//BY 简单的元清//部分内容引用了其他博主的文章，对这些博主表示感谢，时间关系就不一一指出了。//如有转载，请说明，谢谢/*
*********************************************************************************************************
* uC/OS-II
* The Real-Time Kernel
* EVENT FLAG MANAGEMENT
*
* (c) Copyright 2001, Jean J. Labrosse, Weston, FL
* All Rights Reserved
*
* File : OS_FLAG.C
* By : Jean J. Labrosse
*********************************************************************************************************
*/#ifndef OS_MASTER_FILE
#include "INCLUDES.H"
#endif#if (OS_VERSION >= 251) && (OS_FLAG_EN > 0) && (OS_MAX_FLAGS > 0)
/*
*********************************************************************************************************
* LOCAL PROTOTYPES
*********************************************************************************************************
*/static void OS_FlagBlock(OS_FLAG_GRP *pgrp, OS_FLAG_NODE *pnode, OS_FLAGS flags, INT8U wait_type, INT16U timeout);
static BOOLEAN OS_FlagTaskRdy(OS_FLAG_NODE *pnode, OS_FLAGS flags_rdy);/*$PAGE*/
/*
*********************************************************************************************************
* CHECK THE STATUS OF FLAGS IN AN EVENT FLAG GROUP
*
* Description: This function is called to check the status of a combination of bits to be set or cleared
* in an event flag group. Your application can check for ANY bit to be set/cleared or ALL
* bits to be set/cleared.
*
* This call does not block if the desired flags are not present.
*
* 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 check.
* 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/cleared or ANY of the bits
* to be set/cleared.
* You can specify the following argument:
*
* OS_FLAG_WAIT_CLR_ALL You will check ALL bits in 'flags' to be clear (0)
* OS_FLAG_WAIT_CLR_ANY You will check ANY bit in 'flags' to be clear (0)
* OS_FLAG_WAIT_SET_ALL You will check ALL bits in 'flags' to be set (1)
* OS_FLAG_WAIT_SET_ANY You will check ANY bit in 'flags' 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
*
* err is a pointer to an error code and can be:
* OS_NO_ERR No error
* OS_ERR_EVENT_TYPE You are not pointing to an event flag group
* OS_FLAG_ERR_WAIT_TYPE You didn't specify a proper 'wait_type' argument.
* OS_FLAG_INVALID_PGRP You passed a NULL pointer instead of the event flag
* group handle.
* OS_FLAG_ERR_NOT_RDY The desired flags you are waiting for are not
* available.
*
* Returns : The state of the flags in the event flag group.
*
* Called from: Task or ISR
*********************************************************************************************************
*/#if OS_FLAG_ACCEPT_EN > 0
//无等待地获得事件标志组中的事件标志
OS_FLAGS OSFlagAccept (OS_FLAG_GRP *pgrp, OS_FLAGS flags, INT8U wait_type, INT8U *err)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */OS_CPU_SR cpu_sr;
#endif OS_FLAGS flags_cur;OS_FLAGS flags_rdy;BOOLEAN consume;#if OS_ARG_CHK_EN > 0if (pgrp == (OS_FLAG_GRP *)0) { /* Validate 'pgrp' */*err = OS_FLAG_INVALID_PGRP;return ((OS_FLAGS)0);//如果事件组无效，发送错误码并返回0}if (pgrp->OSFlagType != OS_EVENT_TYPE_FLAG) { /* Validate event block type */*err = OS_ERR_EVENT_TYPE;return ((OS_FLAGS)0);//如果不是事件类型，发送错误码并返回0}
