-int nbd_rand (void) {
- LOCALIZE_THREAD_LOCAL(rand_seed_, unsigned);
- unsigned r = rand_r(&rand_seed_);
- SET_THREAD_LOCAL(rand_seed_, r);
+// George Marsaglia's KISS generator
+uint64_t nbd_rand (void) {
+ LOCALIZE_THREAD_LOCAL(rx_, unsigned);
+ LOCALIZE_THREAD_LOCAL(ry_, unsigned);
+ LOCALIZE_THREAD_LOCAL(rz_, unsigned);
+ LOCALIZE_THREAD_LOCAL(rc_, unsigned);
+
+ uint32_t rx = 69069 * rx_ + 12345;
+ uint32_t ry = ry_;
+ uint32_t rz = rz_;
+ ry ^= (ry << 13);
+ ry ^= (ry >> 17);
+ ry ^= (ry << 5);
+ uint64_t t = rz * 698769069LL + rc_;
+ uint64_t r = rx + ry + (rz = t);
+
+ SET_THREAD_LOCAL(rx_, rx);
+ SET_THREAD_LOCAL(ry_, ry);
+ SET_THREAD_LOCAL(rz_, rz);
+ SET_THREAD_LOCAL(rc_, (unsigned)(t >> 32));
+