Skip to content

C
capnproto
Commit 8e4943b4 authored by Kenton Varda's avatar Kenton Varda
Browse files
Options

Merge pull request #104 from dwrensha/xorshift 

switch from linear congruential to Xorshift generator
parents 7b6ef1d5 dcf4b945
Hide whitespace changes
Inline Side-by-side
Showing with 13 additions and 5 deletions
c++/src/capnp/benchmark/common.h
View file @ 8e4943b4
...@@ -41,12 +41,20 @@ ...@@ -41,12 +41,20 @@
namespace capnp { namespace capnp {
namespace benchmark { namespace benchmark {
// Use a 128-bit Xorshift algorithm.
static inline uint32_t nextFastRand() { static inline uint32_t nextFastRand() {
static constexpr uint32_t A = 1664525; // These values are arbitrary. Any seed other than all zeroes is OK.
static constexpr uint32_t C = 1013904223; static uint32_t x = 0x1d2acd47;
static uint32_t state = C; static uint32_t y = 0x58ca3e14;
state = A * state + C; static uint32_t z = 0xf563f232;
return state; static uint32_t w = 0x0bc76199;
uint32_t tmp = x ^ (x << 11);
x = y;
y = z;
z = w;
w = w ^ (w >> 19) ^ tmp ^ (tmp >> 8);
return w;
} }
static inline uint32_t fastRand(uint32_t range) { static inline uint32_t fastRand(uint32_t range) {
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment