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// *Really* minimal PCG32 code / (c) 2014 M.E. O'Neill / pcg-random.org
// Licensed under Apache License 2.0 (NO WARRANTY, etc. see website)
#include "pcg.h"
uint32_t pcg32_random_r(pcg32_random_t* rng)
{
uint64_t oldstate = rng->state;
// Advance internal state
rng->state = oldstate * 6364136223846793005ULL + (rng->inc|1);
// Calculate output function (XSH RR), uses old state for max ILP
uint32_t xorshifted = ((oldstate >> 18u) ^ oldstate) >> 27u;
uint32_t rot = oldstate >> 59u;
return (xorshifted >> rot) | (xorshifted << ((-rot) & 31));
}
// Source from http://www.pcg-random.org/downloads/pcg-c-basic-0.9.zip
void pcg32_srandom_r(pcg32_random_t* rng, uint64_t initstate, uint64_t initseq)
{
rng->state = 0U;
rng->inc = (initseq << 1u) | 1u;
pcg32_random_r(rng);
rng->state += initstate;
pcg32_random_r(rng);
}
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