blob: 7d705adcaa7f1632a488c6dff1edcd4ae695b615 [file] [log] [blame]
lh9ed821d2023-04-07 01:36:19 -07001/* Copyright (C) 1995, 1996, 2001 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, August 1995.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18 02111-1307 USA. */
19
20#include <errno.h>
21#include <stdlib.h>
22#include <limits.h>
23#include <stdint.h>
24#include <stdlib.h>
25#include <sys/types.h>
26
27/* Global state for non-reentrant functions. */
28struct drand48_data __libc_drand48_data;
29
30#ifdef __UCLIBC_MJN3_ONLY__
31#warning turn int __drand48_iterate into void
32#endif /* __UCLIBC_MJN3_ONLY__ */
33int __drand48_iterate (unsigned short int xsubi[3], struct drand48_data *buffer)
34{
35 uint64_t X;
36 uint64_t result;
37
38 /* Initialize buffer, if not yet done. */
39 if (unlikely(!buffer->__init))
40 {
41 buffer->__a = 0x5deece66dull;
42 buffer->__c = 0xb;
43 buffer->__init = 1;
44 }
45
46 /* Do the real work. We choose a data type which contains at least
47 48 bits. Because we compute the modulus it does not care how
48 many bits really are computed. */
49
50 X = (uint64_t) xsubi[2] << 32 | (uint32_t) xsubi[1] << 16 | xsubi[0];
51
52 result = X * buffer->__a + buffer->__c;
53
54 xsubi[0] = result & 0xffff;
55 xsubi[1] = (result >> 16) & 0xffff;
56 xsubi[2] = (result >> 32) & 0xffff;
57
58 return 0;
59}