嵌入式实时操作系统μCOS原理与实践+事件部分代码
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//事件等待表的初始化函数；pevent表示事件控制块的指针
#if (OS_EVENT_EN)
void OS_EventWaitListInit (OS_EVENT *pevent)
{
INT8U i;
pevent->OSEventGrp = 0u; /* No task waiting on event */
for (i = 0u; i < OS_EVENT_TBL_SIZE; i++) {
pevent->OSEventTbl[i] = 0u;
}
}
//事件等待表的初始化函数；pevent表示事件控制块的指针
#if (OS_EVENT_EN)
void OS_EventWaitListInit (OS_EVENT *pevent)
{
INT8U i;
pevent->OSEventGrp = 0u; /* No task waiting on event */
for (i = 0u; i < OS_EVENT_TBL_SIZE; i++) {
pevent->OSEventTbl[i] = 0u;
}
}
#endif
//事件控制块的初始化
static void OS_InitEventList (void)
{
//OS_EVENT_EN判断是否使用事件管理--事件是否大于0
#if (OS_EVENT_EN) && (OS_MAX_EVENTS > 0u)
#if (OS_MAX_EVENTS > 1u)//OS_MAX_EVENTS=10
INT16U ix;
INT16U ix_next;
//指向事假控制块的指针变量
OS_EVENT *pevent1;
OS_EVENT *pevent2;
//清空事件表---但是可能其他事件给清0了
OS_MemClr((INT8U *)&OSEventTbl[0], sizeof(OSEventTbl)); /* Clear the event table */
//初始事件控制块OS_MAX_EVENTS=10--
for (ix = 0u; ix < (OS_MAX_EVENTS - 1u); ix++) { /* Init. list of free EVENT control blocks */
ix_next = ix + 1u;
pevent1 = &OSEventTbl[ix];
pevent2 = &OSEventTbl[ix_next];
pevent1->OSEventType = OS_EVENT_TYPE_UNUSED;
pevent1->OSEventPtr = pevent2;
#if OS_EVENT_NAME_EN > 0u
//给事件区名称
pevent1->OSEventName = (INT8U *)(void *)"?"; /* Unknown name */
#endif
}
//OS_EVENT_TYPE_UNUSED=0--ix=9-表尾部
pevent1 = &OSEventTbl[ix];
pevent1->OSEventType = OS_EVENT_TYPE_UNUSED;
pevent1->OSEventPtr = (OS_EVENT *)0;
#if OS_EVENT_NAME_EN > 0u
pevent1->OSEventName = (INT8U *)(void *)"?"; /* Unknown name */
#endif
//OSEventFreeList指向控制块的头部--基本就是初始化成功
OSEventFreeList = &OSEventTbl[0];
#else
OSEventFreeList = &OSEventTbl[0]; /* Only have ONE event control block */
OSEventFreeList->OSEventType = OS_EVENT_TYPE_UNUSED;
OSEventFreeList->OSEventPtr = (OS_EVENT *)0;
#if OS_EVENT_NAME_EN > 0u
OSEventFreeList->OSEventName = (INT8U *)"?"; /* Unknown name */
#endif
#endif
#endif
}
//移除任务控制块
#if ((OS_EVENT_EN) && (OS_EVENT_MULTI_EN > 0u))
void OS_EventTaskRemoveMulti (OS_TCB *ptcb,
OS_EVENT **pevents_multi)
{
OS_EVENT **pevents;
OS_EVENT *pevent;
INT8U y;
OS_PRIO bity;
OS_PRIO bitx;
y = ptcb->OSTCBY;
bity = ptcb->OSTCBBitY;
bitx = ptcb->OSTCBBitX;
pevents = pevents_multi;
pevent = *pevents;
while (pevent != (OS_EVENT *)0) { /* Remove task from all events‘ wait lists */
pevent->OSEventTbl[y] &= (OS_PRIO)~bitx;
if (pevent->OSEventTbl[y] == 0u) {
pevent->OSEventGrp &= (OS_PRIO)~bity;
}
pevents++;
pevent = *pevents;
}
}
//取消事件的等待；
#if (OS_EVENT_EN)
void OS_EventTaskRemove (OS_TCB *ptcb,
OS_EVENT *pevent)
{
INT8U y;
//在事件等待表删除事件等待标志
y = ptcb->OSTCBY;
