/* ********************************************************************************************************* * uC/OS-II * The Real-Time Kernel * TASK MANAGEMENT * * (c) Copyright 1992-2002, Jean J. Labrosse, Weston, FL * All Rights Reserved * * File : OS_TASK.C * By : Jean J. Labrosse ********************************************************************************************************* */ #ifndef OS_MASTER_FILE #include "includes.h" #endif /* ********************************************************************************************************* * 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 > 0 INT8U OSTaskChangePrio (INT8U oldprio, INT8U newprio) { #if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */ OS_CPU_SR cpu_sr; #endif #if OS_EVENT_EN > 0 OS_EVENT *pevent; #endif OS_TCB *ptcb; INT8U x; INT8U y; INT8U bitx; INT8U bity; #if OS_ARG_CHK_EN > 0 if ((oldprio >= OS_LOWEST_PRIO && oldprio != OS_PRIO_SELF) || newprio >= OS_LOWEST_PRIO) { return (OS_PRIO_INVALID); } #endif 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 */ } ptcb = OSTCBPrioTbl[oldprio]; if (ptcb != (OS_TCB *)0) { /* Task to change must exist */ OSTCBPrioTbl[oldprio] = (OS_TCB *)0; /* Remove TCB from old priority */ if ((OSRdyTbl[ptcb->OSTCBY] & ptcb->OSTCBBitX) != 0x00) { /* If task is ready make it not */ if ((OSRdyTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0x00) { OSRdyGrp &= ~ptcb->OSTCBBitY; } OSRdyGrp |= bity; /* Make new priority ready to run */ OSRdyTbl[y] |= bitx; #if OS_EVENT_EN > 0 } else { pevent = ptcb->OSTCBEventPtr; if (pevent != (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; } #endif } 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(); OS_Sched(); /* 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 * * pdata 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 'pdata' as follows: * * void Task (void *pdata) * { * 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 > 0 INT8U OSTaskCreate (void (*task)(void *pd), void *pdata, OS_STK *ptos, INT8U prio) { #if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */ OS_CPU_SR cpu_sr; #endif OS_STK *psp; INT8U err; #if OS_ARG_CHK_EN > 0 if (prio > OS_LOWEST_PRIO) { /* Make sure priority is within allowable range */ return (OS_PRIO_INVALID); } #endif 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 = (OS_STK *)OSTaskStkInit(task, pdata, ptos, 0); /* Initialize the task's stack */ err = OS_TCBInit(prio, psp, (OS_STK *)0, 0, 0, (void *)0, 0); if (err == OS_NO_ERR) { OS_ENTER_CRITICAL(); OSTaskCtr++; /* Increment the #tasks counter */ OS_EXIT_CRITICAL(); if (OSRunning == 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_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 * * pdata 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 'pdata' as follows: * * void Task (void *pdata) * { * 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) ********************************************************************************************************* */ /*$PAGE*/ #if OS_TASK_CREATE_EXT_EN > 0 INT8U OSTaskCreateExt (void (*task)(void *pd), void *pdata, OS_STK *ptos, INT8U prio, INT16U id, OS_STK *pbos, INT32U stk_size, void *pext, INT16U opt) { #if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */ OS_CPU_SR cpu_sr; #endif OS_STK *psp; INT8U err; #if OS_ARG_CHK_EN > 0 if (prio > OS_LOWEST_PRIO) { /* Make sure priority is within allowable range */ return (OS_PRIO_INVALID); } #endif OS_ENTER_CRITICAL(); if (OSTCBPrioTbl[prio] == (OS_TCB *)0) { /* Make sure task doesn't already exist at this priority */ OSTCBPrioTbl[prio] = (OS_TCB *)1; /* Reserve the priority to prevent others from doing ... */ /* ... the same thing until task is created. */ OS_EXIT_CRITICAL(); if (((opt & OS_TASK_OPT_STK_CHK) != 0x0000) || /* See if stack checking has been enabled */ ((opt & OS_TASK_OPT_STK_CLR) != 0x0000)) { /* See if stack needs to be cleared */ #if OS_STK_GROWTH == 1 (void)memset(pbos, 0, stk_size * sizeof(OS_STK)); #else (void)memset(ptos, 0, stk_size * sizeof(OS_STK)); #endif } psp = (OS_STK *)OSTaskStkInit(task, pdata, ptos, opt); /* Initialize the task's stack */ err = OS_TCBInit(prio, psp, pbos, id, stk_size, pext, opt); if (err == OS_NO_ERR) { OS_ENTER_CRITICAL(); OSTaskCtr++; /* Increment the #tasks counter */ OS_EXIT_CRITICAL(); if (OSRunning == TRUE) { /* Find HPT if multitasking has started */ OS_Sched(); } } else { OS_ENTER_CRITICAL(); OSTCBPrioTbl[prio] = (OS_TCB *)0; /* Make this priority avail. to others */ OS_EXIT_CRITICAL(); } return (err); } OS_EXIT_CRITICAL(); return (OS_PRIO_EXIST); } #endif /*$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 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. ********************************************************************************************************* */ /*$PAGE*/ #if OS_TASK_DEL_EN > 0 INT8U OSTaskDel (INT8U prio) { #if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */ OS_CPU_SR cpu_sr; #endif #if OS_EVENT_EN > 0 OS_EVENT *pevent; #endif #if (OS_VERSION >= 251) && (OS_FLAG_EN > 