www.pudn.com > ucos.rar > os_task.c, change:2010-06-03,size:57757b


/* 
********************************************************************************************************* 
*                                                uC/OS-II 
*                                          The Real-Time Kernel 
*                                            TASK MANAGEMENT 
* 
*                              (c) Copyright 1992-2009, Micrium, Weston, FL 
*                                           All Rights Reserved 
* 
* File    : OS_TASK.C 
* By      : Jean J. Labrosse 
* Version : V2.91 
* 
* LICENSING TERMS: 
* --------------- 
*   uC/OS-II is provided in source form for FREE evaluation, for educational use or for peaceful research. 
* If you plan on using  uC/OS-II  in a commercial product you need to contact Micriµm to properly license 
* its use in your product. We provide ALL the source code for your convenience and to help you experience 
* uC/OS-II.   The fact that the  source is provided does  NOT  mean that you can use it without  paying a 
* licensing fee. 
********************************************************************************************************* 
*/ 
 
#ifndef  OS_MASTER_FILE 
#include <ucos_ii.h> 
#endif 
 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                        CHANGE PRIORITY OF A TASK 
* 
* Description: This function allows you to change the priority of a task dynamically.  Note that the new 
*              priority MUST be available. 
* 
* Arguments  : oldp     is the old priority 
* 
*              newp     is the new priority 
* 
* Returns    : OS_ERR_NONE            is the call was successful 
*              OS_ERR_PRIO_INVALID    if the priority you specify is higher that the maximum allowed 
*                                     (i.e. >= OS_LOWEST_PRIO) 
*              OS_ERR_PRIO_EXIST      if the new priority already exist. 
*              OS_ERR_PRIO            there is no task with the specified OLD priority (i.e. the OLD task does 
*                                     not exist. 
*              OS_ERR_TASK_NOT_EXIST  if the task is assigned to a Mutex PIP. 
********************************************************************************************************* 
*/ 
 
#if OS_TASK_CHANGE_PRIO_EN > 0u 
INT8U  OSTaskChangePrio (INT8U  oldprio, 
                         INT8U  newprio) 
{ 
#if (OS_EVENT_EN) 
    OS_EVENT  *pevent; 
#if (OS_EVENT_MULTI_EN > 0u) 
    OS_EVENT **pevents; 
#endif 
#endif 
    OS_TCB    *ptcb; 
    INT8U      y_new; 
    INT8U      x_new; 
    INT8U      y_old; 
    OS_PRIO    bity_new; 
    OS_PRIO    bitx_new; 
    OS_PRIO    bity_old; 
    OS_PRIO    bitx_old; 
#if OS_CRITICAL_METHOD == 3u 
    OS_CPU_SR  cpu_sr = 0u;                                 /* Storage for CPU status register         */ 
#endif 
 
 
/*$PAGE*/ 
#if OS_ARG_CHK_EN > 0u 
    if (oldprio >= OS_LOWEST_PRIO) { 
        if (oldprio != OS_PRIO_SELF) { 
            return (OS_ERR_PRIO_INVALID); 
        } 
    } 
    if (newprio >= OS_LOWEST_PRIO) { 
        return (OS_ERR_PRIO_INVALID); 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    if (OSTCBPrioTbl[newprio] != (OS_TCB *)0) {             /* New priority must not already exist     */ 
        OS_EXIT_CRITICAL(); 
        return (OS_ERR_PRIO_EXIST); 
    } 
    if (oldprio == OS_PRIO_SELF) {                          /* See if changing self                    */ 
        oldprio = OSTCBCur->OSTCBPrio;                      /* Yes, get priority                       */ 
    } 
    ptcb = OSTCBPrioTbl[oldprio]; 
    if (ptcb == (OS_TCB *)0) {                              /* Does task to change exist?              */ 
        OS_EXIT_CRITICAL();                                 /* No, can't change its priority!          */ 
        return (OS_ERR_PRIO); 
    } 
    if (ptcb == OS_TCB_RESERVED) {                          /* Is task assigned to Mutex               */ 
        OS_EXIT_CRITICAL();                                 /* No, can't change its priority!          */ 
        return (OS_ERR_TASK_NOT_EXIST); 
    } 
#if OS_LOWEST_PRIO <= 63u 
    y_new                 = (INT8U)(newprio >> 3u);         /* Yes, compute new TCB fields             */ 
    x_new                 = (INT8U)(newprio & 0x07u); 
#else 
    y_new                 = (INT8U)((INT8U)(newprio >> 4u) & 0x0Fu); 
    x_new                 = (INT8U)(newprio & 0x0Fu); 
#endif 
    bity_new              = (OS_PRIO)(1uL << y_new); 
    bitx_new              = (OS_PRIO)(1uL << x_new); 
 
    OSTCBPrioTbl[oldprio] = (OS_TCB *)0;                    /* Remove TCB from old priority            */ 
    OSTCBPrioTbl[newprio] =  ptcb;                          /* Place pointer to TCB @ new priority     */ 
    y_old                 =  ptcb->OSTCBY; 
    bity_old              =  ptcb->OSTCBBitY; 
    bitx_old              =  ptcb->OSTCBBitX; 
    if ((OSRdyTbl[y_old] &   bitx_old) != 0u) {             /* If task is ready make it not            */ 
         OSRdyTbl[y_old] &= (OS_PRIO)~bitx_old; 
         if (OSRdyTbl[y_old] == 0u) { 
             OSRdyGrp &= (OS_PRIO)~bity_old; 
         } 
         OSRdyGrp        |= bity_new;                       /* Make new priority ready to run          */ 
         OSRdyTbl[y_new] |= bitx_new; 
    } 
 
#if (OS_EVENT_EN) 
    pevent = ptcb->OSTCBEventPtr; 
    if (pevent != (OS_EVENT *)0) { 
        pevent->OSEventTbl[y_old] &= (OS_PRIO)~bitx_old;    /* Remove old task prio from wait list     */ 
        if (pevent->OSEventTbl[y_old] == 0u) { 
            pevent->OSEventGrp    &= (OS_PRIO)~bity_old; 
        } 
        pevent->OSEventGrp        |= bity_new;              /* Add    new task prio to   wait list     */ 
        pevent->OSEventTbl[y_new] |= bitx_new; 
    } 
#if (OS_EVENT_MULTI_EN > 0u) 
    if (ptcb->OSTCBEventMultiPtr != (OS_EVENT **)0) { 
        pevents =  ptcb->OSTCBEventMultiPtr; 
        pevent  = *pevents; 
        while (pevent != (OS_EVENT *)0) { 
            pevent->OSEventTbl[y_old] &= (OS_PRIO)~bitx_old;   /* Remove old task prio from wait lists */ 
            if (pevent->OSEventTbl[y_old] == 0u) { 
                pevent->OSEventGrp    &= (OS_PRIO)~bity_old; 
            } 
            pevent->OSEventGrp        |= bity_new;          /* Add    new task prio to   wait lists    */ 
            pevent->OSEventTbl[y_new] |= bitx_new; 
            pevents++; 
            pevent                     = *pevents; 
        } 
    } 
#endif 
#endif 
 
