/* 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 xoshiro128** 1.0, our 32-bit all-purpose, rock-solid generator. It
has excellent (sub-ns) speed, a state size (128 bits) that is large
enough for mild parallelism, and it passes all tests we are aware of.
For generating just single-precision (i.e., 32-bit) floating-point
numbers, xoshiro128+ is even faster.
The state must be seeded so that it is not everywhere zero. */
static inline uint32_t rotl(const uint32_t x, int k) {
return (x << k) | (x >> (32 - k));
}
static uint32_t s[4];
uint32_t next(void) {
const uint32_t result_starstar = rotl(s[0] * 5, 7) * 9;
const uint32_t t = s[1] << 9;
s[2] ^= s[0];
s[3] ^= s[1];
s[1] ^= s[2];
s[0] ^= s[3];
s[2] ^= t;
s[3] = rotl(s[3], 11);
return result_starstar;
}
/* This is the jump function for the generator. It is equivalent
to 2^64 calls to next(); it can be used to generate 2^64
non-overlapping subsequences for parallel computations. */
void jump(void) {
static const uint32_t JUMP[] = { 0x8764000b, 0xf542d2d3, 0x6fa035c3, 0x77f2db5b };
uint32_t s0 = 0;
uint32_t s1 = 0;
uint32_t s2 = 0;
uint32_t s3 = 0;
for(int i = 0; i < sizeof JUMP / sizeof *JUMP; i++)
for(int b = 0; b < 32; b++) {
if (JUMP[i] & UINT32_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;
}