1*c2c925deSespie /* $OpenBSD: _rand48.c,v 1.3 2005/08/08 08:05:36 espie Exp $ */ 2df930be7Sderaadt /* 3df930be7Sderaadt * Copyright (c) 1993 Martin Birgmeier 4df930be7Sderaadt * All rights reserved. 5df930be7Sderaadt * 6df930be7Sderaadt * You may redistribute unmodified or modified versions of this source 7df930be7Sderaadt * code provided that the above copyright notice and this and the 8df930be7Sderaadt * following conditions are retained. 9df930be7Sderaadt * 10df930be7Sderaadt * This software is provided ``as is'', and comes with no warranties 11df930be7Sderaadt * of any kind. I shall in no event be liable for anything that happens 12df930be7Sderaadt * to anyone/anything when using this software. 13df930be7Sderaadt */ 14df930be7Sderaadt 15df930be7Sderaadt #include "rand48.h" 16df930be7Sderaadt 17df930be7Sderaadt unsigned short __rand48_seed[3] = { 18df930be7Sderaadt RAND48_SEED_0, 19df930be7Sderaadt RAND48_SEED_1, 20df930be7Sderaadt RAND48_SEED_2 21df930be7Sderaadt }; 22df930be7Sderaadt unsigned short __rand48_mult[3] = { 23df930be7Sderaadt RAND48_MULT_0, 24df930be7Sderaadt RAND48_MULT_1, 25df930be7Sderaadt RAND48_MULT_2 26df930be7Sderaadt }; 27df930be7Sderaadt unsigned short __rand48_add = RAND48_ADD; 28df930be7Sderaadt 29df930be7Sderaadt void __dorand48(unsigned short xseed[3])30df930be7Sderaadt__dorand48(unsigned short xseed[3]) 31df930be7Sderaadt { 32df930be7Sderaadt unsigned long accu; 33df930be7Sderaadt unsigned short temp[2]; 34df930be7Sderaadt 35df930be7Sderaadt accu = (unsigned long) __rand48_mult[0] * (unsigned long) xseed[0] + 36df930be7Sderaadt (unsigned long) __rand48_add; 37df930be7Sderaadt temp[0] = (unsigned short) accu; /* lower 16 bits */ 38df930be7Sderaadt accu >>= sizeof(unsigned short) * 8; 39df930be7Sderaadt accu += (unsigned long) __rand48_mult[0] * (unsigned long) xseed[1] + 40df930be7Sderaadt (unsigned long) __rand48_mult[1] * (unsigned long) xseed[0]; 41df930be7Sderaadt temp[1] = (unsigned short) accu; /* middle 16 bits */ 42df930be7Sderaadt accu >>= sizeof(unsigned short) * 8; 43df930be7Sderaadt accu += __rand48_mult[0] * xseed[2] + __rand48_mult[1] * xseed[1] + __rand48_mult[2] * xseed[0]; 44df930be7Sderaadt xseed[0] = temp[0]; 45df930be7Sderaadt xseed[1] = temp[1]; 46df930be7Sderaadt xseed[2] = (unsigned short) accu; 47df930be7Sderaadt } 48