/* ** Command & Conquer Generals Zero Hour(tm) ** Copyright 2025 Electronic Arts Inc. ** ** This program is free software: you can redistribute it and/or modify ** it under the terms of the GNU General Public License as published by ** the Free Software Foundation, either version 3 of the License, or ** (at your option) any later version. ** ** This program is distributed in the hope that it will be useful, ** but WITHOUT ANY WARRANTY; without even the implied warranty of ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ** GNU General Public License for more details. ** ** You should have received a copy of the GNU General Public License ** along with this program. If not, see . */ #include "rand.h" #include static const double theMultFactor = 1.0 / (pow(2, 8 * sizeof(unsigned int)) - 1.0); RandClass::RandClass(int start) { seed[0] = 0xf22d0e56L; seed[1] = 0x883126e9L; seed[2] = 0xc624dd2fL; seed[3] = 0x702c49cL; seed[4] = 0x9e353f7dL; seed[5] = 0x6fdf3b64L; unsigned int ax; ax = start; /* mov eax,SEED */ ax += 0xf22d0e56; /* add eax,0f22d0e56h */ seed[0] = ax; /* mov seed,eax */ ax += 0x883126e9 - 0xf22d0e56; /* add eax,0883126e9h-0f22d0e56h */ seed[1] = ax; /* mov seed+4,eax */ ax += 0xc624dd2f - 0x883126e9; /* add eax,0c624dd2fh-0883126e9h */ seed[2] = ax; /* mov seed+8,eax */ ax += 0x0702c49c - 0xc624dd2f; /* add eax,00702c49ch-0c624dd2fh */ seed[3] = ax; /* mov seed+12,eax */ ax += 0x9e353f7d - 0x0702c49c; /* add eax,09e353f7dh-00702c49ch */ seed[4] = ax; /* mov seed+16,eax */ ax += 0x6fdf3b64 - 0x9e353f7d; /* add eax,06fdf3b64h-09e353f7dh */ seed[5] = ax; /* mov seed+20,eax */ } // Add with carry. SUM is replaced with A + B + C, C is replaced with 1 if there was a carry, 0 if there wasn't. A carry occurred if the sum is less than one of the inputs. This is addition, so carry can never be more than one. #define ADC(SUM, A, B, C) SUM = (A) + (B) + (C); C = ((SUM < (A)) || (SUM < (B))) unsigned int RandClass::randomValue( void ) { unsigned int ax; unsigned int c = 0; ADC(ax, seed[5], seed[4], c); /* mov ax,seed+20 */ /* add ax,seed+16 */ seed[4] = ax; /* mov seed+8,ax */ ADC(ax, ax, seed[3], c); /* adc ax,seed+12 */ seed[3] = ax; /* mov seed+12,ax */ ADC(ax, ax, seed[2], c); /* adc ax,seed+8 */ seed[2] = ax; /* mov seed+8,ax */ ADC(ax, ax, seed[1], c); /* adc ax,seed+4 */ seed[1] = ax; /* mov seed+4,ax */ ADC(ax, ax, seed[0], c); /* adc ax,seed+0 */ seed[0] = ax; /* mov seed+0,ax */ /* Increment seed array, bubbling up the carries. */ if (!++seed[5]) { if (!++seed[4]) { if (!++seed[3]) { if (!++seed[2]) { if (!++seed[1]) { ++seed[0]; ++ax; } } } } } return(ax); } int RandClass::Int(void) { return (int)randomValue(); } int RandClass::Int(int low, int high) { unsigned int delta = high - low + 1; int rval; if (delta == 0) return high; rval = ((int)(randomValue()%delta)) + low; return rval; } double RandClass::Double(void) { return Double(0.0, 1.0); } double RandClass::Double(double low, double high) { double delta = high - low; double rval; if (delta <= 0.0) return high; rval = ((double)(randomValue()) * theMultFactor) * delta + low; return rval; }