src/core/random_func.cpp
changeset 9288 bf11c6775f84
parent 8973 25542dd165b2
child 10429 1b99254f9607
equal deleted inserted replaced
9287:2e497ff0d009 9288:bf11c6775f84
    26 {
    26 {
    27 	this->state[0] = seed;
    27 	this->state[0] = seed;
    28 	this->state[1] = seed;
    28 	this->state[1] = seed;
    29 }
    29 }
    30 
    30 
    31 #ifdef MERSENNE_TWISTER
       
    32 // Source code for Mersenne Twister.
       
    33 // A Random number generator with much higher quality random numbers.
       
    34 
       
    35 #define N              (624)                 // length of _mt_state vector
       
    36 #define M              (397)                 // a period parameter
       
    37 #define K              (0x9908B0DFU)         // a magic constant
       
    38 #define hiBit(u)       ((u) & 0x80000000U)   // mask all but highest   bit of u
       
    39 #define loBit(u)       ((u) & 0x00000001U)   // mask all but lowest    bit of u
       
    40 #define loBits(u)      ((u) & 0x7FFFFFFFU)   // mask     the highest   bit of u
       
    41 #define mixBits(u, v)  (hiBit(u)|loBits(v))  // move hi bit of u to hi bit of v
       
    42 
       
    43 static uint32 _mt_state[N+1];     // _mt_state vector + 1 extra to not violate ANSI C
       
    44 static uint32 *_mt_next;          // _mt_next random value is computed from here
       
    45 static int    _mt_left = -1;      // can *_mt_next++ this many times before reloading
       
    46 
       
    47 void SetRandomSeed(register uint32 seed)
       
    48 {
       
    49 	register uint32 *s = _mt_state;
       
    50 	_mt_left = 0;
       
    51 
       
    52 	seed |= 1U;
       
    53 	seed &= 0xFFFFFFFFU;
       
    54 
       
    55 	*s = seed;
       
    56 
       
    57 	for (register uint i = N; i != 0; i--) {
       
    58 		seed *= 69069U;
       
    59 		*s++;
       
    60 		*s = seed & 0xFFFFFFFFU;
       
    61 	}
       
    62 }
       
    63 
       
    64 static uint32 ReloadRandom()
       
    65 {
       
    66 	if (_mt_left < -1) SetRandomSeed(4357U);
       
    67 
       
    68 	_mt_left = N - 1;
       
    69 	_mt_next = _mt_state + 1;
       
    70 
       
    71 	register uint32 *p0 = _mt_state;
       
    72 	register uint32 *p2 = _mt_state + 2;
       
    73 	register uint32 *pM = _mt_state + M;
       
    74 
       
    75 	register uint32 s0 = _mt_state[0];
       
    76 	register uint32 s1 = _mt_state[1];
       
    77 
       
    78 	register uint i = 0;
       
    79 
       
    80 	for (i = (N - M + 1); i != 0; i--) {
       
    81 		s0 = s1;
       
    82 		s1 = *p2;
       
    83 		*p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);
       
    84 		*p0++;
       
    85 		*p2++;
       
    86 		*pM++;
       
    87 	}
       
    88 
       
    89 	pM = _mt_state;
       
    90 
       
    91 	for (i = M; i != 0; i--) {
       
    92 		s0 = s1;
       
    93 		s1 = *p2;
       
    94 		*p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);
       
    95 		*p0++;
       
    96 		*p2++;
       
    97 		*pM++;
       
    98 	}
       
    99 
       
   100 	s1 = _mt_state[0];
       
   101 	*p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);
       
   102 
       
   103 	s1 ^= (s1 >> 11);
       
   104 	s1 ^= (s1 <<  7) & 0x9D2C5680U;
       
   105 	s1 ^= (s1 << 15) & 0xEFC60000U;
       
   106 	s1 ^= (s1 >> 18);
       
   107 	return s1;
       
   108 }
       
   109 
       
   110 uint32 Random()
       
   111 {
       
   112 	_mt_left--;
       
   113 	if (_mt_left < 0) return ReloadRandom();
       
   114 
       
   115 	uint32 y = *_mt_next;
       
   116 	*_mt_next++;
       
   117 
       
   118 	y ^= (y >> 11);
       
   119 	y ^= (y <<  7) & 0x9D2C5680U;
       
   120 	y ^= (y << 15) & 0xEFC60000U;
       
   121 	y ^= (y >> 18);
       
   122 	return y;
       
   123 }
       
   124 
       
   125 #else /* MERSENNE_TWISTER */
       
   126 void SetRandomSeed(uint32 seed)
    31 void SetRandomSeed(uint32 seed)
   127 {
    32 {
   128 	_random.SetSeed(seed);
    33 	_random.SetSeed(seed);
   129 	_interactive_random.SetSeed(seed * 0x1234567);
    34 	_interactive_random.SetSeed(seed * 0x1234567);
   130 }
    35 }
   140 		printf("Random [%d/%d] %s:%d\n",_frame_counter, (byte)_current_player, file, line);
    45 		printf("Random [%d/%d] %s:%d\n",_frame_counter, (byte)_current_player, file, line);
   141 	}
    46 	}
   142 
    47 
   143 	return _random.Next();
    48 	return _random.Next();
   144 }
    49 }
   145 #endif /* RANDOM_DEBUG */
       
   146 #endif /* MERSENNE_TWISTER */
       
   147 
    50 
   148 #if defined(RANDOM_DEBUG) && !defined(MERSENNE_TWISTER)
       
   149 uint DoRandomRange(uint max, int line, const char *file)
    51 uint DoRandomRange(uint max, int line, const char *file)
   150 {
    52 {
   151 	return GB(DoRandom(line, file), 0, 16) * max >> 16;
    53 	return GB(DoRandom(line, file), 0, 16) * max >> 16;
   152 }
    54 }
   153 #endif /* RANDOM_DEBUG & !MERSENNE_TWISTER */
    55 #endif /* RANDOM_DEBUG */