www.pudn.com > 51ucosii.zip > OS_TASK.C, change:2002-04-14,size:35787b


/* 
********************************************************************************************************* 
*                                                uC/OS-II 
*                                          The Real-Time Kernel 
*                                            TASK MANAGEMENT 
* 
*                        (c) Copyright 1992-1998, Jean J. Labrosse, Plantation, FL 
*                                           All Rights Reserved 
* 
*                                                  V2.00 
* 
* File : OS_TASK.C 
* By   : Jean J. Labrosse 
********************************************************************************************************* 
*/ 
 
#ifndef  OS_MASTER_FILE 
#include "includes.h" 
#endif 
 
/* 
********************************************************************************************************* 
*                                        LOCAL FUNCTION PROTOTYPES 
********************************************************************************************************* 
*/ 
 
#if OS_TASK_DEL_EN 
static  void  OSDummy(void); 
 
/* 
********************************************************************************************************* 
*                                            DUMMY FUNCTION 
* 
* Description: This function doesn't do anything.  It is called by OSTaskDel() to ensure that interrupts 
*              are disabled immediately after they are enabled. 
* 
* Arguments  : none 
* 
* Returns    : none 
********************************************************************************************************* 
*/ 
 
static void  OSDummy (void)reentrant 
{ 
} 
#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_NO_ERR        is the call was successful 
*              OS_PRIO_INVALID  if the priority you specify is higher that the maximum allowed  
*                               (i.e. >= OS_LOWEST_PRIO) 
*              OS_PRIO_EXIST    if the new priority already exist. 
*              OS_PRIO_ERR      there is no task with the specified OLD priority (i.e. the OLD task does 
*                               not exist. 
********************************************************************************************************* 
*/ 
 
#if OS_TASK_CHANGE_PRIO_EN 
INT8U OSTaskChangePrio (INT8U oldprio, INT8U newprio)reentrant 
{ 
    OS_TCB   *ptcb; 
    OS_EVENT *pevent; 
    INT8U     x; 
    INT8U     y; 
    INT8U     bitx; 
    INT8U     bity; 
 
 
    if ((oldprio >= OS_LOWEST_PRIO && oldprio != OS_PRIO_SELF)  ||  
         newprio >= OS_LOWEST_PRIO) { 
        return (OS_PRIO_INVALID); 
    } 
    OS_ENTER_CRITICAL(); 
    if (OSTCBPrioTbl[newprio] != (OS_TCB *)0) {                 /* New priority must not already exist */ 
        OS_EXIT_CRITICAL(); 
        return (OS_PRIO_EXIST); 
    } else { 
        OSTCBPrioTbl[newprio] = (OS_TCB *)1;                    /* Reserve the entry to prevent others */ 
        OS_EXIT_CRITICAL(); 
        y    = newprio >> 3;                                    /* Precompute to reduce INT. latency   */ 
        bity = OSMapTbl[y]; 
        x    = newprio & 0x07; 
        bitx = OSMapTbl[x]; 
        OS_ENTER_CRITICAL(); 
        if (oldprio == OS_PRIO_SELF) {                          /* See if changing self                */ 
            oldprio = OSTCBCur->OSTCBPrio;                      /* Yes, get priority                   */ 
        } 
        if ((ptcb = OSTCBPrioTbl[oldprio]) != (OS_TCB *)0) {    /* Task to change must exist           */ 
            OSTCBPrioTbl[oldprio] = (OS_TCB *)0;                /* Remove TCB from old priority        */ 
            if (OSRdyTbl[ptcb->OSTCBY] & ptcb->OSTCBBitX) {     /* If task is ready make it not ready  */ 
                if ((OSRdyTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0) { 
                    OSRdyGrp &= ~ptcb->OSTCBBitY; 
                } 
                OSRdyGrp    |= bity;                            /* Make new priority ready to run      */ 
                OSRdyTbl[y] |= bitx; 
            } else { 
                if ((pevent = ptcb->OSTCBEventPtr) != (OS_EVENT *)0) { /* Remove from event wait list  */ 
                    if ((pevent->OSEventTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0) { 
                        pevent->OSEventGrp &= ~ptcb->OSTCBBitY; 
                    } 
                    pevent->OSEventGrp    |= bity;              /* Add new priority to wait list       */ 
                    pevent->OSEventTbl[y] |= bitx; 
                } 
            } 
            OSTCBPrioTbl[newprio] = ptcb;                       /* Place pointer to TCB @ new priority */ 
            ptcb->OSTCBPrio       = newprio;                    /* Set new task priority               */ 
            ptcb->OSTCBY          = y; 
            ptcb->OSTCBX          = x; 
            ptcb->OSTCBBitY       = bity; 
            ptcb->OSTCBBitX       = bitx; 
            OS_EXIT_CRITICAL(); 
            OSSched();                                          /* Run highest priority task ready     */ 
            return (OS_NO_ERR); 
        } else { 
            OSTCBPrioTbl[newprio] = (OS_TCB *)0;                /* Release the reserved prio.          */ 
            OS_EXIT_CRITICAL(); 
            return (OS_PRIO_ERR);                               /* Task to change didn't exist         */ 
        } 
    } 
} 
#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 
* 
*              dataptr    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 'dataptr' as follows: 
* 
*                           void Task (void *dataptr) 
*                           { 
*                               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_NO_ERR        if the function was successful. 
*              OS_PRIO_EXIT     if the task priority already exist  
*                               (each task MUST have a unique priority). 
*              OS_PRIO_INVALID  if the priority you specify is higher that the maximum allowed  
*                               (i.e. >= OS_LOWEST_PRIO) 
********************************************************************************************************* 
*/ 
 