pevent->OSEventTbl[y] &= (OS_PRIO)~ptcb->OSTCBBitX; /* Remove task from wait list */
//若该行已没有任务等待
if (pevent->OSEventTbl[y] == 0u) {
//删除事件等待组的事件等待标志；
pevent->OSEventGrp &= (OS_PRIO)~ptcb->OSTCBBitY;
}
}
#endif
#if (OS_EVENT_EN)
//事件等待函数
void OS_EventTaskWait (OS_EVENT *pevent)
{
INT8U y;
//在tcb的OSTCBEventPtr域存储ecb指针-以后通过该任务的tcb可直接找到正事件的ecb
OSTCBCur->OSTCBEventPtr = pevent; /* Store ptr to ECB in TCB */
//在事件等待组和事件等待表中进行标识
pevent->OSEventTbl[OSTCBCur->OSTCBY] |= OSTCBCur->OSTCBBitX; /* Put task in waiting list */
pevent->OSEventGrp |= OSTCBCur->OSTCBBitY;
//OSTCBY指把任务优先级右移三位；任务优先级低三位OSTCBBitX具体在哪个位置
//以上将该任务在ecb中登记完毕，下面将阻塞这个任务-等待任务事件的发生
y = OSTCBCur->OSTCBY; /* Task no longer ready */
//把就绪表中给删除掉 取反 在与操作-给对应位给清掉；
OSRdyTbl[y] &= (OS_PRIO)~OSTCBCur->OSTCBBitX;
if (OSRdyTbl[y] == 0u) { /* Clear event grp bit if this was only task pending */
//得给就绪表里是否没有事件发生了；
OSRdyGrp &= (OS_PRIO)~OSTCBCur->OSTCBBitY;
}
}
#endif
//等待事件的任务就绪函数
#if (OS_EVENT_EN)
INT8U OS_EventTaskRdy (OS_EVENT *pevent,//对应ecb指针
void *pmsg,//信息指针
INT8U msk,//信息状态位的掩码--清除tcb状态位
INT8U pend_stat)//等待事件的原因/OS_STAT_PEND_OK/OS_STAT_PEND_ABORT
{
OS_TCB *ptcb;
INT8U y;
INT8U x;
INT8U prio;
//判断优先级
#if OS_LOWEST_PRIO > 63u
OS_PRIO *ptbl;
#endif
#if OS_LOWEST_PRIO <= 63u
//在事件等待等待表和事件组找到优先级最高的任务；
y = OSUnMapTbl[pevent->OSEventGrp]; /* Find HPT waiting for message */
x = OSUnMapTbl[pevent->OSEventTbl[y]];
prio = (INT8U)((y << 3u) + x); /* Find priority of task getting the msg */
#else
if ((pevent->OSEventGrp & 0xFFu) != 0u) { /* Find HPT waiting for message */
y = OSUnMapTbl[ pevent->OSEventGrp & 0xFFu];
} else {
y = OSUnMapTbl[(OS_PRIO)(pevent->OSEventGrp >> 8u) & 0xFFu] + 8u;
}
//查找优先级指标表找到对应的TCB指针；
ptbl = &pevent->OSEventTbl[y];
if ((*ptbl & 0xFFu) != 0u) { //若不为0 调度器每个时钟滴答对该值-1 减到0后 将任务就绪；
x = OSUnMapTbl[*ptbl & 0xFFu];
} else {
//本函数发生冲突--强制为0
x = OSUnMapTbl[(OS_PRIO)(*ptbl >> 8u) & 0xFFu] + 8u;
}
prio = (INT8U)((y << 4u) + x); /* Find priority of task getting the msg */
#endif
//任务控制块ptcb
ptcb = OSTCBPrioTbl[prio]; /* Point to this task‘s OS_TCB */
ptcb->OSTCBDly = 0u; /* Prevent OSTimeTick() from readying task */
#if ((OS_Q_EN > 0u) && (OS_MAX_QS > 0u)) || (OS_MBOX_EN > 0u)
//给TCB中信息指针赋值
ptcb->OSTCBMsg = pmsg; /* Send message directly to waiting task */
#else
//防止编译器发送警告
pmsg = pmsg; /* Prevent compiler warning if not used */
#endif
//清除任务状态中对应等待标志，--任务已经不再等待给事件了
ptcb->OSTCBStat &= (INT8U)~msk; /* Clear bit associated with event type */
//s设置等待状态
ptcb->OSTCBStatPend = pend_stat; /* Set pend status of post or abort */
//判断任务数是否被挂起 为0 不是挂起 -就让他就绪；挂起的任务不能因为事件的发生而就绪； /* See if task is ready (could be susp‘d) */
