23 lines
741 B
C
23 lines
741 B
C
// *Really* minimal PCG32 code / (c) 2014 M.E. O'Neill / pcg-random.org
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// Licensed under Apache License 2.0 (NO WARRANTY, etc. see website)
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#pragma once
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#include <stdint.h>
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typedef struct { uint64_t state; uint64_t inc; } pcg32_random_t;
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uint32_t pcg32_random_r(pcg32_random_t* rng);
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#if defined(PCG_IMPLEMENT)
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uint32_t pcg32_random_r(pcg32_random_t* rng)
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{
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uint64_t oldstate = rng->state;
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// Advance internal state
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rng->state = oldstate * 6364136223846793005ULL + (rng->inc|1);
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// Calculate output function (XSH RR), uses old state for max ILP
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uint32_t xorshifted = ((oldstate >> 18u) ^ oldstate) >> 27u;
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uint32_t rot = oldstate >> 59u;
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return (xorshifted >> rot) | (xorshifted << ((-rot) & 31));
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}
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#endif
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