bl00mbox: plugin stuff

components/bl00mbox/extern/xoroshiro64star.c

+/*  Written in 2016 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 xoroshiro64* 1.0, our best and fastest 32-bit small-state
+   generator for 32-bit floating-point numbers. We suggest to use its
+   upper bits for floating-point generation, as it is slightly faster than
+   xoroshiro64**. It passes all tests we are aware of except for linearity
+   tests, as the lowest six bits have low linear complexity, so if low
+   linear complexity is not considered an issue (as it is usually the
+   case) it can be used to generate 32-bit outputs, too.
+
+   We suggest to use a sign test to extract a random Boolean value, and
+   right shifts to extract subsets of bits.
+
+   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));
+}
+
+// mod1: state seed
+static uint32_t s[2] = {420, 69};
+
+//uint32_t next(void) {
+uint32_t xoroshiro64star(void) {
+    // mod2: changed name to avoid namespace collisions.
+	const uint32_t s0 = s[0];
+	uint32_t s1 = s[1];
+	const uint32_t result = s0 * 0x9E3779BB;
+
+	s1 ^= s0;
+	s[0] = rotl(s0, 26) ^ s1 ^ (s1 << 9); // a, b
+	s[1] = rotl(s1, 13); // c
+
+	return result;
+}
+