📄 os_core.c
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{
if(OSRunning==OS_TRUE)
{
if(OSIntNesting<255u)
{
OSIntNesting++; /* Increment ISR nesting level */
}
}
}
/*$PAGE*/
/*
*********************************************************************************************************
* EXIT ISR
*
* Description: This function is used to notify uC/OS-II that you have completed serviving an ISR. When
* the last nested ISR has completed, uC/OS-II will call the scheduler to determine whether
* a new, high-priority task, is ready to run.
*
* Arguments : none
*
* Returns : none
*
* Notes : 1) You MUST invoke OSIntEnter() and OSIntExit() in pair. In other words, for every call
* to OSIntEnter() at the beginning of the ISR you MUST have a call to OSIntExit() at the
* end of the ISR.
* 2) Rescheduling is prevented when the scheduler is locked (see OS_SchedLock())
*********************************************************************************************************
*/
void OSIntExit (void)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr = 0;
#endif
if(OSRunning==OS_TRUE)
{
OS_ENTER_CRITICAL(); //保存全局中断标志,关中断
if(OSIntNesting>0) /* Prevent OSIntNesting from wrapping */
{
OSIntNesting--;
}
if(OSIntNesting==0) /* Reschedule only if all ISRs complete ... */
{
if(OSLockNesting==0) /* ... and not locked. */
{
OS_SchedNew();
if(OSPrioHighRdy!=OSPrioCur) /* No Ctx Sw if current task is highest rdy */
{
OSTCBHighRdy = OSTCBPrioTbl[OSPrioHighRdy];
#if OS_TASK_PROFILE_EN > 0
OSTCBHighRdy->OSTCBCtxSwCtr++; /* Inc. # of context switches to this task */
#endif
OSCtxSwCtr++; /* Keep track of the number of ctx switches */
OSIntCtxSw(); /* Perform interrupt level ctx switch */
}
}
}
OS_EXIT_CRITICAL(); //恢复之前的中断标志
}
}
/*$PAGE*/
/*
*********************************************************************************************************
* PREVENT SCHEDULING
*
* Description: This function is used to prevent rescheduling to take place. This allows your application
* to prevent context switches until you are ready to permit context switching.
*
* Arguments : none
*
* Returns : none
*
* Notes : 1) You MUST invoke OSSchedLock() and OSSchedUnlock() in pair. In other words, for every
* call to OSSchedLock() you MUST have a call to OSSchedUnlock().
*********************************************************************************************************
*/
#if OS_SCHED_LOCK_EN > 0
void OSSchedLock (void)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr = 0;
#endif
if (OSRunning == OS_TRUE) { /* Make sure multitasking is running */
OS_ENTER_CRITICAL();
if (OSIntNesting == 0) { /* Can't call from an ISR */
if (OSLockNesting < 255u) { /* Prevent OSLockNesting from wrapping back to 0 */
OSLockNesting++; /* Increment lock nesting level */
}
}
OS_EXIT_CRITICAL();
}
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* ENABLE SCHEDULING
*
* Description: This function is used to re-allow rescheduling.
*
* Arguments : none
*
* Returns : none
*
* Notes : 1) You MUST invoke OSSchedLock() and OSSchedUnlock() in pair. In other words, for every
* call to OSSchedLock() you MUST have a call to OSSchedUnlock().
*********************************************************************************************************
*/
#if OS_SCHED_LOCK_EN > 0
void OSSchedUnlock (void)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr = 0;
#endif
if (OSRunning == OS_TRUE) { /* Make sure multitasking is running */
OS_ENTER_CRITICAL();
if (OSLockNesting > 0) { /* Do not decrement if already 0 */
OSLockNesting--; /* Decrement lock nesting level */
if (OSLockNesting == 0) { /* See if scheduler is enabled and ... */
if (OSIntNesting == 0) { /* ... not in an ISR */
OS_EXIT_CRITICAL();
OS_Sched(); /* See if a HPT is ready */
} else {
OS_EXIT_CRITICAL();
}
} else {
OS_EXIT_CRITICAL();
}
} else {
OS_EXIT_CRITICAL();
}
}
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* START MULTITASKING
*
* Description: This function is used to start the multitasking process which lets uC/OS-II manages the
* task that you have created. Before you can call OSStart(), you MUST have called OSInit()
* and you MUST have created at least one task.