#endifif (wait_type & OS_FLAG_CONSUME) { /* See if we need to consume the flags *///判断是否为恢复状态wait_type &= ~OS_FLAG_CONSUME;//wait_type清空为0consume = TRUE;//恢复标志位置位} else {consume = FALSE;}
/*$PAGE*/*err = OS_NO_ERR; /* Assume NO error until proven otherwise. *///返回错误码OS_ENTER_CRITICAL();//进入临界区switch (wait_type) {//判断wait_type状态case OS_FLAG_WAIT_SET_ALL: /* See if all required flags are set *///所有的请求标志位都置位flags_rdy = pgrp->OSFlagFlags & flags; /* Extract only the bits we want *///提取出我们需要的那一位if (flags_rdy == flags) { /* Must match ALL the bits that we want *///需要所有的位都匹配if (consume == TRUE) { /* See if we need to consume the flags //如果是恢复状态pgrp->OSFlagFlags &= ~flags_rdy; /* Clear ONLY the flags that we wanted *///清除我们提取的那位}} else {*err = OS_FLAG_ERR_NOT_RDY;//返回错误码}flags_cur = pgrp->OSFlagFlags; /* Will return the state of the group *///返回组的状态OS_EXIT_CRITICAL();//退出临界区break;case OS_FLAG_WAIT_SET_ANY://置其中任意一位flags_rdy = pgrp->OSFlagFlags & flags; /* Extract only the bits we want *///提取我们需要的那一位if (flags_rdy != (OS_FLAGS)0) { /* See if any flag set *///判断是否有位置位if (consume == TRUE) { /* See if we need to consume the flags *///判断是否需要恢复状态pgrp->OSFlagFlags &= ~flags_rdy; /* Clear ONLY the flags that we got *///清除我们获得那一位}} else {*err = OS_FLAG_ERR_NOT_RDY;//返回错误码}flags_cur = pgrp->OSFlagFlags; /* Will return the state of the group *///返回错误码OS_EXIT_CRITICAL();//退出临界区break;#if OS_FLAG_WAIT_CLR_EN > 0case OS_FLAG_WAIT_CLR_ALL: //清除所有位。/* See if all required flags are cleared */flags_rdy = ~pgrp->OSFlagFlags & flags; /* Extract only the bits we want *///提取我们需要的那一位if (flags_rdy == flags) { /* Must match ALL the bits that we want *///需要匹配我们需要的每一位if (consume == TRUE) { /* See if we need to consume the flags *///如果是恢复状态 pgrp->OSFlagFlags |= flags_rdy; /* Set ONLY the flags that we wanted *///把我们需要的每一位都置位}} else {*err = OS_FLAG_ERR_NOT_RDY;//返货错误码}flags_cur = pgrp->OSFlagFlags; /* Will return the state of the group *///返回错误码OS_EXIT_CRITICAL();//退出临界区break;case OS_FLAG_WAIT_CLR_ANY://清除其中任意一位，和上面的分析类似。flags_rdy = ~pgrp->OSFlagFlags & flags; /* Extract only the bits we want */if (flags_rdy != (OS_FLAGS)0) { /* See if any flag cleared */if (consume == TRUE) { /* See if we need to consume the flags */pgrp->OSFlagFlags |= flags_rdy; /* Set ONLY the flags that we got */}} else {*err = OS_FLAG_ERR_NOT_RDY;}flags_cur = pgrp->OSFlagFlags; /* Will return the state of the group */OS_EXIT_CRITICAL();break;
#endifdefault:OS_EXIT_CRITICAL();flags_cur = (OS_FLAGS)0;*err = OS_FLAG_ERR_WAIT_TYPE;break;}return (flags_cur);、、 //返回flags_cur}
#endif /*$PAGE*/
/*
*********************************************************************************************************
* CREATE AN EVENT FLAG
*
* Description: This function is called to create an event flag group.
*
* Arguments : flags Contains the initial value to store in the event flag group.
*
* err is a pointer to an error code which will be returned to your application:
* OS_NO_ERR if the call was successful.
* OS_ERR_CREATE_ISR if you attempted to create an Event Flag from an
* ISR.
* OS_FLAG_GRP_DEPLETED if there are no more event flag groups
*
* Returns : A pointer to an event flag group or a NULL pointer if no more groups are available.