    ptcb->OSTCBPrio = newprio;                              /* Set new task priority                   */ 
    ptcb->OSTCBY    = y_new; 
    ptcb->OSTCBX    = x_new; 
    ptcb->OSTCBBitY = bity_new; 
    ptcb->OSTCBBitX = bitx_new; 
    OS_EXIT_CRITICAL(); 
    if (OSRunning == OS_TRUE) { 
        OS_Sched();                                         /* Find new highest priority task          */ 
    } 
    return (OS_ERR_NONE); 
} 
#endif 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                            CREATE A TASK 
* 
* Description: This function is used to have uC/OS-II manage the execution of a task.  Tasks can either 
*              be created prior to the start of multitasking or by a running task.  A task cannot be 
*              created by an ISR. 
* 
* Arguments  : task     is a pointer to the task's code 
* 
*              p_arg    is a pointer to an optional data area which can be used to pass parameters to 
*                       the task when the task first executes.  Where the task is concerned it thinks 
*                       it was invoked and passed the argument 'p_arg' as follows: 
* 
*                           void Task (void *p_arg) 
*                           { 
*                               for (;;) { 
*                                   Task code; 
*                               } 
*                           } 
* 
*              ptos     is a pointer to the task's top of stack.  If the configuration constant 
*                       OS_STK_GROWTH is set to 1, the stack is assumed to grow downward (i.e. from high 
*                       memory to low memory).  'pstk' will thus point to the highest (valid) memory 
*                       location of the stack.  If OS_STK_GROWTH is set to 0, 'pstk' will point to the 
*                       lowest memory location of the stack and the stack will grow with increasing 
*                       memory locations. 
* 
*              prio     is the task's priority.  A unique priority MUST be assigned to each task and the 
*                       lower the number, the higher the priority. 
* 
* Returns    : OS_ERR_NONE             if the function was successful. 
*              OS_PRIO_EXIT            if the task priority already exist 
*                                      (each task MUST have a unique priority). 
*              OS_ERR_PRIO_INVALID     if the priority you specify is higher that the maximum allowed 
*                                      (i.e. >= OS_LOWEST_PRIO) 
*              OS_ERR_TASK_CREATE_ISR  if you tried to create a task from an ISR. 
********************************************************************************************************* 
*/ 
 
#if OS_TASK_CREATE_EN > 0u 
INT8U  OSTaskCreate (void   (*task)(void *p_arg), 
                     void    *p_arg, 
                     OS_STK  *ptos, 
                     INT8U    prio) 
{ 
    OS_STK    *psp; 
    INT8U      err; 
#if OS_CRITICAL_METHOD == 3u                 /* Allocate storage for CPU status register               */ 
    OS_CPU_SR  cpu_sr = 0u; 
#endif 
 
 
 
#ifdef OS_SAFETY_CRITICAL_IEC61508 
    if (OSSafetyCriticalStartFlag == OS_TRUE) { 
        OS_SAFETY_CRITICAL_EXCEPTION(); 
    } 
#endif 
 
#if OS_ARG_CHK_EN > 0u 
    if (prio > OS_LOWEST_PRIO) {             /* Make sure priority is within allowable range           */ 
        return (OS_ERR_PRIO_INVALID); 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    if (OSIntNesting > 0u) {                 /* Make sure we don't create the task from within an ISR  */ 
        OS_EXIT_CRITICAL(); 
        return (OS_ERR_TASK_CREATE_ISR); 
    } 
    if (OSTCBPrioTbl[prio] == (OS_TCB *)0) { /* Make sure task doesn't already exist at this priority  */ 
        OSTCBPrioTbl[prio] = OS_TCB_RESERVED;/* Reserve the priority to prevent others from doing ...  */ 
                                             /* ... the same thing until task is created.              */ 
        OS_EXIT_CRITICAL(); 
        psp = OSTaskStkInit(task, p_arg, ptos, 0u);             /* Initialize the task's stack         */ 
        err = OS_TCBInit(prio, psp, (OS_STK *)0, 0u, 0u, (void *)0, 0u); 
        if (err == OS_ERR_NONE) { 
            if (OSRunning == OS_TRUE) {      /* Find highest priority task if multitasking has started */ 
                OS_Sched(); 
            } 
        } else { 
            OS_ENTER_CRITICAL(); 
            OSTCBPrioTbl[prio] = (OS_TCB *)0;/* Make this priority available to others                 */ 
            OS_EXIT_CRITICAL(); 
        } 
        return (err); 
    } 
    OS_EXIT_CRITICAL(); 
    return (OS_ERR_PRIO_EXIST); 
} 
#endif 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                     CREATE A TASK (Extended Version) 
* 
* Description: This function is used to have uC/OS-II manage the execution of a task.  Tasks can either 
*              be created prior to the start of multitasking or by a running task.  A task cannot be 
*              created by an ISR.  This function is similar to OSTaskCreate() except that it allows 
*              additional information about a task to be specified. 
* 
* Arguments  : task      is a pointer to the task's code 
* 
*              p_arg     is a pointer to an optional data area which can be used to pass parameters to 
*                        the task when the task first executes.  Where the task is concerned it thinks 
*                        it was invoked and passed the argument 'p_arg' as follows: 
* 
*                            void Task (void *p_arg) 
*                            { 
*                                for (;;) { 
*                                    Task code; 
*                                } 
*                            } 
* 
*              ptos      is a pointer to the task's top of stack.  If the configuration constant 
*                        OS_STK_GROWTH is set to 1, the stack is assumed to grow downward (i.e. from high 
*                        memory to low memory).  'ptos' will thus point to the highest (valid) memory 
*                        location of the stack.  If OS_STK_GROWTH is set to 0, 'ptos' will point to the 
*                        lowest memory location of the stack and the stack will grow with increasing 
*                        memory locations.  'ptos' MUST point to a valid 'free' data item. 
* 
*              prio      is the task's priority.  A unique priority MUST be assigned to each task and the 
*                        lower the number, the higher the priority. 
* 
*              id        is the task's ID (0..65535) 
* 
*              pbos      is a pointer to the task's bottom of stack.  If the configuration constant 
*                        OS_STK_GROWTH is set to 1, the stack is assumed to grow downward (i.e. from high 
*                        memory to low memory).  'pbos' will thus point to the LOWEST (valid) memory 
*                        location of the stack.  If OS_STK_GROWTH is set to 0, 'pbos' will point to the 
*                        HIGHEST memory location of the stack and the stack will grow with increasing 
*                        memory locations.  'pbos' MUST point to a valid 'free' data item. 
* 
*              stk_size  is the size of the stack in number of elements.  If OS_STK is set to INT8U, 
*                        'stk_size' corresponds to the number of bytes available.  If OS_STK is set to 
*                        INT16U, 'stk_size' contains the number of 16-bit entries available.  Finally, if 
*                        OS_STK is set to INT32U, 'stk_size' contains the number of 32-bit entries 
*                        available on the stack. 
* 
*              pext      is a pointer to a user supplied memory location which is used as a TCB extension. 
*                        For example, this user memory can hold the contents of floating-point registers 
*                        during a context switch, the time each task takes to execute, the number of times 
*                        the task has been switched-in, etc. 
* 
*              opt       contains additional information (or options) about the behavior of the task.  The 
*                        LOWER 8-bits are reserved by uC/OS-II while the upper 8 bits can be application 
*                        specific.  See OS_TASK_OPT_??? in uCOS-II.H.  Current choices are: 
* 
*                        OS_TASK_OPT_STK_CHK      Stack checking to be allowed for the task 
*                        OS_TASK_OPT_STK_CLR      Clear the stack when the task is created 
*                        OS_TASK_OPT_SAVE_FP      If the CPU has floating-point registers, save them 
*                                                 during a context switch. 
* 
* Returns    : OS_ERR_NONE             if the function was successful. 
*              OS_PRIO_EXIT            if the task priority already exist 
*                                      (each task MUST have a unique priority). 
*              OS_ERR_PRIO_INVALID     if the priority you specify is higher that the maximum allowed 
*                                      (i.e. > OS_LOWEST_PRIO) 
*              OS_ERR_TASK_CREATE_ISR  if you tried to create a task from an ISR. 
********************************************************************************************************* 
*/ 
/*$PAGE*/ 
#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) 
{ 
    OS_STK    *psp; 
    INT8U      err; 
#if OS_CRITICAL_METHOD == 3u                 /* Allocate storage for CPU status register               */ 
    OS_CPU_SR  cpu_sr = 0u; 
#endif 
 
