/*
*********************************************************************************************************
* 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.
*********************************************************************************************************
*/
//改變任務的優先級 allows you to change the priority of a task dynamically.
#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;
//jungle
#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 {
//書包--Reserve預定
OSTCBPrioTbl[newprio] = (OS_TCB *)1; /* Reserve the entry to prevent others */
OS_EXIT_CRITICAL();
//Precompute--交換
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 */
}
//把剛才書包給占到
ptcb = OSTCBPrioTbl[oldprio];
if (ptcb != (OS_TCB *)0) { /* Task to change must exist */
//Remove TCB from old priority
OSTCBPrioTbl[oldprio] = (OS_TCB *)0; /* Remove TCB from old priority */
//If task is ready make it not have osrdygrp
if ((OSRdyTbl[ptcb->OSTCBY] & ptcb->OSTCBBitX) != 0x00) { /* If task is ready make it not */
//就緒表是否有任務運作
if ((OSRdyTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0x00) {
//no 就直接把就緒組置位
OSRdyGrp &= ~ptcb->OSTCBBitY;
}
//就緒先的任務的就緒表
OSRdyGrp |= bity; /* Make new priority ready to run */
OSRdyTbl[y] |= bitx;
#if OS_EVENT_EN > 0
} else {
//若任務已經就緒
pevent = ptcb->OSTCBEventPtr;
//Remove from event wait list
if (pevent != (OS_EVENT *)0) { /* Remove from event wait list */
if ((pevent->OSEventTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0) {
pevent->OSEventGrp &= ~ptcb->OSTCBBitY;
}
//改變就緒組和就緒表
pevent->OSEventGrp |= bity; /* Add new priority to wait list */
pevent->OSEventTbl[y] |= bitx;
}
#endif
}
//Place -設定 Place pointer to TCB @ new priority
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();
// Run highest priority task ready
OS_Sched(); /* Run highest priority task ready */
return (OS_NO_ERR);
} else {
//把書包拿走
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)
*********************************************************************************************************
*/
//execution--執行==This function is used to have uC/OS-II manage the execution of a task.
#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 */
//書包
OSTCBPrioTbl[prio] = (OS_TCB *)1; /* Reserve the priority to prevent others from doing ... */
/* ... the same thing until task is created. */
OS_EXIT_CRITICAL();
//cs:ip flag Initialize the task's stack
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();
//書包--還回去
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)
*********************************************************************************************************
*/
//建立任務
/*$PAGE*/
#if OS_TASK_CREATE_EXT_EN > 0
INT8U OSTaskCreateExt (void (*task)(void *pd),
void *pdata,
OS_STK *ptos,
INT8U prio,
INT16U id,
OS_STK *pbos,
INT32U stk_size,
void *pext,
INT16U opt)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
OS_STK *psp;
INT8U err;
#if OS_ARG_CHK_EN > 0
if (prio > OS_LOWEST_PRIO) { /* Make sure priority is within allowable range */
return (OS_PRIO_INVALID);
}
#endif
OS_ENTER_CRITICAL();
if (OSTCBPrioTbl[prio] == (OS_TCB *)0) { /* Make sure task doesn't already exist at this priority */
//書包
OSTCBPrioTbl[prio] = (OS_TCB *)1; /* Reserve the priority to prevent others from doing ... */
/* ... the same thing until task is created. */
OS_EXIT_CRITICAL();
if (((opt & OS_TASK_OPT_STK_CHK) != 0x0000) || /* See if stack checking has been enabled */
((opt & OS_TASK_OPT_STK_CLR) != 0x0000)) { /* See if stack needs to be cleared */
#if OS_STK_GROWTH == 1
(void)memset(pbos, 0, stk_size * sizeof(OS_STK));
#else
(void)memset(ptos, 0, stk_size * sizeof(OS_STK));
#endif
}
//Initialize the task's stack
psp = (OS_STK *)OSTaskStkInit(task, pdata, ptos, opt); /* Initialize the task's stack */
err = OS_TCBInit(prio, psp, pbos, id, stk_size, pext, opt);
if (err == OS_NO_ERR) {
OS_ENTER_CRITICAL();
OSTaskCtr++; /* Increment the #tasks counter */
OS_EXIT_CRITICAL();
if (OSRunning == TRUE) { /* Find HPT if multitasking has started */
OS_Sched();
}
} else {
OS_ENTER_CRITICAL();
//把空間還回去
OSTCBPrioTbl[prio] = (OS_TCB *)0; /* Make this priority avail. to others */
OS_EXIT_CRITICAL();
}
return (err);
}
OS_EXIT_CRITICAL();
return (OS_PRIO_EXIST);
}
#endif
/*$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*/
/* ============================================================== */
//删除一個任務
#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;
//看是否在中斷
if (OSIntNesting > 0) { /* See if trying to delete from ISR */
return (OS_TASK_DEL_ISR);
}
#if OS_ARG_CHK_EN > 0
//是否是空閑任務
if (prio == OS_IDLE_PRIO) { /* Not allowed to delete idle task */
return (OS_TASK_DEL_IDLE);
}
//優先級是否有效
