mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >> 30)) * 1566083941UL))
          - i; /* non linear */
    mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
    i++;

    if (i >= N)
    {
      mt[0] = mt[N - 1];
      i = 1;
    }
  }

  mt[0] = 0x80000000UL; /* MSB is 1; assuring non-zero initial array */ 
}

/* generates a random number on [0,0xffffffff]-interval */
unsigned long
genrand_int32(void)
{
  unsigned long y;
  static unsigned long mag01[2]={ 0x0UL, MATRIX_A };
  /* mag01[x] = x * MATRIX_A  for x=0,1 */

  if (mti >= N)
  { /* generate N words at one time */
    int kk;

    if (mti == N + 1)   /* if init_genrand() has not been called, */
      init_genrand(5489UL); /* a default initial seed is used */

    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) & 0x9d2c5680UL;
  y ^= (y << 15) & 0xefc60000UL;
  y ^= (y >> 18);

  return y;
}
Revision:	1156
Committed:	Tue Aug 9 20:29:20 2011 UTC (14 years ago) by michael
Content type:	text/x-csrc
Original Path:	*ircd-hybrid-8/src/rng_mt.c*
File size:	4979 byte(s)
Log Message:	- create ircd-hybrid-8 "branch"
#	User	Rev	Content
1	michael	982	/*
2			A C-program for MT19937, with initialization improved 2002/1/26.
3			Coded by Takuji Nishimura and Makoto Matsumoto.
4
5			Before using, initialize the state by using init_genrand(seed)
6			or init_by_array(init_key, key_length).
7
8			Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
9			All rights reserved.
10
11			Redistribution and use in source and binary forms, with or without
12			modification, are permitted provided that the following conditions
13			are met:
14
15			1. Redistributions of source code must retain the above copyright
16			notice, this list of conditions and the following disclaimer.
17
18			2. Redistributions in binary form must reproduce the above copyright
19			notice, this list of conditions and the following disclaimer in the
20			documentation and/or other materials provided with the distribution.
21
22			3. The names of its contributors may not be used to endorse or promote
23			products derived from this software without specific prior written
24			permission.
25
26			THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
27			"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
28			LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
29			A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
30			CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
31			EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
32			PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
33			PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34			LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35			NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
36			SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37
38
39			Any feedback is very welcome.
40			http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
41			email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)
42
43			$Id$
44			*/
45
46			#include "rng_mt.h"
47
48			/* Period parameters */
49			#define N 624
50			#define M 397
51			#define MATRIX_A 0x9908b0dfUL /* constant vector a */
52			#define UPPER_MASK 0x80000000UL /* most significant w-r bits */
53			#define LOWER_MASK 0x7fffffffUL /* least significant r bits */
54
55			static unsigned long mt[N]; /* the array for the state vector */
56			static int mti = N + 1; /* mti==N+1 means mt[N] is not initialized */
57
58			/* initializes mt[N] with a seed */
59			void
60			init_genrand(unsigned long s)
61			{
62			mt[0] = s & 0xffffffffUL;
63
64			for (mti = 1; mti < N; mti++)
65			{
66			mt[mti] = (1812433253UL * (mt[mti - 1] ^ (mt[mti - 1] >> 30)) + mti);
67			/* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
68			/* In the previous versions, MSBs of the seed affect */
69			/* only MSBs of the array mt[]. */
70			/* 2002/01/09 modified by Makoto Matsumoto */
71			mt[mti] &= 0xffffffffUL;
72			/* for >32 bit machines */
73			}
74			}
75
76			/* initialize by an array with array-length */
77			/* init_key is the array for initializing keys */
78			/* key_length is its length */
79			/* slight change for C++, 2004/2/26 */
80			void
81			init_by_array(unsigned long init_key[], int key_length)
82			{
83			int i, j, k;
84
85			init_genrand(19650218UL);
86
87			i = 1; j = 0;
88			k = (N > key_length ? N : key_length);
89
90			for (; k; k--)
91			{
92			mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >> 30)) * 1664525UL))
93			+ init_key[j] + j; /* non linear */
94			mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
95			i++; j++;
96
97			if (i >= N)
98			{
99			mt[0] = mt[N - 1];
100			i = 1;
101			}
102
103			if (j >= key_length)
104			j = 0;
105			}
106
107			for (k = N - 1; k; k--)
108			{
109			mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >> 30)) * 1566083941UL))
110			- i; /* non linear */
111			mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
112			i++;
113
114			if (i >= N)
115			{
116			mt[0] = mt[N - 1];
117			i = 1;
118			}
119			}
120
121			mt[0] = 0x80000000UL; /* MSB is 1; assuring non-zero initial array */
122			}
123
124			/* generates a random number on [0,0xffffffff]-interval */
125			unsigned long
126			genrand_int32(void)
127			{
128			unsigned long y;
129			static unsigned long mag01[2]={ 0x0UL, MATRIX_A };
130			/* mag01[x] = x * MATRIX_A for x=0,1 */
131
132			if (mti >= N)
133			{ /* generate N words at one time */
134			int kk;
135
136			if (mti == N + 1) /* if init_genrand() has not been called, */
137			init_genrand(5489UL); /* a default initial seed is used */
138
139			for (kk = 0; kk < N - M; kk++)
140			{
141			y = (mt[kk] & UPPER_MASK) \| (mt[kk + 1] & LOWER_MASK);
142			mt[kk] = mt[kk + M] ^ (y >> 1) ^ mag01[y & 0x1UL];
143			}
144
145			for (; kk < N - 1; kk++)
146			{
147			y = (mt[kk] & UPPER_MASK) \| (mt[kk + 1] & LOWER_MASK);
148			mt[kk] = mt[kk + (M - N)] ^ (y >> 1) ^ mag01[y & 0x1UL];
149			}
150
151			y = (mt[N - 1] & UPPER_MASK) \| (mt[0] & LOWER_MASK);
152			mt[N - 1] = mt[M - 1] ^ (y >> 1) ^ mag01[y & 0x1UL];
153
154			mti = 0;
155			}
156
157			y = mt[mti++];
158
159			/* Tempering */
160			y ^= (y >> 11);
161			y ^= (y << 7) & 0x9d2c5680UL;
162			y ^= (y << 15) & 0xefc60000UL;
163			y ^= (y >> 18);
164
165			return y;
166			}