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分类: LINUX

2011-02-26 10:33:46

//为简洁方便,将代码中的一些注释删除掉了。

#ifndef  OS_MASTER_FILE
#define  OS_GLOBALS
#include "includes.h"
#endif

//在求最高优先级任务时要用到下面两个数组。

INT8U  const  OSMapTbl[]   = {0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80};

INT8U  const  OSUnMapTbl[] = {
    0, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,       

    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,      

    5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,       

    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,       

    6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,       

    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,       

    5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,       

    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,       

    7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,       

    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,       

    5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,     

    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,      

    6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,       

    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,      

    5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,      

    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0       

};

static  void  OS_InitEventList(void);
static  void  OS_InitMisc(void);
static  void  OS_InitRdyList(void);
static  void  OS_InitTaskIdle(void);
static  void  OS_InitTaskStat(void);
static  void  OS_InitTCBList(void);

void  OSInit (void)
{
#if OS_VERSION >= 204
    OSInitHookBegin();             /* Call port specific initialization code   */
#endif

    OS_InitMisc();                 /* Initialize miscellaneous variables       */

    OS_InitRdyList();             /* Initialize the Ready List                */
    OS_InitTCBList();             /* Initialize the free list of OS_TCBs      */
    OS_InitEventList();           /* Initialize the free list of OS_EVENTs    */

#if (OS_VERSION >= 251) && (OS_FLAG_EN > 0) && (OS_MAX_FLAGS > 0)
    OS_FlagInit();              /* Initialize the event flag structures     */
#endif

#if (OS_MEM_EN > 0) && (OS_MAX_MEM_PART > 0)
    OS_MemInit();           /* Initialize the memory manager            */
#endif

#if (OS_Q_EN > 0) && (OS_MAX_QS > 0)
    OS_QInit();              /* Initialize the message queue structures  */
#endif

    OS_InitTaskIdle();               /* Create the Idle Task              */
#if OS_TASK_STAT_EN > 0
    OS_InitTaskStat();            /* Create the Statistic Task         */
#endif

#if OS_VERSION >= 204
    OSInitHookEnd();                  /* Call port specific init. code      */
#endif
}

//void  OSIntEnter (void)和void  OSIntExit (void)是成对出现的。

void  OSIntEnter (void)
{
    if (OSRunning == TRUE) {
        if (OSIntNesting < 255) {
            OSIntNesting++;           /* Increment ISR nesting level           */
        }
    }
}

void  OSIntExit (void)
{
#if OS_CRITICAL_METHOD == 3             /* Allocate storage for CPU status register */
    OS_CPU_SR  cpu_sr;
#endif
   
   
    if (OSRunning == TRUE) {
        OS_ENTER_CRITICAL();
        if (OSIntNesting > 0) {        /* Prevent OSIntNesting from wrapping       */
            OSIntNesting--;
        }
        if ((OSIntNesting == 0) && (OSLockNesting == 0)) { /* Reschedule only if all ISRs complete ... */
            OSIntExitY    = OSUnMapTbl[OSRdyGrp];    /* ... and not locked.                      */
            OSPrioHighRdy = (INT8U)((OSIntExitY << 3) + OSUnMapTbl[OSRdyTbl[OSIntExitY]]);
            if (OSPrioHighRdy != OSPrioCur) { 

                                              /* No Ctx Sw if current task is highest rdy */
                OSTCBHighRdy  = OSTCBPrioTbl[OSPrioHighRdy];
                OSCtxSwCtr++;          /* Keep track of the number of ctx switches */
                OSIntCtxSw();            /* Perform interrupt level ctx switch       */
            }
        }
        OS_EXIT_CRITICAL();
    }
}

//void  OSSchedLock (void)和void  OSSchedUnlock (void)也是成对出现的。

#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;
#endif   
   
   
    if (OSRunning == TRUE) {         /* Make sure multitasking is running                  */
        OS_ENTER_CRITICAL();
        if (OSLockNesting < 255) {    /* Prevent OSLockNesting from wrapping back to 0      */
            OSLockNesting++;       /* Increment lock nesting level                       */
        }
        OS_EXIT_CRITICAL();
    }
}
#endif   

#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;
#endif   
   
   
    if (OSRunning == 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) && (OSIntNesting == 0)) {