 
 
#ifdef OS_SAFETY_CRITICAL_IEC61508 
    if (OSSafetyCriticalStartFlag == OS_TRUE) { 
        OS_SAFETY_CRITICAL_EXCEPTION(); 
    } 
#endif 
 
#if OS_ARG_CHK_EN > 0u 
    if (prio > OS_LOWEST_PRIO) {             /* Make sure priority is within allowable range           */ 
        return (OS_ERR_PRIO_INVALID); 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    if (OSIntNesting > 0u) {                 /* Make sure we don't create the task from within an ISR  */ 
        OS_EXIT_CRITICAL(); 
        return (OS_ERR_TASK_CREATE_ISR); 
    } 
    if (OSTCBPrioTbl[prio] == (OS_TCB *)0) { /* Make sure task doesn't already exist at this priority  */ 
        OSTCBPrioTbl[prio] = OS_TCB_RESERVED;/* Reserve the priority to prevent others from doing ...  */ 
                                             /* ... the same thing until task is created.              */ 
        OS_EXIT_CRITICAL(); 
 
#if (OS_TASK_STAT_STK_CHK_EN > 0u) 
        OS_TaskStkClr(pbos, stk_size, opt);                    /* Clear the task stack (if needed)     */ 
#endif 
 
        psp = OSTaskStkInit(task, p_arg, ptos, opt);           /* Initialize the task's stack          */ 
        err = OS_TCBInit(prio, psp, pbos, id, stk_size, pext, opt); 
        if (err == OS_ERR_NONE) { 
            if (OSRunning == OS_TRUE) {                        /* Find HPT if multitasking has started */ 
                OS_Sched(); 
            } 
        } else { 
            OS_ENTER_CRITICAL(); 
            OSTCBPrioTbl[prio] = (OS_TCB *)0;                  /* Make this priority avail. to others  */ 
            OS_EXIT_CRITICAL(); 
        } 
        return (err); 
    } 
    OS_EXIT_CRITICAL(); 
    return (OS_ERR_PRIO_EXIST); 
} 
#endif 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                            DELETE A TASK 
* 
* Description: This function allows you to delete a task.  The calling task can delete itself by 
*              its own priority number.  The deleted task is returned to the dormant state and can be 
*              re-activated by creating the deleted task again. 
* 
* Arguments  : prio    is the priority of the task to delete.  Note that you can explicitely delete 
*                      the current task without knowing its priority level by setting 'prio' to 
*                      OS_PRIO_SELF. 
* 
* Returns    : OS_ERR_NONE             if the call is successful 
*              OS_ERR_TASK_DEL_IDLE    if you attempted to delete uC/OS-II's idle task 
*              OS_ERR_PRIO_INVALID     if the priority you specify is higher that the maximum allowed 
*                                      (i.e. >= OS_LOWEST_PRIO) or, you have not specified OS_PRIO_SELF. 
*              OS_ERR_TASK_DEL         if the task is assigned to a Mutex PIP. 
*              OS_ERR_TASK_NOT_EXIST   if the task you want to delete does not exist. 
*              OS_ERR_TASK_DEL_ISR     if you tried to delete a task from an ISR 
* 
* Notes      : 1) To reduce interrupt latency, OSTaskDel() 'disables' the task: 
*                    a) by making it not ready 
*                    b) by removing it from any wait lists 
*                    c) by preventing OSTimeTick() from making the task ready to run. 
*                 The task can then be 'unlinked' from the miscellaneous structures in uC/OS-II. 
*              2) The function OS_Dummy() is called after OS_EXIT_CRITICAL() because, on most processors, 
*                 the next instruction following the enable interrupt instruction is ignored. 
*              3) An ISR cannot delete a task. 
*              4) The lock nesting counter is incremented because, for a brief instant, if the current 
*                 task is being deleted, the current task would not be able to be rescheduled because it 
*                 is removed from the ready list.  Incrementing the nesting counter prevents another task 
*                 from being schedule.  This means that an ISR would return to the current task which is 
*                 being deleted.  The rest of the deletion would thus be able to be completed. 
********************************************************************************************************* 
*/ 
 
#if OS_TASK_DEL_EN > 0u 
INT8U  OSTaskDel (INT8U prio) 
{ 
#if (OS_FLAG_EN > 0u) && (OS_MAX_FLAGS > 0u) 
    OS_FLAG_NODE *pnode; 
#endif 
    OS_TCB       *ptcb; 
#if OS_CRITICAL_METHOD == 3u                            /* Allocate storage for CPU status register    */ 
    OS_CPU_SR     cpu_sr = 0u; 
#endif 
 
 
 
    if (OSIntNesting > 0u) {                            /* See if trying to delete from ISR            */ 
        return (OS_ERR_TASK_DEL_ISR); 
    } 
    if (prio == OS_TASK_IDLE_PRIO) {                    /* Not allowed to delete idle task             */ 
        return (OS_ERR_TASK_DEL_IDLE); 
    } 
#if OS_ARG_CHK_EN > 0u 
    if (prio >= OS_LOWEST_PRIO) {                       /* Task priority valid ?                       */ 
        if (prio != OS_PRIO_SELF) { 
            return (OS_ERR_PRIO_INVALID); 
        } 
    } 
#endif 
 
