OS_RESULT os_mut_release (OS_ID mutex) {
/* Release a mutex object */
P_MUCB p_MCB = mutex;
P_TCB p_TCB;
tsk_lock();
if (p_MCB->level == 0 || p_MCB->owner != os_runtask) {
/* Unbalanced mutex release or task is not the owner */
tsk_unlock ();
return (OS_R_NOK);
}
if (--p_MCB->level != 0) {
goto ok;
}
/* Restore owner task's priority. */
os_runtask->prio = p_MCB->prio;
if (p_MCB->p_lnk != NULL) {
/* A task is waiting for this mutex. */
p_TCB = os_get_first ((P_XCB)p_MCB);
p_TCB->ret_val = OS_R_MUT;
os_rmv_dly (p_TCB);
/* A waiting task becomes the owner of this mutex. */
p_MCB->level = 1;
p_MCB->owner = p_TCB;
p_MCB->prio = p_TCB->prio;
/* Priority inversion, check which task continues. */
if (os_runtask->prio >= os_rdy_prio()) {
os_dispatch (p_TCB);
}
else {
/* Ready task has higher priority than running task. */
os_put_prio (&os_rdy, os_runtask);
os_put_prio (&os_rdy, p_TCB);
os_runtask->state = READY;
p_TCB->state = READY;
os_dispatch (NULL);
}
}
else {
/* Check if own priority raised by priority inversion. */
if (os_rdy_prio() > os_runtask->prio) {
os_put_prio (&os_rdy, os_runtask);
os_runtask->state = READY;
os_dispatch (NULL);
}
}
ok:tsk_unlock();
return (OS_R_OK);
}
OS_RESULT os_tsk_prio (OS_TID task_id, U8 new_prio) {
/* Change execution priority of a task to "new_prio". */
P_TCB p_task;
tsk_lock();
if (task_id == 0) {
/* Change execution priority of calling task. */
os_runtask->prio = new_prio;
os_runtask->prio_base = new_prio;
run:if (os_rdy_prio() > new_prio) {
os_put_prio (&os_rdy, os_runtask);
os_runtask->state = READY;
os_dispatch (NULL);
}
tsk_unlock();
return (OS_R_OK);
}
/* Find the task in the "os_active_TCB" array. */
if (task_id > os_maxtaskrun || os_active_TCB[task_id-1] == NULL) {
/* Task with "task_id" not found or not started. */
tsk_unlock ();
return (OS_R_NOK);
}
p_task = os_active_TCB[task_id-1];
p_task->prio = new_prio;
p_task->prio_base = new_prio;
if (p_task == os_runtask) {
goto run;
}
os_resort_prio (p_task);
if (p_task->state == READY) {
/* Task enqueued in a ready list. */
p_task = os_get_first (&os_rdy);
os_dispatch (p_task);
}
tsk_unlock ();
return (OS_R_OK);
}
OS_RESULT os_tsk_delete (OS_TID task_id) {
/* Terminate the task identified with "task_id". */
P_TCB task_context;
P_TCB p_TCB;
P_MUCB p_MCB, p_MCB0;
tsk_lock();
if (task_id == 0 || task_id == os_runtask->task_id) {
/* Terminate itself. */
os_runtask->state = INACTIVE;
os_stk_check (0);
p_MCB = os_runtask->p_mlnk;
while (p_MCB) {
/* Release mutexes owned by this task */
if (p_MCB->p_lnk) {
/* A task is waiting for mutex. */
p_TCB = os_get_first ((P_XCB)p_MCB);
p_TCB->ret_val = OS_R_MUT;
os_rmv_dly (p_TCB);
p_TCB->state = READY;
os_put_prio (&os_rdy, p_TCB);
/* A waiting task becomes the owner of this mutex. */
p_MCB0 = p_MCB;
p_MCB->level = 1;
p_MCB->owner = p_TCB;
p_MCB->p_mlnk = p_TCB->p_mlnk;
p_TCB->p_mlnk = p_MCB;
p_MCB = p_MCB0->p_mlnk;
}
else {
p_MCB = p_MCB->p_mlnk;
}
}
os_active_TCB[os_runtask->task_id-1] = NULL;
_free_box (mp_stk, os_runtask->stack);
os_runtask->stack = NULL;
rt_notify (os_runtask->ptask, (__FALSE << 8) | os_runtask->task_id);
_free_box (mp_tcb, os_runtask);
os_runtask = NULL;
os_dispatch (NULL);
/* The program should never come to this point. */
}
else {
/* Find the task in the "os_active_TCB" array. */
if (task_id > os_maxtaskrun || os_active_TCB[task_id-1] == NULL) {
/* Task with "task_id" not found or not started. */
tsk_unlock ();
return (OS_R_NOK);
}
task_context = os_active_TCB[task_id-1];
os_rmv_list (task_context);
os_rmv_dly (task_context);
p_MCB = task_context->p_mlnk;
while (p_MCB) {
/* Release mutexes owned by this task */
if (p_MCB->p_lnk) {
/* A task is waiting for mutex. */
p_TCB = os_get_first ((P_XCB)p_MCB);
p_TCB->ret_val = OS_R_MUT;
os_rmv_dly (p_TCB);
p_TCB->state = READY;
os_put_prio (&os_rdy, p_TCB);
/* A waiting task becomes the owner of this mutex. */
p_MCB0 = p_MCB;
p_MCB->level = 1;
p_MCB->owner = p_TCB;
p_MCB->p_mlnk = p_TCB->p_mlnk;
p_TCB->p_mlnk = p_MCB;
p_MCB = p_MCB0->p_mlnk;
}
else {
p_MCB = p_MCB->p_mlnk;
}
}
os_active_TCB[task_id-1] = NULL;
_free_box (mp_stk, task_context->stack);
task_context->stack = NULL;
rt_notify (task_context->ptask, (__FALSE << 8) | task_context->task_id);
_free_box (mp_tcb, task_context);
tsk_unlock ();
if (os_rdy_prio() > os_runtask->prio) {
/* Ready task has higher priority than running task. */
os_runtask->state = READY;
os_put_prio (&os_rdy, os_runtask);
os_dispatch (NULL);
}
}
return (OS_R_OK);
}