0) && (OS_MAX_FLAGS > 0) OS_FLAG_NODE *pnode; #endif OS_TCB *ptcb; BOOLEAN self; if (OSIntNesting > 0) { /* See if trying to delete from ISR */ return (OS_TASK_DEL_ISR); } #if OS_ARG_CHK_EN > 0 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); } #endif 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 */ if ((OSRdyTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0x00) { /* Make task not ready */ OSRdyGrp &= ~ptcb->OSTCBBitY; } #if OS_EVENT_EN > 0 pevent = ptcb->OSTCBEventPtr; if (pevent != (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 */ } } #endif #if (OS_VERSION >= 251) && (OS_FLAG_EN > 0) && (OS_MAX_FLAGS > 0) 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 = 0; /* Prevent OSTimeTick() from updating */ ptcb->OSTCBStat = OS_STAT_RDY; /* Prevent task from being resumed */ if (OSLockNesting < 255) { OSLockNesting++; } OS_EXIT_CRITICAL(); /* Enabling INT. ignores next instruc. */ OS_Dummy(); /* ... Dummy ensures that INTs will be */ OS_ENTER_CRITICAL(); /* ... disabled HERE! */ if (OSLockNesting > 0) { 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(); OS_Sched(); /* Find new highest priority task */ return (OS_NO_ERR); } 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 *data) * { * . * . * 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. ********************************************************************************************************* */ /*$PAGE*/ #if OS_TASK_DEL_EN > 0 INT8U OSTaskDelReq (INT8U prio) { #if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */ OS_CPU_SR cpu_sr; #endif BOOLEAN stat; INT8U err; OS_TCB *ptcb; #if OS_ARG_CHK_EN > 0 if (prio == OS_IDLE_PRIO) { /* Not allowed to delete idle task */ return (OS_TASK_DEL_IDLE); } if (prio >= OS_LOWEST_PRIO && prio != OS_PRIO_SELF) { /* Task priority valid ? */ return (OS_PRIO_INVALID); } #endif if (prio == OS_PRIO_SELF) { /* See if a task is requesting to ... */ OS_ENTER_CRITICAL(); /* ... this task to delete itself */ stat = OSTCBCur->OSTCBDelReq; /* Return request status to caller */ OS_EXIT_CRITICAL(); return (stat); } OS_ENTER_CRITICAL(); ptcb = OSTCBPrioTbl[prio]; if (ptcb != (OS_TCB *)0) { /* Task to delete must exist */ ptcb->OSTCBDelReq = OS_TASK_DEL_REQ; /* Set flag indicating task to be DEL. */ err = OS_NO_ERR; } else { err = OS_TASK_NOT_EXIST; /* Task must be deleted */ } OS_EXIT_CRITICAL(); return (err); } #endif /*$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 > 0 INT8U OSTaskResume (INT8U prio) { #if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */ OS_CPU_SR cpu_sr; #endif OS_TCB *ptcb; #if OS_ARG_CHK_EN > 0 if (prio >= OS_LOWEST_PRIO) { /* Make sure task priority is valid */ return (OS_PRIO_INVALID); } #endif OS_ENTER_CRITICAL(); ptcb = OSTCBPrioTbl[prio]; if (ptcb == (OS_TCB *)0) { /* Task to suspend must exist */ OS_EXIT_CRITICAL(); return (OS_TASK_RESUME_PRIO); } if ((ptcb->OSTCBStat & OS_STAT_SUSPEND) != OS_STAT_RDY) { /* 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(); OS_Sched(); } else { OS_EXIT_CRITICAL(); } return (OS_NO_ERR); } 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 * * pdata 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 > 0 INT8U OSTaskStkChk (INT8U prio, OS_STK_DATA *pdata) { #if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */ OS_CPU_SR cpu_sr; #endif OS_TCB *ptcb; OS_STK *pchk; INT32U free; INT32U size; #if OS_ARG_CHK_EN > 0 if (prio > OS_LOWEST_PRIO && prio != OS_PRIO_SELF) { /* Make sure task priority is valid */ return (OS_PRIO_INVALID); } #endif pdata->OSFree = 0; /* Assume failure, set to 0 size */ pdata->OSUsed = 0; 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++ == (OS_STK)0) { /* Compute the number of zero entries on the stk */ free++; } #else while (*pchk-- == (OS_STK)0) { free++; } #endif pdata->OSFree = free * sizeof(OS_STK); /* Compute number of free bytes on the stack */ pdata->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 > 0 INT8U OSTaskSuspend (INT8U prio) { #if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */ OS_CPU_SR cpu_sr; #endif BOOLEAN self; OS_TCB *ptcb; #if OS_ARG_CHK_EN > 0 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); } #endif 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 */ } ptcb = OSTCBPrioTbl[prio]; if (ptcb == (OS_TCB *)0) { /* Task to suspend must exist */ OS_EXIT_CRITICAL(); return (OS_TASK_SUSPEND_PRIO); } if ((OSRdyTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0x00) { /* 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 */ OS_Sched(); } 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 > 0 INT8U OSTaskQuery (INT8U prio, OS_TCB *pdata) { #if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */ OS_CPU_SR cpu_sr; #endif OS_TCB *ptcb; #if OS_ARG_CHK_EN > 0 if (prio > OS_LOWEST_PRIO && prio != OS_PRIO_SELF) { /* Task priority valid ? */ return (OS_PRIO_INVALID); } #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_PRIO_ERR); } memcpy(pdata, ptcb, sizeof(OS_TCB)); /* Copy TCB into user storage area */ OS_EXIT_CRITICAL(); return (OS_NO_ERR); } #endif