mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-12 22:30:12 +00:00
41bdb6e20c
2001-07-06 Paul Eggert <eggert@twinsun.com> * manual/argp.texi: Remove ignored LGPL copyright notice; it's not appropriate for documentation anyway. * manual/libc-texinfo.sh: "Library General Public License" -> "Lesser General Public License". 2001-07-06 Andreas Jaeger <aj@suse.de> * All files under GPL/LGPL version 2: Place under LGPL version 2.1.
92 lines
2.4 KiB
C
92 lines
2.4 KiB
C
/* Get frequency of the system processor. i386/Linux version.
|
|
Copyright (C) 2000, 2001 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, write to the Free
|
|
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
|
|
02111-1307 USA. */
|
|
|
|
#include <ctype.h>
|
|
#include <fcntl.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
#include <libc-internal.h>
|
|
|
|
|
|
hp_timing_t
|
|
__get_clockfreq (void)
|
|
{
|
|
/* We read the information from the /proc filesystem. It contains at
|
|
least one line like
|
|
cpu MHz : 497.840237
|
|
or also
|
|
cpu MHz : 497.841
|
|
We search for this line and convert the number in an integer. */
|
|
static hp_timing_t result;
|
|
int fd;
|
|
|
|
/* If this function was called before, we know the result. */
|
|
if (result != 0)
|
|
return result;
|
|
|
|
fd = open ("/proc/cpuinfo", O_RDONLY);
|
|
if (__builtin_expect (fd != -1, 1))
|
|
{
|
|
/* XXX AFAIK the /proc filesystem can generate "files" only up
|
|
to a size of 4096 bytes. */
|
|
char buf[4096];
|
|
ssize_t n;
|
|
|
|
n = read (fd, buf, sizeof buf);
|
|
if (__builtin_expect (n, 1) > 0)
|
|
{
|
|
char *mhz = memmem (buf, n, "cpu MHz", 7);
|
|
|
|
if (__builtin_expect (mhz != NULL, 1))
|
|
{
|
|
char *endp = buf + n;
|
|
int seen_decpoint = 0;
|
|
int ndigits = 0;
|
|
|
|
/* Search for the beginning of the string. */
|
|
while (mhz < endp && (*mhz < '0' || *mhz > '9') && *mhz != '\n')
|
|
++mhz;
|
|
|
|
while (mhz < endp && *mhz != '\n')
|
|
{
|
|
if (*mhz >= '0' && *mhz <= '9')
|
|
{
|
|
result *= 10;
|
|
result += *mhz - '0';
|
|
if (seen_decpoint)
|
|
++ndigits;
|
|
}
|
|
else if (*mhz == '.')
|
|
seen_decpoint = 1;
|
|
|
|
++mhz;
|
|
}
|
|
|
|
/* Compensate for missing digits at the end. */
|
|
while (ndigits++ < 6)
|
|
result *= 10;
|
|
}
|
|
}
|
|
|
|
close (fd);
|
|
}
|
|
|
|
return result;
|
|
}
|