                                           /* See if sched. enabled and not an ISR */
                OS_EXIT_CRITICAL();
                OS_Sched();         /* See if a HPT is ready                */
            } else {
                OS_EXIT_CRITICAL();
            }
        } else {
            OS_EXIT_CRITICAL();
        }
    }
}
#endif   

void  OSStart (void)
{
    INT8U y;
    INT8U x;


    if (OSRunning == FALSE) {
        y             = OSUnMapTbl[OSRdyGrp];  

                                    /* Find highest priority's task priority number   */
        x             = OSUnMapTbl[OSRdyTbl[y]];
        OSPrioHighRdy = (INT8U)((y << 3) + x);
        OSPrioCur     = OSPrioHighRdy;
        OSTCBHighRdy  = OSTCBPrioTbl[OSPrioHighRdy];

                                         /* Point to highest priority task ready to run    */
        OSTCBCur      = OSTCBHighRdy;
        OSStartHighRdy();                           

                                        /* Execute target specific code to start task     */
    }
}

//统计任务的初始化。

#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;
#endif   
   
   
    OSTimeDly(2);              /* Synchronize with clock tick            */
    OS_ENTER_CRITICAL();
    OSIdleCtr    = 0L;        /* Clear idle counter           */
    OS_EXIT_CRITICAL();
    OSTimeDly(OS_TICKS_PER_SEC);      /* Determine MAX. idle counter value for 1 second     */
    OS_ENTER_CRITICAL();
    OSIdleCtrMax = OSIdleCtr;    /* Store maximum idle counter count in 1 second       */
    OSStatRdy    = TRUE;
    OS_EXIT_CRITICAL();
}
#endif

//时钟节拍函数。

void  OSTimeTick (void)
{
#if OS_CRITICAL_METHOD == 3          /* Allocate storage for CPU status register */
    OS_CPU_SR  cpu_sr;
#endif   
    OS_TCB    *ptcb;


    OSTimeTickHook();          /* Call user definable hook     */
  //OSTimeTickHook1();

#if OS_TIME_GET_SET_EN > 0  
    OS_ENTER_CRITICAL();       /* Update the 32-bit tick counter           */
    OSTime++;
    OS_EXIT_CRITICAL();
#endif
    if (OSRunning == TRUE) {   
        ptcb = OSTCBList;           /* Point at first TCB in TCB list           */
        while (ptcb->OSTCBPrio != OS_IDLE_PRIO) {

                                              /* Go through all TCBs in TCB list          */
            OS_ENTER_CRITICAL();
            if (ptcb->OSTCBDly != 0) {     /* Delayed or waiting for event with TO     */
                if (--ptcb->OSTCBDly == 0) {   

                                             /* Decrement nbr of ticks to end of delay   */
                    if ((ptcb->OSTCBStat & OS_STAT_SUSPEND) == OS_STAT_RDY) {

                                                              /* Is task suspended?    */
                        OSRdyGrp               |= ptcb->OSTCBBitY;

                                                      /* No,  Make task R-to-R (timed out)*/
                        OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
                    } else {      

                                 /* Yes, Leave 1 tick to prevent ...         */
                        ptcb->OSTCBDly = 1;    

                                  /* ... loosing the task when the ...        */
                    }              /* ... suspension is removed.               */
                }
            }
            ptcb = ptcb->OSTCBNext;   /* Point at next TCB in TCB list            */
            OS_EXIT_CRITICAL();
        }
    }
}

//取得版本函数。

INT16U  OSVersion (void)
{
    return (OS_VERSION);
}

/*$PAGE*/

#if OS_TASK_DEL_EN > 0
void  OS_Dummy (void)
{
}
#endif

//事件控制块。

#if OS_EVENT_EN > 0
INT8U  OS_EventTaskRdy (OS_EVENT *pevent, void *msg, INT8U msk)
{
    OS_TCB *ptcb;
    INT8U   x;
    INT8U   y;
    INT8U   bitx;
    INT8U   bity;
    INT8U   prio;


    y    = OSUnMapTbl[pevent->OSEventGrp]; /* Find highest prio. task waiting for message   */
    bity = OSMapTbl[y];
    x    = OSUnMapTbl[pevent->OSEventTbl[y]];
    bitx = OSMapTbl[x];
    prio = (INT8U)((y << 3) + x);    * Find priority of task getting the msg         */
    if ((pevent->OSEventTbl[y] &= ~bitx) == 0x00) {  

