/* $NetBSD: xoshiro128starstar.c,v 1.1.2.2 2024/02/24 13:07:22 martin Exp $ */ /* * Copyright (C) Internet Systems Consortium, Inc. ("ISC") * * SPDX-License-Identifier: MPL-2.0 * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, you can obtain one at https://mozilla.org/MPL/2.0/. * * See the COPYRIGHT file distributed with this work for additional * information regarding copyright ownership. */ /* * Written in 2018 by David Blackman and Sebastiano Vigna (vigna@acm.org) * * To the extent possible under law, the author has dedicated all * copyright and related and neighboring rights to this software to the * public domain worldwide. This software is distributed without any * warranty. * * See . */ #include #include /* * This is xoshiro128** 1.0, our 32-bit all-purpose, rock-solid generator. * It has excellent (sub-ns) speed, a state size (128 bits) that is large * enough for mild parallelism, and it passes all tests we are aware of. * * For generating just single-precision (i.e., 32-bit) floating-point * numbers, xoshiro128+ is even faster. * * The state must be seeded so that it is not everywhere zero. */ ISC_THREAD_LOCAL uint32_t seed[4] = { 0 }; static uint32_t rotl(const uint32_t x, int k) { return ((x << k) | (x >> (32 - k))); } static uint32_t next(void) { uint32_t result_starstar, t; result_starstar = rotl(seed[0] * 5, 7) * 9; t = seed[1] << 9; seed[2] ^= seed[0]; seed[3] ^= seed[1]; seed[1] ^= seed[2]; seed[0] ^= seed[3]; seed[2] ^= t; seed[3] = rotl(seed[3], 11); return (result_starstar); }