37 lines
950 B
C
37 lines
950 B
C
// Copyright 2013-2018 Nicholas J. Kain <njkain at gmail dot com>
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// SPDX-License-Identifier: MIT
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#include <stdint.h>
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#include "nk/hwrng.h"
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#include "nk/random.h"
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// GJrand64: https://gjrand.sourceforge.net
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void nk_random_init(struct nk_random_state *s)
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{
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nk_get_hwrng(s->seed, sizeof(uint64_t) * 2);
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s->seed[2] = 2000001;
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s->seed[3] = 0;
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for (size_t i = 0; i < 14; ++i) nk_random_u64(s);
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}
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static inline uint64_t rotl64(const uint64_t x, int k) {
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return (x << k) | (x >> (64 - k));
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}
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uint64_t nk_random_u64(struct nk_random_state *s)
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{
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s->seed[1] += s->seed[2];
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s->seed[0] = rotl64(s->seed[0], 32);
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s->seed[2] ^= s->seed[1];
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s->seed[3] += 0x55aa96a5;
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s->seed[0] += s->seed[1];
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s->seed[2] = rotl64(s->seed[2], 23);
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s->seed[1] ^= s->seed[0];
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s->seed[0] += s->seed[2];
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s->seed[1] = rotl64(s->seed[1], 19);
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s->seed[2] += s->seed[0];
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s->seed[1] += s->seed[3];
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return s->seed[0];
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}
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