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Move random number generator from Math.random to jerry-libc, replace the logic with call to rand in Math.random.

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JerryScript-DCO-1.0-Signed-off-by: Ruben Ayrapetyan r.ayrapetyan@samsung.com
This commit is contained in:
Ruben Ayrapetyan
2015-06-15 22:08:24 +03:00
parent 30277153b9
commit 6d6c913bdc
3 changed files with 68 additions and 18 deletions
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jerry-core/ecma/builtin-objects/ecma-builtin-math.cpp
+17 -18
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@@ -25,8 +25,9 @@
#include "ecma-objects.h"
#include "ecma-objects-general.h"
#include "ecma-try-catch-macro.h"
#include "jrt.h"
#include "fdlibm-math.h"
#include "jrt.h"
#include "jrt-libc-includes.h"
#ifndef CONFIG_ECMA_COMPACT_PROFILE_DISABLE_MATH_BUILTIN
@@ -528,26 +529,24 @@ ecma_builtin_math_object_pow (ecma_value_t this_arg __attr_unused___, /**< 'this
static ecma_completion_value_t
ecma_builtin_math_object_random (ecma_value_t this_arg __attr_unused___) /**< 'this' argument */
{
/* Implementation of George Marsaglia's XorShift random number generator */
TODO (/* Check for license issues */);
uint32_t rnd = 1;
uint32_t reps_count;
#if RAND_MAX < 0x100
reps_count = 4;
#elif RAND_MAX < 0x10000
reps_count = 2;
#else /* RAND_MAX < 0x10000 */
reps_count = 1;
#endif /* RAND_MAX >= 0x10000 */
static uint32_t word1 = 1455997910;
static uint32_t word2 = 1999515274;
static uint32_t word3 = 1234451287;
static uint32_t word4 = 1949149569;
uint32_t intermediate = word1 ^ (word1 << 11);
intermediate ^= intermediate >> 8;
word1 = word2;
word2 = word3;
word3 = word4;
word4 ^= word4 >> 19;
word4 ^= intermediate;
for (uint32_t i = 0; i < reps_count; i++)
{
uint32_t next_rand = (uint32_t) rand ();
rnd *= next_rand;
}
const uint32_t max_uint32 = (uint32_t) -1;
ecma_number_t rand = (ecma_number_t) word4;
ecma_number_t rand = (ecma_number_t) rnd;
rand /= (ecma_number_t) max_uint32;
rand *= (ecma_number_t) (max_uint32 - 1) / (ecma_number_t) max_uint32;