2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright 2020 Conrad Meyer <cem@FreeBSD.org>. All rights reserved.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
31 #include <sys/param.h>
32 #include <sys/kernel.h>
36 #include <sys/systm.h>
38 #if !PCG_HAS_128BIT_OPS
39 /* On 32-bit platforms, gang together two 32-bit generators. */
41 pcg32u_random_t states[2];
45 pcg64u_srandom_r(pcg64u_random_t *state64, uint64_t seed)
47 pcg32u_srandom_r(&state64->states[0], seed);
48 pcg32u_srandom_r(&state64->states[1], seed);
51 static inline uint64_t
52 pcg64u_random_r(pcg64u_random_t *state64)
54 return ((((uint64_t)pcg32u_random_r(&state64->states[0])) << 32) |
55 pcg32u_random_r(&state64->states[1]));
58 static inline uint64_t
59 pcg64u_boundedrand_r(pcg64u_random_t *state64, uint64_t bound)
61 uint64_t threshold = -bound % bound;
63 uint64_t r = pcg64u_random_r(state64);
70 DPCPU_DEFINE_STATIC(pcg32u_random_t, pcpu_prng32_state);
71 DPCPU_DEFINE_STATIC(pcg64u_random_t, pcpu_prng64_state);
74 prng_init(void *dummy __unused)
76 pcg32u_random_t *state;
77 pcg64u_random_t *state64;
81 state = DPCPU_ID_PTR(i, pcpu_prng32_state);
82 pcg32u_srandom_r(state, 1);
83 state64 = DPCPU_ID_PTR(i, pcpu_prng64_state);
84 pcg64u_srandom_r(state64, 1);
87 SYSINIT(prng_init, SI_SUB_CPU, SI_ORDER_ANY, prng_init, NULL);
95 r = pcg32u_random_r(DPCPU_PTR(pcpu_prng32_state));
101 prng32_bounded(uint32_t bound)
106 r = pcg32u_boundedrand_r(DPCPU_PTR(pcpu_prng32_state), bound);
117 r = pcg64u_random_r(DPCPU_PTR(pcpu_prng64_state));
123 prng64_bounded(uint64_t bound)
128 r = pcg64u_boundedrand_r(DPCPU_PTR(pcpu_prng64_state), bound);