Subversion Repositories openrisc

/*

 *  Thread Handler

 *

 *

 *  COPYRIGHT (c) 1989-1999.

 *  On-Line Applications Research Corporation (OAR).

 *

 *  The license and distribution terms for this file may be

 *  found in found in the file LICENSE in this distribution or at

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

 *

 *  $Id: threadstartmultitasking.c,v 1.2 2001-09-27 11:59:34 chris Exp $

 */

#include <rtems/system.h>

#include <rtems/score/apiext.h>

#include <rtems/score/context.h>

#include <rtems/score/interr.h>

#include <rtems/score/isr.h>

#include <rtems/score/object.h>

#include <rtems/score/priority.h>

#include <rtems/score/states.h>

#include <rtems/score/sysstate.h>

#include <rtems/score/thread.h>

#include <rtems/score/threadq.h>

#include <rtems/score/userext.h>

#include <rtems/score/wkspace.h>

/*PAGE

 *

 *  _Thread_Start_multitasking

 *

 *  This kernel routine readies the requested thread, the thread chain

 *  is adjusted.  A new heir thread may be selected.

 *

 *  Input parameters:

 *    system_thread - pointer to system initialization thread control block

 *    idle_thread   - pointer to idle thread control block

 *

 *  Output parameters:  NONE

 *

 *  NOTE:  This routine uses the "blocking" heir selection mechanism.

 *         This insures the correct heir after a thread restart.

 *

 *  INTERRUPT LATENCY:

 *    ready chain

 *    select heir

 */

void _Thread_Start_multitasking( void )

{

  /*

   *  The system is now multitasking and completely initialized.

   *  This system thread now either "goes away" in a single processor

   *  system or "turns into" the server thread in an MP system.

   */

  _System_state_Set( SYSTEM_STATE_UP );

  _Context_Switch_necessary = FALSE;

  _Thread_Executing = _Thread_Heir;

   /*

    * Get the init task(s) running.

    *

    * Note: Thread_Dispatch() is normally used to dispatch threads.  As

    *       part of its work, Thread_Dispatch() restores floating point

    *       state for the heir task.

    *

    *       This code avoids Thread_Dispatch(), and so we have to restore

    *       (actually initialize) the floating point state "by hand".

    *

    *       Ignore the CPU_USE_DEFERRED_FP_SWITCH because we must always

    *       switch in the first thread if it is FP.

    */

#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )

   /*

    *  don't need to worry about saving BSP's floating point state

    */

   if ( _Thread_Heir->fp_context != NULL )

     _Context_Restore_fp( &_Thread_Heir->fp_context );

#endif

  _Context_Switch( &_Thread_BSP_context, &_Thread_Heir->Registers );

}