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/*

 *  RTEMS Task Manager

 *

 *

 *  COPYRIGHT (c) 1989-1999.

 *  On-Line Applications Research Corporation (OAR).

 *

 *  The license and distribution terms for this file may be

 *  found in the file LICENSE in this distribution or at

 *  http://www.OARcorp.com/rtems/license.html.

 *

 *  $Id: tasksetpriority.c,v 1.2 2001-09-27 11:59:19 chris Exp $

 */

#include <rtems/system.h>

#include <rtems/rtems/status.h>

#include <rtems/rtems/support.h>

#include <rtems/rtems/modes.h>

#include <rtems/score/object.h>

#include <rtems/score/stack.h>

#include <rtems/score/states.h>

#include <rtems/rtems/tasks.h>

#include <rtems/score/thread.h>

#include <rtems/score/threadq.h>

#include <rtems/score/tod.h>

#include <rtems/score/userext.h>

#include <rtems/score/wkspace.h>

#include <rtems/score/apiext.h>

#include <rtems/score/sysstate.h>

/*PAGE

 *

 *  rtems_task_set_priority

 *

 *  This directive changes the priority of the specified thread.

 *  The specified thread can be any thread in the system including

 *  the requesting thread.

 *

 *  Input parameters:

 *    id           - thread id (0 indicates requesting thread)

 *    new_priority - thread priority (0 indicates current priority)

 *    old_priority - pointer to previous priority

 *

 *  Output parameters:

 *    old_priority      - previous priority

 *    RTEMS_SUCCESSFUL - if successful

 *    error code        - if unsuccessful

 */

rtems_status_code rtems_task_set_priority(

  Objects_Id           id,

  rtems_task_priority  new_priority,

  rtems_task_priority *old_priority

)

{

  register Thread_Control *the_thread;

  Objects_Locations               location;

  if ( new_priority != RTEMS_CURRENT_PRIORITY &&

       !_RTEMS_tasks_Priority_is_valid( new_priority ) )

    return RTEMS_INVALID_PRIORITY;

  if ( !old_priority )

    return RTEMS_INVALID_ADDRESS;

  the_thread = _Thread_Get( id, &location );

  switch ( location ) {

    case OBJECTS_REMOTE:

#if defined(RTEMS_MULTIPROCESSING)

      _Thread_Executing->Wait.return_argument = old_priority;

      return _RTEMS_tasks_MP_Send_request_packet(

          RTEMS_TASKS_MP_SET_PRIORITY_REQUEST,

          id,

          new_priority,

          0,          /* Not used */

      );

#endif

    case OBJECTS_ERROR:

      return RTEMS_INVALID_ID;

    case OBJECTS_LOCAL:

      /* XXX convert from core priority */

      *old_priority = the_thread->current_priority;

      if ( new_priority != RTEMS_CURRENT_PRIORITY ) {

        the_thread->real_priority = new_priority;

        if ( the_thread->resource_count == 0 ||

             the_thread->current_priority > new_priority )

          _Thread_Change_priority( the_thread, new_priority, FALSE );

      }

      _Thread_Enable_dispatch();

      return RTEMS_SUCCESSFUL;

  }

  return RTEMS_INTERNAL_ERROR;   /* unreached - only to remove warnings */

}