UCOS中OSTaskDel函数的疑问
INT8UOSTaskDel (INT8U prio) reentrant{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
#if OS_EVENT_EN > 0
OS_EVENT *pevent;
#endif
#if (OS_VERSION >= 251) && (OS_FLAG_EN > 0) && (OS_MAX_FLAGS > 0)
OS_FLAG_NODE *pnode;
#endif
OS_TCB *ptcb;
if (OSIntNesting > 0) { /* See if trying to delete from ISR */
return (OS_TASK_DEL_ISR);
}
#if OS_ARG_CHK_EN > 0
if (prio == OS_IDLE_PRIO) { /* Not allowed to delete idle task */
return (OS_TASK_DEL_IDLE);
}
if (prio >= OS_LOWEST_PRIO && prio != OS_PRIO_SELF) { /* Task priority valid ? */
return (OS_PRIO_INVALID);
}
#endif
OS_ENTER_CRITICAL();
if (prio == OS_PRIO_SELF) { /* See if requesting to delete self */
prio = OSTCBCur->OSTCBPrio; /* Set priority to delete to current */
}
if ((ptcb = OSTCBPrioTbl) != (OS_TCB *)0) { /* Task to delete must exist */
if ((OSRdyTbl &= ~ptcb->OSTCBBitX) == 0x00) {/* Make task not ready */
OSRdyGrp &= ~ptcb->OSTCBBitY;
}
#if OS_EVENT_EN > 0
pevent = ptcb->OSTCBEventPtr;
if (pevent != (OS_EVENT *)0) { /* If task is waiting on event */
if ((pevent->OSEventTbl &= ~ptcb->OSTCBBitX) == 0) { /* ... remove task from */
pevent->OSEventGrp &= ~ptcb->OSTCBBitY; /* ... event ctrl block */
}
}
#endif
#if (OS_VERSION >= 251) && (OS_FLAG_EN > 0) && (OS_MAX_FLAGS > 0)
pnode = ptcb->OSTCBFlagNode;
if (pnode != (OS_FLAG_NODE *)0) { /* If task is waiting on event flag */
OS_FlagUnlink(pnode); /* Remove from wait list */
}
#endif
ptcb->OSTCBDly= 0; /* Prevent OSTimeTick() from updating*/
ptcb->OSTCBStat = OS_STAT_RDY; /* Prevent task from being resumed */
if (OSLockNesting < 255) {
OSLockNesting++;
}
OS_EXIT_CRITICAL(); /* Enabling INT. ignores next instruc. */
OS_Dummy(); /* ... Dummy ensures that INTs will be */
OS_ENTER_CRITICAL(); /* ... disabled HERE! */
if (OSLockNesting > 0) {
OSLockNesting--;
}
OSTaskDelHook(ptcb); /* Call user defined hook */
OSTaskCtr--; /* One less task being managed */
OSTCBPrioTbl = (OS_TCB *)0; /* Clear old priority entry */
if (ptcb->OSTCBPrev == (OS_TCB *)0) { /* Remove from TCB chain */
ptcb->OSTCBNext->OSTCBPrev = (OS_TCB *)0;
OSTCBList = ptcb->OSTCBNext;
} else {
ptcb->OSTCBPrev->OSTCBNext = ptcb->OSTCBNext;
ptcb->OSTCBNext->OSTCBPrev = ptcb->OSTCBPrev;
}
ptcb->OSTCBNext = OSTCBFreeList; /* Return TCB to free TCB list */
OSTCBFreeList = ptcb;
OS_EXIT_CRITICAL();
OS_Sched(); /* Find new highest priority task */
return (OS_NO_ERR); ========================================================================>>OS_Sched()如果检测到更高优先级的就绪任务，该语句岂不是不能返回了？
}
OS_EXIT_CRITICAL();
return (OS_TASK_DEL_ERR);
}
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