/* Copyright (C) 1995, 1996 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, August 1995. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU C Library 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 Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with the GNU C Library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include <errno.h> #include <stdlib.h> #include <limits.h> #include <sys/types.h> /* Global state for non-reentrant functions. */ struct drand48_data __libc_drand48_data; int __drand48_iterate (xsubi, buffer) unsigned short int xsubi[3]; struct drand48_data *buffer; { u_int64_t X, a, result; /* Initialize buffer, if not yet done. */ if (!buffer->init) { #if (USHRT_MAX == 0xffffU) buffer->a[2] = 0x5; buffer->a[1] = 0xdeec; buffer->a[0] = 0xe66d; #else buffer->a[2] = 0x5deecUL; buffer->a[1] = 0xe66d0000UL; buffer->a[0] = 0; #endif buffer->c = 0xb; buffer->init = 1; } /* Do the real work. We choose a data type which contains at least 48 bits. Because we compute the modulus it does not care how many bits really are computed. */ if (sizeof (unsigned short int) == 2) { X = (u_int64_t)xsubi[2] << 32 | (u_int64_t)xsubi[1] << 16 | xsubi[0]; a = ((u_int64_t)buffer->a[2] << 32 | (u_int64_t)buffer->a[1] << 16 | buffer->a[0]); result = X * a + buffer->c; xsubi[0] = result & 0xffff; xsubi[1] = (result >> 16) & 0xffff; xsubi[2] = (result >> 32) & 0xffff; } else { X = (u_int64_t)xsubi[2] << 16 | xsubi[1] >> 16; a = (u_int64_t)buffer->a[2] << 16 | buffer->a[1] >> 16; result = X * a + buffer->c; xsubi[0] = result >> 16 & 0xffffffffl; xsubi[1] = result << 16 & 0xffff0000l; } return 0; }