                                      /* Remove this task from the waiting list        */
        pevent->OSEventGrp &= ~bity;    /* Clr group bit if this was only task pending   */
    }
    ptcb                 =  OSTCBPrioTbl[prio]; 

                                 /* Point to this task's OS_TCB                   */
    ptcb->OSTCBDly       =  0;      /* Prevent OSTimeTick() from readying task       */
    ptcb->OSTCBEventPtr  = (OS_EVENT *)0;  

                                     /* Unlink ECB from this task                     */
#if ((OS_Q_EN > 0) && (OS_MAX_QS > 0)) || (OS_MBOX_EN > 0)
    ptcb->OSTCBMsg       = msg;    /* Send message directly to waiting task         */
#else
    msg                  = msg;      /* Prevent compiler warning if not used          */
#endif
    ptcb->OSTCBStat     &= ~msk;       /* Clear bit associated with event type          */
    if (ptcb->OSTCBStat == OS_STAT_RDY) {      

                                         /* See if task is ready (could be susp'd)        */
        OSRdyGrp        |=  bity;      /* Put task in the ready to run list             */
        OSRdyTbl[y]     |=  bitx;
    }
    return (prio);
}
#endif

 

//事件等待

#if OS_EVENT_EN > 0
void  OS_EventTaskWait (OS_EVENT *pevent)
{
    OSTCBCur->OSTCBEventPtr = pevent;            /* Store pointer to event control block in TCB        */
    if ((OSRdyTbl[OSTCBCur->OSTCBY] &= ~OSTCBCur->OSTCBBitX) == 0x00) {   /* Task no longer ready      */
        OSRdyGrp &= ~OSTCBCur->OSTCBBitY;        /* Clear event grp bit if this was only task pending  */
    }
    pevent->OSEventTbl[OSTCBCur->OSTCBY] |= OSTCBCur->OSTCBBitX;          /* Put task in waiting list  */
    pevent->OSEventGrp                   |= OSTCBCur->OSTCBBitY;
}
#endif

 

//等待超时时,调用这个函数。

#if OS_EVENT_EN > 0
void  OS_EventTO (OS_EVENT *pevent)
{
    if ((pevent->OSEventTbl[OSTCBCur->OSTCBY] &= ~OSTCBCur->OSTCBBitX) == 0x00) {
        pevent->OSEventGrp &= ~OSTCBCur->OSTCBBitY;
    }
    OSTCBCur->OSTCBStat     = OS_STAT_RDY;      

                            /* Set status to ready              */
    OSTCBCur->OSTCBEventPtr = (OS_EVENT *)0;    

                           /* No longer waiting for event           */
}
#endif

/*
*********************************************************************************************************
*                             MAKE TASK READY TO RUN BASED ON EVENT OCCURING
*
* Description: This function is called by other uC/OS-II services and is used to ready a task that was
*              waiting for an event to occur.
*
* Arguments  : pevent    is a pointer to the event control block corresponding to the event.
*
*              msg       is a pointer to a message.  This pointer is used by message oriented services
*                        such as MAILBOXEs and QUEUEs.  The pointer is not used when called by other
*                        service functions.
*
*              msk       is a mask that is used to clear the status byte of the TCB.  For example,
*                        OSSemPost() will pass OS_STAT_SEM, OSMboxPost() will pass OS_STAT_MBOX etc.
*
* Returns    : none
*
* Note       : This function is INTERNAL to uC/OS-II and your application should not call it.
*********************************************************************************************************
*/

#if ((OS_Q_EN > 0) && (OS_MAX_QS > 0)) || (OS_MBOX_EN > 0) || (OS_SEM_EN > 0) || (OS_MUTEX_EN > 0)
void  OS_EventWaitListInit (OS_EVENT *pevent)
{
    INT8U  *ptbl;


    pevent->OSEventGrp = 0x00;                 /* No task waiting on event              */
    ptbl               = &pevent->OSEventTbl[0];

