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/******************************************************************************

*                                                                             *

* License Agreement                                                           *

*                                                                             *

* Copyright (c) 2004 Altera Corporation, San Jose, California, USA.           *

* All rights reserved.                                                        *

*                                                                             *

* Permission is hereby granted, free of charge, to any person obtaining a     *

* copy of this software and associated documentation files (the "Software"),  *

* to deal in the Software without restriction, including without limitation   *

* the rights to use, copy, modify, merge, publish, distribute, sublicense,    *

* and/or sell copies of the Software, and to permit persons to whom the       *

* Software is furnished to do so, subject to the following conditions:        *

*                                                                             *

* The above copyright notice and this permission notice shall be included in  *

* all copies or substantial portions of the Software.                         *

*                                                                             *

* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR  *

* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,    *

* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE *

* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER      *

* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING     *

* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER         *

* DEALINGS IN THE SOFTWARE.                                                   *

*                                                                             *

* This agreement shall be governed in all respects by the laws of the State   *

* of California and by the laws of the United States of America.              *

*                                                                             *

* Altera does not recommend, suggest or require that this reference design    *

* file be used in conjunction or combination with any other product.          *

******************************************************************************/

#include <sys/time.h>

#include <sys/times.h>

#include "sys/alt_errno.h"

#include "sys/alt_alarm.h"

#include "os/alt_syscall.h"

/*

 * "alt_timezone" and "alt_resettime" are the values of the the reset time and

 * time zone set through the last call to settimeofday(). By default they are

 * zero initialised.

 */

extern struct timezone alt_timezone;

extern struct timeval  alt_resettime;

/*

 * Macro defining the number of micoseconds in a second.

 */

#define ALT_US (1000000)

/*

 * settimeofday() can be called to calibrate the system clock, so that

 * subsequent calls to gettimeofday() will return the elapsed "wall clock"

 * time.

 *

 * This is done by updating the global structures "alt_resettime" and

 * "alt_timezone" so that an immediate call to gettimeofday() would return

 * the value specified by "t" and "tz".

 *

 * Warning: if this function is called concurrently with a call to

 * gettimeofday(), the value returned by gettimeofday() will be unreliable.

 *

 * ALT_SETTIMEOFDAY is mapped onto the settimeofday() system call in

 * alt_syscall.h

 */

int ALT_SETTIMEOFDAY (const struct timeval  *t,

                      const struct timezone *tz)

{

  alt_u32 nticks    = alt_nticks ();

  alt_u32 tick_rate = alt_ticks_per_second ();

  /* If there is a system clock available, update the current time */

  if (tick_rate)

  {

    alt_resettime.tv_sec  = t->tv_sec - nticks/tick_rate;

    alt_resettime.tv_usec = t->tv_usec -

      ((nticks*(ALT_US/tick_rate))%ALT_US);

    alt_timezone.tz_minuteswest = tz->tz_minuteswest;

    alt_timezone.tz_dsttime     = tz->tz_dsttime;

    return 0;

  }

  /* There's no system clock available */

  ALT_ERRNO = ENOSYS;

  return -1;

}