]>
Commit | Line | Data |
---|---|---|
d5efd131 MF |
1 | /* Get frequency of the system processor. IA-64/Linux version. |
2 | Copyright (C) 2001 Free Software Foundation, Inc. | |
3 | This file is part of the GNU C Library. | |
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 | |
75efb018 MF |
16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. */ | |
d5efd131 MF |
18 | |
19 | #include <ctype.h> | |
20 | #include <fcntl.h> | |
21 | #include <string.h> | |
22 | #include <unistd.h> | |
23 | #include <libc-internal.h> | |
24 | ||
25 | ||
26 | hp_timing_t | |
27 | __get_clockfreq (void) | |
28 | { | |
29 | /* We read the information from the /proc filesystem. It contains at | |
30 | least one line like | |
31 | itc MHz : 733.390988 | |
32 | We search for this line and convert the number in an integer. */ | |
33 | static hp_timing_t result; | |
34 | int fd; | |
35 | ||
36 | /* If this function was called before, we know the result. */ | |
37 | if (result != 0) | |
38 | return result; | |
39 | ||
40 | fd = open ("/proc/cpuinfo", O_RDONLY); | |
41 | if (__builtin_expect (fd != -1, 1)) | |
42 | { | |
43 | /* XXX AFAIK the /proc filesystem can generate "files" only up | |
44 | to a size of 4096 bytes. */ | |
45 | char buf[4096]; | |
46 | ssize_t n; | |
47 | ||
48 | n = read (fd, buf, sizeof buf); | |
49 | if (__builtin_expect (n, 1) > 0) | |
50 | { | |
51 | char *mhz = memmem (buf, n, "itc MHz", 7); | |
52 | ||
53 | if (__builtin_expect (mhz != NULL, 1)) | |
54 | { | |
55 | char *endp = buf + n; | |
56 | int seen_decpoint = 0; | |
57 | int ndigits = 0; | |
58 | ||
59 | /* Search for the beginning of the string. */ | |
60 | while (mhz < endp && (*mhz < '0' || *mhz > '9') && *mhz != '\n') | |
61 | ++mhz; | |
62 | ||
63 | while (mhz < endp && *mhz != '\n') | |
64 | { | |
65 | if (*mhz >= '0' && *mhz <= '9') | |
66 | { | |
67 | result *= 10; | |
68 | result += *mhz - '0'; | |
69 | if (seen_decpoint) | |
70 | ++ndigits; | |
71 | } | |
72 | else if (*mhz == '.') | |
73 | seen_decpoint = 1; | |
74 | ||
75 | ++mhz; | |
76 | } | |
77 | ||
78 | /* Compensate for missing digits at the end. */ | |
79 | while (ndigits++ < 6) | |
80 | result *= 10; | |
81 | } | |
82 | } | |
83 | ||
84 | close (fd); | |
85 | } | |
86 | ||
87 | return result; | |
88 | } |