#if OS_TASK_CREATE_EN 
INT8U OSTaskCreate (void (*task)(void *pd)reentrant,  
		    void *dataptr,  
		    OS_STK *ptos,  
		    INT8U prio)reentrant 
{ 
    void   *psp; 
    INT8U   err; 
 
 
    if (prio > OS_LOWEST_PRIO) {             /* Make sure priority is within allowable range           */ 
        return (OS_PRIO_INVALID); 
    } 
    OS_ENTER_CRITICAL(); 
    if (OSTCBPrioTbl[prio] == (OS_TCB *)0) { /* Make sure task doesn't already exist at this priority  */ 
        OSTCBPrioTbl[prio] = (OS_TCB *)1;    /* Reserve the priority to prevent others from doing ...  */ 
                                             /* ... the same thing until task is created.              */ 
        OS_EXIT_CRITICAL(); 
        psp = (void *)OSTaskStkInit(task, dataptr, ptos, 0); /* Initialize the task's stack              */ 
        err = OSTCBInit(prio, psp, (void *)0, 0, 0, (void *)0, 0);          
        if (err == OS_NO_ERR) { 
            OS_ENTER_CRITICAL(); 
            OSTaskCtr++;                                   /* Increment the #tasks counter             */ 
            OSTaskCreateHook(OSTCBPrioTbl[prio]);          /* Call user defined hook                   */ 
            OS_EXIT_CRITICAL(); 
            if (OSRunning) {                 /* Find highest priority task if multitasking has started */ 
                OSSched(); 
            } 
        } else { 
            OS_ENTER_CRITICAL(); 
            OSTCBPrioTbl[prio] = (OS_TCB *)0;/* Make this priority available to others                 */ 
            OS_EXIT_CRITICAL(); 
        } 
        return (err); 
    } else { 
        OS_EXIT_CRITICAL(); 
        return (OS_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 
* 
*              dataptr    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 'dataptr' as follows: 
* 
*                           void Task (void *dataptr) 
*                           { 
*                               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.  'pstk' 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. 
* 
* Returns    : OS_NO_ERR        if the function was successful. 
*              OS_PRIO_EXIT     if the task priority already exist  
*                               (each task MUST have a unique priority). 
*              OS_PRIO_INVALID  if the priority you specify is higher that the maximum allowed  
*                               (i.e. > OS_LOWEST_PRIO) 
********************************************************************************************************* 
*/ 
/*$PAGE*/ 
#if   OS_TASK_CREATE_EXT_EN     
INT8U OSTaskCreateExt (void   (*task)(void *pd),  
                       void    *dataptr,  
                       OS_STK  *ptos,  
                       INT8U    prio, 
                       INT16U   id, 
                       OS_STK  *pbos, 
                       INT32U   stk_size, 
                       void    *pext, 
                       INT16U   opt)reentrant 
{ 
    void    *psp; 
    INT8U    err; 
    INT16U   i; 
    OS_STK  *pfill; 
 
 
    if (prio > OS_LOWEST_PRIO) {             /* Make sure priority is within allowable range           */ 
        return (OS_PRIO_INVALID); 
    } 
    OS_ENTER_CRITICAL(); 
    if (OSTCBPrioTbl[prio] == (OS_TCB *)0) { /* Make sure task doesn't already exist at this priority  */ 
        OSTCBPrioTbl[prio] = (OS_TCB *)1;    /* Reserve the priority to prevent others from doing ...  */ 
                                             /* ... the same thing until task is created.              */ 
        OS_EXIT_CRITICAL(); 
         
