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authorRĂ©mi Verschelde <rverschelde@gmail.com>2017-04-29 22:57:49 +0200
committerGitHub <noreply@github.com>2017-04-29 22:57:49 +0200
commitde7eba887e9fe940dac0958836fa8fb778628d2a (patch)
tree93b80fde60db3117b649190daa7918105a4d4e11 /thirdparty/misc/pcg.cpp
parentea9dd6c0c1997b2c6d8bba6caa1da965ef40804f (diff)
parentd4029aa51a0f0bce5dc73885af74b592e3aa33b7 (diff)
Merge pull request #8572 from akien-mga/thirdparty
Moving more thirdparty stuff (minizip, some single-file external libs) to the thirdparty directory
Diffstat (limited to 'thirdparty/misc/pcg.cpp')
-rw-r--r--thirdparty/misc/pcg.cpp15
1 files changed, 15 insertions, 0 deletions
diff --git a/thirdparty/misc/pcg.cpp b/thirdparty/misc/pcg.cpp
new file mode 100644
index 0000000000..eac3b36d36
--- /dev/null
+++ b/thirdparty/misc/pcg.cpp
@@ -0,0 +1,15 @@
+// *Really* minimal PCG32 code / (c) 2014 M.E. O'Neill / pcg-random.org
+// Licensed under Apache License 2.0 (NO WARRANTY, etc. see website)
+
+#include "pcg.h"
+
+uint32_t pcg32_random_r(pcg32_random_t* rng)
+{
+ uint64_t oldstate = rng->state;
+ // Advance internal state
+ rng->state = oldstate * 6364136223846793005ULL + (rng->inc|1);
+ // Calculate output function (XSH RR), uses old state for max ILP
+ uint32_t xorshifted = ((oldstate >> 18u) ^ oldstate) >> 27u;
+ uint32_t rot = oldstate >> 59u;
+ return (xorshifted >> rot) | (xorshifted << ((-rot) & 31));
+}