*
* Arguments : none
*
* Returns : none
*
* Note : OSStartHighRdy() MUST:
* a) Call OSTaskSwHook() then,
* b) Set OSRunning to OS_TRUE.
* c) Load the context of the task pointed to by OSTCBHighRdy.
* d_ Execute the task.
*********************************************************************************************************
*/
void OSStart (void)
{
if (OSRunning == OS_FALSE) {
OS_SchedNew(); /* Find highest priority's task priority number */
OSPrioCur = OSPrioHighRdy;
OSTCBHighRdy = OSTCBPrioTbl[OSPrioHighRdy]; /* Point to highest priority task ready to run */
OSTCBCur = OSTCBHighRdy;
OSStartHighRdy(); /* Execute target specific code to start task */
}
}
/*$PAGE*/
/*
*********************************************************************************************************
* STATISTICS INITIALIZATION
*
* Description: This function is called by your application to establish CPU usage by first determining
* how high a 32-bit counter would count to in 1 second if no other tasks were to execute
* during that time. CPU usage is then determined by a low priority task which keeps track
* of this 32-bit counter every second but this time, with other tasks running. CPU usage is
* determined by:
*
* OSIdleCtr
* CPU Usage (%) = 100 * (1 - ------------)
* OSIdleCtrMax
*
* Arguments : none
*
* Returns : none
*********************************************************************************************************
*/
#if OS_TASK_STAT_EN > 0
void OSStatInit (void)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr = 0;
#endif
OSTimeDly(2); /* Synchronize with clock tick */
OS_ENTER_CRITICAL();
OSIdleCtr = 0L; /* Clear idle counter */
OS_EXIT_CRITICAL();
OSTimeDly(OS_TICKS_PER_SEC / 10); /* Determine MAX. idle counter value for 1/10 second */
OS_ENTER_CRITICAL();
OSIdleCtrMax = OSIdleCtr; /* Store maximum idle counter count in 1/10 second */
OSStatRdy = OS_TRUE;
OS_EXIT_CRITICAL();
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* PROCESS SYSTEM TICK
*
* Description: This function is used to signal to uC/OS-II the occurrence of a 'system tick' (also known
* as a 'clock tick'). This function should be called by the ticker ISR but, can also be
* called by a high priority task.
*
* Arguments : none
*
* Returns : none
*********************************************************************************************************
*/
void OSTimeTick (void)
{
OS_TCB *ptcb;
#if OS_TICK_STEP_EN > 0
BOOLEAN step;
#endif
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr = 0;
#endif
#if OS_TIME_TICK_HOOK_EN > 0
OSTimeTickHook(); /* Call user definable hook */
#endif
#if OS_TIME_GET_SET_EN > 0
OS_ENTER_CRITICAL(); /* Update the 32-bit tick counter */
OSTime++;
OS_EXIT_CRITICAL();
#endif
if(OSRunning==OS_TRUE)
{
#if OS_TICK_STEP_EN > 0
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
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!=0) /* No, Delayed or waiting for event with TO */
{
if(--ptcb->OSTCBDly==0) /* Decrement nbr of ticks to end of delay */
{
/* Check for timeout */
if((ptcb->OSTCBStat&OS_STAT_PEND_ANY)!=OS_STAT_RDY)
{
ptcb->OSTCBStat&=~(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;
}
if((ptcb->OSTCBStat&OS_STAT_SUSPEND)==OS_STAT_RDY) /*Is task suspended? */
{
OSRdyGrp|= ptcb->OSTCBBitY; /* No, Make ready */
OSRdyTbl[ptcb->OSTCBY]|=ptcb->OSTCBBitX;
}
}
}
ptcb = ptcb->OSTCBNext; /* Point at next TCB in TCB list */
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