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/**
* @file
*
* @brief Start Thread Multitasking
* @ingroup ScoreThread
*/
/*
* COPYRIGHT (c) 1989-2006.
* 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.rtems.org/license/LICENSE.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/score/threadimpl.h>
void _Thread_Start_multitasking( void )
{
Per_CPU_Control *cpu_self = _Per_CPU_Get();
Thread_Control *heir;
#if defined(RTEMS_SMP)
_Per_CPU_State_change( cpu_self, PER_CPU_STATE_UP );
/*
* Threads begin execution in the _Thread_Handler() function. This
* function will set the thread dispatch disable level to zero.
*/
cpu_self->thread_dispatch_disable_level = 1;
#endif
heir = _Thread_Get_heir_and_make_it_executing( cpu_self );
/*
* 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 ( heir->fp_context != NULL )
_Context_Restore_fp( &heir->fp_context );
#endif
_Profiling_Thread_dispatch_disable( cpu_self, 0 );
#if defined(RTEMS_SMP)
/*
* The _CPU_Context_Restart_self() implementations usually assume that self
* context is executing.
*
* FIXME: We have a race condition here in case another thread already
* performed scheduler operations and moved our heir thread to another
* processor. The time frame for this is likely too small to be practically
* relevant.
*/
_CPU_Context_Set_is_executing( &heir->Registers, true );
#endif
#if defined(_CPU_Start_multitasking)
_CPU_Start_multitasking( &heir->Registers );
#else
_CPU_Context_Restart_self( &heir->Registers );
#endif
}
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