/*$PAGE*/ 
    OS_ENTER_CRITICAL(); 
    if (prio == OS_PRIO_SELF) {                         /* See if requesting to delete self            */ 
        prio = OSTCBCur->OSTCBPrio;                     /* Set priority to delete to current           */ 
    } 
    ptcb = OSTCBPrioTbl[prio]; 
    if (ptcb == (OS_TCB *)0) {                          /* Task to delete must exist                   */ 
        OS_EXIT_CRITICAL(); 
        return (OS_ERR_TASK_NOT_EXIST); 
    } 
    if (ptcb == OS_TCB_RESERVED) {                      /* Must not be assigned to Mutex               */ 
        OS_EXIT_CRITICAL(); 
        return (OS_ERR_TASK_DEL); 
    } 
 
    OSRdyTbl[ptcb->OSTCBY] &= (OS_PRIO)~ptcb->OSTCBBitX; 
    if (OSRdyTbl[ptcb->OSTCBY] == 0u) {                 /* Make task not ready                         */ 
        OSRdyGrp           &= (OS_PRIO)~ptcb->OSTCBBitY; 
    } 
 
#if (OS_EVENT_EN) 
    if (ptcb->OSTCBEventPtr != (OS_EVENT *)0) { 
        OS_EventTaskRemove(ptcb, ptcb->OSTCBEventPtr);  /* Remove this task from any event   wait list */ 
    } 
#if (OS_EVENT_MULTI_EN > 0u) 
    if (ptcb->OSTCBEventMultiPtr != (OS_EVENT **)0) {   /* Remove this task from any events' wait lists*/ 
        OS_EventTaskRemoveMulti(ptcb, ptcb->OSTCBEventMultiPtr); 
    } 
#endif 
#endif 
 
#if (OS_FLAG_EN > 0u) && (OS_MAX_FLAGS > 0u) 
    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      = 0u;                           /* Prevent OSTimeTick() from updating          */ 
    ptcb->OSTCBStat     = OS_STAT_RDY;                  /* Prevent task from being resumed             */ 
    ptcb->OSTCBStatPend = OS_STAT_PEND_OK; 
    if (OSLockNesting < 255u) {                         /* Make sure we don't context switch           */ 
        OSLockNesting++; 
    } 
    OS_EXIT_CRITICAL();                                 /* Enabling INT. ignores next instruc.         */ 
    OS_Dummy();                                         /* ... Dummy ensures that INTs will be         */ 
    OS_ENTER_CRITICAL();                                /* ... disabled HERE!                          */ 
    if (OSLockNesting > 0u) {                           /* Remove context switch lock                  */ 
        OSLockNesting--; 
    } 
    OSTaskDelHook(ptcb);                                /* Call user defined hook                      */ 
    OSTaskCtr--;                                        /* One less task being managed                 */ 
    OSTCBPrioTbl[prio] = (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; 
#if OS_TASK_NAME_EN > 0u 
    ptcb->OSTCBTaskName = (INT8U *)(void *)"?"; 
#endif 
    OS_EXIT_CRITICAL(); 
    if (OSRunning == OS_TRUE) { 
        OS_Sched();                                     /* Find new highest priority task              */ 
    } 
    return (OS_ERR_NONE); 
} 
#endif 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                    REQUEST THAT A TASK DELETE ITSELF 
* 
* Description: This function is used to: 
*                   a) notify a task to delete itself. 
*                   b) to see if a task requested that the current task delete itself. 
*              This function is a little tricky to understand.  Basically, you have a task that needs 
*              to be deleted however, this task has resources that it has allocated (memory buffers, 
*              semaphores, mailboxes, queues etc.).  The task cannot be deleted otherwise these 
*              resources would not be freed.  The requesting task calls OSTaskDelReq() to indicate that 
*              the task needs to be deleted.  Deleting of the task is however, deferred to the task to 
*              be deleted.  For example, suppose that task #10 needs to be deleted.  The requesting task 
*              example, task #5, would call OSTaskDelReq(10).  When task #10 gets to execute, it calls 
*              this function by specifying OS_PRIO_SELF and monitors the returned value.  If the return 
*              value is OS_ERR_TASK_DEL_REQ, another task requested a task delete.  Task #10 would look like 
*              this: 
* 
*                   void Task(void *p_arg) 
*                   { 
*                       . 
*                       . 
*                       while (1) { 
*                           OSTimeDly(1); 
*                           if (OSTaskDelReq(OS_PRIO_SELF) == OS_ERR_TASK_DEL_REQ) { 
*                               Release any owned resources; 
*                               De-allocate any dynamic memory; 
*                               OSTaskDel(OS_PRIO_SELF); 
*                           } 
*                       } 
*                   } 
* 
* Arguments  : prio    is the priority of the task to request the delete from 
* 
* Returns    : OS_ERR_NONE            if the task exist and the request has been registered 
*              OS_ERR_TASK_NOT_EXIST  if the task has been deleted.  This allows the caller to know whether 
*                                     the request has been executed. 
*              OS_ERR_TASK_DEL        if the task is assigned to a Mutex. 
*              OS_ERR_TASK_DEL_IDLE   if you requested to delete uC/OS-II's idle task 
*              OS_ERR_PRIO_INVALID    if the priority you specify is higher that the maximum allowed 
*                                     (i.e. >= OS_LOWEST_PRIO) or, you have not specified OS_PRIO_SELF. 
*              OS_ERR_TASK_DEL_REQ    if a task (possibly another task) requested that the running task be 
*                                     deleted. 
********************************************************************************************************* 
*/ 
/*$PAGE*/ 
#if OS_TASK_DEL_EN > 0u 
INT8U  OSTaskDelReq (INT8U prio) 
{ 
    INT8U      stat; 
    OS_TCB    *ptcb; 
#if OS_CRITICAL_METHOD == 3u                     /* Allocate storage for CPU status register           */ 
    OS_CPU_SR  cpu_sr = 0u; 
#endif 
 
 
 