*
* Called from: Task ONLY
*********************************************************************************************************
*/
//事件标志组事件标志组创建函数
OS_FLAG_GRP *OSFlagCreate (OS_FLAGS flags, INT8U *err)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */OS_CPU_SR cpu_sr;
#endif OS_FLAG_GRP *pgrp;if (OSIntNesting > 0) { /* See if called from ISR ... */*err = OS_ERR_CREATE_ISR; /* ... can't CREATE from an ISR */return ((OS_FLAG_GRP *)0); //如果有中断发生，返回错误码 }OS_ENTER_CRITICAL();//进入临界区pgrp = OSFlagFreeList; /* Get next free event flag *///获取下一个事件标志if (pgrp != (OS_FLAG_GRP *)0) { /* See if we have event flag groups available *//* Adjust free list *///判断组是否有效OSFlagFreeList = (OS_FLAG_GRP *)OSFlagFreeList->OSFlagWaitList;//OSFlagFreeList赋值为OSFlagWaitListpgrp->OSFlagType = OS_EVENT_TYPE_FLAG; /* Set to event flag group type *///类型为事件pgrp->OSFlagFlags = flags; /* Set to desired initial value *///初始化事件pgrp->OSFlagWaitList = (void *)0; /* Clear list of tasks waiting on flags *///OSFlagWaitList清空OS_EXIT_CRITICAL();//退出临界区*err = OS_NO_ERR;//退出临界区} else {OS_EXIT_CRITICAL();*err = OS_FLAG_GRP_DEPLETED;}return (pgrp); /* Return pointer to event flag group */
}/*$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 You are not pointing to an event flag group
* 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.
*********************************************************************************************************
*/#if OS_FLAG_DEL_EN > 0//删除事件标志组函数
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);//如果有中断发生，返回错误码}
#if OS_ARG_CHK_EN > 0if (pgrp == (OS_FLAG_GRP *)0) { /* Validate 'pgrp' */*err = OS_FLAG_INVALID_PGRP;return (pgrp);//【判断如果不是有效的组，返回错误码}if (pgrp->OSFlagType != OS_EVENT_TYPE_FLAG) { /* Validate event group type */*err = OS_ERR_EVENT_TYPE;return (pgrp);//判断不是事件组类型，返回错误码}
#endifOS_ENTER_CRITICAL();//进入临界区if (pgrp->OSFlagWaitList != (void *)0) { /* See if any tasks waiting on event flags */tasks_waiting = TRUE; /* Yes *///判断事件等待列表如果不为零，tasks_waiting置位} else {tasks_waiting = FALSE; /* No */}switch (opt) {case OS_DEL_NO_PEND: /* Delete group if no task waiting *///没有任务在等待时删除组if (tasks_waiting == FALSE) {//先判断tasks_waiting是FALSEpgrp->OSFlagType = OS_EVENT_TYPE_UNUSED;//事件的类型是OS_EVENT_TYPE_UNUSEDpgrp->OSFlagWaitList = (void *)OSFlagFreeList; /* Return group to free list *///OSFlagWaitList指针指向空链表OSFlagFreeList = pgrp;//空链表指向新的列表OS_EXIT_CRITICAL();//退出临界区*err = OS_NO_ERR;//返回错误码return ((OS_FLAG_GRP *)0); /* Event Flag Group has been deleted *///返回0} else { //有任务在等待OS_EXIT_CRITICAL();//退出临界区*err = OS_ERR_TASK_WAITING;//返回错误码return (pgrp);//返回pgrp}case OS_DEL_ALWAYS: /* Always delete the event flag group *///不管有没有任务直接删除pnode = pgrp->OSFlagWaitList;//*指向等待事件组的节点链表*/ while (pnode != (OS_FLAG_NODE *)0) { /* Ready ALL tasks waiting for flags *////遍历该链表OS_FlagTaskRdy(pnode, (OS_FLAGS)0);//将该链表中的节点指向的任务转为就绪状态pnode = pnode->OSFlagNodeNext;//查找下一个节点}pgrp->OSFlagType = OS_EVENT_TYPE_UNUSED;//标志类型为OS_EVENT_TYPE_UNUSEDpgrp->OSFlagWaitList = (void *)OSFlagFreeList;/* Return group to free list */// 将该组返回到空闲列表中OSFlagFreeList = pgrp;//OSFlagFreeList指向pgrpOS_EXIT_CRITICAL();//退出临界区if (tasks_waiting == TRUE) { /* Reschedule only if task(s) were waiting */OS_Sched(); /* Find highest priority task ready to run *///如果任务等待是真。进行一次任务调度}*err = OS_NO_ERR;return ((OS_FLAG_GRP *)0); /* Event Flag Group has been deleted *///返回错误码和OS_FLAG_GRP为0default:OS_EXIT_CRITICAL();//退出临界区*err = OS_ERR_INVALID_OPT;return (pgrp);//返回错误码和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
OS_FLAGS OSFlagPend (OS_FLAG_GRP *pgrp, OS_FLAGS flags, INT8U wait_type, INT16U timeout, INT8U *err)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */OS_CPU_SR cpu_sr;
#endif OS_FLAG_NODE node;OS_FLAGS flags_cur;OS_FLAGS flags_rdy;BOOLEAN consume;if (OSIntNesting > 0) { /* See if called from ISR ... */*err = OS_ERR_PEND_ISR; /* ... can't PEND from an ISR */return ((OS_FLAGS)0);//如果有中断事件发生，返回错误码
#if OS_ARG_CHK_EN > 0if (pgrp == (OS_FLAG_GRP *)0) { /* Validate 'pgrp' */*err = OS_FLAG_INVALID_PGRP;return ((OS_FLAGS)0);//如果不是有效的组，返回错误码}if (pgrp->OSFlagType != OS_EVENT_TYPE_FLAG) { /* Validate event block type */*err = OS_ERR_EVENT_TYPE;return ((OS_FLAGS)0);//如果不是有效的事件类型，返回错误码}
#endifif (wait_type & OS_FLAG_CONSUME) { /* See if we need to consume the flags */wait_type &= ~OS_FLAG_CONSUME;consume = TRUE;//如果有consume事件发生,进行置位} else {consume = FALSE;}
/*$PAGE*/OS_ENTER_CRITICAL();//进入临界区switch (wait_type) {case OS_FLAG_WAIT_SET_ALL: /* See if all required flags are set *///置位所有的等待，见上面函数分析，不展开flags_rdy = pgrp->OSFlagFlags & flags; /* Extract only the bits we want */if (flags_rdy == flags) { /* Must match ALL the bits that we want */if (consume == TRUE) { /* See if we need to consume the flags */pgrp->OSFlagFlags &= ~flags_rdy; /* Clear ONLY the flags that we wanted */}flags_cur = pgrp->OSFlagFlags; /* Will return the state of the group */OS_EXIT_CRITICAL(); /* Yes, condition met, return to caller */*err = OS_NO_ERR;return (flags_cur);} else { /* Block task until events occur or timeout */OS_FlagBlock(pgrp, &node, flags, wait_type, timeout); OS_EXIT_CRITICAL();}break;case OS_FLAG_WAIT_SET_ANY://置位任意一个等待flags_rdy = pgrp->OSFlagFlags & flags; /* Extract only the bits we want */if (flags_rdy != (OS_FLAGS)0) { /* See if any flag set */if (consume == TRUE) { /* See if we need to consume the flags */pgrp->OSFlagFlags &= ~flags_rdy; /* Clear ONLY the flags that we got */}flags_cur = pgrp->OSFlagFlags; /* Will return the state of the group */OS_EXIT_CRITICAL(); /* Yes, condition met, return to caller */*err = OS_NO_ERR;return (flags_cur);} else { /* Block task until events occur or timeout */OS_FlagBlock(pgrp, &node, flags, wait_type, timeout); OS_EXIT_CRITICAL();}break;#if OS_FLAG_WAIT_CLR_EN > 0case OS_FLAG_WAIT_CLR_ALL: /* See if all required flags are cleared *//清除所有的等待flags_rdy = ~pgrp->OSFlagFlags & flags; /* Extract only the bits we want */if (flags_rdy == flags) { /* Must match ALL the bits that we want */if (consume == TRUE) { /* See if we need to consume the flags */pgrp->OSFlagFlags |= flags_rdy; /* Set ONLY the flags that we wanted */}flags_cur = pgrp->OSFlagFlags; /* Will return the state of the group */OS_EXIT_CRITICAL(); /* Yes, condition met, return to caller */*err = OS_NO_ERR;return (flags_cur);} else { /* Block task until events occur or timeout */OS_FlagBlock(pgrp, &node, flags, wait_type, timeout); OS_EXIT_CRITICAL();}break;case OS_FLAG_WAIT_CLR_ANY://清除任意一个等待flags_rdy = ~pgrp->OSFlagFlags & flags; /* Extract only the bits we want */if (flags_rdy != (OS_FLAGS)0) { /* See if any flag cleared */if (consume == TRUE) { /* See if we need to consume the flags */pgrp->OSFlagFlags |= flags_rdy; /* Set ONLY the flags that we got */}flags_cur = pgrp->OSFlagFlags; /* Will return the state of the group */OS_EXIT_CRITICAL(); /* Yes, condition met, return to caller */*err = OS_NO_ERR;return (flags_cur);} else { /* Block task until events occur or timeout */OS_FlagBlock(pgrp, &node, flags, wait_type, timeout); OS_EXIT_CRITICAL();}break;
#endifdefault:OS_EXIT_CRITICAL();flags_cur = (OS_FLAGS)0;*err = OS_FLAG_ERR_WAIT_TYPE;return (flags_cur);}OS_Sched(); /* Find next HPT ready to run *///进行一次调度OS_ENTER_CRITICAL();//进入临界区if (OSTCBCur->OSTCBStat & OS_STAT_FLAG) { /* Have we timed-out? *///*当前TCB挂起状态为取消或者超时状态*/ OS_FlagUnlink(&node);//删除节点OSTCBCur->OSTCBStat = OS_STAT_RDY; /* Yes, make task ready-to-run *///TCB的状态为OS_STAT_RDYOS_EXIT_CRITICAL();//退出临界区flags_cur = (OS_FLAGS)0;*err = OS_TIMEOUT; /* Indicate that we timed-out waiting *///返回错误码} else {//没有超时发生if (consume == TRUE) { /* See if we need to consume the flags *///consume为真switch (wait_type) {case OS_FLAG_WAIT_SET_ALL:case OS_FLAG_WAIT_SET_ANY: /* Clear ONLY the flags we got */pgrp->OSFlagFlags &= ~OSTCBCur->OSTCBFlagsRdy;//清除我们得到的位break;#if OS_FLAG_WAIT_CLR_EN > 0case OS_FLAG_WAIT_CLR_ALL:case OS_FLAG_WAIT_CLR_ANY: /* Set ONLY the flags we got */pgrp->OSFlagFlags |= OSTCBCur->OSTCBFlagsRdy;//置位我们得到的位break;
#endif}}flags_cur = pgrp->OSFlagFlags;//返回flags_curOS_EXIT_CRITICAL();//退出临界区*err = OS_NO_ERR; /* Event(s) must have occurred */} //返回错误码return (flags_cur);
}
/*$PAGE*/
/*
*********************************************************************************************************
* POST EVENT FLAG BIT(S)
*
* Description: This function is called to set or clear some bits in an event flag group. The bits to
* set or clear are specified by a 'bit mask'.
*
* Arguments : pgrp is a pointer to the desired event flag group.
