skidd13@8431: /* $Id$ */
skidd13@8431: 
skidd13@8431: /** @file random_func.cpp */
skidd13@8431: 
skidd13@8431: #include "../stdafx.h"
skidd13@8431: #include "random_func.hpp"
rubidium@8609: #include "bitmath_func.hpp"
skidd13@8431: 
rubidium@8930: Randomizer _random, _interactive_random;
rubidium@8638: 
rubidium@8930: uint32 Randomizer::Next()
skidd13@8431: {
rubidium@8930: 	const uint32 s = this->state[0];
rubidium@8930: 	const uint32 t = this->state[1];
skidd13@8431: 
rubidium@8930: 	this->state[0] = s + ROR(t ^ 0x1234567F, 7) + 1;
rubidium@8930: 	return this->state[1] = ROR(s, 3) - 1;
skidd13@8431: }
skidd13@8431: 
rubidium@8930: uint32 Randomizer::Next(uint16 max)
skidd13@8431: {
rubidium@8930: 	return GB(this->Next(), 0, 16) * max >> 16;
rubidium@8930: }
rubidium@8930: 
rubidium@8930: void Randomizer::SetSeed(uint32 seed)
rubidium@8930: {
rubidium@8930: 	this->state[0] = seed;
rubidium@8930: 	this->state[1] = seed;
skidd13@8431: }
skidd13@8431: 
skidd13@8431: #ifdef MERSENNE_TWISTER
skidd13@8431: // Source code for Mersenne Twister.
skidd13@8431: // A Random number generator with much higher quality random numbers.
skidd13@8431: 
skidd13@8431: #define N              (624)                 // length of _mt_state vector
skidd13@8431: #define M              (397)                 // a period parameter
skidd13@8431: #define K              (0x9908B0DFU)         // a magic constant
skidd13@8431: #define hiBit(u)       ((u) & 0x80000000U)   // mask all but highest   bit of u
skidd13@8431: #define loBit(u)       ((u) & 0x00000001U)   // mask all but lowest    bit of u
skidd13@8431: #define loBits(u)      ((u) & 0x7FFFFFFFU)   // mask     the highest   bit of u
skidd13@8431: #define mixBits(u, v)  (hiBit(u)|loBits(v))  // move hi bit of u to hi bit of v
skidd13@8431: 
skidd13@8431: static uint32 _mt_state[N+1];     // _mt_state vector + 1 extra to not violate ANSI C
skidd13@8431: static uint32 *_mt_next;          // _mt_next random value is computed from here
skidd13@8431: static int    _mt_left = -1;      // can *_mt_next++ this many times before reloading
skidd13@8431: 
skidd13@8431: void SetRandomSeed(register uint32 seed)
skidd13@8431: {
skidd13@8431: 	register uint32 *s = _mt_state;
skidd13@8431: 	_mt_left = 0;
skidd13@8431: 
skidd13@8431: 	seed |= 1U;
skidd13@8431: 	seed &= 0xFFFFFFFFU;
skidd13@8431: 
skidd13@8431: 	*s = seed;
skidd13@8431: 
skidd13@8431: 	for (register uint i = N; i != 0; i--) {
skidd13@8431: 		seed *= 69069U;
skidd13@8431: 		*s++;
skidd13@8431: 		*s = seed & 0xFFFFFFFFU;
skidd13@8431: 	}
skidd13@8431: }
skidd13@8431: 
skidd13@8431: static uint32 ReloadRandom()
skidd13@8431: {
skidd13@8431: 	if (_mt_left < -1) SetRandomSeed(4357U);
skidd13@8431: 
skidd13@8431: 	_mt_left = N - 1;
skidd13@8431: 	_mt_next = _mt_state + 1;
