Light Implementation of Multiply-With-Carry PRNG

/*
 * Lightweight adaptation of the example multiply with carry PRNG
 * code from wikipedia
 * Version: 1
 */

#include <stdint.h>

#define PHI 0x9e3779b9

static uint32_t Q, c = 362436;

void init_rand(uint32_t x)
{   Q = x;
}

uint32_t rand_cmwc(void)
{   uint64_t t, a = 18782LL;
    uint32_t x, r = 0xfffffffe;
    t = a * Q + c;
    c = (t >> 32);
    x = t + c;
    if(x < c)
    {   x++;
        c++;
    }
    return (Q = r - x);
}