*
* flags If 'opt' (see below) is OS_FLAG_SET, each bit that is set in 'flags' will
* set the corresponding bit in the event flag group. e.g. to set bits 0, 4
* and 5 you would set 'flags' to:
*
* 0x31 (note, bit 0 is least significant bit)
*
* If 'opt' (see below) is OS_FLAG_CLR, each bit that is set in 'flags' will
* CLEAR the corresponding bit in the event flag group. e.g. to clear bits 0,
* 4 and 5 you would specify 'flags' as:
*
* 0x31 (note, bit 0 is least significant bit)
*
* opt indicates whether the flags will be:
* set (OS_FLAG_SET) or
* cleared (OS_FLAG_CLR)
*
* err is a pointer to an error code and can be:
* OS_NO_ERR The call was successfull
* OS_FLAG_INVALID_PGRP You passed a NULL pointer
* OS_ERR_EVENT_TYPE You are not pointing to an event flag group
* OS_FLAG_INVALID_OPT You specified an invalid option
*
* Returns : the new value of the event flags bits that are still set.
*
* Called From: Task or ISR
*
* WARNING(s) : 1) The execution time of this function depends on the number of tasks waiting on the event
* flag group.
* 2) The amount of time interrupts are DISABLED depends on the number of tasks waiting on
* the event flag group.
*********************************************************************************************************
*/
//设置或清除事件标志组
OS_FLAGS OSFlagPost (OS_FLAG_GRP *pgrp, OS_FLAGS flags, INT8U opt, INT8U *err)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */OS_CPU_SR cpu_sr;
#endif OS_FLAG_NODE *pnode;BOOLEAN sched;OS_FLAGS flags_cur;OS_FLAGS flags_rdy;#if OS_ARG_CHK_EN > 0if (pgrp == (OS_FLAG_GRP *)0) { /* Validate 'pgrp' */*err = OS_FLAG_INVALID_PGRP;return ((OS_FLAGS)0);// 判断是否是有效的组}if (pgrp->OSFlagType != OS_EVENT_TYPE_FLAG) { /* Make sure we are pointing to an event flag grp */*err = OS_ERR_EVENT_TYPE;return ((OS_FLAGS)0);//判断是否是有效的事件类型}
#endif
/*$PAGE*/OS_ENTER_CRITICAL();//进入临界区switch (opt) case OS_FLAG_CLRpgrp->OSFlagFlags &= ~flags; /* Clear the flags specified in the group */break;//*清除在事件标志组中设置的位*/ case OS_FLAG_SET:pgrp->OSFlagFlags |= flags; /* Set the flags specified in the group */break;//置位在事件标志组中设置的位default:OS_EXIT_CRITICAL(); /* INVALID option */*err = OS_FLAG_INVALID_OPT;return ((OS_FLAGS)0);//退出临界区并返回错误码}sched = FALSE; /* Indicate that we don't need rescheduling *///不进行调度pnode = pgrp->OSFlagWaitList; //获得OSFlagWaitList指针while (pnode != (OS_FLAG_NODE *)0) { /* Go through all tasks waiting on event flag(s) *///轮询事件组switch (pnode->OSFlagNodeWaitType) {case OS_FLAG_WAIT_SET_ALL: /* See if all req. flags are set for current node *///所有的位都置位flags_rdy = pgrp->OSFlagFlags & pnode->OSFlagNodeFlags;//得到事件中就绪表if (flags_rdy == pnode->OSFlagNodeFlags) { //判断是否就绪if (OS_FlagTaskRdy(pnode, flags_rdy) == TRUE) { /* Make task RTR, event(s) Rx'd */sched = TRUE;
