首页 > 代码库 > uC/OS-II互斥信号(OS_mutex)块
uC/OS-II互斥信号(OS_mutex)块
/*
*********************************************************************************************************
* uC/OS-II
* The Real-Time Kernel
* MUTUAL EXCLUSION SEMAPHORE MANAGEMENT
*
* (c) Copyright 1992-2002, Jean J. Labrosse, Weston, FL
* All Rights Reserved
*
* File : OS_MUTEX.C
* By : Jean J. Labrosse
*********************************************************************************************************
*/
#ifndef OS_MASTER_FILE
#include "includes.h"
#endif
/*
*********************************************************************************************************
* LOCAL CONSTANTS
*********************************************************************************************************
*/
#define OS_MUTEX_KEEP_LOWER_8 0x00FF
#define OS_MUTEX_KEEP_UPPER_8 0xFF00
#define OS_MUTEX_AVAILABLE 0x00FF
#if OS_MUTEX_EN > 0
/*
*********************************************************************************************************
* ACCEPT MUTUAL EXCLUSION SEMAPHORE
*
* Description: This function checks the mutual exclusion semaphore to see if a resource is available.
* Unlike OSMutexPend(), OSMutexAccept() does not suspend the calling task if the resource is
* not available or the event did not occur.
*
* Arguments : pevent is a pointer to the event control block
*
* err is a pointer to an error code which will be returned to your application:
* OS_NO_ERR if the call was successful.
* OS_ERR_EVENT_TYPE if ‘pevent‘ is not a pointer to a mutex
* OS_ERR_PEVENT_NULL ‘pevent‘ is a NULL pointer
* OS_ERR_PEND_ISR if you called this function from an ISR
*
* Returns : == 1 if the resource is available, the mutual exclusion semaphore is acquired
* == 0 a) if the resource is not available
* b) you didn‘t pass a pointer to a mutual exclusion semaphore
* c) you called this function from an ISR
*
* Warning(s) : This function CANNOT be called from an ISR because mutual exclusion semaphores are
* intended to be used by tasks only.
*********************************************************************************************************
*/
//This function checks the mutual exclusion semaphore to see if a resource is available.
#if OS_MUTEX_ACCEPT_EN > 0
INT8U OSMutexAccept (OS_EVENT *pevent, INT8U *err)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
if (OSIntNesting > 0) { /* Make sure it‘s not called from an ISR */
*err = OS_ERR_PEND_ISR;
return (0);
}
#if OS_ARG_CHK_EN > 0
if (pevent == (OS_EVENT *)0) { /* Validate ‘pevent‘ */
*err = OS_ERR_PEVENT_NULL;
return (0);
}
if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX) { /* Validate event block type */
*err = OS_ERR_EVENT_TYPE;
return (0);
}
#endif
OS_ENTER_CRITICAL(); /* Get value (0 or 1) of Mutex */
if ((pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8) == OS_MUTEX_AVAILABLE) {
pevent->OSEventCnt &= OS_MUTEX_KEEP_UPPER_8; /* Mask off LSByte (Acquire Mutex) */
pevent->OSEventCnt |= OSTCBCur->OSTCBPrio; /* Save current task priority in LSByte */
pevent->OSEventPtr = (void *)OSTCBCur; /* Link TCB of task owning Mutex */
OS_EXIT_CRITICAL();
*err = OS_NO_ERR;
return (1);
}
OS_EXIT_CRITICAL();
*err = OS_NO_ERR;
return (0);
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* CREATE A MUTUAL EXCLUSION SEMAPHORE
*
* Description: This function creates a mutual exclusion/排斥 semaphore.
*
* Arguments : prio is the priority to use when accessing the mutual exclusion semaphore. In
* other words, when the semaphore is acquired and a higher priority task
* attempts to obtain the semaphore then the priority of the task owning the
* semaphore is raised to this priority. It is assumed that you will specify
* a priority that is LOWER in value than ANY of the tasks competing for the
* mutex.
*
* err is a pointer to an error code which will be returned to your application:
* OS_NO_ERR if the call was successful.
* OS_ERR_CREATE_ISR if you attempted to create a MUTEX from an ISR
* OS_PRIO_EXIST if a task at the priority inheritance priority
* already exist.
* OS_ERR_PEVENT_NULL No more event control blocks available.
