mirror of
https://sourceware.org/git/glibc.git
synced 2025-11-03 20:53:13 +03:00
56 lines
1.7 KiB
C
56 lines
1.7 KiB
C
/* Copyright (C) 1995-2024 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
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
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#include <errno.h>
|
|
#include <stdlib.h>
|
|
#include <limits.h>
|
|
#include <stdint.h>
|
|
#include <sys/types.h>
|
|
|
|
/* Global state for non-reentrant functions. */
|
|
struct drand48_data __libc_drand48_data;
|
|
|
|
|
|
int
|
|
__drand48_iterate (unsigned short int xsubi[3], struct drand48_data *buffer)
|
|
{
|
|
uint64_t X;
|
|
uint64_t result;
|
|
|
|
/* Initialize buffer, if not yet done. */
|
|
if (__glibc_unlikely (!buffer->__init))
|
|
{
|
|
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;
|
|
}
|