1 /* 2 * Copyright (c) 1993 Martin Birgmeier 3 * All rights reserved. 4 * 5 * You may redistribute unmodified or modified versions of this source 6 * code provided that the above copyright notice and this and the 7 * following conditions are retained. 8 * 9 * This software is provided ``as is'', and comes with no warranties 10 * of any kind. I shall in no event be liable for anything that happens 11 * to anyone/anything when using this software. 12 */ 13 14 #if defined(LIBC_SCCS) && !defined(lint) 15 static char rcsid[] = "$OpenBSD: _rand48.c,v 1.2 1996/08/19 08:33:19 tholo Exp $"; 16 #endif /* LIBC_SCCS and not lint */ 17 18 #include "rand48.h" 19 20 unsigned short __rand48_seed[3] = { 21 RAND48_SEED_0, 22 RAND48_SEED_1, 23 RAND48_SEED_2 24 }; 25 unsigned short __rand48_mult[3] = { 26 RAND48_MULT_0, 27 RAND48_MULT_1, 28 RAND48_MULT_2 29 }; 30 unsigned short __rand48_add = RAND48_ADD; 31 32 void 33 __dorand48(unsigned short xseed[3]) 34 { 35 unsigned long accu; 36 unsigned short temp[2]; 37 38 accu = (unsigned long) __rand48_mult[0] * (unsigned long) xseed[0] + 39 (unsigned long) __rand48_add; 40 temp[0] = (unsigned short) accu; /* lower 16 bits */ 41 accu >>= sizeof(unsigned short) * 8; 42 accu += (unsigned long) __rand48_mult[0] * (unsigned long) xseed[1] + 43 (unsigned long) __rand48_mult[1] * (unsigned long) xseed[0]; 44 temp[1] = (unsigned short) accu; /* middle 16 bits */ 45 accu >>= sizeof(unsigned short) * 8; 46 accu += __rand48_mult[0] * xseed[2] + __rand48_mult[1] * xseed[1] + __rand48_mult[2] * xseed[0]; 47 xseed[0] = temp[0]; 48 xseed[1] = temp[1]; 49 xseed[2] = (unsigned short) accu; 50 } 51