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Code Issues 1 Releases Wiki Activity

Switch back to well tested RNG.

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Calvin Rose
2019-11-21 23:22:21 -06:00
parent 02fc4ae27b
commit 4b24d77b2c
1 changed files with 3 additions and 2 deletions
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5
src/core/math.c
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@@ -83,12 +83,13 @@ void janet_rng_longseed(JanetRNG *rng, const uint8_t *bytes, int32_t len) {
rng->c = state[8] + (state[9] << 8) + (state[10] << 16) + (state[11] << 24);
rng->d = state[12] + (state[13] << 8) + (state[14] << 16) + (state[15] << 24);
rng->counter = 0u;
/* a, b, c, d can't all be 0 */
if (rng->a == 0) rng->a = 1;
for (int i = 0; i < 16; i++) janet_rng_u32(rng);
}
uint32_t janet_rng_u32(JanetRNG *rng) {
/* Algorithm "xorwow" from p. 5 of Marsaglia, "Xorshift RNGs" */
/* Modified to remove constraint that a, b, c, d != 0 */
uint32_t t = rng->d;
uint32_t const s = rng->a;
rng->d = rng->c;
@@ -97,7 +98,7 @@ uint32_t janet_rng_u32(JanetRNG *rng) {
t ^= t >> 2;
t ^= t << 1;
t ^= s ^ (s << 4);
rng->a = t + 33;
rng->a = t;
rng->counter += 362437;
return t + rng->counter;
}