Light Implementation of Multiply-With-Carry PRNG v2

/*
 * Lightweight adaptation of the example multiply with carry PRNG
 * code from wikipedia
 * Version: 2
 */

#include <stdint.h>

#define MWC_A 18782LL
#define MWC_R 0xfffffffe

static uint32_t Q, c = 362436;

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

uint32_t rand_cmwc(void)
{   uint32_t x;
    uint64_t t = MWC_A * Q + c;
    c = (t >> 32);
    x = t + c;
    if(x < c)
    {   x++;
        c++;
    }
    return (Q = MWC_R - x);
}