Collatz-Weyl Chaotic Pseudo-random number generator (64-bit)

cw_prng.c

#include "cw_prng.h"
#include <stdio.h>

uint64_t cw_g64(struct CW_Rng* rng) {
        rng -> weyl += rng -> s;
        uint64_t out = rng -> xbits;
        rng -> abits += out;
        out = (out >> 1)*(rng -> abits | 1);
        out ^= rng -> weyl;
        rng -> xbits = out;
        out ^= rng -> abits >> 48;
        return out;
}

void cw_init(struct CW_Rng* rng, uint64_t seed) {
        // Set these to zero, as they are affected by s immediately after first pass.
        rng -> abits = 0;
        rng -> weyl =  0;
        // Initial state, and increment s are determined by seed
        // Use splitmix64 for x bits ...
        seed += 0x9e3779b97f4a7c15;
        uint64_t x = seed;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        x = x ^ (x >> 31);
        // .. and splitmix63 for s
        seed += 0x9e3779b97f4a7c15;
        uint64_t z = seed & 0x7fffffffffffffff;
        z = ((z ^ (z >> 30)) * 0xbf58476d1ce4e5b9) & 0x7fffffffffffffff;
        z = ((z ^ (z >> 27)) * 0x94d049bb133111eb) & 0x7fffffffffffffff;
        z = z ^ (z >> 31);
        rng -> s = (z << 1) | 1;
        rng -> xbits = x;
}

int main() {
        // Test
        struct CW_Rng rng;
        cw_init(&rng, 612);
        for(size_t i = 0; i < 100; i++) {
                printf("%u\n", cw_g64(&rng));
        }
        return 0;
}

cw_prng.h

#ifndef CW_PRNG

#include <stdint.h>
#define CW_PRNG

/*
 * A simple C-implementation of the Collatz-Weyl Pseudo-random number generator.
 */

struct CW_Rng {
        // 'Main' sequence of bits to be operated on by CW-scheme.
        uint64_t xbits;
        // 'Auxiliary' sequence of bits
        uint64_t abits;
        uint64_t weyl;
        // Odd number used to update Weyl bits.
        uint64_t s;
};

/**
 * Generate 64 random bits.
 */
uint64_t cw_g64(struct CW_Rng* rng);

/**
 * Initialize the Random number generator using the provided seed.
 */
void cw_init(struct CW_Rng* rng, uint64_t seed);

#endif