#if OS_EVENT_TBL_SIZE > 0
    *ptbl++            = 0x00;
#endif

#if OS_EVENT_TBL_SIZE > 1
    *ptbl++            = 0x00;
#endif

#if OS_EVENT_TBL_SIZE > 2
    *ptbl++            = 0x00;
#endif

#if OS_EVENT_TBL_SIZE > 3
    *ptbl++            = 0x00;
#endif

#if OS_EVENT_TBL_SIZE > 4
    *ptbl++            = 0x00;
#endif

#if OS_EVENT_TBL_SIZE > 5
    *ptbl++            = 0x00;
#endif

#if OS_EVENT_TBL_SIZE > 6
    *ptbl++            = 0x00;
#endif

#if OS_EVENT_TBL_SIZE > 7
    *ptbl              = 0x00;
#endif
}
#endif

/*
*********************************************************************************************************
*                                             INITIALIZATION
*                           INITIALIZE THE FREE LIST OF EVENT CONTROL BLOCKS
*
* Description: This function is called by OSInit() to initialize the free list of event control blocks.
*
* Arguments  : none
*
* Returns    : none
*********************************************************************************************************
*/

static  void  OS_InitEventList (void)
{
#if (OS_EVENT_EN > 0) && (OS_MAX_EVENTS > 0)
#if (OS_MAX_EVENTS > 1)
    INT16U     i;
    OS_EVENT  *pevent1;
    OS_EVENT  *pevent2;


    pevent1 = &OSEventTbl[0];
    pevent2 = &OSEventTbl[1];
    for (i = 0; i < (OS_MAX_EVENTS - 1); i++) {   

                                              /* Init. list of free EVENT control blocks  */
        pevent1->OSEventType = OS_EVENT_TYPE_UNUSED;
        pevent1->OSEventPtr  = pevent2;
        pevent1++;
        pevent2++;
    }
    pevent1->OSEventType = OS_EVENT_TYPE_UNUSED;
    pevent1->OSEventPtr  = (OS_EVENT *)0;
    OSEventFreeList      = &OSEventTbl[0];
#else
    OSEventFreeList              = &OSEventTbl[0];  

                                       /* Only have ONE event control block        */
    OSEventFreeList->OSEventType = OS_EVENT_TYPE_UNUSED;
    OSEventFreeList->OSEventPtr  = (OS_EVENT *)0;
#endif
#endif
}

/*
*********************************************************************************************************
*                                             INITIALIZATION
*                                    INITIALIZE MISCELLANEOUS VARIABLES
*
* Description: This function is called by OSInit() to initialize miscellaneous variables.
*
* Arguments  : none
*
* Returns    : none
*********************************************************************************************************
*/

static  void  OS_InitMisc (void)
{
#if OS_TIME_GET_SET_EN > 0  
    OSTime        = 0L;              /* Clear the 32-bit system clock            */
#endif

    OSIntNesting  = 0;                /* Clear the interrupt nesting counter      */
    OSLockNesting = 0;               /* Clear the scheduling lock counter        */

    OSTaskCtr     = 0;              /* Clear the number of tasks                */

    OSRunning     = FALSE;          /* Indicate that multitasking not started   */
   
    OSCtxSwCtr    = 0;                 /* Clear the context switch counter         */
    OSIdleCtr     = 0L;               /* Clear the 32-bit idle counter            */

#if (OS_TASK_STAT_EN > 0) && (OS_TASK_CREATE_EXT_EN > 0)
    OSIdleCtrRun  = 0L;
    OSIdleCtrMax  = 0L;
    OSStatRdy     = FALSE;          /* Statistic task is not ready              */
#endif
}

/*
*********************************************************************************************************
*                                             INITIALIZATION
*                                       INITIALIZE THE READY LIST
*
* Description: This function is called by OSInit() to initialize the Ready List.
*
* Arguments  : none
*
* Returns    : none
*********************************************************************************************************
*/

static  void  OS_InitRdyList (void)
{
    INT16U   i;
    INT8U   *prdytbl;


    OSRdyGrp      = 0x00;            /* Clear the ready list                     */
    prdytbl       = &OSRdyTbl[0];
    for (i = 0; i < OS_RDY_TBL_SIZE; i++) {
        *prdytbl++ = 0x00;
    }

    OSPrioCur     = 0;
    OSPrioHighRdy = 0;

    OSTCBHighRdy  = (OS_TCB *)0;                                
    OSTCBCur      = (OS_TCB *)0;
}

/*$PAGE*/
/*
*********************************************************************************************************
*                                             INITIALIZATION
*                                         CREATING THE IDLE TASK
*
* Description: This function creates the Idle Task.
*
* Arguments  : none
*
* Returns    : none
*********************************************************************************************************
*/

static  void  OS_InitTaskIdle (void)
{
#if OS_TASK_CREATE_EXT_EN > 0
    #if OS_STK_GROWTH == 1
    (void)OSTaskCreateExt(OS_TaskIdle,
                          (void *)0,      /* No arguments passed to OS_TaskIdle() */
                          &OSTaskIdleStk[OS_TASK_IDLE_STK_SIZE - 1],