    if (prio == OS_TASK_IDLE_PRIO) {                            /* Not allowed to delete idle task     */ 
        return (OS_ERR_TASK_DEL_IDLE); 
    } 
#if OS_ARG_CHK_EN > 0u 
    if (prio >= OS_LOWEST_PRIO) {                               /* Task priority valid ?               */ 
        if (prio != OS_PRIO_SELF) { 
            return (OS_ERR_PRIO_INVALID); 
        } 
    } 
#endif 
    if (prio == OS_PRIO_SELF) {                                 /* See if a task is requesting to ...  */ 
        OS_ENTER_CRITICAL();                                    /* ... this task to delete itself      */ 
        stat = OSTCBCur->OSTCBDelReq;                           /* Return request status to caller     */ 
        OS_EXIT_CRITICAL(); 
        return (stat); 
    } 
    OS_ENTER_CRITICAL(); 
    ptcb = OSTCBPrioTbl[prio]; 
    if (ptcb == (OS_TCB *)0) {                                  /* Task to delete must exist           */ 
        OS_EXIT_CRITICAL(); 
        return (OS_ERR_TASK_NOT_EXIST);                         /* Task must already be deleted        */ 
    } 
    if (ptcb == OS_TCB_RESERVED) {                              /* Must NOT be assigned to a Mutex     */ 
        OS_EXIT_CRITICAL(); 
        return (OS_ERR_TASK_DEL); 
    } 
    ptcb->OSTCBDelReq = OS_ERR_TASK_DEL_REQ;                    /* Set flag indicating task to be DEL. */ 
    OS_EXIT_CRITICAL(); 
    return (OS_ERR_NONE); 
} 
#endif 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                        GET THE NAME OF A TASK 
* 
* Description: This function is called to obtain the name of a task. 
* 
* Arguments  : prio      is the priority of the task that you want to obtain the name from. 
* 
*              pname     is a pointer to a pointer to an ASCII string that will receive the name of the task. 
* 
*              perr      is a pointer to an error code that can contain one of the following values: 
* 
*                        OS_ERR_NONE                if the requested task is resumed 
*                        OS_ERR_TASK_NOT_EXIST      if the task has not been created or is assigned to a Mutex 
*                        OS_ERR_PRIO_INVALID        if you specified an invalid priority: 
*                                                   A higher value than the idle task or not OS_PRIO_SELF. 
*                        OS_ERR_PNAME_NULL          You passed a NULL pointer for 'pname' 
*                        OS_ERR_NAME_GET_ISR        You called this function from an ISR 
* 
* 
* Returns    : The length of the string or 0 if the task does not exist. 
********************************************************************************************************* 
*/ 
 
#if OS_TASK_NAME_EN > 0u 
INT8U  OSTaskNameGet (INT8U    prio, 
                      INT8U  **pname, 
                      INT8U   *perr) 
{ 
    OS_TCB    *ptcb; 
    INT8U      len; 
#if OS_CRITICAL_METHOD == 3u                             /* Allocate storage for CPU status register   */ 
    OS_CPU_SR  cpu_sr = 0u; 
#endif 
 
 
 
#ifdef OS_SAFETY_CRITICAL 
    if (perr == (INT8U *)0) { 
        OS_SAFETY_CRITICAL_EXCEPTION(); 
    } 
#endif 
 
#if OS_ARG_CHK_EN > 0u 
    if (prio > OS_LOWEST_PRIO) {                         /* Task priority valid ?                      */ 
        if (prio != OS_PRIO_SELF) { 
            *perr = OS_ERR_PRIO_INVALID;                 /* No                                         */ 
            return (0u); 
        } 
    } 
    if (pname == (INT8U **)0) {                          /* Is 'pname' a NULL pointer?                 */ 
        *perr = OS_ERR_PNAME_NULL;                       /* Yes                                        */ 
        return (0u); 
    } 
#endif 
    if (OSIntNesting > 0u) {                              /* See if trying to call from an ISR          */ 
        *perr = OS_ERR_NAME_GET_ISR; 
        return (0u); 
    } 
    OS_ENTER_CRITICAL(); 
    if (prio == OS_PRIO_SELF) {                          /* See if caller desires it's own name        */ 
        prio = OSTCBCur->OSTCBPrio; 
    } 
    ptcb = OSTCBPrioTbl[prio]; 
    if (ptcb == (OS_TCB *)0) {                           /* Does task exist?                           */ 
        OS_EXIT_CRITICAL();                              /* No                                         */ 
        *perr = OS_ERR_TASK_NOT_EXIST; 
        return (0u); 
    } 
    if (ptcb == OS_TCB_RESERVED) {                       /* Task assigned to a Mutex?                  */ 
        OS_EXIT_CRITICAL();                              /* Yes                                        */ 
        *perr = OS_ERR_TASK_NOT_EXIST; 
        return (0u); 
    } 
    *pname = ptcb->OSTCBTaskName; 
    len    = OS_StrLen(*pname); 
    OS_EXIT_CRITICAL(); 
    *perr  = OS_ERR_NONE; 
    return (len); 
} 
#endif 
 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                        ASSIGN A NAME TO A TASK 
* 
* Description: This function is used to set the name of a task. 
* 
* Arguments  : prio      is the priority of the task that you want the assign a name to. 
* 
*              pname     is a pointer to an ASCII string that contains the name of the task. 
* 
*              perr       is a pointer to an error code that can contain one of the following values: 
* 
*                        OS_ERR_NONE                if the requested task is resumed 
*                        OS_ERR_TASK_NOT_EXIST      if the task has not been created or is assigned to a Mutex 
*                        OS_ERR_PNAME_NULL          You passed a NULL pointer for 'pname' 
*                        OS_ERR_PRIO_INVALID        if you specified an invalid priority: 
*                                                   A higher value than the idle task or not OS_PRIO_SELF. 
*                        OS_ERR_NAME_SET_ISR        if you called this function from an ISR 
* 
* Returns    : None 
********************************************************************************************************* 
*/ 
#if OS_TASK_NAME_EN > 0u 
void  OSTaskNameSet (INT8U   prio, 
                     INT8U  *pname, 
                     INT8U  *perr) 
{ 
    OS_TCB    *ptcb; 
#if OS_CRITICAL_METHOD == 3u                         /* Allocate storage for CPU status register       */ 
    OS_CPU_SR  cpu_sr = 0u; 
#endif 
 
 
 
#ifdef OS_SAFETY_CRITICAL 
    if (perr == (INT8U *)0) { 
        OS_SAFETY_CRITICAL_EXCEPTION(); 
    } 
#endif 
 
#if OS_ARG_CHK_EN > 0u 
    if (prio > OS_LOWEST_PRIO) {                     /* Task priority valid ?                          */ 
        if (prio != OS_PRIO_SELF) { 
            *perr = OS_ERR_PRIO_INVALID;             /* No                                             */ 
            return; 
        } 
    } 
    if (pname == (INT8U *)0) {                       /* Is 'pname' a NULL pointer?                     */ 
        *perr = OS_ERR_PNAME_NULL;                   /* Yes                                            */ 
        return; 
    } 
#endif 
    if (OSIntNesting > 0u) {                         /* See if trying to call from an ISR              */ 
        *perr = OS_ERR_NAME_SET_ISR; 
        return; 
    } 
    OS_ENTER_CRITICAL(); 
    if (prio == OS_PRIO_SELF) {                      /* See if caller desires to set it's own name     */ 
        prio = OSTCBCur->OSTCBPrio; 
    } 
    ptcb = OSTCBPrioTbl[prio]; 
    if (ptcb == (OS_TCB *)0) {                       /* Does task exist?                               */ 
        OS_EXIT_CRITICAL();                          /* No                                             */ 
        *perr = OS_ERR_TASK_NOT_EXIST; 
        return; 
    } 
    if (ptcb == OS_TCB_RESERVED) {                   /* Task assigned to a Mutex?                      */ 
        OS_EXIT_CRITICAL();                          /* Yes                                            */ 
        *perr = OS_ERR_TASK_NOT_EXIST; 
        return; 
    } 
    ptcb->OSTCBTaskName = pname; 
    OS_EXIT_CRITICAL(); 
    *perr               = OS_ERR_NONE; 
} 
#endif 
 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                        RESUME A SUSPENDED TASK 
* 
* Description: This function is called to resume a previously suspended task.  This is the only call that 
*              will remove an explicit task suspension. 
* 
* Arguments  : prio     is the priority of the task to resume. 
* 
* Returns    : OS_ERR_NONE                if the requested task is resumed 
*              OS_ERR_PRIO_INVALID        if the priority you specify is higher that the maximum allowed 
*                                         (i.e. >= OS_LOWEST_PRIO) 
*              OS_ERR_TASK_RESUME_PRIO    if the task to resume does not exist 
*              OS_ERR_TASK_NOT_EXIST      if the task is assigned to a Mutex PIP 
*              OS_ERR_TASK_NOT_SUSPENDED  if the task to resume has not been suspended 
********************************************************************************************************* 
*/ 
 
