RTEMS: Context Handler

| RTEMS 5.4-rc2

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Files | Macros
Context Handler
Internal » SuperCore

Functionality for Abstraction of Thread Context Management. More...

## Files
file | context.h
| Information About Each Thread's Context.

## Macros
#define | CONTEXT_FP_SIZE
| Size of floating point context area.
#define | _Context_Initialize(_the_context, _stack, _size, _isr, _entry, _is_fp, _tls_area)
| Initialize context area.
#define | _Context_Initialization_at_thread_begin()
#define | _Context_Switch(_executing, _heir) _CPU_Context_switch( _executing, _heir )
| Perform context switch.
#define | _Context_Restart_self(_the_context) _CPU_Context_Restart_self( _the_context )
| Restart currently executing thread.
#define | _Context_Initialize_fp(_fp_area) _CPU_Context_Initialize_fp( _fp_area )
| Initialize floating point context area.
#define | _Context_Restore_fp(_fp) _CPU_Context_restore_fp( _fp )
| Restore floating point context area.
#define | _Context_Save_fp(_fp) _CPU_Context_save_fp( _fp )
| Save floating point context area.
#define | _Context_Destroy(_the_thread, _the_context)

## Detailed Description

Functionality for Abstraction of Thread Context Management.

This handler encapsulates functionality which abstracts thread context management in a portable manner.

The context switch needed variable is contained in the per cpu data structure.

## Macro Definition Documentation

## ◆ _Context_Initialization_at_thread_begin

#define _Context_Initialization_at_thread_begin | ( |  | ) |

This macro is invoked from _Thread_Handler to do whatever CPU specific magic is required that must be done in the context of the thread when it starts.

If the CPU architecture does not require any magic, then this macro is empty.

## ◆ _Context_Initialize

#define _Context_Initialize | ( |  | _the_context,
|  |  | _stack,
|  |  | _size,
|  |  | _isr,
|  |  | _entry,
|  |  | _is_fp,
|  |  | _tls_area
| ) |  |

Value:
_CPU_Context_Initialize( _the_context, _stack, _size, _isr, _entry, \
_is_fp, _tls_area )

Initialize context area.

This routine initializes _the_context such that the stack pointer, interrupt level, and entry point are correct for the thread's initial state.

Parameters

  [in] | _the_context | will be initialized
  [in] | _stack | is the lowest physical address of the thread's context
  [in] | _size | is the size in octets of the thread's context
  [in] | _isr | is the ISR enable level for this thread
  [in] | _entry | is this thread's entry point
  [in] | _is_fp | is set to true if this thread has floating point enabled
  [in] | _tls_area | The thread-local storage (TLS) area begin.

## ◆ _Context_Initialize_fp

#define _Context_Initialize_fp | ( |  | _fp_area | ) | _CPU_Context_Initialize_fp( _fp_area )

Initialize floating point context area.

This routine initializes the floating point context save area to contain an initial known state.

Parameters

  [in] | _fp_area | is the base address of the floating point context save area to initialize.

## ◆ _Context_Restart_self

#define _Context_Restart_self | ( |  | _the_context | ) | _CPU_Context_Restart_self( _the_context )

Restart currently executing thread.

This routine restarts the calling thread by restoring its initial stack pointer and returning to the thread's entry point.

Parameters

  [in] | _the_context | is the context of the thread to restart

## ◆ _Context_Restore_fp

#define _Context_Restore_fp | ( |  | _fp | ) | _CPU_Context_restore_fp( _fp )

Restore floating point context area.

This routine restores the floating point context contained in the _fp area. It is assumed that the current floating point context has been saved by a previous invocation of _Context_Save_fp.

Parameters

  [in] | _fp | points to the floating point context area to restore.

## ◆ _Context_Save_fp

#define _Context_Save_fp | ( |  | _fp | ) | _CPU_Context_save_fp( _fp )

Save floating point context area.

This routine saves the current floating point context in the _fp area.

Parameters

  [in] | _fp | points to the floating point context area to restore.

## ◆ _Context_Switch

#define _Context_Switch | ( |  | _executing,
|  |  | _heir
| ) |  | _CPU_Context_switch( _executing, _heir )

Perform context switch.

This routine saves the current context into the _executing context record and restores the context specified by _heir.

Parameters

  [in] | _executing | is the currently executing thread's context
  [in] | _heir | is the context of the thread to be switched to

## ◆ CONTEXT_FP_SIZE

#define CONTEXT_FP_SIZE

Value:
( ( CPU_CONTEXT_FP_SIZE + CPU_HEAP_ALIGNMENT - 1 ) \
& ~( CPU_HEAP_ALIGNMENT - 1 ) )

Size of floating point context area.

This constant defines the number of bytes required to store a full floating point context.