* OS_PRIO_INVALID if the priority you specify is higher that the
* maximum allowed (i.e. > OS_LOWEST_PRIO)
*
* Returns : != (void *)0 is a pointer to the event control clock (OS_EVENT) associated with the
* created mutex.
* == (void *)0 if an error is detected.
*
* Note(s) : 1) The LEAST significant 8 bits of ‘.OSEventCnt‘ are used to hold the priority number
* of the task owning the mutex or 0xFF if no task owns the mutex.
* 2) The MOST significant 8 bits of ‘.OSEventCnt‘ are used to hold the priority number
* to use to reduce priority inversion.
*********************************************************************************************************
*/
//创建一个互斥信号量
OS_EVENT *OSMutexCreate (INT8U prio, INT8U *err)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
OS_EVENT *pevent;
//各种判断
if (OSIntNesting > 0) { /* See if called from ISR ... */
*err = OS_ERR_CREATE_ISR; /* ... can‘t CREATE mutex from an ISR */
return ((OS_EVENT *)0);
}
#if OS_ARG_CHK_EN > 0
if (prio >= OS_LOWEST_PRIO) { /* Validate PIP */
*err = OS_PRIO_INVALID;
return ((OS_EVENT *)0);
}
#endif
OS_ENTER_CRITICAL();
if (OSTCBPrioTbl[prio] != (OS_TCB *)0) { /* Mutex priority must not already exist */
OS_EXIT_CRITICAL(); /* Task already exist at priority ... */
*err = OS_PRIO_EXIST; /* ... inheritance priority */
return ((OS_EVENT *)0);
}
//书包
OSTCBPrioTbl[prio] = (OS_TCB *)1; /* Reserve the table entry */
pevent = OSEventFreeList; /* Get next free event control block */
//判断事件控制块是否可用
if (pevent == (OS_EVENT *)0) { /* See if an ECB was available */
//还回去
OSTCBPrioTbl[prio] = (OS_TCB *)0; /* No, Release the table entry */
OS_EXIT_CRITICAL();
*err = OS_ERR_PEVENT_NULL; /* No more event control blocks */
return (pevent);
}
//否则
OSEventFreeList = (OS_EVENT *)OSEventFreeList->OSEventPtr; /* Adjust the free list */
OS_EXIT_CRITICAL();
//类型是互斥信息号量--4
pevent->OSEventType = OS_EVENT_TYPE_MUTEX;
//把优先级左移动8位 且低8位标记为11111111OSEventCnt的高八位是prio 低八位是8个1
pevent->OSEventCnt = (prio << 8) | OS_MUTEX_AVAILABLE;/* Resource is available */
//表示任务没有使用本次信号量
pevent->OSEventPtr = (void *)0; /* No task owning the mutex */
//然后对事件控制块进行初始化
OS_EventWaitListInit(pevent);
*err = OS_NO_ERR;
return (pevent);
}
/*$PAGE*/
/*
*********************************************************************************************************
* DELETE A MUTEX
*
* Description: This function deletes a mutual exclusion semaphore and readies all tasks pending on the it.
*
* Arguments : pevent is a pointer to the event control block associated with the desired mutex.
*
* opt determines delete options as follows:
* opt == OS_DEL_NO_PEND Delete mutex ONLY if no task pending
* opt == OS_DEL_ALWAYS Deletes the mutex even if tasks are waiting.
* In this case, all the tasks pending will be readied.
*
* err is a pointer to an error code that can contain one of the following values:
* OS_NO_ERR The call was successful and the mutex was deleted
* OS_ERR_DEL_ISR If you attempted to delete the MUTEX from an ISR
* OS_ERR_INVALID_OPT An invalid option was specified
* OS_ERR_TASK_WAITING One or more tasks were waiting on the mutex
* OS_ERR_EVENT_TYPE If you didn‘t pass a pointer to a mutex
* OS_ERR_PEVENT_NULL If ‘pevent‘ is a NULL pointer.
*
* Returns : pevent upon error
* (OS_EVENT *)0 if the mutex was successfully deleted.
*
* Note(s) : 1) This function must be used with care. Tasks that would normally expect the presence of
* the mutex MUST check the return code of OSMutexPend().
* 2) This call can potentially disable interrupts for a long time. The interrupt disable
* time is directly proportional to the number of tasks waiting on the mutex.
