* Period parameters */

#define N 624

#define M 397

#define MATRIX_A 0x9908b0df /* constant vector a */

#define UPPER_MASK 0x80000000 /* most significant w-r bits */

#define LOWER_MASK 0x7fffffff /* least significant r bits */



unsigned long seed;

/* Tempering parameters */

#define TEMPERING_MASK_B 0x9d2c5680

#define TEMPERING_MASK_C 0xefc60000

#define TEMPERING_SHIFT_U(y) (y >> 11)

#define TEMPERING_SHIFT_S(y) (y << 7)

#define TEMPERING_SHIFT_T(y) (y << 15)

#define TEMPERING_SHIFT_L(y) (y >> 18)



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 */



/* initializing the array with a NONZERO seed */

void

sgenrand(unsigned long seedvalue)

{

/* setting initial seeds to mt[N] using */

/* the generator Line 25 of Table 1 in */

/* [KNUTH 1981, The Art of Computer Programming */

/* Vol. 2 (2nd Ed.), pp102] */

mt[0]= seedvalue & 0xffffffff;

for (mti=1; mti<N; mti++)

mt[mti] = (69069 * mt[mti-1]) & 0xffffffff;

}



unsigned long

genrand()

{

unsigned long y;

static unsigned long mag01[2]={0x0, 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 sgenrand() has not been called, */

sgenrand(4357); /* 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 & 0x1];

}

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 & 0x1];

}

y = (mt[N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK);

mt[N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1];



mti = 0;

}



y = mt[mti++];

y ^= TEMPERING_SHIFT_U(y);

y ^= TEMPERING_SHIFT_S(y) & TEMPERING_MASK_B;

y ^= TEMPERING_SHIFT_T(y) & TEMPERING_MASK_C;

y ^= TEMPERING_SHIFT_L(y);



return y;

}