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/*

 *  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.

 *

 *  threadstackallocate.c,v 1.2 1999/11/17 17:50:42 joel 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_Stack_Allocate

 *

 *  Allocate the requested stack space for the thread.

 *  return the actual size allocated after any adjustment

 *  or return zero if the allocation failed.

 *  Set the Start.stack field to the address of the stack

 */

unsigned32 _Thread_Stack_Allocate(

  Thread_Control *the_thread,

  unsigned32 stack_size

)

{

  void *stack_addr = 0;

  if ( !_Stack_Is_enough( stack_size ) )

    stack_size = STACK_MINIMUM_SIZE;

  /*

   * Call ONLY the CPU table stack allocate hook, _or_ the

   * the RTEMS workspace allocate.  This is so the stack free

   * routine can call the correct deallocation routine.

   */

  if ( _CPU_Table.stack_allocate_hook )

  {

    stack_addr = (*_CPU_Table.stack_allocate_hook)( stack_size );

  } else {

    /*

     *  First pad the requested size so we allocate enough memory

     *  so the context initialization can align it properly.  The address

     *  returned the workspace allocate must be directly stored in the

     *  stack control block because it is later used in the free sequence.

     *

     *  Thus it is the responsibility of the CPU dependent code to

     *  get and keep the stack adjust factor, the stack alignment, and

     *  the context initialization sequence in sync.

     */

    stack_size = _Stack_Adjust_size( stack_size );

    stack_addr = _Workspace_Allocate( stack_size );

  }

  if ( !stack_addr )

      stack_size = 0;

  the_thread->Start.stack = stack_addr;

  return stack_size;

}