* 3) Because ALL tasks pending on the mutex will be readied, you MUST be careful because the
* resource(s) will no longer be guarded by the mutex.
*********************************************************************************************************
*/
//删除一个互斥信号量0000opt删除的方式--类似于信号量的删除
#if OS_MUTEX_DEL_EN
OS_EVENT *OSMutexDel (OS_EVENT *pevent, INT8U opt, INT8U *err)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
BOOLEAN tasks_waiting;
INT8U pip;
if (OSIntNesting > 0) { /* See if called from ISR ... */
*err = OS_ERR_DEL_ISR; /* ... can‘t DELETE from an ISR */
return (pevent);
}
#if OS_ARG_CHK_EN > 0
if (pevent == (OS_EVENT *)0) { /* Validate ‘pevent‘ */
*err = OS_ERR_PEVENT_NULL;
return ((OS_EVENT *)0);
}
if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX) { /* Validate event block type */
*err = OS_ERR_EVENT_TYPE;
return (pevent);
}
#endif
OS_ENTER_CRITICAL();
if (pevent->OSEventGrp != 0x00) { /* See if any tasks waiting on mutex */
tasks_waiting = TRUE; /* Yes */
} else {
tasks_waiting = FALSE; /* No */
}
switch (opt) {
/* Delete mutex only if no task waiting */
case OS_DEL_NO_PEND: /* Delete mutex only if no task waiting */
if (tasks_waiting == FALSE) {
pip = (INT8U)(pevent->OSEventCnt >> 8);
OSTCBPrioTbl[pip] = (OS_TCB *)0; /* Free up the PIP */
pevent->OSEventType = OS_EVENT_TYPE_UNUSED;
pevent->OSEventPtr = OSEventFreeList; /* Return Event Control Block to free list */
OSEventFreeList = pevent;
OS_EXIT_CRITICAL();
*err = OS_NO_ERR;
return ((OS_EVENT *)0); /* Mutex has been deleted */
} else {
OS_EXIT_CRITICAL();
*err = OS_ERR_TASK_WAITING;
return (pevent);
}
case OS_DEL_ALWAYS: /* Always delete the mutex */
while (pevent->OSEventGrp != 0x00) { /* Ready ALL tasks waiting for mutex */
OS_EventTaskRdy(pevent, (void *)0, OS_STAT_MUTEX);
}
pip = (INT8U)(pevent->OSEventCnt >> 8);
OSTCBPrioTbl[pip] = (OS_TCB *)0; /* Free up the PIP */
pevent->OSEventType = OS_EVENT_TYPE_UNUSED;
pevent->OSEventPtr = OSEventFreeList; /* Return Event Control Block to free list */
OSEventFreeList = pevent; /* Get next free event control block */
OS_EXIT_CRITICAL();
if (tasks_waiting == TRUE) { /* Reschedule only if task(s) were waiting */
OS_Sched(); /* Find highest priority task ready to run */
}
*err = OS_NO_ERR;
return ((OS_EVENT *)0); /* Mutex has been deleted */
default:
OS_EXIT_CRITICAL();
*err = OS_ERR_INVALID_OPT;
return (pevent);
}
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* PEND ON MUTUAL EXCLUSION SEMAPHORE
*
* Description: This function waits for a mutual exclusion semaphore.
*
* Arguments : pevent is a pointer to the event control block associated with the desired
* mutex.
*
* timeout is an optional timeout period (in clock ticks). If non-zero, your task will
* wait for the resource up to the amount of time specified by this argument.
* If you specify 0, however, your task will wait forever at the specified
* mutex or, until the resource becomes available.
*
* err is a pointer to where an error message will be deposited. Possible error
* messages are:
* OS_NO_ERR The call was successful and your task owns the mutex
* OS_TIMEOUT The mutex was not available within the specified time.
* OS_ERR_EVENT_TYPE If you didn‘t pass a pointer to a mutex
* OS_ERR_PEVENT_NULL ‘pevent‘ is a NULL pointer
* OS_ERR_PEND_ISR If you called this function from an ISR and the result
* would lead to a suspension.
*
* Returns : none
*
* Note(s) : 1) The task that owns the Mutex MUST NOT pend on any other event while it owns the mutex.
