qemu-timer-common.c

   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-timer.h"
  25
  26 /***********************************************************/
  27 /* real time host monotonic timer */
  28
  29 #ifdef _WIN32
  30
  31 int64_t clock_freq;
  32
  33 static void __attribute__((constructor)) init_get_clock(void)
  34 {
  35     LARGE_INTEGER freq;
  36     int ret;
  37     ret = QueryPerformanceFrequency(&freq);
  38     if (ret == 0) {
  39         fprintf(stderr, "Could not calibrate ticks\n");
  40         exit(1);
  41     }
  42     clock_freq = freq.QuadPart;
  43 }
  44
  45 #else
  46
  47 int use_rt_clock;
  48
  49 static void __attribute__((constructor)) init_get_clock(void)
  50 {
  51     use_rt_clock = 0;
  52 #if defined(__linux__) || (defined(__FreeBSD__) && __FreeBSD_version >= 500000) \
  53     || defined(__DragonFly__) || defined(__FreeBSD_kernel__) \
  54     || defined(__OpenBSD__)
  55     {
  56         struct timespec ts;
  57         if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0) {
  58             use_rt_clock = 1;
  59         }
  60     }
  61 #endif
  62 }
  63 #endif