/**  *  @file  rtems/score/context.h * *  This include file contains all information about each thread's context. *//* *  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.com/license/LICENSE. * *  $Id: context.h,v 1.17 2006/01/16 15:13:58 joel Exp $ */#ifndef _RTEMS_SCORE_CONTEXT_H#define _RTEMS_SCORE_CONTEXT_H/** *  @defgroup ScoreContext Context Handler * *  This handler encapsulates functionality which abstracts thread context *  management in a portable manner. *//**@{*/#ifdef __cplusplusextern "C" {#endif#include <rtems/score/cpu.h>/** *  @brief Size of Floating Point Context Area * *  This constant defines the number of bytes required *  to store a full floating point context. */#define CONTEXT_FP_SIZE CPU_CONTEXT_FP_SIZE/** *  @brief Is Context Switch Needed? * *  This variable is set to TRUE when a reschedule operation *  has determined that the processor should be taken away from the *  currently executing thread and given to the heir thread. */SCORE_EXTERN volatile boolean _Context_Switch_necessary;/** *  @brief Initialize Context Area *  This routine initializes @a _the_context such that the stack *  pointer, interrupt level, and entry point are correct for the *  thread's initial state. * *  @param[in] _the_context will be initialized *  @param[in] _stack is the lowest physical address of the thread's  *         context *  @param[in] _size is the size in octets of the thread's context *  @param[in] _isr is the ISR enable level for this thread *  @param[in] _entry is this thread's entry point *  @param[in] _is_fp is set to TRUE if this thread has floating point *         enabled */#define _Context_Initialize(_the_context, _stack, _size, _isr, _entry, _is_fp) \   _CPU_Context_Initialize( _the_context, _stack, _size, _isr, _entry, _is_fp )/** *  @brief Perform Context Switch * *  This routine saves the current context into the @a _executing *  context record and restores the context specified by @a _heir. * *  @param[in] _executing is the currently executing thread's context *  @param[in] _heir is the context of the thread to be switched to */#define _Context_Switch( _executing, _heir ) \   _CPU_Context_switch( _executing, _heir )/** *  @brief Restart Currently Executing Thread * *  This routine restarts the calling thread by restoring its initial *  stack pointer and returning to the thread's entry point. * *  @param[in] _the_context is the context of the thread to restart */#define _Context_Restart_self( _the_context ) \   _CPU_Context_Restart_self( _the_context )/** *  @brief Return Starting Address of Floating Point Context * *  This function returns the starting address of the floating *  point context save area.  It is assumed that the are reserved *  for the floating point save area is large enough. * *  @param[in] _base is lowest physical address of the floating point *         context save area. *  @param[in] _offset is the offset into the floating point area * *  @return the initial FP context pointer */#define _Context_Fp_start( _base, _offset ) \   _CPU_Context_Fp_start( (_base), (_offset) )/** *  @brief Initialize Floating Point Context Area * *  This routine initializes the floating point context save *  area to contain an initial known state. * *  @param[in] _fp_area is the base address of the floating point *         context save area to initialize. */#define _Context_Initialize_fp( _fp_area ) \   _CPU_Context_Initialize_fp( _fp_area )/** *  @brief Restore Floating Point Context Area * *  This routine restores the floating point context contained *  in the @a _fp area.  It is assumed that the current *  floating point context has been saved by a previous invocation *  of @a _Context_Save_fp. * *  @param[in] _fp points to the floating point context area to restore. */#define _Context_Restore_fp( _fp ) \   _CPU_Context_restore_fp( _fp )/** *  @brief Save Floating Point Context Area * *  This routine saves the current floating point context *  in the @a _fp area. * *  @param[in] _fp points to the floating point context area to restore. */#define _Context_Save_fp( _fp ) \   _CPU_Context_save_fp( _fp )#ifdef __cplusplus}#endif/**@}*/#endif/* end of include file */