/*

SDL - Simple DirectMedia Layer

Copyright (C) 1997-2006 Sam Lantinga

This 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.

This 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 this library; if not, write to the Free Software

Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

Sam Lantinga

slouken@libsdl.org

RDTSC stuff by lompik (lompik@voila.fr) 20/03/2002

*/

#include <stdio.h>

#include <sys/time.h>

#include <signal.h>

#include <unistd.h>

#include <string.h>

#include <errno.h>

/* The clock_gettime provides monotonous time, so we should use it if

it's available. The clock_gettime function is behind ifdef

for __USE_POSIX199309

Tommi Kyntola (tommi.kyntola@ray.fi) 27/09/2005

*/

#if (defined _POSIX_TIMERS && _POSIX_TIMERS + 0 > 0)

#include <time.h>

/*

* clock_gettime() is missing in my system's glibc, and apparently isn't

* available before Linux kernel 2.6...you can uncomment the following

* define to use it, since it may be a better solution than

* gettimeofday() on systems that support the newer syscall. --ryan.

*/

/*#define USE_CLOCK_GETTIME*/

#endif

#include "SDL_error.h"

#include "SDL_timer.h"

#include "SDL_timer_c.h"

#if _POSIX_THREAD_SYSCALL_SOFT

#include <pthread.h>

#endif

#ifdef ENABLE_PTH

#include <pth.h>

#endif

#if defined(DISABLE_THREADS) || defined(FORK_HACK)

#define USE_ITIMER

#endif

/* The following defines should really be determined at configure time */

#if defined(linux)

/* Linux select() changes its timeout parameter upon return to contain

the remaining time. Most other unixen leave it unchanged or undefined. */

#define SELECT_SETS_REMAINING

#elif defined(__bsdi__) || defined(__FreeBSD__) || defined(__sun) || defined(MACOSX)

#define USE_NANOSLEEP

#endif

#if defined(i386) || defined(__i386__)

/* This only works on pentium or newer x86 processors */

/* Actually, this isn't reliable on multi-cpu systems, so is disabled */

/*#define USE_RDTSC*/

#endif

#ifdef USE_RDTSC

/* The first ticks value of the application */

static unsigned long long start;

static float cpu_mhz1000 = 0.0f;

#if 1

/* This is for old binutils version that don't recognize rdtsc mnemonics.

But all binutils version supports this.

*/

#define rdtsc(t) asm __volatile__ (".byte 0x0f, 0x31; " : "=A" (t))

#else

#define rdtsc(t) asm __volatile__ ("rdtsc" : "=A" (t))

#endif

static float calc_cpu_mhz(void)

{

float cpu_mhz;

unsigned long long tsc_start;

unsigned long long tsc_end;

/* Slight code doubling here for the sake of readability */

#ifdef USE_CLOCK_GETTIME

struct timespec tv_start, tv_end;

long usec_delay;

rdtsc(tsc_start);

clock_gettime(CLOCK_MONOTONIC,&tv_start);

sleep(1);

rdtsc(tsc_end);

clock_gettime(CLOCK_MONOTONIC,&tv_end);

usec_delay = (1000000000L * (tv_end.tv_sec - tv_start.tv_sec) +

(tv_end.tv_nsec - tv_start.tv_nsec)) / 1000;

#else

struct timeval tv_start, tv_end;

long usec_delay;

rdtsc(tsc_start);

gettimeofday(&tv_start, NULL);

sleep(1);

rdtsc(tsc_end);

gettimeofday(&tv_end, NULL);

usec_delay = 1000000L * (tv_end.tv_sec - tv_start.tv_sec) +

(tv_end.tv_usec - tv_start.tv_usec);

#endif /* USE_CLOCK_GETTIME */

cpu_mhz = (float)(tsc_end-tsc_start) / usec_delay;

#if 0

printf("cpu MHz\t\t: %.3f\n", cpu_mhz);

#endif

return cpu_mhz;

}

#else

/* The first ticks value of the application */

#ifdef USE_CLOCK_GETTIME

static struct timespec start;

#else

static struct timeval start;

#endif /* USE_CLOCK_GETTIME */

#endif /* USE_RDTSC */

void SDL_StartTicks(void)

{

/* Set first ticks value */

#ifdef USE_RDTSC

if ( ! cpu_mhz1000 ) {

cpu_mhz1000 = calc_cpu_mhz() * 1000.0f;

}

rdtsc(start);

#elif defined(USE_CLOCK_GETTIME)

clock_gettime(CLOCK_MONOTONIC,&start);

#else

gettimeofday(&start, NULL);

#endif

}

Uint32 SDL_GetTicks (void)

{

#ifdef USE_RDTSC

unsigned long long now;

if ( ! cpu_mhz1000 ) {

return 0; /* Shouldn't happen. BUG!! */

}

rdtsc(now);

return (Uint32)((now-start)/cpu_mhz1000);