        if (opt & OS_TASK_OPT_STK_CHK) {     /* See if stack checking has been enabled                 */ 
            if (opt & OS_TASK_OPT_STK_CLR) { /* See if stack needs to be cleared                       */ 
                pfill = pbos;                /* Yes, fill the stack with zeros                         */ 
                for (i = 0; i < stk_size; i++) { 
                    #if OS_STK_GROWTH == 1 
                    *pfill++ = (OS_STK)0; 
                    #else 
                    *pfill-- = (OS_STK)0; 
                    #endif 
                } 
            } 
        } 
         
        psp = (void *)OSTaskStkInit(task, dataptr, ptos, opt); /* Initialize the task's stack            */ 
        err = OSTCBInit(prio, psp, pbos, id, stk_size, pext, opt);          
        if (err == OS_NO_ERR) { 
            OS_ENTER_CRITICAL(); 
            OSTaskCtr++;                                     /* Increment the #tasks counter           */ 
            OSTaskCreateHook(OSTCBPrioTbl[prio]);            /* Call user defined hook                 */ 
            OS_EXIT_CRITICAL(); 
            if (OSRunning) {                 /* Find highest priority task if multitasking has started */ 
                OSSched(); 
            } 
        } else { 
            OS_ENTER_CRITICAL(); 
            OSTCBPrioTbl[prio] = (OS_TCB *)0;/* Make this priority available to others                 */ 
            OS_EXIT_CRITICAL(); 
        } 
        return (err); 
    } else { 
        OS_EXIT_CRITICAL(); 
        return (OS_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_NO_ERR           if the call is successful 
*              OS_TASK_DEL_IDLE    if you attempted to delete uC/OS-II's idle task 
*              OS_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_TASK_DEL_ERR     if the task you want to delete does not exist 
*              OS_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 OSDummy() is called after OS_EXIT_CRITICAL() because, on most processors,  
*                 the next instruction following the enable interrupt instruction is ignored.  You can  
*                 replace OSDummy() with a macro that basically executes a NO OP (i.e. OS_NOP()).  The  
*                 NO OP macro would avoid the execution time of the function call and return. 
*              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 the ISR would return to the current task which is 
*                 being deleted.  The rest of the deletion would thus be able to be completed. 
********************************************************************************************************* 
*/ 
/*$PAGE*/ 
#if OS_TASK_DEL_EN 
INT8U OSTaskDel (INT8U prio)reentrant 
{ 
    OS_TCB   *ptcb; 
    OS_EVENT *pevent; 
 
 
    if (prio == OS_IDLE_PRIO) {                                 /* Not allowed to delete idle task     */ 
        return (OS_TASK_DEL_IDLE); 
    } 
    if (prio >= OS_LOWEST_PRIO && prio != OS_PRIO_SELF) {       /* Task priority valid ?               */ 
        return (OS_PRIO_INVALID); 
    } 
    OS_ENTER_CRITICAL(); 
    if (OSIntNesting > 0) {                                     /* See if trying to delete from ISR    */ 
        OS_EXIT_CRITICAL(); 
        return (OS_TASK_DEL_ISR); 
    } 
    if (prio == OS_PRIO_SELF) {                                 /* See if requesting to delete self    */ 
        prio = OSTCBCur->OSTCBPrio;                             /* Set priority to delete to current   */ 
    } 
    if ((ptcb = OSTCBPrioTbl[prio]) != (OS_TCB *)0) {           /* Task to delete must exist           */ 
        if ((OSRdyTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0) {/* Make task not ready                 */ 
            OSRdyGrp &= ~ptcb->OSTCBBitY; 
        } 
        if ((pevent = ptcb->OSTCBEventPtr) != (OS_EVENT *)0) {  /* If task is waiting on event         */ 
            if ((pevent->OSEventTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0) { /* ... remove task from */ 
                pevent->OSEventGrp &= ~ptcb->OSTCBBitY;                        /* ... event ctrl block */ 
            } 
        } 
        ptcb->OSTCBDly  = 0;                                    /* Prevent OSTimeTick() from updating  */ 
        ptcb->OSTCBStat = OS_STAT_RDY;                          /* Prevent task from being resumed     */ 
        OSLockNesting++; 
        OS_EXIT_CRITICAL();                                     /* Enabling INT. ignores next instruc. */ 
        OSDummy();                                              /* ... Dummy ensures that INTs will be */ 
        OS_ENTER_CRITICAL();                                    /* ... disabled HERE!                  */ 
        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; 
        OS_EXIT_CRITICAL(); 
        OSSched();                                              /* Find new highest priority task      */ 
        return (OS_NO_ERR); 
    } else { 
        OS_EXIT_CRITICAL(); 
        return (OS_TASK_DEL_ERR); 
    } 
} 
#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_TASK_DEL_REQ, another task requested a task delete.  Task #10 would look like 
*              this: 
* 
*                   void Task(void *dataptr) 
*                   { 
*                       . 
*                       . 
*                       while (1) { 
*                           OSTimeDly(1); 
*                           if (OSTaskDelReq(OS_PRIO_SELF) == OS_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_NO_ERR          if the task exist and the request has been registered 
*              OS_TASK_NOT_EXIST  if the task has been deleted.  This allows the caller to know whether 
*                                 the request has been executed. 
*              OS_TASK_DEL_IDLE   if you requested to delete uC/OS-II's idle task 
*              OS_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_TASK_DEL_REQ    if a task (possibly another task) requested that the running task be  
*                                 deleted. 
********************************************************************************************************* 
*/ 
/*$PAGE*/ 
#if OS_TASK_DEL_EN 
INT8U OSTaskDelReq (INT8U prio)reentrant 
{ 
    BOOLEAN  stat; 
    INT8U    err; 
    OS_TCB  *ptcb; 
 
