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rand: switch to 'Numerical Recipes' constants and remove random8 to increase period

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Tomas Susanka 2018-12-18 11:56:25 +01:00
parent c5227fdb96
commit 54727e6650
1 changed files with 5 additions and 14 deletions
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19
rand.c
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@ -35,22 +35,13 @@
// You are supposed to replace the random8() and random32() function with your own secure code.
// There is also a possibility to replace the random_buffer() function as it is defined as a weak symbol.
static uint8_t random8(void)
{
// Linear congruential generator used in glibc
// https://en.wikipedia.org/wiki/Linear_congruential_generator
static int seed = 0;
seed = (1103515245 * seed + 12345) & 0x7FFFFFFF;
return seed & 0xFF;
}
uint32_t random32(void)
{
uint32_t r1 = random8();
uint32_t r2 = random8();
uint32_t r3 = random8();
uint32_t r4 = random8();
return ((r1 << 24) | (r2 << 16) | (r3 << 8) | r4);
// Linear congruential generator used in glibc
// https://en.wikipedia.org/wiki/Linear_congruential_generator
static uint32_t seed = 0;
seed = 1664525 * seed + 1013904223;
return seed;
}
#endif /* RAND_PLATFORM_INDEPENDENT */