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Update mruby-random gem to support 32 bit platforms.

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`sizeof(rand_state)` had been bigger than `sizeof(void*)*3`. Changed
random number generator to `Xorshift96` on 32 bit platforms.
This commit is contained in:
Yukihiro "Matz" Matsumoto
2020-08-26 23:00:31 +09:00
parent 2b188ed8a1
commit 3e71359d7a
1 changed files with 38 additions and 8 deletions
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mrbgems/mruby-random/src/random.c
+38 -8
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@@ -34,13 +34,18 @@ See <http://creativecommons.org/publicdomain/zero/1.0/>. */
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));
}
#ifdef MRB_32BIT
# define XORSHIFT96
# define NSEEDS 3
# define SEEDPOS 2
#else
# define NSEEDS 4
# define SEEDPOS 0
#endif
#define LASTSEED (NSEEDS-1)
typedef struct rand_state {
uint32_t seed[4];
uint32_t seed[NSEEDS];
} rand_state;
static void
@@ -49,21 +54,45 @@ 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[0];
uint32_t old_seed = t->seed[SEEDPOS];
rand_init(t);
t->seed[0] = seed;
t->seed[SEEDPOS] = seed;
return old_seed;
}
#ifndef XORSHIFT96
static inline uint32_t
rotl(const uint32_t x, int k) {
return (x << k) | (x >> (32 - k));
}
#endif
static uint32_t
rand_uint32(rand_state *state)
{
#ifdef XORSHIFT96
uint32_t *seed = state->seed;
uint32_t x = seed[0];
uint32_t y = seed[1];
uint32_t z = seed[2];
uint32_t t;
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;
return z;
#else
uint32_t *s = state->seed;
const uint32_t result = rotl(s[0] + s[3], 7) + s[0];
const uint32_t t = s[1] << 9;
@@ -77,7 +106,8 @@ rand_uint32(rand_state *state)
s[3] = rotl(s[3], 11);
return result;
}
#endif /* XORSHIFT96 */
}
#ifndef MRB_NO_FLOAT
static double