📄 os_flag.c
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参数：flags：包含存储在事件标志组中的初始值
err：将返回到你应用程序的错误信息
* OS_NO_ERR 如果成功
* OS_ERR_CREATE_ISR 如果你想从ISR中建立
* OS_FLAG_GRP_DEPLETED 如果没有多余的事件标志组了
*********************************************************************************************************
*/
OS_FLAG_GRP *OSFlagCreate (OS_FLAGS flags, INT8U *err)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
OS_FLAG_GRP *pgrp;
if (OSIntNesting > 0) { /* See if called from ISR ... */
*err = OS_ERR_CREATE_ISR; /* ... can't CREATE from an ISR */
return ((OS_FLAG_GRP *)0);//不能从ISR中建立
}
OS_ENTER_CRITICAL();
pgrp = OSFlagFreeList; /* Get next free event flag */
//指向空链表的空地址 ，取得一个空闲事件标志
if (pgrp != (OS_FLAG_GRP *)0) { /* See if we have event flag groups available */
/* Adjust free list *///如果为0，表明没有空闲的事件标志组了
OSFlagFreeList = (OS_FLAG_GRP *)OSFlagFreeList->OSFlagWaitList;
//调整系统的空闲事件标志组链表指针，使之指向新的表头
pgrp->OSFlagType = OS_EVENT_TYPE_FLAG; /* Set to event flag group type */
//分配它是事件标志组，确保能系统正常运行
pgrp->OSFlagFlags = flags; /* Set to desired initial value */
//将初始化值传入这个事件标志组
pgrp->OSFlagWaitList = (void *)0; /* Clear list of tasks waiting on flags */
//因为是刚刚建立的事件标志组，没有任何任务等待这个事件标志组，
//所以等待任务链表指针初始化为0
OS_EXIT_CRITICAL();
*err = OS_NO_ERR;
} else {//如果没有空闲的事件标志组了
OS_EXIT_CRITICAL();
*err = OS_FLAG_GRP_DEPLETED;
}
return (pgrp); /* Return pointer to event flag group */
//返回刚刚建立的事件标志组指针，如果没有空闲的事件标志组，
//将返回NULL指针
}
/*$PAGE*/
/*
*********************************************************************************************************
* DELETE AN EVENT FLAG GROUP
*
* Description: This function deletes an event flag group and readies all tasks pending on the event flag
* group.
* Arguments : pgrp is a pointer to the desired event flag group.
*
* opt determines delete options as follows:
* opt == OS_DEL_NO_PEND Deletes the event flag group ONLY if no task pending
* opt == OS_DEL_ALWAYS Deletes the event flag group 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 event flag group was
* deleted
* OS_ERR_DEL_ISR If you attempted to delete the event flag group from
* an ISR
* OS_FLAG_INVALID_PGRP If 'pgrp' is a NULL pointer.
* OS_ERR_EVENT_TYPE If you didn't pass a pointer to an event flag group
* OS_ERR_INVALID_OPT An invalid option was specified
* OS_ERR_TASK_WAITING One or more tasks were waiting on the event flag
* group.
* Returns : pevent upon error
* (OS_EVENT *)0 if the semaphore was successfully deleted.
*
* Note(s) : 1) This function must be used with care. Tasks that would normally expect the presence of
* the event flag group MUST check the return code of OSFlagAccept() and OSFlagPend().
* 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 event flag group.
删除一个事件标志组
描述：删除一个事件标志组，将事件标志组中所有挂起的任务就绪。
参数：pgrp：指向目标事件标志组的指针
opt：决定以下删除选项：
* opt == OS_DEL_NO_PEND 没有任务挂起的时候才删事件标志组
* opt == OS_DEL_ALWAYS 即使有任务等待也删除，这个，所有挂起的
任务将就绪。
* err 包含以下错误信息之一的指针
* OS_NO_ERR 调用成功，事件标志组成功删除
* OS_ERR_DEL_ISR 如果想从ISR中删除事件标志组
* OS_FLAG_INVALID_PGRP 如果pgrp是一个空指针
* OS_ERR_EVENT_TYPE 如果没有传递指针到事件标志组
* OS_ERR_INVALID_OPT 有非法选项
* OS_ERR_TASK_WAITING 一个或多个任务在事件标志组中等待
*返回 : pevent 有错
* (OS_EVENT *)0 如果成功删除
*********************************************************************************************************
*/
#if OS_FLAG_DEL_EN > 0
OS_FLAG_GRP *OSFlagDel (OS_FLAG_GRP *pgrp, INT8U opt, INT8U *err)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
BOOLEAN tasks_waiting;
OS_FLAG_NODE *pnode;
if (OSIntNesting > 0) { /* See if called from ISR ... */
*err = OS_ERR_DEL_ISR; /* ... can't DELETE from an ISR */
return (pgrp);//不允许从ISR中删除
}
#if OS_ARG_CHK_EN > 0
if (pgrp == (OS_FLAG_GRP *)0) { /* Validate 'pgrp' */
*err = OS_FLAG_INVALID_PGRP;
return (pgrp);//pgrp必须有效。不能为零，并指向事件标志组
}
if (pgrp->OSFlagType != OS_EVENT_TYPE_FLAG) { /* Validate event group type */
*err = OS_ERR_EVENT_TYPE;