#elif defined(USE_CLOCK_GETTIME)

Uint32 ticks;

struct timespec now;

clock_gettime(CLOCK_MONOTONIC,&now);

ticks=(now.tv_sec-start.tv_sec)*1000+(now.tv_nsec-start.tv_nsec)/1000000;

return(ticks);

#else

Uint32 ticks;

struct timeval now;

gettimeofday(&now, NULL);

ticks=(now.tv_sec-start.tv_sec)*1000+(now.tv_usec-start.tv_usec)/1000;

return(ticks);

#endif

}

void SDL_Delay (Uint32 ms)

{

#ifdef ENABLE_PTH

pth_time_t tv;

tv.tv_sec = ms/1000;

tv.tv_usec = (ms%1000)*1000;

pth_nap(tv);

#else

int was_error;

#ifdef USE_NANOSLEEP

struct timespec elapsed, tv;

#else

struct timeval tv;

#ifndef SELECT_SETS_REMAINING

Uint32 then, now, elapsed;

#endif

#endif

/* Set the timeout interval - Linux only needs to do this once */

#ifdef SELECT_SETS_REMAINING

tv.tv_sec = ms/1000;

tv.tv_usec = (ms%1000)*1000;

#elif defined(USE_NANOSLEEP)

elapsed.tv_sec = ms/1000;

elapsed.tv_nsec = (ms%1000)*1000000;

#else

then = SDL_GetTicks();

#endif

do {

errno = 0;

#if _POSIX_THREAD_SYSCALL_SOFT

pthread_yield_np();

#endif

#ifdef USE_NANOSLEEP

tv.tv_sec = elapsed.tv_sec;

tv.tv_nsec = elapsed.tv_nsec;

was_error = nanosleep(&tv, &elapsed);

#else

#ifndef SELECT_SETS_REMAINING

/* Calculate the time interval left (in case of interrupt) */

now = SDL_GetTicks();

elapsed = (now-then);

then = now;

if ( elapsed >= ms ) {

break;

}

ms -= elapsed;

tv.tv_sec = ms/1000;

tv.tv_usec = (ms%1000)*1000;

#endif

was_error = select(0, NULL, NULL, NULL, &tv);

#endif /* USE_NANOSLEEP */

} while ( was_error && (errno == EINTR) );

#endif /* ENABLE_PTH */

}

#ifdef USE_ITIMER

static void HandleAlarm(int sig)

{

Uint32 ms;

if ( SDL_alarm_callback ) {

ms = (*SDL_alarm_callback)(SDL_alarm_interval);

if ( ms != SDL_alarm_interval ) {

SDL_SetTimer(ms, SDL_alarm_callback);

}

}

}

int SDL_SYS_TimerInit(void)

{

struct sigaction action;

/* Set the alarm handler (Linux specific) */

memset(&action, 0, sizeof(action));

action.sa_handler = HandleAlarm;

action.sa_flags = SA_RESTART;

sigemptyset(&action.sa_mask);

sigaction(SIGALRM, &action, NULL);

return(0);

}

void SDL_SYS_TimerQuit(void)

{

SDL_SetTimer(0, NULL);

}

int SDL_SYS_StartTimer(void)

{

struct itimerval timer;

timer.it_value.tv_sec = (SDL_alarm_interval/1000);

timer.it_value.tv_usec = (SDL_alarm_interval%1000)*1000;

timer.it_interval.tv_sec = (SDL_alarm_interval/1000);

timer.it_interval.tv_usec = (SDL_alarm_interval%1000)*1000;

setitimer(ITIMER_REAL, &timer, NULL);

return(0);

}

void SDL_SYS_StopTimer(void)

{

struct itimerval timer;

memset(&timer, 0, (sizeof timer));

setitimer(ITIMER_REAL, &timer, NULL);

}

#else /* USE_ITIMER */

#include "SDL_thread.h"

/* Data to handle a single periodic alarm */

static int timer_alive = 0;

static SDL_Thread *timer = NULL;

static int RunTimer(void *unused)

{

while ( timer_alive ) {

if ( SDL_timer_running ) {

SDL_ThreadedTimerCheck();

}

SDL_Delay(1);

}

return(0);

}

/* This is only called if the event thread is not running */

int SDL_SYS_TimerInit(void)

{

timer_alive = 1;

timer = SDL_CreateThread(RunTimer, NULL);

if ( timer == NULL )

return(-1);

return(SDL_SetTimerThreaded(1));

}

void SDL_SYS_TimerQuit(void)

{

timer_alive = 0;

if ( timer ) {

SDL_WaitThread(timer, NULL);

timer = NULL;

}

}

int SDL_SYS_StartTimer(void)

{

SDL_SetError("Internal logic error: Linux uses threaded timer");

return(-1);

}

void SDL_SYS_StopTimer(void)

{

return;

}

#endif /* USE_ITIMER */