                                                 /* Set Top-Of-Stack                     */
                          OS_IDLE_PRIO,         /* Lowest priority level                */
                          OS_TASK_IDLE_ID,
                          &OSTaskIdleStk[0],     /* Set Bottom-Of-Stack                  */
                          OS_TASK_IDLE_STK_SIZE,
                          (void *)0,             /* No TCB extension                     */
                          OS_TASK_OPT_STK_CHK | OS_TASK_OPT_STK_CLR);

                                                  /* Enable stack checking + clear stack  */
    #else
    (void)OSTaskCreateExt(OS_TaskIdle,
                          (void *)0,        /* No arguments passed to OS_TaskIdle() */
                          &OSTaskIdleStk[0],   /* Set Top-Of-Stack                     */
                          OS_IDLE_PRIO,     /* Lowest priority level                */
                          OS_TASK_IDLE_ID,
                          &OSTaskIdleStk[OS_TASK_IDLE_STK_SIZE - 1],

                                              /* Set Bottom-Of-Stack                  */
                          OS_TASK_IDLE_STK_SIZE,
                          (void *)0,          /* No TCB extension                     */
                          OS_TASK_OPT_STK_CHK | OS_TASK_OPT_STK_CLR);

                                                /* Enable stack checking + clear stack  */
    #endif
#else
    #if OS_STK_GROWTH == 1
    (void)OSTaskCreate(OS_TaskIdle,
                       (void *)0,
                       &OSTaskIdleStk[OS_TASK_IDLE_STK_SIZE - 1],
                       OS_IDLE_PRIO);
    #else
    (void)OSTaskCreate(OS_TaskIdle,
                       (void *)0,
                       &OSTaskIdleStk[0],
                       OS_IDLE_PRIO);
    #endif
#endif
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                             INITIALIZATION
*                                      CREATING THE STATISTIC TASK
*
* Description: This function creates the Statistic Task.
*
* Arguments  : none
*
* Returns    : none
*********************************************************************************************************
*/

#if OS_TASK_STAT_EN > 0
static  void  OS_InitTaskStat (void)
{
#if OS_TASK_CREATE_EXT_EN > 0
    #if OS_STK_GROWTH == 1
    (void)OSTaskCreateExt(OS_TaskStat,
                          (void *)0,        /* No args passed to OS_TaskStat()*/
                          &OSTaskStatStk[OS_TASK_STAT_STK_SIZE - 1],  

                                            /* Set Top-Of-Stack               */
                          OS_STAT_PRIO,       /* One higher than the idle task  */
                          OS_TASK_STAT_ID,
                          &OSTaskStatStk[0],    /* Set Bottom-Of-Stack            */
                          OS_TASK_STAT_STK_SIZE,
                          (void *)0,             /* No TCB extension               */
                          OS_TASK_OPT_STK_CHK | OS_TASK_OPT_STK_CLR); 

                                                        /* Enable stack checking + clear  */
    #else
    (void)OSTaskCreateExt(OS_TaskStat,
                          (void *)0,        /* No args passed to OS_TaskStat()*/
                          &OSTaskStatStk[0],     /* Set Top-Of-Stack               */
                          OS_STAT_PRIO,         /* One higher than the idle task  */
                          OS_TASK_STAT_ID,
                          &OSTaskStatStk[OS_TASK_STAT_STK_SIZE - 1],  

                                                    /* Set Bottom-Of-Stack            */
                          OS_TASK_STAT_STK_SIZE,
                          (void *)0,              /* No TCB extension               */
                          OS_TASK_OPT_STK_CHK | OS_TASK_OPT_STK_CLR); 

                                                        /* Enable stack checking + clear  */
    #endif
#else
    #if OS_STK_GROWTH == 1
    (void)OSTaskCreate(OS_TaskStat,
                       (void *)0,         /* No args passed to OS_TaskStat()*/
                       &OSTaskStatStk[OS_TASK_STAT_STK_SIZE - 1],     