return (pgrp);//如果不是事件组类型
}
#endif
OS_ENTER_CRITICAL();
if (pgrp->OSFlagWaitList != (void *)0) { /* See if any tasks waiting on event flags */
//是否有任务在此等待？
tasks_waiting = TRUE; /* Yes */
} else {//
tasks_waiting = FALSE; /* No */
}
switch (opt) {
case OS_DEL_NO_PEND: /* Delete group if no task waiting */
//如果没有任务等待才删除
if (tasks_waiting == FALSE) {//没有任务等待
pgrp->OSFlagType = OS_EVENT_TYPE_UNUSED;//将它标记为未使用
pgrp->OSFlagWaitList = (void *)OSFlagFreeList; /* Return group to free list */
//将其返回到空闲链表中
OSFlagFreeList = pgrp;
OS_EXIT_CRITICAL();
*err = OS_NO_ERR;//无错
return ((OS_FLAG_GRP *)0); /* Event Flag Group has been deleted */
} else {//有任务等待
OS_EXIT_CRITICAL();
*err = OS_ERR_TASK_WAITING;
return (pgrp);//返回事件标志组指针
}
case OS_DEL_ALWAYS: /* Always delete the event flag group */
//有任务等待也删除
pnode = (OS_FLAG_NODE *)pgrp->OSFlagWaitList;//指向事件标志中等待任务结点的指针
while (pnode != (OS_FLAG_NODE *)0) { /* Ready ALL tasks waiting for flags */
//就绪所有的任务
OS_FlagTaskRdy(pnode, (OS_FLAGS)0);//使任务就绪，事件发生
pnode = (OS_FLAG_NODE *)pnode->OSFlagNodeNext;//只要不为零，就继续指向下一个结点。继续就绪
}
pgrp->OSFlagType = OS_EVENT_TYPE_UNUSED;//标记为未用
pgrp->OSFlagWaitList = (void *)OSFlagFreeList;/* Return group to free list */
OSFlagFreeList = pgrp;//将其返回到空闲链表
OS_EXIT_CRITICAL();
if (tasks_waiting == TRUE) { /* Reschedule only if task(s) were waiting */
//有任务等待的情况下，要重新任务调度。因为挂起的任务就绪了。
OS_Sched(); /* Find highest priority task ready to run */
}
*err = OS_NO_ERR;//无错
return ((OS_FLAG_GRP *)0); /* Event Flag Group has been deleted */
default://其它异常情况
OS_EXIT_CRITICAL();
*err = OS_ERR_INVALID_OPT;
return (pgrp);
}
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* WAIT ON AN EVENT FLAG GROUP
*
* Description: This function is called to wait for a combination of bits to be set in an event flag
* group. Your application can wait for ANY bit to be set or ALL bits to be set.
*
* Arguments : pgrp is a pointer to the desired event flag group.
*
* flags Is a bit pattern indicating which bit(s) (i.e. flags) you wish to wait for.
* The bits you want are specified by setting the corresponding bits in
* 'flags'. e.g. if your application wants to wait for bits 0 and 1 then
* 'flags' would contain 0x03.
*
* wait_type specifies whether you want ALL bits to be set or ANY of the bits to be set.
* You can specify the following argument:
*
* OS_FLAG_WAIT_CLR_ALL You will wait for ALL bits in 'mask' to be clear (0)
* OS_FLAG_WAIT_SET_ALL You will wait for ALL bits in 'mask' to be set (1)
* OS_FLAG_WAIT_CLR_ANY You will wait for ANY bit in 'mask' to be clear (0)
* OS_FLAG_WAIT_SET_ANY You will wait for ANY bit in 'mask' to be set (1)
*
* NOTE: Add OS_FLAG_CONSUME if you want the event flag to be 'consumed' by
* the call. Example, to wait for any flag in a group AND then clear
* the flags that are present, set 'wait_type' to:
*
* OS_FLAG_WAIT_SET_ANY + OS_FLAG_CONSUME
*
* timeout is an optional timeout (in clock ticks) that your task will wait for the
* desired bit combination. If you specify 0, however, your task will wait
* forever at the specified event flag group or, until a message arrives.
*
* err is a pointer to an error code and can be:
* OS_NO_ERR The desired bits have been set within the specified
* 'timeout'.
* OS_ERR_PEND_ISR If you tried to PEND from an ISR
* OS_FLAG_INVALID_PGRP If 'pgrp' is a NULL pointer.
* OS_ERR_EVENT_TYPE You are not pointing to an event flag group
* OS_TIMEOUT The bit(s) have not been set in the specified
* 'timeout'.
* OS_FLAG_ERR_WAIT_TYPE You didn't specify a proper 'wait_type' argument.
*
* Returns : The new state of the flags in the event flag group when the task is resumed or,
* 0 if a timeout or an error occurred.
*
* Called from: Task ONLY
等待事件标志组的事件标志位
描述：去检查事件标志组中结合位的状态是置位还是被清除，你能
检查任何将被置位或者清除的位或者全部位
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