Semaphore Handler

Files
file	coresem.c
	Core Semaphore Initialize.

Data Structures
struct	CORE_semaphore_Control

Functions
void	_CORE_semaphore_Initialize (CORE_semaphore_Control *the_semaphore, uint32_t initial_value)
	Initialize the semaphore based on the parameters passed. More...
RTEMS_INLINE_ROUTINE void	_CORE_semaphore_Acquire_critical (CORE_semaphore_Control *the_semaphore, Thread_queue_Context *queue_context)
RTEMS_INLINE_ROUTINE void	_CORE_semaphore_Release (CORE_semaphore_Control *the_semaphore, Thread_queue_Context *queue_context)
RTEMS_INLINE_ROUTINE void	_CORE_semaphore_Destroy (CORE_semaphore_Control *the_semaphore, const Thread_queue_Operations *operations, Thread_queue_Context *queue_context)
RTEMS_INLINE_ROUTINE Status_Control	_CORE_semaphore_Surrender (CORE_semaphore_Control *the_semaphore, const Thread_queue_Operations *operations, uint32_t maximum_count, Thread_queue_Context *queue_context)
	Surrender a unit to a semaphore. More...
RTEMS_INLINE_ROUTINE uint32_t	_CORE_semaphore_Get_count (const CORE_semaphore_Control *the_semaphore)
RTEMS_INLINE_ROUTINE Status_Control	_CORE_semaphore_Seize (CORE_semaphore_Control *the_semaphore, const Thread_queue_Operations *operations, Thread_Control *executing, bool wait, Thread_queue_Context *queue_context)

Detailed Description

This handler encapsulates functionality which provides the foundation Semaphore services used in all of the APIs supported by RTEMS.

Function Documentation

_CORE_semaphore_Get_count()

RTEMS_INLINE_ROUTINE uint32_t _CORE_semaphore_Get_count

(

const CORE_semaphore_Control *

the_semaphore

)

This routine returns the current count associated with the semaphore.

Parameters

[in]

the_semaphore

is the semaphore to obtain the count of

Returns

the current count of this semaphore

_CORE_semaphore_Initialize()

void _CORE_semaphore_Initialize	(	CORE_semaphore_Control *	the_semaphore,
		uint32_t	initial_value
	)

Initialize the semaphore based on the parameters passed.

This package is the implementation of the CORE Semaphore Handler. This core object utilizes standard Dijkstra counting semaphores to provide synchronization and mutual exclusion capabilities.

This routine initializes the semaphore based on the parameters passed.

Parameters

[in]	the_semaphore	is the semaphore to initialize
[in]	initial_value	is the initial count of the semaphore

_CORE_semaphore_Seize()

RTEMS_INLINE_ROUTINE Status_Control _CORE_semaphore_Seize	(	CORE_semaphore_Control *	the_semaphore,
		const Thread_queue_Operations *	operations,
		Thread_Control *	executing,
		bool	wait,
		Thread_queue_Context *	queue_context
	)

This routine attempts to receive a unit from the_semaphore. If a unit is available or if the wait flag is false, then the routine returns. Otherwise, the calling task is blocked until a unit becomes available.

Parameters

[in]	the_semaphore	is the semaphore to obtain
[in]	operations	The thread queue operations.
[in]	executing	The currently executing thread.
[in]	wait	is true if the thread is willing to wait
[in]	queue_context	is a temporary variable used to contain the ISR disable level cookie

_CORE_semaphore_Surrender()

RTEMS_INLINE_ROUTINE Status_Control _CORE_semaphore_Surrender	(	CORE_semaphore_Control *	the_semaphore,
		const Thread_queue_Operations *	operations,
		uint32_t	maximum_count,
		Thread_queue_Context *	queue_context
	)

Surrender a unit to a semaphore.

This routine frees a unit to the semaphore. If a task was blocked waiting for a unit from this semaphore, then that task will be readied and the unit given to that task. Otherwise, the unit will be returned to the semaphore.

Parameters

[in]	the_semaphore	is the semaphore to surrender
[in]	operations	The thread queue operations.
[in]	queue_context	is a temporary variable used to contain the ISR disable level cookie

Return values

an	indication of whether the routine succeeded or failed