                                                     /* Set Top-Of-Stack               */
                       OS_STAT_PRIO);          /* One higher than the idle task  */
    #else
    (void)OSTaskCreate(OS_TaskStat,
                       (void *)0,            /* No args passed to OS_TaskStat()*/
                       &OSTaskStatStk[0],     /* Set Top-Of-Stack               */
                       OS_STAT_PRIO);         /* One higher than the idle task  */
    #endif
#endif
}
#endif


/*$PAGE*/
/*
*********************************************************************************************************
*                                             INITIALIZATION
*                            INITIALIZE THE FREE LIST OF TASK CONTROL BLOCKS
*
* Description: This function is called by OSInit() to initialize the free list of OS_TCBs.
*
* Arguments  : none
*
* Returns    : none
*********************************************************************************************************
*/

static  void  OS_InitTCBList (void)
{
    INT8U    i;
    OS_TCB  *ptcb1;
    OS_TCB  *ptcb2;


    OSTCBList     = (OS_TCB *)0;     /* TCB Initialization                       */
    for (i = 0; i < (OS_LOWEST_PRIO + 1); i++) {    

                                    /* Clear the priority table                 */
        OSTCBPrioTbl[i] = (OS_TCB *)0;
    }
    ptcb1 = &OSTCBTbl[0];
    ptcb2 = &OSTCBTbl[1];
    for (i = 0; i < (OS_MAX_TASKS + OS_N_SYS_TASKS - 1); i++) { 

                                        /* Init. list of free TCBs                  */
        ptcb1->OSTCBNext = ptcb2;
        ptcb1++;
        ptcb2++;
    }
    ptcb1->OSTCBNext = (OS_TCB *)0;       /* Last OS_TCB                    */
    OSTCBFreeList    = &OSTCBTbl[0];
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                              SCHEDULER
*
* Description: This function is called by other uC/OS-II services to determine whether a new, high
*              priority task has been made ready to run.  This function is invoked by TASK level code
*              and is not used to reschedule tasks from ISRs (see OSIntExit() for ISR rescheduling).
*
* Arguments  : none
*
* Returns    : none
*
* Notes      : 1) This function is INTERNAL to uC/OS-II and your application should not call it.
*              2) Rescheduling is prevented when the scheduler is locked (see OS_SchedLock())
*********************************************************************************************************
*/

void  OS_Sched (void)
{
#if OS_CRITICAL_METHOD == 3       /* Allocate storage for CPU status register     */
    OS_CPU_SR  cpu_sr;
#endif   
    INT8U      y;


    OS_ENTER_CRITICAL();
    if ((OSIntNesting == 0) && (OSLockNesting == 0)) {

                                          /* Sched. only if all ISRs done & not locked    */
        y             = OSUnMapTbl[OSRdyGrp];        

                                        /* Get pointer to HPT ready to run              */
        OSPrioHighRdy = (INT8U)((y << 3) + OSUnMapTbl[OSRdyTbl[y]]);
        if (OSPrioHighRdy != OSPrioCur) {             

                                       /* No Ctx Sw if current task is highest rdy     */
            OSTCBHighRdy = OSTCBPrioTbl[OSPrioHighRdy];
            OSCtxSwCtr++;             /* Increment context switch counter             */
            OS_TASK_SW();        /* Perform a context switch                     */
        }
    }
    OS_EXIT_CRITICAL();
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                              IDLE TASK
*
* Description: This task is internal to uC/OS-II and executes whenever no other higher priority tasks
*              executes because they are ALL waiting for event(s) to occur.
*
* Arguments  : none
*
* Returns    : none
*
* Note(s)    : 1) OSTaskIdleHook() is called after the critical section to ensure that interrupts will be
*                 enabled for at least a few instructions.  On some processors (ex. Philips XA), enabling
*                 and then disabling interrupts didn't allow the processor enough time to have interrupts
*                 enabled before they were disabled again.  uC/OS-II would thus never recognize
*                 interrupts.
*              2) This hook has been added to allow you to do such things as STOP the CPU to conserve
*                 power.
*********************************************************************************************************
*/