if (prio >= OS_LOWEST_PRIO && prio != OS_PRIO_SELF) { /* Task priority valid ? */
return (OS_PRIO_INVALID);
}
#endif
OS_ENTER_CRITICAL();
//檢查是否删除自己
if (prio == OS_PRIO_SELF) { /* See if requesting to delete self */
prio = OSTCBCur->OSTCBPrio; /* Set priority to delete to current */
}
ptcb = OSTCBPrioTbl[prio];
//删除的任務必須存在
if (ptcb != (OS_TCB *)0) { /* Task to delete must exist */
//比較任務就緒表是否有任務就緒
if ((OSRdyTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0x00) { /* Make task not ready */
//沒有則标志就緒組
OSRdyGrp &= ~ptcb->OSTCBBitY;
}
#if OS_EVENT_EN > 0
pevent = ptcb->OSTCBEventPtr;
//若事件控制塊不為0
if (pevent != (OS_EVENT *)0) { /* If task is waiting on event */
//檢視事件就緒表是否有任務就緒
if ((pevent->OSEventTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0) { /* ... remove task from */
//沒有就把事件就緒組标志
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 */
//避免中斷
if (OSLockNesting < 255) {
OSLockNesting++;
}
OS_EXIT_CRITICAL(); /* Enabling INT. ignores next instruc. */
//啥也不做
OS_Dummy(); /* ... Dummy ensures that INTs will be */
OS_ENTER_CRITICAL(); /* ... disabled HERE! */
//減回去
if (OSLockNesting > 0) {
OSLockNesting--;
}
OSTaskDelHook(ptcb); /* Call user defined hook */
//任務次數減一
OSTaskCtr--; /* One less task being managed */
//設定
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 {
//否則就指向下一個
ptcb->OSTCBPrev->OSTCBNext = ptcb->OSTCBNext;
ptcb->OSTCBNext->OSTCBPrev = ptcb->OSTCBPrev;
}
//還給空閑連結清單
ptcb->OSTCBNext = OSTCBFreeList; /* Return TCB to free TCB list */
OSTCBFreeList = ptcb;
OS_EXIT_CRITICAL();
//執行一次任務排程
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.
*********************************************************************************************************
*/
/*$PAGE*/
//通知一個任務删除他自己
#if OS_TASK_DEL_EN > 0
INT8U OSTaskDelReq (INT8U prio)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
BOOLEAN stat;
INT8U err;
OS_TCB *ptcb;
#if OS_ARG_CHK_EN > 0
//各種判斷
if (prio == OS_IDLE_PRIO) { /* Not allowed to delete idle task */
return (OS_TASK_DEL_IDLE);
}
if (prio >= OS_LOWEST_PRIO && prio != OS_PRIO_SELF) { /* Task priority valid ? */
return (OS_PRIO_INVALID);
}
#endif
//檢查是否删除自己
if (prio == OS_PRIO_SELF) { /* See if a task is requesting to ... */
OS_ENTER_CRITICAL(); /* ... this task to delete itself */
stat = OSTCBCur->OSTCBDelReq; /* Return request status to caller */
OS_EXIT_CRITICAL();
return (stat);
}
OS_ENTER_CRITICAL();
//否則請求的不是删除自己
ptcb = OSTCBPrioTbl[prio];
//去任務表找删除的任務
if (ptcb != (OS_TCB *)0) { /* Task to delete must exist */
ptcb->OSTCBDelReq = OS_TASK_DEL_REQ; /* Set flag indicating task to be DEL. */
err = OS_NO_ERR;
} else {
//删除的任務不存在
err = OS_TASK_NOT_EXIST; /* Task must be deleted */
}
OS_EXIT_CRITICAL();
return (err);
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* RESUME A SUSPENDED TASK
*
* Description: This function is called to resume(重新開始) 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
*********************************************************************************************************
*/
//恢複任務函數
#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;
//各種判斷
#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);
}
//檢查此任務是否在被等待
if ((ptcb->OSTCBStat & OS_STAT_SUSPEND) != OS_STAT_RDY) { /* Task must be suspended */
//取消任務挂起 且延時時間為0
if (((ptcb->OSTCBStat &= ~OS_STAT_SUSPEND) == OS_STAT_RDY) && /* Remove suspension */
(ptcb->OSTCBDly == 0)) { /* Must not be delayed */
//使得此任務就緒
OSRdyGrp |= ptcb->OSTCBBitY; /* Make task ready to run */
OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
OS_EXIT_CRITICAL();
OS_Sched();//觸發一次任務排程
} 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.
*********************************************************************************************************
*/
//This function is called to suspend a task
#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;
//各種判斷
#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();
//是否是自己和目前的任務
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 */
}
//取出控制塊
ptcb = OSTCBPrioTbl[prio];
//Task to suspend must exist
if (ptcb == (OS_TCB *)0) { /* Task to suspend must exist */
OS_EXIT_CRITICAL();
return (OS_TASK_SUSPEND_PRIO);
}
//使得就緒表設定 且檢視就緒表是否有無任務就緒
if ((OSRdyTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0x00) { /* Make task not ready */
OSRdyGrp &= ~ptcb->OSTCBBitY;
}
//在任務控制塊給自己标記
ptcb->OSTCBStat |= OS_STAT_SUSPEND; /* Status of task is 'SUSPENDED' */
OS_EXIT_CRITICAL();
//若挂起的是自己或目前的任務
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
*********************************************************************************************************
*/
//查詢任務的資訊
#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