295 lines
6.3 KiB
C
295 lines
6.3 KiB
C
/*
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SDL - Simple DirectMedia Layer
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Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 Sam Lantinga
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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Sam Lantinga
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slouken@libsdl.org
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RDTSC stuff by lompik (lompik@voila.fr) 20/03/2002
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*/
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#ifdef SAVE_RCSID
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static char rcsid =
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"@(#) $Id$";
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#endif
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#include <stdio.h>
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#include <sys/time.h>
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#include <signal.h>
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#include <unistd.h>
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#include <string.h>
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#include <errno.h>
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#include "SDL_error.h"
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#include "SDL_timer.h"
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#include "SDL_timer_c.h"
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#if _POSIX_THREAD_SYSCALL_SOFT
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#include <pthread.h>
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#endif
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#if defined(DISABLE_THREADS) || defined(FORK_HACK)
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#define USE_ITIMER
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#endif
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/* The following defines should really be determined at configure time */
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#if defined(linux)
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/* Linux select() changes its timeout parameter upon return to contain
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the remaining time. Most other unixen leave it unchanged or undefined. */
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#define SELECT_SETS_REMAINING
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#elif defined(__bsdi__) || defined(__FreeBSD__) || defined(__sun)
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#define USE_NANOSLEEP
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#endif
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#if defined(i386) || defined(__i386__)
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/* This only works on pentium or newer x86 processors */
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/* Actually, this isn't reliable on multi-cpu systems, so is disabled */
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/*#define USE_RDTSC*/
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#endif
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#ifdef USE_RDTSC
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/* The first ticks value of the application */
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static unsigned long long start;
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static float cpu_mhz1000 = 0.0f;
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#if 1
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/* This is for old binutils version that don't recognize rdtsc mnemonics.
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But all binutils version supports this.
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*/
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#define rdtsc(t) asm __volatile__ (".byte 0x0f, 0x31; " : "=A" (t))
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#else
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#define rdtsc(t) asm __volatile__ ("rdtsc" : "=A" (t))
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#endif
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static float calc_cpu_mhz(void)
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{
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float cpu_mhz;
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unsigned long long tsc_start;
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unsigned long long tsc_end;
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struct timeval tv_start, tv_end;
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long usec_delay;
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rdtsc(tsc_start);
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gettimeofday(&tv_start, NULL);
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sleep(1);
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rdtsc(tsc_end);
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gettimeofday(&tv_end, NULL);
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usec_delay = 1000000L * (tv_end.tv_sec - tv_start.tv_sec) +
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(tv_end.tv_usec - tv_start.tv_usec);
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cpu_mhz = (float)(tsc_end-tsc_start) / usec_delay;
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#if 0
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printf("cpu MHz\t\t: %.3f\n", cpu_mhz);
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#endif
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return cpu_mhz;
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}
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#else
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/* The first ticks value of the application */
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static struct timeval start;
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#endif /* USE_RDTSC */
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void SDL_StartTicks(void)
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{
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/* Set first ticks value */
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#ifdef USE_RDTSC
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if ( ! cpu_mhz1000 ) {
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cpu_mhz1000 = calc_cpu_mhz() * 1000.0f;
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}
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rdtsc(start);
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#else
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gettimeofday(&start, NULL);
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#endif /* USE_RDTSC */
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}
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Uint32 SDL_GetTicks (void)
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{
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#ifdef USE_RDTSC
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unsigned long long now;
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if ( ! cpu_mhz1000 ) {
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return 0; /* Shouldn't happen. BUG!! */
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}
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rdtsc(now);
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return (Uint32)((now-start)/cpu_mhz1000);
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#else
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struct timeval now;
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Uint32 ticks;
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gettimeofday(&now, NULL);
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ticks=(now.tv_sec-start.tv_sec)*1000+(now.tv_usec-start.tv_usec)/1000;
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return(ticks);
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#endif /* USE_RDTSC */
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}
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void SDL_Delay (Uint32 ms)
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{
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int was_error;
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#ifdef USE_NANOSLEEP
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struct timespec elapsed, tv;
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#else
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struct timeval tv;
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#ifndef SELECT_SETS_REMAINING
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Uint32 then, now, elapsed;
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#endif
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#endif