//空闲任务。

void  OS_TaskIdle (void *pdata)
{
#if OS_CRITICAL_METHOD == 3       /* Allocate storage for CPU status register           */
    OS_CPU_SR  cpu_sr;
#endif   
   
   
    pdata = pdata;           /* Prevent compiler warning for not using 'pdata'     */
    for (;;) {
        OS_ENTER_CRITICAL();
        OSIdleCtr++;
        OS_EXIT_CRITICAL();
        OSTaskIdleHook();        /* Call user definable HOOK                           */
    }
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                            STATISTICS TASK
*
* Description: This task is internal to uC/OS-II and is used to compute some statistics about the
*              multitasking environment.  Specifically, OS_TaskStat() computes the CPU usage.
*              CPU usage is determined by:
*
*                                          OSIdleCtr
*                 OSCPUUsage = 100 * (1 - ------------)     (units are in %)
*                                         OSIdleCtrMax
*
* Arguments  : pdata     this pointer is not used at this time.
*
* Returns    : none
*
* Notes      : 1) This task runs at a priority level higher than the idle task.  In fact, it runs at the
*                 next higher priority, OS_IDLE_PRIO-1.
*              2) You can disable this task by setting the configuration #define OS_TASK_STAT_EN to 0.
*              3) We delay for 5 seconds in the beginning to allow the system to reach steady state and
*                 have all other tasks created before we do statistics.  You MUST have at least a delay
*                 of 2 seconds to allow for the system to establish the maximum value for the idle
*                 counter.
*********************************************************************************************************
*/

#if OS_TASK_STAT_EN > 0
void  OS_TaskStat (void *pdata)
{
#if OS_CRITICAL_METHOD == 3        /* Allocate storage for CPU status register           */
    OS_CPU_SR  cpu_sr;
#endif   
    INT32U     run;
    INT32U     max;
    INT8S      usage;


    pdata = pdata;           /* Prevent compiler warning for not using 'pdata'     */
    while (OSStatRdy == FALSE) {
        OSTimeDly(2 * OS_TICKS_PER_SEC);        

                                /* Wait until statistic task is ready                 */
    }
    max = OSIdleCtrMax / 100L;
    for (;;) {
        OS_ENTER_CRITICAL();
        OSIdleCtrRun = OSIdleCtr;    /* Obtain the of the idle counter for the past second */
        run          = OSIdleCtr;
        OSIdleCtr    = 0L;         /* Reset the idle counter for the next second         */
        OS_EXIT_CRITICAL();
        if (max > 0L) {
            usage = (INT8S)(100L - run / max);
            if (usage >= 0) {      /* Make sure we don't have a negative percentage      */
                OSCPUUsage = usage;
            } else {
                OSCPUUsage = 0;
            }
        } else {
            OSCPUUsage = 0;
            max        = OSIdleCtrMax / 100L;
        }
        OSTaskStatHook();     /* Invoke user definable hook                         */
        OSTimeDly(OS_TICKS_PER_SEC);            

                                  /* Accumulate OSIdleCtr for the next second           */
    }
}
#endif


/*$PAGE*/
/*
*********************************************************************************************************
*                                            INITIALIZE TCB
*
* Description: This function is internal to uC/OS-II and is used to initialize a Task Control Block when
*              a task is created (see OSTaskCreate() and OSTaskCreateExt()).
*
* Arguments  : prio          is the priority of the task being created
*
*              ptos          is a pointer to the task's top-of-stack assuming that the CPU registers
*                            have been placed on the stack.  Note that the top-of-stack corresponds to a
*                            'high' memory location is OS_STK_GROWTH is set to 1 and a 'low' memory
*                            location if OS_STK_GROWTH is set to 0.  Note that stack growth is CPU
*                            specific.
*
*              pbos          is a pointer to the bottom of stack.  A NULL pointer is passed if called by
*                            'OSTaskCreate()'.
*
*              id            is the task's ID (0..65535)
*
*              stk_size      is the size of the stack (in 'stack units').  If the stack units are INT8Us
*                            then, 'stk_size' contains the number of bytes for the stack.  If the stack
*                            units are INT32Us then, the stack contains '4 * stk_size' bytes.  The stack
*                            units are established by the #define constant OS_STK which is CPU
*                            specific.  'stk_size' is 0 if called by 'OSTaskCreate()'.
*
*              pext          is a pointer to a user supplied memory area that is used to extend the task
*                            control block.  This allows you to store the contents of floating-point
*                            registers, MMU registers or anything else you could find useful during a
*                            context switch.  You can even assign a name to each task and store this name
*                            in this TCB extension.  A NULL pointer is passed if called by OSTaskCreate().
*
*              opt           options as passed to 'OSTaskCreateExt()' or,
*                            0 if called from 'OSTaskCreate()'.
*
* Returns    : OS_NO_ERR         if the call was successful
*              OS_NO_MORE_TCB    if there are no more free TCBs to be allocated and thus, the task cannot
*                                be created.
*
* Note       : This function is INTERNAL to uC/OS-II and your application should not call it.
*********************************************************************************************************
*/

