rubidium@9722: /* $Id$ */
rubidium@9722: 
rubidium@9722: /** @file random_func.cpp */
rubidium@9722: 
rubidium@9722: #include "../stdafx.h"
rubidium@9722: #include "../macros.h"
rubidium@9722: #include "../variables.h"
rubidium@9722: #include "random_func.hpp"
rubidium@9722: 
rubidium@9722: uint32 InteractiveRandom()
rubidium@9722: {
rubidium@9722: 	const uint32 s = _random_seeds[1][0];
rubidium@9722: 	const uint32 t = _random_seeds[1][1];
rubidium@9722: 
rubidium@9722: 	_random_seeds[1][0] = s + ROR(t ^ 0x1234567F, 7) + 1;
rubidium@9722: 	return _random_seeds[1][1] = ROR(s, 3) - 1;
rubidium@9722: }
rubidium@9722: 
rubidium@9722: uint InteractiveRandomRange(uint max)
rubidium@9722: {
rubidium@9722: 	return GB(InteractiveRandom(), 0, 16) * max >> 16;
rubidium@9722: }
rubidium@9722: 
rubidium@9722: #ifdef MERSENNE_TWISTER
rubidium@9722: // Source code for Mersenne Twister.
rubidium@9722: // A Random number generator with much higher quality random numbers.
rubidium@9722: 
rubidium@9722: #define N              (624)                 // length of _mt_state vector
rubidium@9722: #define M              (397)                 // a period parameter
rubidium@9722: #define K              (0x9908B0DFU)         // a magic constant
rubidium@9722: #define hiBit(u)       ((u) & 0x80000000U)   // mask all but highest   bit of u
rubidium@9722: #define loBit(u)       ((u) & 0x00000001U)   // mask all but lowest    bit of u
rubidium@9722: #define loBits(u)      ((u) & 0x7FFFFFFFU)   // mask     the highest   bit of u
rubidium@9722: #define mixBits(u, v)  (hiBit(u)|loBits(v))  // move hi bit of u to hi bit of v
rubidium@9722: 
rubidium@9722: static uint32 _mt_state[N+1];     // _mt_state vector + 1 extra to not violate ANSI C
rubidium@9722: static uint32 *_mt_next;          // _mt_next random value is computed from here
rubidium@9722: static int    _mt_left = -1;      // can *_mt_next++ this many times before reloading
rubidium@9722: 
rubidium@9722: void SetRandomSeed(register uint32 seed)
rubidium@9722: {
rubidium@9722: 	register uint32 *s = _mt_state;
rubidium@9722: 	_mt_left = 0;
rubidium@9722: 
rubidium@9722: 	seed |= 1U;
rubidium@9722: 	seed &= 0xFFFFFFFFU;
rubidium@9722: 
rubidium@9722: 	*s = seed;
rubidium@9722: 
rubidium@9722: 	for (register uint i = N; i != 0; i--) {
rubidium@9722: 		seed *= 69069U;
rubidium@9722: 		*s++;
rubidium@9722: 		*s = seed & 0xFFFFFFFFU;
rubidium@9722: 	}
rubidium@9722: }
rubidium@9722: 
rubidium@9722: static uint32 ReloadRandom()
rubidium@9722: {
rubidium@9722: 	if (_mt_left < -1) SetRandomSeed(4357U);
rubidium@9722: 
rubidium@9722: 	_mt_left = N - 1;
rubidium@9722: 	_mt_next = _mt_state + 1;
rubidium@9722: 
rubidium@9722: 	register uint32 *p0 = _mt_state;
rubidium@9722: 	register uint32 *p2 = _mt_state + 2;
rubidium@9722: 	register uint32 *pM = _mt_state + M;
rubidium@9722: 
rubidium@9722: 	register uint32 s0 = _mt_state[0];
rubidium@9722: 	register uint32 s1 = _mt_state[1];
rubidium@9722: 
rubidium@9722: 	register uint i = 0;
rubidium@9722: 
rubidium@9722: 	for (i = (N - M + 1); i != 0; i--) {
