1*c54f35caSApple OSS Distributions /*-
2*c54f35caSApple OSS Distributions * Copyright (c) 2016 (Graeme Jenkinson)
3*c54f35caSApple OSS Distributions * All rights reserved.
4*c54f35caSApple OSS Distributions *
5*c54f35caSApple OSS Distributions * This software was developed by BAE Systems, the University of Cambridge
6*c54f35caSApple OSS Distributions * Computer Laboratory, and Memorial University under DARPA/AFRL contract
7*c54f35caSApple OSS Distributions * FA8650-15-C-7558 ("CADETS"), as part of the DARPA Transparent Computing
8*c54f35caSApple OSS Distributions * (TC) research program.
9*c54f35caSApple OSS Distributions *
10*c54f35caSApple OSS Distributions * Redistribution and use in source and binary forms, with or without
11*c54f35caSApple OSS Distributions * modification, are permitted provided that the following conditions
12*c54f35caSApple OSS Distributions * are met:
13*c54f35caSApple OSS Distributions * 1. Redistributions of source code must retain the above copyright
14*c54f35caSApple OSS Distributions * notice, this list of conditions and the following disclaimer.
15*c54f35caSApple OSS Distributions * 2. Redistributions in binary form must reproduce the above copyright
16*c54f35caSApple OSS Distributions * notice, this list of conditions and the following disclaimer in the
17*c54f35caSApple OSS Distributions * documentation and/or other materials provided with the distribution.
18*c54f35caSApple OSS Distributions *
19*c54f35caSApple OSS Distributions * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20*c54f35caSApple OSS Distributions * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21*c54f35caSApple OSS Distributions * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22*c54f35caSApple OSS Distributions * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23*c54f35caSApple OSS Distributions * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24*c54f35caSApple OSS Distributions * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25*c54f35caSApple OSS Distributions * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26*c54f35caSApple OSS Distributions * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27*c54f35caSApple OSS Distributions * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28*c54f35caSApple OSS Distributions * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29*c54f35caSApple OSS Distributions * SUCH DAMAGE.
30*c54f35caSApple OSS Distributions *
31*c54f35caSApple OSS Distributions */
32*c54f35caSApple OSS Distributions
33*c54f35caSApple OSS Distributions #include <sys/types.h>
34*c54f35caSApple OSS Distributions
35*c54f35caSApple OSS Distributions #include "dtrace_xoroshiro128_plus.h"
36*c54f35caSApple OSS Distributions
37*c54f35caSApple OSS Distributions static __inline uint64_t
rotl(const uint64_t x,int k)38*c54f35caSApple OSS Distributions rotl(const uint64_t x, int k)
39*c54f35caSApple OSS Distributions {
40*c54f35caSApple OSS Distributions return (x << k) | (x >> (64 - k));
41*c54f35caSApple OSS Distributions }
42*c54f35caSApple OSS Distributions
43*c54f35caSApple OSS Distributions /*
44*c54f35caSApple OSS Distributions * This is the jump function for the generator. It is equivalent to 2^64 calls
45*c54f35caSApple OSS Distributions * to next(); it can be used to generate 2^64 non-overlapping subsequences for
46*c54f35caSApple OSS Distributions * parallel computations.
47*c54f35caSApple OSS Distributions */
48*c54f35caSApple OSS Distributions void
dtrace_xoroshiro128_plus_jump(uint64_t * const state,uint64_t * const jump_state)49*c54f35caSApple OSS Distributions dtrace_xoroshiro128_plus_jump(uint64_t * const state,
50*c54f35caSApple OSS Distributions uint64_t * const jump_state)
51*c54f35caSApple OSS Distributions {
52*c54f35caSApple OSS Distributions static const uint64_t JUMP[] = { 0xbeac0467eba5facb,
53*c54f35caSApple OSS Distributions 0xd86b048b86aa9922 };
54*c54f35caSApple OSS Distributions
55*c54f35caSApple OSS Distributions uint64_t s0 = 0;
56*c54f35caSApple OSS Distributions uint64_t s1 = 0;
57*c54f35caSApple OSS Distributions size_t i = 0;
58*c54f35caSApple OSS Distributions int b = 0;
59*c54f35caSApple OSS Distributions for (i = 0; i < sizeof JUMP / sizeof *JUMP; i++) {
60*c54f35caSApple OSS Distributions for (b = 0; b < 64; b++) {
61*c54f35caSApple OSS Distributions if (JUMP[i] & 1ULL << b) {
62*c54f35caSApple OSS Distributions s0 ^= state[0];
63*c54f35caSApple OSS Distributions s1 ^= state[1];
64*c54f35caSApple OSS Distributions }
65*c54f35caSApple OSS Distributions dtrace_xoroshiro128_plus_next(state);
66*c54f35caSApple OSS Distributions }
67*c54f35caSApple OSS Distributions }
68*c54f35caSApple OSS Distributions jump_state[0] = s0;
69*c54f35caSApple OSS Distributions jump_state[1] = s1;
70*c54f35caSApple OSS Distributions }
71*c54f35caSApple OSS Distributions
72*c54f35caSApple OSS Distributions /*
73*c54f35caSApple OSS Distributions * xoroshiro128+ - XOR/rotate/shift/rotate
74*c54f35caSApple OSS Distributions * xorshift.di.unimi.it
75*c54f35caSApple OSS Distributions */
76*c54f35caSApple OSS Distributions uint64_t
dtrace_xoroshiro128_plus_next(uint64_t * const state)77*c54f35caSApple OSS Distributions dtrace_xoroshiro128_plus_next(uint64_t * const state)
78*c54f35caSApple OSS Distributions {
79*c54f35caSApple OSS Distributions const uint64_t s0 = state[0];
80*c54f35caSApple OSS Distributions uint64_t s1 = state[1];
81*c54f35caSApple OSS Distributions uint64_t result;
82*c54f35caSApple OSS Distributions result = s0 + s1;
83*c54f35caSApple OSS Distributions
84*c54f35caSApple OSS Distributions s1 ^= s0;
85*c54f35caSApple OSS Distributions state[0] = rotl(s0, 55) ^ s1 ^ (s1 << 14);
86*c54f35caSApple OSS Distributions state[1] = rotl(s1, 36);
87*c54f35caSApple OSS Distributions
88*c54f35caSApple OSS Distributions return result;
89*c54f35caSApple OSS Distributions }
90