/* Copyright (C) 1995-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper , August 1995.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
. */
#include
#include
#include
#include
#include
/* 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;
{
uint64_t X;
uint64_t result;
/* Initialize buffer, if not yet done. */
if (__builtin_expect (!buffer->__init, 0))
{
buffer->__a = 0x5deece66dull;
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. */
X = (uint64_t) xsubi[2] << 32 | (uint32_t) xsubi[1] << 16 | xsubi[0];
result = X * buffer->__a + buffer->__c;
xsubi[0] = result & 0xffff;
xsubi[1] = (result >> 16) & 0xffff;
xsubi[2] = (result >> 32) & 0xffff;
return 0;
}