if ((ptcb->OSTCBStat & OS_STAT_SUSPEND) == OS_STAT_RDY) {
OSRdyGrp |= ptcb->OSTCBBitY; /* Put task in the ready to run list */
OSRdyTbl[y] |= ptcb->OSTCBBitX;
}
//在事件等待表删除该任务；
OS_EventTaskRemove(ptcb, pevent); /* Remove this task from event wait list */
#if (OS_EVENT_MULTI_EN > 0u)
if (ptcb->OSTCBEventMultiPtr != (OS_EVENT **)0) { /* Remove this task from events‘ wait lists */
OS_EventTaskRemoveMulti(ptcb, ptcb->OSTCBEventMultiPtr);
ptcb->OSTCBEventPtr = (OS_EVENT *)pevent;/* Return event as first multi-pend event ready*/
}
#endif
return (prio);
}
#endif
//时钟中断
void OSTimeTick (void)
{
OS_TCB *ptcb;
BOOLEAN step;
OSTimeTickHook(); /*调用用户钩子函数，默认是空函数 */
#if OS_TIME_GET_SET_EN > 0u
OS_ENTER_CRITICAL(); /* Update the 32-bit tick counter */
OSTime++; //调度计数+1
OS_EXIT_CRITICAL();
#endif
//成立表示已经启动多任务
if (OSRunning == OS_TRUE) {
#if OS_TICK_STEP_EN > 0u
switch (OSTickStepState) { /* Determine whether we need to process a tick */
case OS_TICK_STEP_DIS: /* Yes, stepping is disabled */
step = OS_TRUE;
break;
case OS_TICK_STEP_WAIT: /* No, waiting for uC/OS-View to set ... */
step = OS_FALSE; /* .. OSTickStepState to OS_TICK_STEP_ONCE */
break;
case OS_TICK_STEP_ONCE: /* Yes, process tick once and wait for next ... */
step = OS_TRUE; /* ... step command from uC/OS-View */
OSTickStepState = OS_TICK_STEP_WAIT;
break;
default: /* Invalid case, correct situation */
step = OS_TRUE;
OSTickStepState = OS_TICK_STEP_DIS;
break;
}
if (step == OS_FALSE) { /* Return if waiting for step command */
return;
}
#endif
/* Point at first TCB in TCB list */
ptcb = OSTCBList; /* Point at first TCB in TCB list */
while (ptcb->OSTCBPrio != OS_TASK_IDLE_PRIO) { /* Go through all TCBs in TCB list */
OS_ENTER_CRITICAL();
if (ptcb->OSTCBDly != 0u) { /* No, Delayed or waiting for event with TO */
ptcb->OSTCBDly--; /* Decrement nbr of ticks to end of delay */
//Check for timeout
if (ptcb->OSTCBDly == 0u) { /* Check for timeout */
//若有任务等待一事件的发生
if ((ptcb->OSTCBStat & OS_STAT_PEND_ANY) != OS_STAT_RDY) {
// Clear status flag
ptcb->OSTCBStat &= (INT8U)~(INT8U)OS_STAT_PEND_ANY; /* Yes, Clear status flag */
ptcb->OSTCBStatPend = OS_STAT_PEND_TO; /* Indicate PEND timeout */
} else {
ptcb->OSTCBStatPend = OS_STAT_PEND_OK;
}
//如果任务不是被挂起的
if ((ptcb->OSTCBStat & OS_STAT_SUSPEND) == OS_STAT_RDY) { /* Is task suspended? */
OSRdyGrp |= ptcb->OSTCBBitY; /* No, Make ready */
OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
}
}
}
// Point at next TCB in TCB list
ptcb = ptcb->OSTCBNext; /* Point at next TCB in TCB list */
OS_EXIT_CRITICAL();
}
}
}
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