* 2) You MUST NOT change the priority of the task that owns the mutex
*********************************************************************************************************
*/
//请求一个互斥信号量---timeout延时时间 This function waits for a mutual exclusion semaphore.
void OSMutexPend (OS_EVENT *pevent, INT16U timeout, INT8U *err)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
//优先级继承优先级
INT8U pip; /* Priority Inheritance Priority (PIP) */
INT8U mprio; /* Mutex owner priority */
//任务是否就绪标志
BOOLEAN rdy; /* Flag indicating task was ready */
OS_TCB *ptcb;
//是否在中断
if (OSIntNesting > 0) { /* See if called from ISR ... */
*err = OS_ERR_PEND_ISR; /* ... can‘t PEND from an ISR */
return;
}
#if OS_ARG_CHK_EN > 0
//事件指针是否可用
if (pevent == (OS_EVENT *)0) { /* Validate ‘pevent‘ */
*err = OS_ERR_PEVENT_NULL;
return;
}
//是否是互斥信号量
if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX) { /* Validate event block type */
*err = OS_ERR_EVENT_TYPE;
return;
}
#endif
OS_ENTER_CRITICAL(); /* Is Mutex available? */
//查看互斥信号量有效
//若有信号OSEventCnt的低八位是8个1 说明该信号量未被占用 与OS_MUTEX_KEEP_LOWER_8进行与 若为111111111
if ((INT8U)(pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8) == OS_MUTEX_AVAILABLE) {
//与OS_MUTEX_KEEP_UPPER_8保存到高八位
//把低八位置0 表示资源被占用 这时OSEventCnt高八位为pip 低八位为0
pevent->OSEventCnt &= OS_MUTEX_KEEP_UPPER_8; /* Yes, Acquire the resource */
//这时OSEventCnt高八位为pip 低八位为任务的优先级
pevent->OSEventCnt |= OSTCBCur->OSTCBPrio; /* Save priority of owning task */
//OSEventPtr指向任务控制块
pevent->OSEventPtr = (void *)OSTCBCur; /* Point to owning task‘s OS_TCB */
OS_EXIT_CRITICAL();
*err = OS_NO_ERR;
return;
}
//取出优先级继承优先级pip
pip = (INT8U)(pevent->OSEventCnt >> 8); /* No, Get PIP from mutex */
//否则信号量被占用--取出互斥信号量所有者的优先级 赋值给mprio
mprio = (INT8U)(pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8); /* Get priority of mutex owner */
//取出互斥信号量所有者的tcb地址 赋值给ptcb
ptcb = (OS_TCB *)(pevent->OSEventPtr); /* Point to TCB of mutex owner */
//判断当前的是否等觘cb优先级 且 请求的任务块大于当前的优先级
if (ptcb->OSTCBPrio != pip && mprio > OSTCBCur->OSTCBPrio) { /* Need to promote prio of owner?*/
//查看互斥信号量所有者是否就绪--若就绪
if ((OSRdyTbl[ptcb->OSTCBY] & ptcb->OSTCBBitX) != 0x00) { /* See if mutex owner is ready */
/* Yes, Remove owner from Rdy ...*/
//是否在就绪表中取消互斥信号量所有者的就绪标志 /* ... list at current prio */
if ((OSRdyTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0x00) {
//已取消---就直接把就绪组中对应置0
OSRdyGrp &= ~ptcb->OSTCBBitY;
}
//就绪
rdy = TRUE;
} else {
rdy = FALSE; /* No */
}
//对互斥信号量所有者做优先级升级，改变TCB中所有者关于优先级域
ptcb->OSTCBPrio = pip; /* Change owner task prio to PIP */
ptcb->OSTCBY = ptcb->OSTCBPrio >> 3;
ptcb->OSTCBBitY = OSMapTbl[ptcb->OSTCBY];
ptcb->OSTCBX = ptcb->OSTCBPrio & 0x07;
ptcb->OSTCBBitX = OSMapTbl[ptcb->OSTCBX];
//就绪
if (rdy == TRUE) { /* If task was ready at owner‘s priority ...*/
//在就绪表和就绪组中重新提升后的优先级设置就绪标志
OSRdyGrp |= ptcb->OSTCBBitY; /* ... make it ready at new priority. */
OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
}
//互斥信号量原来未就绪
OSTCBPrioTbl[pip] = (OS_TCB *)ptcb;
}
//完成对优先级升级，继续对本任务就绪操作--设置等待互斥信号量的标志
OSTCBCur->OSTCBStat |= OS_STAT_MUTEX; /* Mutex not available, pend current task */