skidd13@8431: 
skidd13@8431: 	register uint32 *p0 = _mt_state;
skidd13@8431: 	register uint32 *p2 = _mt_state + 2;
skidd13@8431: 	register uint32 *pM = _mt_state + M;
skidd13@8431: 
skidd13@8431: 	register uint32 s0 = _mt_state[0];
skidd13@8431: 	register uint32 s1 = _mt_state[1];
skidd13@8431: 
skidd13@8431: 	register uint i = 0;
skidd13@8431: 
skidd13@8431: 	for (i = (N - M + 1); i != 0; i--) {
skidd13@8431: 		s0 = s1;
skidd13@8431: 		s1 = *p2;
skidd13@8431: 		*p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);
skidd13@8431: 		*p0++;
skidd13@8431: 		*p2++;
skidd13@8431: 		*pM++;
skidd13@8431: 	}
skidd13@8431: 
skidd13@8431: 	pM = _mt_state;
skidd13@8431: 
skidd13@8431: 	for (i = M; i != 0; i--) {
skidd13@8431: 		s0 = s1;
skidd13@8431: 		s1 = *p2;
skidd13@8431: 		*p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);
skidd13@8431: 		*p0++;
skidd13@8431: 		*p2++;
skidd13@8431: 		*pM++;
skidd13@8431: 	}
skidd13@8431: 
skidd13@8431: 	s1 = _mt_state[0];
skidd13@8431: 	*p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);
skidd13@8431: 
skidd13@8431: 	s1 ^= (s1 >> 11);
skidd13@8431: 	s1 ^= (s1 <<  7) & 0x9D2C5680U;
skidd13@8431: 	s1 ^= (s1 << 15) & 0xEFC60000U;
skidd13@8431: 	s1 ^= (s1 >> 18);
skidd13@8431: 	return s1;
skidd13@8431: }
skidd13@8431: 
skidd13@8431: uint32 Random()
skidd13@8431: {
skidd13@8431: 	_mt_left--;
skidd13@8431: 	if (_mt_left < 0) return ReloadRandom();
skidd13@8431: 
skidd13@8431: 	uint32 y = *_mt_next;
skidd13@8431: 	*_mt_next++;
skidd13@8431: 
skidd13@8431: 	y ^= (y >> 11);
skidd13@8431: 	y ^= (y <<  7) & 0x9D2C5680U;
skidd13@8431: 	y ^= (y << 15) & 0xEFC60000U;
skidd13@8431: 	y ^= (y >> 18);
skidd13@8431: 	return y;
skidd13@8431: }
skidd13@8431: 
skidd13@8431: #else /* MERSENNE_TWISTER */
skidd13@8431: void SetRandomSeed(uint32 seed)
skidd13@8431: {
rubidium@8930: 	_random.SetSeed(seed);
rubidium@8930: 	_interactive_random.SetSeed(seed * 0x1234567);
skidd13@8431: }
skidd13@8431: 
skidd13@8431: #ifdef RANDOM_DEBUG
rubidium@8575: #include "../network/network_data.h"
skidd13@8431: uint32 DoRandom(int line, const char *file)
skidd13@8431: {
rubidium@8930: 	if (_networking && (DEREF_CLIENT(0)->status != STATUS_INACTIVE || !_network_server)) {
skidd13@8431: 		printf("Random [%d/%d] %s:%d\n",_frame_counter, (byte)_current_player, file, line);
rubidium@8930: 	}
rubidium@8930: 
rubidium@8930: 	return _random->Next()
rubidium@8930: }
skidd13@8431: #endif /* RANDOM_DEBUG */
skidd13@8431: #endif /* MERSENNE_TWISTER */
skidd13@8431: 
skidd13@8431: #if defined(RANDOM_DEBUG) && !defined(MERSENNE_TWISTER)
skidd13@8431: uint DoRandomRange(uint max, int line, const char *file)
skidd13@8431: {
skidd13@8431: 	return GB(DoRandom(line, file), 0, 16) * max >> 16;
skidd13@8431: }
skidd13@8431: #endif /* RANDOM_DEBUG & !MERSENNE_TWISTER */