 
    if (prio == OS_IDLE_PRIO) {                                 /* Not allowed to delete idle task     */ 
        return (OS_TASK_DEL_IDLE); 
    } 
    if (prio >= OS_LOWEST_PRIO && prio != OS_PRIO_SELF) {       /* Task priority valid ?               */ 
        return (OS_PRIO_INVALID); 
    } 
    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); 
    } else { 
        OS_ENTER_CRITICAL(); 
        if ((ptcb = OSTCBPrioTbl[prio]) != (OS_TCB *)0) {       /* Task to delete must exist           */ 
            ptcb->OSTCBDelReq = OS_TASK_DEL_REQ;                /* Set flag indicating task to be DEL. */ 
            err               = OS_NO_ERR; 
        } else { 
            err               = OS_TASK_NOT_EXIST;              /* Task must be deleted                */ 
        } 
        OS_EXIT_CRITICAL(); 
        return (err); 
    } 
} 
#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_NO_ERR                if the requested task is resumed 
*              OS_PRIO_INVALID          if the priority you specify is higher that the maximum allowed  
*                                       (i.e. >= OS_LOWEST_PRIO) 
*              OS_TASK_RESUME_PRIO      if the task to resume does not exist 
*              OS_TASK_NOT_SUSPENDED    if the task to resume has not been suspended 
********************************************************************************************************* 
*/ 
 
#if OS_TASK_SUSPEND_EN 
INT8U OSTaskResume (INT8U prio)reentrant 
{ 
    OS_TCB   *ptcb; 
 
 
    if (prio >= OS_LOWEST_PRIO) {                               /* Make sure task priority is valid    */ 
        return (OS_PRIO_INVALID); 
    } 
    OS_ENTER_CRITICAL(); 
    if ((ptcb = OSTCBPrioTbl[prio]) == (OS_TCB *)0) {           /* Task to suspend must exist          */ 
        OS_EXIT_CRITICAL(); 
        return (OS_TASK_RESUME_PRIO); 
    } else { 
        if (ptcb->OSTCBStat & OS_STAT_SUSPEND) {                           /* Task must be suspended   */ 
            if (((ptcb->OSTCBStat &= ~OS_STAT_SUSPEND) == OS_STAT_RDY) &&  /* Remove suspension        */ 
                 (ptcb->OSTCBDly  == 0)) {                                 /* Must not be delayed      */ 
                OSRdyGrp               |= ptcb->OSTCBBitY;                 /* Make task ready to run   */ 
                OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX; 
                OS_EXIT_CRITICAL(); 
                OSSched(); 
            } else { 
                OS_EXIT_CRITICAL(); 
            } 
            return (OS_NO_ERR); 
        } else { 
            OS_EXIT_CRITICAL(); 
            return (OS_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 
* 
*              dataptr    is a pointer to a data structure of type OS_STK_DATA. 
* 
* Returns    : OS_NO_ERR           upon success 
*              OS_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_TASK_NOT_EXIST   if the desired task has not been created 
*              OS_TASK_OPT_ERR     if you did NOT specified OS_TASK_OPT_STK_CHK when the task was created 
********************************************************************************************************* 
*/ 
#if   OS_TASK_CREATE_EXT_EN 
INT8U OSTaskStkChk (INT8U prio, OS_STK_DATA *dataptr)reentrant 
{ 
    OS_TCB  *ptcb; 
    OS_STK  *pchk; 
    INT32U   free; 
    INT32U   size; 
 