#if OS_TASK_SUSPEND_EN > 0u 
INT8U  OSTaskResume (INT8U prio) 
{ 
    OS_TCB    *ptcb; 
#if OS_CRITICAL_METHOD == 3u                                  /* Storage for CPU status register       */ 
    OS_CPU_SR  cpu_sr = 0u; 
#endif 
 
 
 
#if OS_ARG_CHK_EN > 0u 
    if (prio >= OS_LOWEST_PRIO) {                             /* Make sure task priority is valid      */ 
        return (OS_ERR_PRIO_INVALID); 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    ptcb = OSTCBPrioTbl[prio]; 
    if (ptcb == (OS_TCB *)0) {                                /* Task to suspend must exist            */ 
        OS_EXIT_CRITICAL(); 
        return (OS_ERR_TASK_RESUME_PRIO); 
    } 
    if (ptcb == OS_TCB_RESERVED) {                            /* See if assigned to Mutex              */ 
        OS_EXIT_CRITICAL(); 
        return (OS_ERR_TASK_NOT_EXIST); 
    } 
    if ((ptcb->OSTCBStat & OS_STAT_SUSPEND) != OS_STAT_RDY) { /* Task must be suspended                */ 
        ptcb->OSTCBStat &= (INT8U)~(INT8U)OS_STAT_SUSPEND;    /* Remove suspension                     */ 
        if (ptcb->OSTCBStat == OS_STAT_RDY) {                 /* See if task is now ready              */ 
            if (ptcb->OSTCBDly == 0u) { 
                OSRdyGrp               |= ptcb->OSTCBBitY;    /* Yes, Make task ready to run           */ 
                OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX; 
                OS_EXIT_CRITICAL(); 
                if (OSRunning == OS_TRUE) { 
                    OS_Sched();                               /* Find new highest priority task        */ 
                } 
            } else { 
                OS_EXIT_CRITICAL(); 
            } 
        } else {                                              /* Must be pending on event              */ 
            OS_EXIT_CRITICAL(); 
        } 
        return (OS_ERR_NONE); 
    } 
    OS_EXIT_CRITICAL(); 
    return (OS_ERR_TASK_NOT_SUSPENDED); 
} 
#endif 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                             STACK CHECKING 
* 
* Description: This function is called to check the amount of free memory left on the specified task's 
*              stack. 
* 
* Arguments  : prio          is the task priority 
* 
*              p_stk_data    is a pointer to a data structure of type OS_STK_DATA. 
* 
* Returns    : OS_ERR_NONE            upon success 
*              OS_ERR_PRIO_INVALID    if the priority you specify is higher that the maximum allowed 
*                                     (i.e. > OS_LOWEST_PRIO) or, you have not specified OS_PRIO_SELF. 
*              OS_ERR_TASK_NOT_EXIST  if the desired task has not been created or is assigned to a Mutex PIP 
*              OS_ERR_TASK_OPT        if you did NOT specified OS_TASK_OPT_STK_CHK when the task was created 
*              OS_ERR_PDATA_NULL      if 'p_stk_data' is a NULL pointer 
********************************************************************************************************* 
*/ 
#if (OS_TASK_STAT_STK_CHK_EN > 0u) && (OS_TASK_CREATE_EXT_EN > 0u) 
INT8U  OSTaskStkChk (INT8U         prio, 
                     OS_STK_DATA  *p_stk_data) 
{ 
    OS_TCB    *ptcb; 
    OS_STK    *pchk; 
    INT32U     nfree; 
    INT32U     size; 
#if OS_CRITICAL_METHOD == 3u                           /* Allocate storage for CPU status register     */ 
    OS_CPU_SR  cpu_sr = 0u; 
#endif 
 
 
 
#if OS_ARG_CHK_EN > 0u 
    if (prio > OS_LOWEST_PRIO) {                       /* Make sure task priority is valid             */ 
        if (prio != OS_PRIO_SELF) { 
            return (OS_ERR_PRIO_INVALID); 
        } 
    } 
    if (p_stk_data == (OS_STK_DATA *)0) {              /* Validate 'p_stk_data'                        */ 
        return (OS_ERR_PDATA_NULL); 
    } 
#endif 
    p_stk_data->OSFree = 0u;                           /* Assume failure, set to 0 size                */ 
    p_stk_data->OSUsed = 0u; 
    OS_ENTER_CRITICAL(); 
    if (prio == OS_PRIO_SELF) {                        /* See if check for SELF                        */ 
        prio = OSTCBCur->OSTCBPrio; 
    } 
    ptcb = OSTCBPrioTbl[prio]; 
    if (ptcb == (OS_TCB *)0) {                         /* Make sure task exist                         */ 
        OS_EXIT_CRITICAL(); 
        return (OS_ERR_TASK_NOT_EXIST); 
    } 
    if (ptcb == OS_TCB_RESERVED) { 
        OS_EXIT_CRITICAL(); 
        return (OS_ERR_TASK_NOT_EXIST); 
    } 
    if ((ptcb->OSTCBOpt & OS_TASK_OPT_STK_CHK) == 0u) { /* Make sure stack checking option is set      */ 
        OS_EXIT_CRITICAL(); 
        return (OS_ERR_TASK_OPT); 
    } 
    nfree = 0u; 
    size  = ptcb->OSTCBStkSize; 
    pchk  = ptcb->OSTCBStkBottom; 
    OS_EXIT_CRITICAL(); 
#if OS_STK_GROWTH == 1u 
    while (*pchk++ == (OS_STK)0) {                    /* Compute the number of zero entries on the stk */ 
        nfree++; 
    } 
#else 
    while (*pchk-- == (OS_STK)0) { 
        nfree++; 
    } 
#endif 
    p_stk_data->OSFree = nfree * sizeof(OS_STK);          /* Compute number of free bytes on the stack */ 
    p_stk_data->OSUsed = (size - nfree) * sizeof(OS_STK); /* Compute number of bytes used on the stack */ 
    return (OS_ERR_NONE); 
} 
#endif 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                            SUSPEND A TASK 
* 
* Description: This function is called to suspend a task.  The task can be the calling task if the 
*              priority passed to OSTaskSuspend() is the priority of the calling task or OS_PRIO_SELF. 
* 
* Arguments  : prio     is the priority of the task to suspend.  If you specify OS_PRIO_SELF, the 
*                       calling task will suspend itself and rescheduling will occur. 
* 
* Returns    : OS_ERR_NONE               if the requested task is suspended 
*              OS_ERR_TASK_SUSPEND_IDLE  if you attempted to suspend the idle task which is not allowed. 
*              OS_ERR_PRIO_INVALID       if the priority you specify is higher that the maximum allowed 
*                                        (i.e. >= OS_LOWEST_PRIO) or, you have not specified OS_PRIO_SELF. 
*              OS_ERR_TASK_SUSPEND_PRIO  if the task to suspend does not exist 
*              OS_ERR_TASK_NOT_EXITS     if the task is assigned to a Mutex PIP 
* 
* Note       : You should use this function with great care.  If you suspend a task that is waiting for 
*              an event (i.e. a message, a semaphore, a queue ...) you will prevent this task from 
*              running when the event arrives. 
********************************************************************************************************* 
*/ 
 