rubidium@9722: 		s0 = s1;
rubidium@9722: 		s1 = *p2;
rubidium@9722: 		*p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);
rubidium@9722: 		*p0++;
rubidium@9722: 		*p2++;
rubidium@9722: 		*pM++;
rubidium@9722: 	}
rubidium@9722: 
rubidium@9722: 	pM = _mt_state;
rubidium@9722: 
rubidium@9722: 	for (i = M; i != 0; i--) {
rubidium@9722: 		s0 = s1;
rubidium@9722: 		s1 = *p2;
rubidium@9722: 		*p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);
rubidium@9722: 		*p0++;
rubidium@9722: 		*p2++;
rubidium@9722: 		*pM++;
rubidium@9722: 	}
rubidium@9722: 
rubidium@9722: 	s1 = _mt_state[0];
rubidium@9722: 	*p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);
rubidium@9722: 
rubidium@9722: 	s1 ^= (s1 >> 11);
rubidium@9722: 	s1 ^= (s1 <<  7) & 0x9D2C5680U;
rubidium@9722: 	s1 ^= (s1 << 15) & 0xEFC60000U;
rubidium@9722: 	s1 ^= (s1 >> 18);
rubidium@9722: 	return s1;
rubidium@9722: }
rubidium@9722: 
rubidium@9722: uint32 Random()
rubidium@9722: {
rubidium@9722: 	_mt_left--;
rubidium@9722: 	if (_mt_left < 0) return ReloadRandom();
rubidium@9722: 
rubidium@9722: 	uint32 y = *_mt_next;
rubidium@9722: 	*_mt_next++;
rubidium@9722: 
rubidium@9722: 	y ^= (y >> 11);
rubidium@9722: 	y ^= (y <<  7) & 0x9D2C5680U;
rubidium@9722: 	y ^= (y << 15) & 0xEFC60000U;
rubidium@9722: 	y ^= (y >> 18);
rubidium@9722: 	return y;
rubidium@9722: }
rubidium@9722: 
rubidium@9722: #else /* MERSENNE_TWISTER */
rubidium@9722: void SetRandomSeed(uint32 seed)
rubidium@9722: {
rubidium@9722: 	_random_seeds[0][0] = seed;
rubidium@9722: 	_random_seeds[0][1] = seed;
rubidium@9722: 	_random_seeds[1][0] = seed * 0x1234567;
rubidium@9722: 	_random_seeds[1][1] = _random_seeds[1][0];
rubidium@9722: }
rubidium@9722: 
rubidium@9722: #ifdef RANDOM_DEBUG
rubidium@9722: #include "network/network_data.h"
rubidium@9722: uint32 DoRandom(int line, const char *file)
rubidium@9722: {
rubidium@9722: 	if (_networking && (DEREF_CLIENT(0)->status != STATUS_INACTIVE || !_network_server))
rubidium@9722: 		printf("Random [%d/%d] %s:%d\n",_frame_counter, (byte)_current_player, file, line);
rubidium@9722: #else /* RANDOM_DEBUG */
rubidium@9722: uint32 Random()
rubidium@9722: {
rubidium@9722: #endif /* RANDOM_DEBUG */
rubidium@9722: 	const uint32 s = _random_seeds[0][0];
rubidium@9722: 	const uint32 t = _random_seeds[0][1];
rubidium@9722: 
rubidium@9722: 	_random_seeds[0][0] = s + ROR(t ^ 0x1234567F, 7) + 1;
rubidium@9722: 	return _random_seeds[0][1] = ROR(s, 3) - 1;
rubidium@9722: }
rubidium@9722: #endif /* MERSENNE_TWISTER */
rubidium@9722: 
rubidium@9722: #if defined(RANDOM_DEBUG) && !defined(MERSENNE_TWISTER)
rubidium@9722: uint DoRandomRange(uint max, int line, const char *file)
rubidium@9722: {
rubidium@9722: 	return GB(DoRandom(line, file), 0, 16) * max >> 16;
rubidium@9722: }
rubidium@9722: #else /* RANDOM_DEBUG & !MERSENNE_TWISTER */
rubidium@9722: uint RandomRange(uint max)
rubidium@9722: {
rubidium@9722: 	return GB(Random(), 0, 16) * max >> 16;
rubidium@9722: }
rubidium@9722: #endif /* RANDOM_DEBUG & !MERSENNE_TWISTER */