//存储超时
OSTCBCur->OSTCBDly = timeout; /* Store timeout in current task‘s TCB */
//取消本任务就绪状态
OS_EventTaskWait(pevent); /* Suspend task until event or timeout occurs */
OS_EXIT_CRITICAL();
OS_Sched(); /* Find next highest priority task ready */
OS_ENTER_CRITICAL();
//若延时时间到了
if (OSTCBCur->OSTCBStat & OS_STAT_MUTEX) { /* Must have timed out if still waiting for event*/
//结束等待状态 转去执行延时时间到 的函数
OS_EventTO(pevent);
OS_EXIT_CRITICAL();
*err = OS_TIMEOUT; /* Indicate that we didn‘t get mutex within TO */
return;
}
//否则把当前指针指向0
OSTCBCur->OSTCBEventPtr = (OS_EVENT *)0;
OS_EXIT_CRITICAL();
*err = OS_NO_ERR;
}
/*$PAGE*/
/*
*********************************************************************************************************
* POST TO A MUTUAL EXCLUSION SEMAPHORE
*
* Description: This function signals a mutual exclusion semaphore
*
* Arguments : pevent is a pointer to the event control block associated with the desired
* mutex.
*
* Returns : OS_NO_ERR The call was successful and the mutex was signaled.
* OS_ERR_EVENT_TYPE If you didn‘t pass a pointer to a mutex
* OS_ERR_PEVENT_NULL ‘pevent‘ is a NULL pointer
* OS_ERR_POST_ISR Attempted to post from an ISR (not valid for MUTEXes)
* OS_ERR_NOT_MUTEX_OWNER The task that did the post is NOT the owner of the MUTEX.
*********************************************************************************************************
*/
//发送互斥信号量---释放一个互斥信号量
INT8U OSMutexPost (OS_EVENT *pevent)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
//优先级继承优先级
INT8U pip; /* Priority inheritance priority */
INT8U prio;
if (OSIntNesting > 0) { /* See if called from ISR ... */
return (OS_ERR_POST_ISR); /* ... can‘t POST mutex from an ISR */
}
#if OS_ARG_CHK_EN > 0
if (pevent == (OS_EVENT *)0) { /* Validate ‘pevent‘ */
return (OS_ERR_PEVENT_NULL);
}
if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX) { /* Validate event block type */
return (OS_ERR_EVENT_TYPE);
}
#endif
OS_ENTER_CRITICAL();
pip = (INT8U)(pevent->OSEventCnt >> 8); /* Get priority inheritance priority of mutex */
//获取原来任务的优先级
prio = (INT8U)(pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8); /* Get owner‘s original priority */
if (OSTCBCur->OSTCBPrio != pip &&
OSTCBCur->OSTCBPrio != prio) { /* See if posting task owns the MUTEX */
OS_EXIT_CRITICAL();
return (OS_ERR_NOT_MUTEX_OWNER);
}
//如果本任务是由于继承机制提高的优先级----恢复原来的优先级
if (OSTCBCur->OSTCBPrio == pip) { /* Did we have to raise current task‘s priority? */
/* Yes, Return to original priority */
/* Remove owner from ready list at ‘pip‘ */
if ((OSRdyTbl[OSTCBCur->OSTCBY] &= ~OSTCBCur->OSTCBBitX) == 0) {
OSRdyGrp &= ~OSTCBCur->OSTCBBitY;
}
OSTCBCur->OSTCBPrio = prio;
OSTCBCur->OSTCBY = prio >> 3;
OSTCBCur->OSTCBBitY = OSMapTbl[OSTCBCur->OSTCBY];
OSTCBCur->OSTCBX = prio & 0x07;
OSTCBCur->OSTCBBitX = OSMapTbl[OSTCBCur->OSTCBX];
OSRdyGrp |= OSTCBCur->OSTCBBitY;
OSRdyTbl[OSTCBCur->OSTCBY] |= OSTCBCur->OSTCBBitX;
OSTCBPrioTbl[prio] = (OS_TCB *)OSTCBCur;
}
//先占优先级指针表中的pip项
OSTCBPrioTbl[pip] = (OS_TCB *)1; /* Reserve table entry */
