+ /*
+ * Period 2^64-1 = 2^32+1 * 2^32-1 has a common divisor with Galois LFSR.
+ * By skipping two possible states (0x1 and 0x2) we reduce period to
+ * 2^64-3 = 13 * 3889 * 364870227143809 which has no common divisors:
+ */
+ if (rnd->xs64_y == 0 && rnd->xs64_x <= 2)
+ goto again;