Multidimensional Priority-based Task Scheduler

Scheduler and related functions. More...

Data Structures
struct	tskPrioArEle
	Task priority element for the second dimension of the scheduler. More...

Typedefs
typedef struct tskPrioArEle	TskPrioArEle
	tskPrioArEle
typedef struct tskPrioArEle *	PTskPrioArEle
	Pointer to a tskPrioArEle.
typedef uint16_t	PrioARFlgs
	Used for priority array flags.

Functions
RetCode	tsk_rmvTskActvTskLst (PTskTCB const tsk)
	Delete a Task from the active task list. More...
RetCode	tsk_insrtTskActvTskLst (PTskTCB const tsk)
	Insert a task into the active task list. More...
void	os_INIT_Scheduler (void)
	Initialize the Scheduler mechanism. More...
void	os_SCHEDULE (void)
	Schedules the next ready task according to its priority. More...

Variables
volatile PTskTCB	p_cur_tsk_tcb = NULL
	Pointer to currently running task's tskTCB. More...
volatile PTskTCB	p_nxt_tsk_tcb = NULL
	Pointer to task's tskTCB, which is scheduled to run next. More...
volatile BitsOSFlags	gOS_FLAGS
	Flags used for maintaining the OS. More...

Detailed Description

Scheduler and related functions.

Function Documentation

void os_INIT_Scheduler

(

void

)

Initialize the Scheduler mechanism.

Warning

MUST BE CALLED BEFORE THE SCHEDULER CAN BE USED!

void os_SCHEDULE

(

void

)

Schedules the next ready task according to its priority.

The task queue is scanned until a task ready to run is found. The queue is sorted according to the tasks' priority beforehand.

Postcondition

p_nxt_tsk_tcb A pointer to the chosen task's tskTCB is stored to this global variable.

If the next task does not equal the current task a context switch is initiated by setting PendSV to pending

RetCode tsk_insrtTskActvTskLst

(

PTskTCB const

tsk

)

Insert a task into the active task list.

Parameters

[in]

tsk

Task to insert into the active task list

Returns

Return the success of the operation

Precondition

The task has to be ready to be run when queued into the active task list.

Warning

The task must not already be in the active task list.

Note

The active task list is always started by the IDLE task as the root node. THIS MUST NOT CHANGE.

RetCode tsk_rmvTskActvTskLst

(

PTskTCB const

tsk

)

Delete a Task from the active task list.

Parameters

[in]

tsk

Task to delete from the active task list

Returns

Return the success of the operation

Variable Documentation

gOS_FLAGS

Flags used for maintaining the OS.

Contains various flags for the operation of the OS.

might be obsolete

volatile PTskTCB p_cur_tsk_tcb = NULL

Pointer to currently running task's tskTCB.

To keep track of the currently running task this pointer stores it. Is set to NULL when the currently running task is ended/killed, which is then acknowledged by the context switch (No saving of the current task's context).

Initialized to NULL

volatile PTskTCB p_nxt_tsk_tcb = NULL

Pointer to task's tskTCB, which is scheduled to run next.

The scheduler sets this pointer to the task which is to be run after the context switch. The context switch automatically assigns its value to p_cur_tst_tcb once the context is switched.

Initialized to NULL