os_tasking.c

一个简单易用的可裁减的小型实时操作系统 移植非常简单

/*
 *******************************************************************************
 *
 * MicroROS
 *
 * Copyright (C) 2007 <[e-mail]>			
 *
 * Description	: 任务
 *
 * File			: os_tasking.c
 * Author		: amwox
 * Edition		: V0.10
 * History		: 2007-10-29  created 
 *				  2008-01-28  添加_AppendEvent,_RemoveEvent,_WakeupEvent
 *				  删除_SerachEvent
 *******************************************************************************
 */
#include "..\include\MicroROS.h"
#include "..\include\os_cpu.h"

KernelData	os_kernel; 


#if (SEMAPHORE_EN > 0) || (MAILBOX_EN > 0) || (MUTEX_EN > 0)
/* 
 * Description	: 在指定列表中追加一事件
 * Arguments	: pList		列表
 *				  pEvent	追加事件的进程指针
 * Returns		: 
 */
void _AppendEvent(pPID *pList, pPID pEvent)
{
	pPID pTmp = *pList;
	pPID pPrev = NULL;
	while (pTmp != NULL) {					/*找到列表尾部*/
		pPrev = pTmp;
		pTmp = pTmp->pEventNext;
	}
	if (pPrev == NULL) {					/*当前列表是一个空表*/
		*pList = pEvent;					/*将列表的首指针指向新的事件*/
	}
	else {
		pPrev->pEventNext = pEvent;			/*追加*/
	}
}
/* 
 * Description	: 在指定列表中删除一事件
 * Arguments	: pList		列表
 *				  pEvent	要删除事件的进程指针
 * Returns		: 返回是否删除成功
 */
BOOL _RemoveEvent(pPID *pList, pPID pEvent)
{
	pPID pTmp = *pList;
	pPID pPrev = NULL;
	while (pTmp != NULL) {
		if (pTmp == pEvent) {				/*找到列表中的事件*/
			break;
		}
		pPrev = pTmp;
		pTmp = pTmp->pEventNext;
	}
	if (pTmp == NULL)						/*不存在当前列表中*/
		return FALSE;
	if (pPrev == NULL) {
		*pList = pEvent->pEventNext;		/*当前节点是首节点*/
	}
	else {
		pPrev->pEventNext = pEvent->pEventNext;	/*删除当前节点*/
	}
	pEvent->pEventNext = NULL;
	return TRUE;
}

/* 
 * Description	: 唤醒列表中的所有事件
 * Arguments	: pList		列表
 * Returns		: 
 */
void _WakeupEvent(pPID pList)
{
	CPU_SREG cpu_sreg;
	
	while (pList != NULL) {
		OS_ENTER_CRITICAL();
		if (pList->TimerCnt != LIMITLESS)		/*无限制地等待是不处于定时器队列的*/
			_RemoveTimer(pList);
		OS_TaskResume(pList);					/*唤醒*/
		OS_EXIT_CRITICAL();
		pList = pList->pEventNext;
	}
}

#endif

/* 
 * Description	: 删除运行队列中的进程
 * Arguments	: pProcess	要删除的进程
 * Returns		: 返回是否删除成功
 */
BOOL _RemovePID(pPID pProcess)
{
	pPID pPrev,pTmp;
	pPrev = NULL;
	pTmp = os_kernel.pRunList ;
	while (pTmp != NULL) {
		if (pTmp == pProcess)
			break;
		pPrev = pTmp;
		pTmp = pTmp->pNext;
	}
	if (pTmp == NULL)
		return FALSE;
	if (pPrev == NULL) 		/*找到的是首节点*/
		os_kernel.pRunList  = os_kernel.pRunList->pNext;
	else 
		pPrev->pNext = pProcess->pNext;
	pProcess->pNext = NULL;
    return TRUE; 
} 

/* 
 * Description	: 按Priority插入指定节点
 * Arguments	: pList		已按Priority排序的列表,0在前,255在后,相同的按FCFS原则排序
 *				  pProcess	要插入的节点
 * Returns		:
 */
void _QueuePID(pPID pProcess)
{
	pPID pPrev,pTmp;

	pPrev = NULL;
	pTmp = os_kernel.pRunList;
	while (pTmp != NULL) {
		if (pTmp->Priority > pProcess->Priority)
			break;
		pPrev = pTmp;
		pTmp = pTmp->pNext;
	}

	if (pPrev == NULL) {
		pProcess->pNext = os_kernel.pRunList ;
		os_kernel.pRunList   = pProcess;
	}
	else {
		pProcess->pNext = pPrev->pNext;
		pPrev->pNext = pProcess;
	} 
}

/* 
 * Description	: 只是调用_Epilog,所以标注为NAKED,减少开消.如果加入了其它的在启
 *				  动时处理,应该去掉NAKED
 * Arguments	:
 * Returns		:
 */                
NAKED void OS_Start(void)
{ 
	os_kernel.SysLevel = 0;
	os_kernel.pRunning = NULL;
	_Schedule();
	OS_IdleTask();
}

/* 
 * Description	: 创建任务
 * Arguments	:
 * Returns		:
 */
void OS_TaskCreate(pPID pProcess)
{
	pProcess->pCP = OS_TaskInit(pProcess->pTaskName,pProcess->pCP);
	OS_TaskResume(pProcess);
}

/* 
 * Description	: 任务恢复到运行列表,按规则排队,等待运行
 *				  注意:仅仅是恢复到运行列表,并不会调用任务切换
 * Arguments	:
 * Returns		:
 */
void OS_TaskResume(pPID pProcess)
{
	pProcess->State |= BV(PID_READY);
	_QueuePID(pProcess);
}

/* 
 * Description	: 任务挂起
 * Arguments	:
 * Returns		:
 */
void OS_TaskSuspend(pPID pProcess)
{
	pProcess->State |= BV(PID_SUSPEND);
	_RemovePID(pProcess);
}

/* 
 * Description	: 任务睡眠,不能通过任务恢复来结束睡眠时间
 * Arguments	:
 * Returns		:
 */
void OS_TaskSleep(WORD ticks)
{
	CPU_SREG cpu_sreg;
	OS_ENTER_CRITICAL();
	pPID pTimer = os_kernel.pRunning;
	OS_TaskSuspend(pTimer);
	pTimer->TimerCnt = ticks;
	pTimer->State |= BV(PID_IDLE);
	_QueueTimer(pTimer);	
	OS_EXIT_CRITICAL();
	_Schedule();
}