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/* Set the timeout interval - Linux only needs to do this once */
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#ifdef SELECT_SETS_REMAINING
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tv.tv_sec = ms/1000;
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tv.tv_usec = (ms%1000)*1000;
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#elif defined(USE_NANOSLEEP)
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elapsed.tv_sec = ms/1000;
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elapsed.tv_nsec = (ms%1000)*1000000;
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#else
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then = SDL_GetTicks();
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#endif
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do {
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errno = 0;
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#if _POSIX_THREAD_SYSCALL_SOFT
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pthread_yield_np();
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#endif
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#ifdef USE_NANOSLEEP
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tv.tv_sec = elapsed.tv_sec;
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tv.tv_nsec = elapsed.tv_nsec;
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was_error = nanosleep(&tv, &elapsed);
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#else
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#ifndef SELECT_SETS_REMAINING
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/* Calculate the time interval left (in case of interrupt) */
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now = SDL_GetTicks();
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elapsed = (now-then);
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then = now;
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if ( elapsed >= ms ) {
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break;
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}
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ms -= elapsed;
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tv.tv_sec = ms/1000;
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tv.tv_usec = (ms%1000)*1000;
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#endif
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was_error = select(0, NULL, NULL, NULL, &tv);
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#endif /* USE_NANOSLEEP */
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} while ( was_error && (errno == EINTR) );
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}
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#ifdef USE_ITIMER
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static void HandleAlarm(int sig)
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{
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Uint32 ms;
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if ( SDL_alarm_callback ) {
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ms = (*SDL_alarm_callback)(SDL_alarm_interval);
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if ( ms != SDL_alarm_interval ) {
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SDL_SetTimer(ms, SDL_alarm_callback);
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}
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}
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}
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int SDL_SYS_TimerInit(void)
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{
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struct sigaction action;
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/* Set the alarm handler (Linux specific) */
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memset(&action, 0, sizeof(action));
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action.sa_handler = HandleAlarm;
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action.sa_flags = SA_RESTART;
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sigemptyset(&action.sa_mask);
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sigaction(SIGALRM, &action, NULL);
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return(0);
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}
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void SDL_SYS_TimerQuit(void)
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{
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SDL_SetTimer(0, NULL);
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}
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int SDL_SYS_StartTimer(void)
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{
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struct itimerval timer;
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timer.it_value.tv_sec = (SDL_alarm_interval/1000);
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timer.it_value.tv_usec = (SDL_alarm_interval%1000)*1000;
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timer.it_interval.tv_sec = (SDL_alarm_interval/1000);
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timer.it_interval.tv_usec = (SDL_alarm_interval%1000)*1000;
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setitimer(ITIMER_REAL, &timer, NULL);
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return(0);
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}
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void SDL_SYS_StopTimer(void)
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{
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struct itimerval timer;
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memset(&timer, 0, (sizeof timer));
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setitimer(ITIMER_REAL, &timer, NULL);
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}
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#else /* USE_ITIMER */
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#include "SDL_thread.h"
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/* Data to handle a single periodic alarm */
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static int timer_alive = 0;
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static SDL_Thread *timer = NULL;
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static int RunTimer(void *unused)
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{
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while ( timer_alive ) {
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if ( SDL_timer_running ) {
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SDL_ThreadedTimerCheck();
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}
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SDL_Delay(1);
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}
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return(0);
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}
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/* This is only called if the event thread is not running */
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int SDL_SYS_TimerInit(void)
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{
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timer_alive = 1;
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timer = SDL_CreateThread(RunTimer, NULL);
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if ( timer == NULL )
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return(-1);
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return(SDL_SetTimerThreaded(1));
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}
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void SDL_SYS_TimerQuit(void)
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{
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timer_alive = 0;
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if ( timer ) {
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SDL_WaitThread(timer, NULL);
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timer = NULL;
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}
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}
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int SDL_SYS_StartTimer(void)
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{
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SDL_SetError("Internal logic error: Linux uses threaded timer");
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return(-1);
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}
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void SDL_SYS_StopTimer(void)
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{
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return;
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}
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#endif /* USE_ITIMER */
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