#if OS_TASK_SUSPEND_EN > 0u 
INT8U  OSTaskSuspend (INT8U prio) 
{ 
    BOOLEAN    self; 
    OS_TCB    *ptcb; 
    INT8U      y; 
#if OS_CRITICAL_METHOD == 3u                     /* Allocate storage for CPU status register           */ 
    OS_CPU_SR  cpu_sr = 0u; 
#endif 
 
 
 
#if OS_ARG_CHK_EN > 0u 
    if (prio == OS_TASK_IDLE_PRIO) {                            /* Not allowed to suspend idle task    */ 
        return (OS_ERR_TASK_SUSPEND_IDLE); 
    } 
    if (prio >= OS_LOWEST_PRIO) {                               /* Task priority valid ?               */ 
        if (prio != OS_PRIO_SELF) { 
            return (OS_ERR_PRIO_INVALID); 
        } 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    if (prio == OS_PRIO_SELF) {                                 /* See if suspend SELF                 */ 
        prio = OSTCBCur->OSTCBPrio; 
        self = OS_TRUE; 
    } else if (prio == OSTCBCur->OSTCBPrio) {                   /* See if suspending self              */ 
        self = OS_TRUE; 
    } else { 
        self = OS_FALSE;                                        /* No suspending another task          */ 
    } 
    ptcb = OSTCBPrioTbl[prio]; 
    if (ptcb == (OS_TCB *)0) {                                  /* Task to suspend must exist          */ 
        OS_EXIT_CRITICAL(); 
        return (OS_ERR_TASK_SUSPEND_PRIO); 
    } 
    if (ptcb == OS_TCB_RESERVED) {                              /* See if assigned to Mutex            */ 
        OS_EXIT_CRITICAL(); 
        return (OS_ERR_TASK_NOT_EXIST); 
    } 
    y            = ptcb->OSTCBY; 
    OSRdyTbl[y] &= (OS_PRIO)~ptcb->OSTCBBitX;                   /* Make task not ready                 */ 
    if (OSRdyTbl[y] == 0u) { 
        OSRdyGrp &= (OS_PRIO)~ptcb->OSTCBBitY; 
    } 
    ptcb->OSTCBStat |= OS_STAT_SUSPEND;                         /* Status of task is 'SUSPENDED'       */ 
    OS_EXIT_CRITICAL(); 
    if (self == OS_TRUE) {                                      /* Context switch only if SELF         */ 
        OS_Sched();                                             /* Find new highest priority task      */ 
    } 
    return (OS_ERR_NONE); 
} 
#endif 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                            QUERY A TASK 
* 
* Description: This function is called to obtain a copy of the desired task's TCB. 
* 
* Arguments  : prio         is the priority of the task to obtain information from. 
* 
*              p_task_data  is a pointer to where the desired task's OS_TCB will be stored. 
* 
* Returns    : OS_ERR_NONE            if the requested task is suspended 
*              OS_ERR_PRIO_INVALID    if the priority you specify is higher that the maximum allowed 
*                                     (i.e. > OS_LOWEST_PRIO) or, you have not specified OS_PRIO_SELF. 
*              OS_ERR_PRIO            if the desired task has not been created 
*              OS_ERR_TASK_NOT_EXIST  if the task is assigned to a Mutex PIP 
*              OS_ERR_PDATA_NULL      if 'p_task_data' is a NULL pointer 
********************************************************************************************************* 
*/ 
 
#if OS_TASK_QUERY_EN > 0u 
INT8U  OSTaskQuery (INT8U    prio, 
                    OS_TCB  *p_task_data) 
{ 
    OS_TCB    *ptcb; 
#if OS_CRITICAL_METHOD == 3u                     /* Allocate storage for CPU status register           */ 
    OS_CPU_SR  cpu_sr = 0u; 
#endif 
 
 
 
#if OS_ARG_CHK_EN > 0u 
    if (prio > OS_LOWEST_PRIO) {                 /* Task priority valid ?                              */ 
        if (prio != OS_PRIO_SELF) { 
            return (OS_ERR_PRIO_INVALID); 
        } 
    } 
    if (p_task_data == (OS_TCB *)0) {            /* Validate 'p_task_data'                             */ 
        return (OS_ERR_PDATA_NULL); 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    if (prio == OS_PRIO_SELF) {                  /* See if suspend SELF                                */ 
        prio = OSTCBCur->OSTCBPrio; 
    } 
    ptcb = OSTCBPrioTbl[prio]; 
    if (ptcb == (OS_TCB *)0) {                   /* Task to query must exist                           */ 
        OS_EXIT_CRITICAL(); 
        return (OS_ERR_PRIO); 
    } 
    if (ptcb == OS_TCB_RESERVED) {               /* Task to query must not be assigned to a Mutex      */ 
        OS_EXIT_CRITICAL(); 
        return (OS_ERR_TASK_NOT_EXIST); 
    } 
                                                 /* Copy TCB into user storage area                    */ 
    OS_MemCopy((INT8U *)p_task_data, (INT8U *)ptcb, sizeof(OS_TCB)); 
    OS_EXIT_CRITICAL(); 
    return (OS_ERR_NONE); 
} 
#endif 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                 GET THE CURRENT VALUE OF A TASK REGISTER 
* 
* Description: This function is called to obtain the current value of a task register.  Task registers 
*              are application specific and can be used to store task specific values such as 'error 
*              numbers' (i.e. errno), statistics, etc.  Each task register can hold a 32-bit value. 
* 
* Arguments  : prio      is the priority of the task you want to get the task register from.  If you 
*                        specify OS_PRIO_SELF then the task register of the current task will be obtained. 
* 
*              id        is the 'id' of the desired task register.  Note that the 'id' must be less 
*                        than OS_TASK_REG_TBL_SIZE 
* 
*              perr      is a pointer to a variable that will hold an error code related to this call. 
* 
*                        OS_ERR_NONE            if the call was successful 
*                        OS_ERR_PRIO_INVALID    if you specified an invalid priority 
*                        OS_ERR_ID_INVALID      if the 'id' is not between 0 and OS_TASK_REG_TBL_SIZE-1 
* 
* Returns    : The current value of the task's register or 0 if an error is detected. 
* 
* Note(s)    : The maximum number of task variables is 254 
********************************************************************************************************* 
*/ 
 
