/* Written in 2018 by David Blackman and Sebastiano Vigna (vigna@acm.org)
To the extent possible under law, the author has dedicated all copyright
and related and neighboring rights to this software to the public domain
worldwide. This software is distributed without any warranty.
See . */
#include
/* This is xoshiro256** 1.0, our all-purpose, rock-solid generator. It has
excellent (sub-ns) speed, a state (256 bits) that is large enough for
any parallel application, and it passes all tests we are aware of.
For generating just floating-point numbers, xoshiro256+ is even faster.
The state must be seeded so that it is not everywhere zero. If you have
a 64-bit seed, we suggest to seed a splitmix64 generator and use its
output to fill s. */
static inline uint64_t rotl(const uint64_t x, int k) {
return (x << k) | (x >> (64 - k));
}
static uint64_t s[4];
uint64_t next(void) {
const uint64_t result_starstar = rotl(s[1] * 5, 7) * 9;
const uint64_t t = s[1] << 17;
s[2] ^= s[0];
s[3] ^= s[1];
s[1] ^= s[2];
s[0] ^= s[3];
s[2] ^= t;
s[3] = rotl(s[3], 45);
return result_starstar;
}
/* This is the jump function for the generator. It is equivalent
to 2^128 calls to next(); it can be used to generate 2^128
non-overlapping subsequences for parallel computations. */
void jump(void) {
static const uint64_t JUMP[] = { 0x180ec6d33cfd0aba, 0xd5a61266f0c9392c, 0xa9582618e03fc9aa, 0x39abdc4529b1661c };
uint64_t s0 = 0;
uint64_t s1 = 0;
uint64_t s2 = 0;
uint64_t s3 = 0;
for(int i = 0; i < sizeof JUMP / sizeof *JUMP; i++)
for(int b = 0; b < 64; b++) {
if (JUMP[i] & UINT64_C(1) << b) {
s0 ^= s[0];
s1 ^= s[1];
s2 ^= s[2];
s3 ^= s[3];
}
next();
}
s[0] = s0;
s[1] = s1;
s[2] = s2;
s[3] = s3;
}