xref: /openbmc/qemu/util/qemu-timer-common.c (revision 2b74dd91)
1 /*
2  * QEMU System Emulator
3  *
4  * Copyright (c) 2003-2008 Fabrice Bellard
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  */
24 #include "qemu/osdep.h"
25 #include "qemu/timer.h"
26 
27 /***********************************************************/
28 /* real time host monotonic timer */
29 
30 int64_t clock_start;
31 
32 #ifdef _WIN32
33 
34 int64_t clock_freq;
35 
36 static void __attribute__((constructor)) init_get_clock(void)
37 {
38     LARGE_INTEGER freq;
39     int ret;
40     ret = QueryPerformanceFrequency(&freq);
41     if (ret == 0) {
42         fprintf(stderr, "Could not calibrate ticks\n");
43         exit(1);
44     }
45     clock_freq = freq.QuadPart;
46     clock_start = get_clock();
47 }
48 
49 #else
50 
51 int use_rt_clock;
52 
53 static void __attribute__((constructor)) init_get_clock(void)
54 {
55     struct timespec ts;
56 
57     use_rt_clock = 0;
58     if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0) {
59         use_rt_clock = 1;
60     }
61     clock_start = get_clock();
62 }
63 #endif
64