ucos任务控制块的初始化问题

只看该作者 · 2017-1-6 23:08

在os_core.c这个文件的 OS_TCBInit （）函数对TCB进行初始化，先发现有个问题

就是我下面的注释中发现的错误

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;  // 最前面的控制块前驱指针置空
      if (OSTCBList != (OS_TCB *)0)    //  此处的一个判断我觉得没有必要，因为不管新建立的TCB是不是第一个建立的任务控制块，都要将
{                                                 //  OSTCBList 的前驱指针指向 ptcb;
         OSTCBList->OSTCBPrev = ptcb;
      }
      OSTCBList             = ptcb;    // 然后更新OSTCBList
      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);
}

只看该作者 · 2017-1-6 23:13

自己来回复，发现问题了，是一个创建的任务时，OSTCBList是（OS_TCB *）0指针，不存在前驱指针了，还是ucos的作者思维严谨

ucos任务控制块的初始化问题

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