static int flip_cycle(RNG *rand)
{ /* this is an auxiliary routine to do 55 more steps of the basic
recurrence, at high speed, and to reset fptr */
int *ii, *jj;
for (ii = &A[1], jj = &A[32]; jj <= &A[55]; ii++, jj++)
*ii = mod_diff(*ii, *jj);
for (jj = &A[1]; ii <= &A[55]; ii++, jj++)
*ii = mod_diff(*ii, *jj);
fptr = &A[54];
return A[55];
}
int gb_flip_cycle()
{
register int*ii,*jj;
for(ii= &A[1],jj= &A[32];jj<=&A[55];ii++,jj++)
*ii= mod_diff(*ii,*jj);
for(jj= &A[1];ii<=&A[55];ii++,jj++)
*ii= mod_diff(*ii,*jj);
gb_fptr= &A[54];
return A[55];
}
void rng_init_rand(RNG *rand, int seed)
{ int i;
int prev = seed, next = 1;
seed = prev = mod_diff(prev, 0);
A[55] = prev;
for (i = 21; i; i = (i + 21) % 55)
{ A[i] = next;
next = mod_diff(prev, next);
if (seed & 1)
seed = 0x40000000 + (seed >> 1);
else
seed >>= 1;
next = mod_diff(next, seed);
prev = A[i];
}
void gb_init_rand(long seed)
{
register long i;
register long prev= seed,next= 1;
seed= prev= mod_diff(prev,0);
A[55]= prev;
for(i= 21;i;i= (i+21)%55){
A[i]= next;
next= mod_diff(prev,next);
if(seed&1)seed= 0x40000000+(seed>>1);
else seed>>= 1;
next= mod_diff(next,seed);
prev= A[i];
}