?? os_task.c
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/*
*********************************************************************************************************
* 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
*********************************************************************************************************
*/
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)
{
}
/*$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)
{
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
*
* 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
INT8U OSTaskCreate (
void (*task)(void *pd), // 任務指針
void *pdata, // 任務參數
OS_STK *ptos, // 分配給任務的堆棧頂指針
INT8U prio // 任務優先級
)
{
void *psp;
INT8U err;
if (prio > OS_LOWEST_PRIO) // 判斷優先級是否合法 /* Make sure priority is within allowable range */
{
return (OS_PRIO_INVALID);
}
OS_ENTER_CRITICAL(); // 關中斷
//判斷 優先級 是否被占用
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(); // 開中斷
psp = (void *)OSTaskStkInit(task, pdata, ptos, 0); //初始化任務堆棧 /* Initialize the task's stack */
err = OSTCBInit(prio, psp, (void *)0, 0, 0, (void *)0, 0);//初始化任務控制塊
if (err == OS_NO_ERR)
{
OS_ENTER_CRITICAL();
OSTaskCtr++; //任務計數加1 /* 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();//任務調度
}
} 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
*
* 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;
* }
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