#if OS_TASK_REG_TBL_SIZE > 0u 
INT32U  OSTaskRegGet (INT8U   prio, 
                      INT8U   id, 
                      INT8U  *perr) 
{ 
#if OS_CRITICAL_METHOD == 3u                     /* Allocate storage for CPU status register           */ 
    OS_CPU_SR  cpu_sr = 0u; 
#endif 
    INT32U     value; 
    OS_TCB    *ptcb; 
 
 
#if OS_ARG_CHK_EN > 0u 
    if (prio >= OS_LOWEST_PRIO) { 
        if (prio != OS_PRIO_SELF) { 
            *perr = OS_ERR_PRIO_INVALID; 
            return (0u); 
        } 
    } 
    if (id >= OS_TASK_REG_TBL_SIZE) { 
        *perr = OS_ERR_ID_INVALID; 
        return (0u); 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    if (prio == OS_PRIO_SELF) {                  /* See if need to get register from current task      */ 
        ptcb = OSTCBCur; 
    } else { 
        ptcb = OSTCBPrioTbl[prio]; 
    } 
    value = ptcb->OSTCBRegTbl[id]; 
    OS_EXIT_CRITICAL(); 
    *perr = OS_ERR_NONE; 
    return (value); 
} 
#endif 
 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                 SET THE CURRENT VALUE OF A TASK VARIABLE 
* 
* Description: This function is called to change the current value of a task register.  Task registers 
*              are application specific and can be used to store task specific values such as 'error 
*              numbers' (i.e. errno), statistics, etc.  Each task register can hold a 32-bit value. 
* 
* Arguments  : prio      is the priority of the task you want to set the task register for.  If you 
*                        specify OS_PRIO_SELF then the task register of the current task will be obtained. 
* 
*              id        is the 'id' of the desired task register.  Note that the 'id' must be less 
*                        than OS_TASK_REG_TBL_SIZE 
* 
*              value     is the desired value for the task register. 
* 
*              perr      is a pointer to a variable that will hold an error code related to this call. 
* 
*                        OS_ERR_NONE            if the call was successful 
*                        OS_ERR_PRIO_INVALID    if you specified an invalid priority 
*                        OS_ERR_ID_INVALID      if the 'id' is not between 0 and OS_TASK_REG_TBL_SIZE-1 
* 
* Returns    : The current value of the task's variable or 0 if an error is detected. 
* 
* Note(s)    : The maximum number of task variables is 254 
********************************************************************************************************* 
*/ 
 
#if OS_TASK_REG_TBL_SIZE > 0u 
void  OSTaskRegSet (INT8U    prio, 
                    INT8U    id, 
                    INT32U   value, 
                    INT8U   *perr) 
{ 
#if OS_CRITICAL_METHOD == 3u                     /* Allocate storage for CPU status register           */ 
    OS_CPU_SR  cpu_sr = 0u; 
#endif 
    OS_TCB    *ptcb; 
 
 
#if OS_ARG_CHK_EN > 0u 
    if (prio >= OS_LOWEST_PRIO) { 
        if (prio != OS_PRIO_SELF) { 
            *perr = OS_ERR_PRIO_INVALID; 
            return; 
        } 
    } 
    if (id >= OS_TASK_REG_TBL_SIZE) { 
        *perr = OS_ERR_ID_INVALID; 
        return; 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    if (prio == OS_PRIO_SELF) {                  /* See if need to get register from current task      */ 
        ptcb = OSTCBCur; 
    } else { 
        ptcb = OSTCBPrioTbl[prio]; 
    } 
    ptcb->OSTCBRegTbl[id] = value; 
    OS_EXIT_CRITICAL(); 
    *perr                 = OS_ERR_NONE; 
} 
#endif 
 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                              CATCH ACCIDENTAL TASK RETURN 
* 
* Description: This function is called if a task accidentally returns without deleting itself.  In other 
*              words, a task should either be an infinite loop or delete itself if it's done. 
* 
* Arguments  : none 
* 
* Returns    : none 
* 
* Note(s)    : This function is INTERNAL to uC/OS-II and your application should not call it. 
********************************************************************************************************* 
*/ 
 
void  OS_TaskReturn (void) 
{ 
    OSTaskReturnHook(OSTCBCur);                   /* Call hook to let user decide on what to do        */ 
 
#if OS_TASK_DEL_EN > 0u 
    (void)OSTaskDel(OS_PRIO_SELF);                /* Delete task if it accidentally returns!           */ 
#else 
    for (;;) { 
        OSTimeDly(OS_TICKS_PER_SEC); 
    } 
#endif 
} 
 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                        CLEAR TASK STACK 
* 
* Description: This function is used to clear the stack of a task (i.e. write all zeros) 
* 
* Arguments  : pbos     is a pointer to the task's bottom of stack.  If the configuration constant 
*                       OS_STK_GROWTH is set to 1, the stack is assumed to grow downward (i.e. from high 
*                       memory to low memory).  'pbos' will thus point to the lowest (valid) memory 
*                       location of the stack.  If OS_STK_GROWTH is set to 0, 'pbos' will point to the 
*                       highest memory location of the stack and the stack will grow with increasing 
*                       memory locations.  'pbos' MUST point to a valid 'free' data item. 
* 
*              size     is the number of 'stack elements' to clear. 
* 
*              opt      contains additional information (or options) about the behavior of the task.  The 
*                       LOWER 8-bits are reserved by uC/OS-II while the upper 8 bits can be application 
*                       specific.  See OS_TASK_OPT_??? in uCOS-II.H. 
* 
* Returns    : none 
********************************************************************************************************* 
*/ 
#if (OS_TASK_STAT_STK_CHK_EN > 0u) && (OS_TASK_CREATE_EXT_EN > 0u) 
void  OS_TaskStkClr (OS_STK  *pbos, 
                     INT32U   size, 
                     INT16U   opt) 
{ 
    if ((opt & OS_TASK_OPT_STK_CHK) != 0x0000u) {      /* See if stack checking has been enabled       */ 
        if ((opt & OS_TASK_OPT_STK_CLR) != 0x0000u) {  /* See if stack needs to be cleared             */ 
#if OS_STK_GROWTH == 1u 
            while (size > 0u) {                        /* Stack grows from HIGH to LOW memory          */ 
                size--; 
                *pbos++ = (OS_STK)0;                   /* Clear from bottom of stack and up!           */ 
            } 
#else 
            while (size > 0u) {                        /* Stack grows from LOW to HIGH memory          */ 
                size--; 
                *pbos-- = (OS_STK)0;                   /* Clear from bottom of stack and down          */ 
            } 
#endif 
        } 
    } 
} 
 
#endif