 
    dataptr->OSFree = 0;                                          /* Assume failure, set to 0 size       */ 
    dataptr->OSUsed = 0; 
    if (prio > OS_LOWEST_PRIO && prio != OS_PRIO_SELF) {        /* Make sure task priority is valid    */ 
        return (OS_PRIO_INVALID); 
    } 
    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_TASK_NOT_EXIST); 
    } 
    if ((ptcb->OSTCBOpt & OS_TASK_OPT_STK_CHK) == 0) { /* Make sure stack checking option is set       */ 
        OS_EXIT_CRITICAL(); 
        return (OS_TASK_OPT_ERR); 
    } 
    free = 0; 
    size = ptcb->OSTCBStkSize; 
    pchk = ptcb->OSTCBStkBottom; 
    OS_EXIT_CRITICAL(); 
#if OS_STK_GROWTH == 1 
    while (*pchk++ == 0) {                            /* Compute the number of zero entries on the stk */ 
        free++; 
    } 
#else 
    while (*pchk-- == 0) { 
        free++; 
    } 
#endif 
    dataptr->OSFree = free * sizeof(OS_STK);            /* Compute number of free bytes on the stack     */ 
    dataptr->OSUsed = (size - free) * sizeof(OS_STK);   /* Compute number of bytes used on the stack     */ 
    return (OS_NO_ERR); 
} 
#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_NO_ERR                if the requested task is suspended 
*              OS_TASK_SUSPEND_IDLE     if you attempted to suspend the idle task which is not allowed. 
*              OS_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_TASK_SUSPEND_PRIO     if the task to suspend does not exist 
* 
* 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 
INT8U OSTaskSuspend (INT8U prio)reentrant 
{ 
    BOOLEAN   self; 
    OS_TCB   *ptcb; 
 
 
    if (prio == OS_IDLE_PRIO) {                                 /* Not allowed to suspend idle task    */ 
        return (OS_TASK_SUSPEND_IDLE); 
    } 
    if (prio >= OS_LOWEST_PRIO && prio != OS_PRIO_SELF) {       /* Task priority valid ?               */ 
        return (OS_PRIO_INVALID); 
    } 
    OS_ENTER_CRITICAL(); 
    if (prio == OS_PRIO_SELF) {                                 /* See if suspend SELF                 */ 
        prio = OSTCBCur->OSTCBPrio; 
        self = TRUE; 
    } else if (prio == OSTCBCur->OSTCBPrio) {                   /* See if suspending self              */ 
        self = TRUE; 
    } else { 
        self = FALSE;                                           /* No suspending another task          */ 
    } 
    if ((ptcb = OSTCBPrioTbl[prio]) == (OS_TCB *)0) {                /* Task to suspend must exist     */ 
        OS_EXIT_CRITICAL(); 
        return (OS_TASK_SUSPEND_PRIO); 
    } else { 
        if ((OSRdyTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0) {     /* Make task not ready            */ 
            OSRdyGrp &= ~ptcb->OSTCBBitY; 
        } 
        ptcb->OSTCBStat |= OS_STAT_SUSPEND;                          /* Status of task is 'SUSPENDED'  */ 
        OS_EXIT_CRITICAL(); 
        if (self == TRUE) {                                          /* Context switch only if SELF    */ 
            OSSched(); 
        } 
        return (OS_NO_ERR); 
    } 
} 
#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.   
* 
* Returns    : OS_NO_ERR       if the requested task is suspended 
*              OS_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_PRIO_ERR     if the desired task has not been created  
********************************************************************************************************* 
*/ 
#if OS_Task_Query_EN 
INT8U OSTaskQuery (INT8U prio, OS_TCB *dataptr)reentrant 
{ 
    OS_TCB *ptcb; 
 
 
    if (prio > OS_LOWEST_PRIO && prio != OS_PRIO_SELF) {   /* Task priority valid ?                    */ 
        return (OS_PRIO_INVALID); 
    } 
    OS_ENTER_CRITICAL(); 
    if (prio == OS_PRIO_SELF) {                            /* See if suspend SELF                      */ 
        prio = OSTCBCur->OSTCBPrio; 
    } 
    if ((ptcb = OSTCBPrioTbl[prio]) == (OS_TCB *)0) {      /* Task to query must exist                 */ 
        OS_EXIT_CRITICAL(); 
        return (OS_PRIO_ERR); 
    } 
    *dataptr = *ptcb;                                        /* Copy TCB into user storage area          */ 
    OS_EXIT_CRITICAL(); 
    return (OS_NO_ERR); 
} 
#endif