μC/OS-II---内核：多任务与调度

内核：多任务（ucos_ii.h文件的函数）

Task创建

#if OS_TASK_CREATE_EN > 0u
INT8U    OSTaskCreate    (void           (*task) (void *p_arg),void            *p_arg,OS_STK          *ptos,INT8U            prio);
#endif

Task创建（扩展）

#if OS_TASK_CREATE_EXT_EN > 0u
INT8U    OSTaskCreateExt  (void           (*task) (void *p_arg),void            *p_arg, OS_STK          *ptos, INT8U            prio, INT16U           id, OS_STK          *pbos, INT32U           stk_size, void            *pext,INT16U           opt);
#endif

Task删除/请求删除Task

#if OS_TASK_DEL_EN > 0u
INT8U         OSTaskDel               (INT8U            prio);
INT8U         OSTaskDelReq            (INT8U            prio);
#endif

改变Task优先级

#if OS_TASK_CHANGE_PRIO_EN > 0u
INT8U         OSTaskChangePrio        (INT8U     oldprio,	 INT8U      newprio);
#endif

Task挂起和恢复

#if OS_TASK_SUSPEND_EN > 0u
INT8U         OSTaskResume            (INT8U            prio);
INT8U         OSTaskSuspend           (INT8U            prio);
#endif

Task信息获取

#if OS_TASK_QUERY_EN > 0u
INT8U         OSTaskQuery             (INT8U            prio,OS_TCB          *p_task_data);
#endif

Task调度器上锁和开锁

#if OS_SCHED_LOCK_EN > 0u
void          OSSchedLock             (void);
void          OSSchedUnlock           (void);
#endif

内核：调度（oc_core.c文件的函数）

OS_TCB（任务控制块）初始化

INT8U   OS_TCBInit    (INT8U            prio,OS_STK          *ptos,OS_STK          *pbos,INT16U           id,INT32U           stk_size,void            *pext,INT16U           opt);

任务控制块列表(ucos_ii.h文件的函数)

OS_EXT  OS_TCB            OSTCBTbl[OS_MAX_TASKS + OS_N_SYS_TASKS];

系统调用，主动让渡CPU

void  OS_Sched (void)
{#if OS_CRITICAL_METHOD == 3u                           /* Allocate storage for CPU status register     */OS_CPU_SR  cpu_sr = 0u;#endifOS_ENTER_CRITICAL();if (OSIntNesting == 0u)                            /* Schedule only if all ISRs done and ...       */{if (OSLockNesting == 0u)                       /* ... scheduler is not locked                  */{OS_SchedNew();OSTCBHighRdy = OSTCBPrioTbl[OSPrioHighRdy];if (OSPrioHighRdy != OSPrioCur)            /* No Ctx Sw if current task is highest rdy     */{#if OS_TASK_PROFILE_EN > 0uOSTCBHighRdy->OSTCBCtxSwCtr++;         /* Inc. # of context switches to this task      */#endifOSCtxSwCtr++;                          /* Increment context switch counter             */OS_TASK_SW();                          /* Perform a context switch                     */}}}OS_EXIT_CRITICAL();
}

发生中断，强制当前任务让渡CPU

void  OSIntExit (void)
{#if OS_CRITICAL_METHOD == 3u                               /* Allocate storage for CPU status register */OS_CPU_SR  cpu_sr = 0u;#endifif (OSRunning == OS_TRUE){OS_ENTER_CRITICAL();if (OSIntNesting > 0u)                             /* Prevent OSIntNesting from wrapping       */{OSIntNesting--;}if (OSIntNesting == 0u)                            /* Reschedule only if all ISRs complete ... */{if (OSLockNesting == 0u)                       /* ... and not locked.                      */{OS_SchedNew();OSTCBHighRdy = OSTCBPrioTbl[OSPrioHighRdy];if (OSPrioHighRdy != OSPrioCur)            /* No Ctx Sw if current task is highest rdy */{#if OS_TASK_PROFILE_EN > 0uOSTCBHighRdy->OSTCBCtxSwCtr++;         /* Inc. # of context switches to this task  */#endifOSCtxSwCtr++;                          /* Keep track of the number of ctx switches */OSIntCtxSw();                          /* Perform interrupt level ctx switch       */}}}OS_EXIT_CRITICAL();}
}

就绪表(ucos_ii.h文件的函数)

OS_EXT  OS_PRIO           OSRdyTbl[OS_RDY_TBL_SIZE];       /* Table of tasks which are ready to run    */

设置任务进入就绪态

设置任务脱离就绪态

在就绪表中找到优先级最高(数最小)的任务