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Diffstat (limited to 'src/mersenne.cpp')
-rw-r--r-- | src/mersenne.cpp | 76 |
1 files changed, 0 insertions, 76 deletions
diff --git a/src/mersenne.cpp b/src/mersenne.cpp deleted file mode 100644 index 70a443149..000000000 --- a/src/mersenne.cpp +++ /dev/null @@ -1,76 +0,0 @@ -/* $Id$ */ - -/** @file mersenne.cpp */ - -#include "stdafx.h" -#include "openttd.h" - -#ifdef MERSENNE_TWISTER - -// Source code for Mersenne Twister. -// A Random number generator with much higher quality random numbers. - -#define N (624) // length of _mt_state vector -#define M (397) // a period parameter -#define K (0x9908B0DFU) // a magic constant -#define hiBit(u) ((u) & 0x80000000U) // mask all but highest bit of u -#define loBit(u) ((u) & 0x00000001U) // mask all but lowest bit of u -#define loBits(u) ((u) & 0x7FFFFFFFU) // mask the highest bit of u -#define mixBits(u, v) (hiBit(u)|loBits(v)) // move hi bit of u to hi bit of v - -static uint32 _mt_state[N+1]; // _mt_state vector + 1 extra to not violate ANSI C -static uint32 *_mt_next; // _mt_next random value is computed from here -static int _mt_left = -1; // can *_mt_next++ this many times before reloading - -void SeedMT(uint32 seed) -{ - register uint32 x = (seed | 1U) & 0xFFFFFFFFU, *s = _mt_state; - register int j; - - for (_mt_left=0, *s++=x, j=N; --j; - *s++ = (x*=69069U) & 0xFFFFFFFFU); - } - - -static uint32 ReloadMT() - { - register uint32 *p0=_mt_state, *p2=_mt_state+2, *pM=_mt_state+M, s0, s1; - register int j; - - if (_mt_left < -1) - SeedMT(4357U); - - _mt_left=N-1, _mt_next=_mt_state+1; - - for (s0=_mt_state[0], s1=_mt_state[1], j=N-M+1; --j; s0=s1, s1=*p2++) - *p0++ = *pM++ ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U); - - for (pM=_mt_state, j=M; --j; s0=s1, s1=*p2++) - *p0++ = *pM++ ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U); - - s1=_mt_state[0], *p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U); - s1 ^= (s1 >> 11); - s1 ^= (s1 << 7) & 0x9D2C5680U; - s1 ^= (s1 << 15) & 0xEFC60000U; - return(s1 ^ (s1 >> 18)); - } - - -uint32 RandomMT() -{ - uint32 y; - - if (--_mt_left < 0) - return ReloadMT(); - - y = *_mt_next++; - y ^= (y >> 11); - y ^= (y << 7) & 0x9D2C5680U; - y ^= (y << 15) & 0xEFC60000U; - return y ^ (y >> 18); -} -#else - -void SeedMT(uint32 seed) {} - -#endif /* MERSENNE_TWISTER */ |