INT8U  OS_TCBInit (INT8U prio, OS_STK *ptos, OS_STK *pbos, INT16U id, INT32U stk_size, void *pext, INT16U opt)
{
#if OS_CRITICAL_METHOD == 3        /* Allocate storage for CPU status register */
    OS_CPU_SR  cpu_sr;
#endif   
    OS_TCB    *ptcb;


    OS_ENTER_CRITICAL();
    ptcb = OSTCBFreeList;                                 

                                   /* Get a free TCB from the free TCB list    */
    if (ptcb != (OS_TCB *)0) {
        OSTCBFreeList        = ptcb->OSTCBNext;  

                                             /* Update pointer to free TCB list     */
        OS_EXIT_CRITICAL();
        ptcb->OSTCBStkPtr    = ptos;           /* Load Stack pointer in TCB       */
        ptcb->OSTCBPrio      = (INT8U)prio;     /* Load task priority into TCB     */
        ptcb->OSTCBStat      = OS_STAT_RDY;     /* Task is ready to run           */
        ptcb->OSTCBDly       = 0;                /* Task is not delayed         */

#if OS_TASK_CREATE_EXT_EN > 0
        ptcb->OSTCBExtPtr    = pext;           /* Store pointer to TCB extension           */
        ptcb->OSTCBStkSize   = stk_size;       /* Store stack size                         */
        ptcb->OSTCBStkBottom = pbos;            /* Store pointer to bottom of stack         */
        ptcb->OSTCBOpt       = opt;           /* Store task options        */
        ptcb->OSTCBId        = id;             /* Store task ID           */
#else
        pext                 = pext;            /* Prevent compiler warning if not used     */
        stk_size             = stk_size;
        pbos                 = pbos;
        opt                  = opt;
        id                   = id;
#endif

#if OS_TASK_DEL_EN > 0
        ptcb->OSTCBDelReq    = OS_NO_ERR;
#endif

        ptcb->OSTCBY         = prio >> 3;       /* Pre-compute X, Y, BitX and BitY        */
        ptcb->OSTCBBitY      = OSMapTbl[ptcb->OSTCBY];
        ptcb->OSTCBX         = prio & 0x07;
        ptcb->OSTCBBitX      = OSMapTbl[ptcb->OSTCBX];

#if OS_EVENT_EN > 0
        ptcb->OSTCBEventPtr  = (OS_EVENT *)0;   /* Task is not pending on an event      */
#endif

#if (OS_VERSION >= 251) && (OS_FLAG_EN > 0) && (OS_MAX_FLAGS > 0) && (OS_TASK_DEL_EN > 0)
        ptcb->OSTCBFlagNode  = (OS_FLAG_NODE *)0;         

                                         /* Task is not pending on an event flag     */
#endif

#if (OS_MBOX_EN > 0) || ((OS_Q_EN > 0) && (OS_MAX_QS > 0))
        ptcb->OSTCBMsg       = (void *)0;                 

                                    /* No message received                      */
#endif

#if OS_VERSION >= 204
        OSTCBInitHook(ptcb);
#endif

        OSTaskCreateHook(ptcb);                      /* Call user defined hook         */
       
        OS_ENTER_CRITICAL();
        OSTCBPrioTbl[prio] = ptcb;
        ptcb->OSTCBNext    = OSTCBList;                 /* Link into TCB chain          */
        ptcb->OSTCBPrev    = (OS_TCB *)0;
        if (OSTCBList != (OS_TCB *)0) {
            OSTCBList->OSTCBPrev = ptcb;
        }
        OSTCBList               = ptcb;
        OSRdyGrp               |= ptcb->OSTCBBitY;       

                                                /* Make task ready to run        */
        OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
        OS_EXIT_CRITICAL();
        return (OS_NO_ERR);
    }
    OS_EXIT_CRITICAL();
    return (OS_NO_MORE_TCB);
}
//888888888888888888888888888888
/*INT8U t=0;
void OSTimeTickHook1(void)
{
 PC_DispChar(t, 8,   //显示字符的位置
  s,
  DISP_BGND_BLACK+DISP_FGND_WHITE );
 t+=1;
}
 */  

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