1*1031c584SApple OSS Distributions /*-
2*1031c584SApple OSS Distributions * Copyright (c) 2016 (Graeme Jenkinson)
3*1031c584SApple OSS Distributions * All rights reserved.
4*1031c584SApple OSS Distributions *
5*1031c584SApple OSS Distributions * This software was developed by BAE Systems, the University of Cambridge
6*1031c584SApple OSS Distributions * Computer Laboratory, and Memorial University under DARPA/AFRL contract
7*1031c584SApple OSS Distributions * FA8650-15-C-7558 ("CADETS"), as part of the DARPA Transparent Computing
8*1031c584SApple OSS Distributions * (TC) research program.
9*1031c584SApple OSS Distributions *
10*1031c584SApple OSS Distributions * Redistribution and use in source and binary forms, with or without
11*1031c584SApple OSS Distributions * modification, are permitted provided that the following conditions
12*1031c584SApple OSS Distributions * are met:
13*1031c584SApple OSS Distributions * 1. Redistributions of source code must retain the above copyright
14*1031c584SApple OSS Distributions * notice, this list of conditions and the following disclaimer.
15*1031c584SApple OSS Distributions * 2. Redistributions in binary form must reproduce the above copyright
16*1031c584SApple OSS Distributions * notice, this list of conditions and the following disclaimer in the
17*1031c584SApple OSS Distributions * documentation and/or other materials provided with the distribution.
18*1031c584SApple OSS Distributions *
19*1031c584SApple OSS Distributions * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20*1031c584SApple OSS Distributions * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21*1031c584SApple OSS Distributions * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22*1031c584SApple OSS Distributions * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23*1031c584SApple OSS Distributions * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24*1031c584SApple OSS Distributions * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25*1031c584SApple OSS Distributions * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26*1031c584SApple OSS Distributions * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27*1031c584SApple OSS Distributions * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28*1031c584SApple OSS Distributions * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29*1031c584SApple OSS Distributions * SUCH DAMAGE.
30*1031c584SApple OSS Distributions *
31*1031c584SApple OSS Distributions */
32*1031c584SApple OSS Distributions
33*1031c584SApple OSS Distributions #include <sys/types.h>
34*1031c584SApple OSS Distributions
35*1031c584SApple OSS Distributions #include "dtrace_xoroshiro128_plus.h"
36*1031c584SApple OSS Distributions
37*1031c584SApple OSS Distributions static __inline uint64_t
rotl(const uint64_t x,int k)38*1031c584SApple OSS Distributions rotl(const uint64_t x, int k)
39*1031c584SApple OSS Distributions {
40*1031c584SApple OSS Distributions return (x << k) | (x >> (64 - k));
41*1031c584SApple OSS Distributions }
42*1031c584SApple OSS Distributions
43*1031c584SApple OSS Distributions /*
44*1031c584SApple OSS Distributions * This is the jump function for the generator. It is equivalent to 2^64 calls
45*1031c584SApple OSS Distributions * to next(); it can be used to generate 2^64 non-overlapping subsequences for
46*1031c584SApple OSS Distributions * parallel computations.
47*1031c584SApple OSS Distributions */
48*1031c584SApple OSS Distributions void
dtrace_xoroshiro128_plus_jump(uint64_t * const state,uint64_t * const jump_state)49*1031c584SApple OSS Distributions dtrace_xoroshiro128_plus_jump(uint64_t * const state,
50*1031c584SApple OSS Distributions uint64_t * const jump_state)
51*1031c584SApple OSS Distributions {
52*1031c584SApple OSS Distributions static const uint64_t JUMP[] = { 0xbeac0467eba5facb,
53*1031c584SApple OSS Distributions 0xd86b048b86aa9922 };
54*1031c584SApple OSS Distributions
55*1031c584SApple OSS Distributions uint64_t s0 = 0;
56*1031c584SApple OSS Distributions uint64_t s1 = 0;
57*1031c584SApple OSS Distributions size_t i = 0;
58*1031c584SApple OSS Distributions int b = 0;
59*1031c584SApple OSS Distributions for (i = 0; i < sizeof JUMP / sizeof *JUMP; i++) {
60*1031c584SApple OSS Distributions for (b = 0; b < 64; b++) {
61*1031c584SApple OSS Distributions if (JUMP[i] & 1ULL << b) {
62*1031c584SApple OSS Distributions s0 ^= state[0];
63*1031c584SApple OSS Distributions s1 ^= state[1];
64*1031c584SApple OSS Distributions }
65*1031c584SApple OSS Distributions dtrace_xoroshiro128_plus_next(state);
66*1031c584SApple OSS Distributions }
67*1031c584SApple OSS Distributions }
68*1031c584SApple OSS Distributions jump_state[0] = s0;
69*1031c584SApple OSS Distributions jump_state[1] = s1;
70*1031c584SApple OSS Distributions }
71*1031c584SApple OSS Distributions
72*1031c584SApple OSS Distributions /*
73*1031c584SApple OSS Distributions * xoroshiro128+ - XOR/rotate/shift/rotate
74*1031c584SApple OSS Distributions * xorshift.di.unimi.it
75*1031c584SApple OSS Distributions */
76*1031c584SApple OSS Distributions uint64_t
dtrace_xoroshiro128_plus_next(uint64_t * const state)77*1031c584SApple OSS Distributions dtrace_xoroshiro128_plus_next(uint64_t * const state)
78*1031c584SApple OSS Distributions {
79*1031c584SApple OSS Distributions const uint64_t s0 = state[0];
80*1031c584SApple OSS Distributions uint64_t s1 = state[1];
81*1031c584SApple OSS Distributions uint64_t result;
82*1031c584SApple OSS Distributions result = s0 + s1;
83*1031c584SApple OSS Distributions
84*1031c584SApple OSS Distributions s1 ^= s0;
85*1031c584SApple OSS Distributions state[0] = rotl(s0, 55) ^ s1 ^ (s1 << 14);
86*1031c584SApple OSS Distributions state[1] = rotl(s1, 36);
87*1031c584SApple OSS Distributions
88*1031c584SApple OSS Distributions return result;
89*1031c584SApple OSS Distributions }
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