if (pevent->OSEventGrp != 0x00) { /* Any task waiting for the mutex? */
/* Yes, Make HPT waiting for mutex ready */
//将事件等待表中的优先级最高任务就绪
prio = OS_EventTaskRdy(pevent, (void *)0, OS_STAT_MUTEX);
pevent->OSEventCnt &= OS_MUTEX_KEEP_UPPER_8; /* Save priority of mutex‘s new owner */
pevent->OSEventCnt |= prio;
//OSEventPtr指向新的互斥信号量所有者的tcb
pevent->OSEventPtr = OSTCBPrioTbl[prio]; /* Link to mutex owner‘s OS_TCB */
OS_EXIT_CRITICAL();
OS_Sched(); /* Find highest priority task ready to run */
return (OS_NO_ERR);
}
//没有任务等待互斥信号量时就运行到这
//Mutex is now available
pevent->OSEventCnt |= OS_MUTEX_AVAILABLE; /* No, Mutex is now available */
pevent->OSEventPtr = (void *)0;
OS_EXIT_CRITICAL();
return (OS_NO_ERR);
}
/*$PAGE*/
/*
*********************************************************************************************************
* QUERY A MUTUAL EXCLUSION SEMAPHORE
*
* Description: This function obtains information about a mutex
*
* Arguments : pevent is a pointer to the event control block associated with the desired mutex
*
* pdata is a pointer to a structure that will contain information about the mutex
*
* Returns : OS_NO_ERR The call was successful and the message was sent
* OS_ERR_QUERY_ISR If you called this function from an ISR
* OS_ERR_PEVENT_NULL ‘pevent‘ is a NULL pointer
* OS_ERR_EVENT_TYPE If you are attempting to obtain data from a non mutex.
*********************************************************************************************************
*/
//This function obtains information about a mutex OS_MUTEX_DATA结构体 用于保存互斥信号量的 信息
#if OS_MUTEX_QUERY_EN > 0
INT8U OSMutexQuery (OS_EVENT *pevent, OS_MUTEX_DATA *pdata)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
INT8U *psrc;
INT8U *pdest;
//各种判断
if (OSIntNesting > 0) { /* See if called from ISR ... */
return (OS_ERR_QUERY_ISR); /* ... can‘t QUERY mutex from an ISR */
}
#if OS_ARG_CHK_EN > 0
if (pevent == (OS_EVENT *)0) { /* Validate ‘pevent‘ */
return (OS_ERR_PEVENT_NULL);
}
if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX) { /* Validate event block type */
return (OS_ERR_EVENT_TYPE);
}
#endif
OS_ENTER_CRITICAL();
pdata->OSMutexPIP = (INT8U)(pevent->OSEventCnt >> 8);
pdata->OSOwnerPrio = (INT8U)(pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8);
if (pdata->OSOwnerPrio == 0xFF) {
pdata->OSValue = http://www.mamicode.com/1;//可用的一个互斥信号量
} else {
pdata->OSValue = http://www.mamicode.com/0;
}
pdata->OSEventGrp = pevent->OSEventGrp; /* Copy wait list */
psrc = &pevent->OSEventTbl[0];
pdest = &pdata->OSEventTbl[0];
#if OS_EVENT_TBL_SIZE > 0
*pdest++ = *psrc++;
#endif
#if OS_EVENT_TBL_SIZE > 1
*pdest++ = *psrc++;
#endif
#if OS_EVENT_TBL_SIZE > 2
*pdest++ = *psrc++;
#endif
#if OS_EVENT_TBL_SIZE > 3
*pdest++ = *psrc++;
#endif
#if OS_EVENT_TBL_SIZE > 4
*pdest++ = *psrc++;
#endif
#if OS_EVENT_TBL_SIZE > 5
*pdest++ = *psrc++;
#endif
#if OS_EVENT_TBL_SIZE > 6
*pdest++ = *psrc++;
#endif
#if OS_EVENT_TBL_SIZE > 7
*pdest = *psrc;
#endif
OS_EXIT_CRITICAL();
return (OS_NO_ERR);
}
#endif /* OS_MUTEX_QUERY_EN */
#endif /* OS_MUTEX_EN */
uC/OS-II互斥信号(OS_mutex)块