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Use xoshiro128++ instead of xorshift96/128.

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This commit is contained in:
Yukihiro "Matz" Matsumoto
2020-08-17 11:04:43 +09:00
parent 0b22bf4a89
commit 44a07393f4
1 changed files with 41 additions and 47 deletions
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mrbgems/mruby-random/src/random.c
+41 -47
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@@ -10,18 +10,37 @@
#include <mruby/data.h>
#include <mruby/array.h>
#include <mruby/istruct.h>
#if INT32_MAX <= INTPTR_MAX
# define XORSHIFT96
# define NSEEDS 3
#else
# define NSEEDS 4
#endif
#define LASTSEED (NSEEDS-1)
#include <time.h>
/* Written in 2019 by David Blackman and Sebastiano Vigna (vigna@acm.org)
To the extent possible under law, the author has dedicated all copyright
and related and neighboring rights to this software to the public domain
worldwide. This software is distributed without any warranty.
See <http://creativecommons.org/publicdomain/zero/1.0/>. */
#include <stdint.h>
/* This is xoshiro128++ 1.0, one of our 32-bit all-purpose, rock-solid
generators. It has excellent speed, a state size (128 bits) that is
large enough for mild parallelism, and it passes all tests we are aware
of.
For generating just single-precision (i.e., 32-bit) floating-point
numbers, xoshiro128+ is even faster.
The state must be seeded so that it is not everywhere zero. */
static inline uint32_t
rotl(const uint32_t x, int k) {
return (x << k) | (x >> (32 - k));
}
typedef struct rand_state {
uint32_t seed[NSEEDS];
uint32_t seed[4];
} rand_state;
static void
@@ -30,60 +49,35 @@ rand_init(rand_state *t)
t->seed[0] = 123456789;
t->seed[1] = 362436069;
t->seed[2] = 521288629;
#ifndef XORSHIFT96
t->seed[3] = 88675123;
#endif
}
static uint32_t
rand_seed(rand_state *t, uint32_t seed)
{
uint32_t old_seed = t->seed[LASTSEED];
uint32_t old_seed = t->seed[0];
rand_init(t);
t->seed[LASTSEED] = seed;
t->seed[0] = seed;
return old_seed;
}
#ifdef XORSHIFT96
static uint32_t
rand_uint32(rand_state *state)
{
uint32_t *seed = state->seed;
uint32_t x = seed[0];
uint32_t y = seed[1];
uint32_t z = seed[2];
uint32_t t;
uint32_t *s = state->seed;
const uint32_t result = rotl(s[0] + s[3], 7) + s[0];
const uint32_t t = s[1] << 9;
t = (x ^ (x << 3)) ^ (y ^ (y >> 19)) ^ (z ^ (z << 6));
x = y; y = z; z = t;
seed[0] = x;
seed[1] = y;
seed[2] = z;
s[2] ^= s[0];
s[3] ^= s[1];
s[1] ^= s[2];
s[0] ^= s[3];
return z;
s[2] ^= t;
s[3] = rotl(s[3], 11);
return result;
}
#else /* XORSHIFT96 */
static uint32_t
rand_uint32(rand_state *state)
{
uint32_t *seed = state->seed;
uint32_t x = seed[0];
uint32_t y = seed[1];
uint32_t z = seed[2];
uint32_t w = seed[3];
uint32_t t;
t = x ^ (x << 11);
x = y; y = z; z = w;
w = (w ^ (w >> 19)) ^ (t ^ (t >> 8));
seed[0] = x;
seed[1] = y;
seed[2] = z;
seed[3] = w;
return w;
}
#endif /* XORSHIFT96 */
#ifndef MRB_NO_FLOAT
static double
@@ -385,7 +379,7 @@ void mrb_mruby_random_gem_init(mrb_state *mrb)
struct RClass *random;
struct RClass *array = mrb->array_class;
mrb_assert(sizeof(rand_state) <= ISTRUCT_DATA_SIZE);
mrb_static_assert1(sizeof(rand_state) <= ISTRUCT_DATA_SIZE);
mrb_define_method(mrb, mrb->kernel_module, "rand", random_f_rand, MRB_ARGS_OPT(1));
mrb_define_method(mrb, mrb->kernel_module, "srand", random_f_srand, MRB_ARGS_OPT(1));