？ /* When done we will reschedule *///如果就绪，进行调度}}break;case OS_FLAG_WAIT_SET_ANY: /* See if any flag set *///任意一个位就置位flags_rdy = pgrp->OSFlagFlags & pnode->OSFlagNodeFlags;if (flags_rdy != (OS_FLAGS)0) { if (OS_FlagTaskRdy(pnode, flags_rdy) == TRUE) { /* Make task RTR, event(s) Rx'd */sched = TRUE; /* When done we will reschedule */}}break;#if OS_FLAG_WAIT_CLR_EN > 0case OS_FLAG_WAIT_CLR_ALL: /* See if all req. flags are set for current node *///所有的位都清零flags_rdy = ~pgrp->OSFlagFlags & pnode->OSFlagNodeFlags;if (flags_rdy == pnode->OSFlagNodeFlags) { if (OS_FlagTaskRdy(pnode, flags_rdy) == TRUE) { /* Make task RTR, event(s) Rx'd */sched = TRUE; /* When done we will reschedule */}}break;case OS_FLAG_WAIT_CLR_ANY: /* See if any flag set *///任意一个位就清零flags_rdy = ~pgrp->OSFlagFlags & pnode->OSFlagNodeFlags;if (flags_rdy != (OS_FLAGS)0) { if (OS_FlagTaskRdy(pnode, flags_rdy) == TRUE) { /* Make task RTR, event(s) Rx'd */sched = TRUE; /* When done we will reschedule */}}break;
#endif }pnode = pnode->OSFlagNodeNext; /* Point to next task waiting for event flag(s) *///指向下一个节点}OS_EXIT_CRITICAL();//退出临界区if (sched == TRUE) {OS_Sched();//存在调度就进行调度}OS_ENTER_CRITICAL();//进入临界区flags_cur = pgrp->OSFlagFlags;//返回flags_curOS_EXIT_CRITICAL();*err = OS_NO_ERR;return (flags_cur);
}
/*$PAGE*/
/*
*********************************************************************************************************
* QUERY EVENT FLAG
*
* Description: This function is used to check the value of the event flag group.
*
* Arguments : pgrp is a pointer to the desired event flag group.
*
* err is a pointer to an error code returned to the called:
* OS_NO_ERR The call was successfull
* OS_FLAG_INVALID_PGRP You passed a NULL pointer
* OS_ERR_EVENT_TYPE You are not pointing to an event flag group
*
* Returns : The current value of the event flag group.
*
* Called From: Task or ISR
*********************************************************************************************************
*/#if OS_FLAG_QUERY_EN > 0 //该功能用来检测事件标志组的值
OS_FLAGS OSFlagQuery (OS_FLAG_GRP *pgrp, INT8U *err)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */OS_CPU_SR cpu_sr;
#endif OS_FLAGS flags;#if OS_ARG_CHK_EN > 0if (pgrp == (OS_FLAG_GRP *)0) { /* Validate 'pgrp' */*err = OS_FLAG_INVALID_PGRP;return ((OS_FLAGS)0);//判断是否是有效的组 }if (pgrp->OSFlagType != OS_EVENT_TYPE_FLAG) { /* Validate event block type */*err = OS_ERR_EVENT_TYPE;return ((OS_FLAGS)0);//判断是否是有效的类型}
#endif OS_ENTER_CRITICAL(); //进入临界区flags = pgrp->OSFlagFlags;//返回事件类型OS_EXIT_CRITICAL();*err = OS_NO_ERR;//退出临界区并返回错误码return (flags); /* Return the current value of the event flags *///返回flags
}
#endif/*$PAGE*/
/*
*********************************************************************************************************
* SUSPEND TASK UNTIL EVENT FLAG(s) RECEIVED OR TIMEOUT OCCURS
*
* Description: This function is internal to uC/OS-II and is used to put a task to sleep until the desired
* event flag bit(s) are set.
*
* Arguments : pgrp is a pointer to the desired event flag group.
*
* pnode is a pointer to a structure which contains data about the task waiting for
* event flag bit(s) to be set.
*
* flags Is a bit pattern indicating which bit(s) (i.e. flags) you wish to check.
* 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/cleared or ANY of the bits
* to be set/cleared.
* You can specify the following argument:
*
* OS_FLAG_WAIT_CLR_ALL You will check ALL bits in 'mask' to be clear (0)
* OS_FLAG_WAIT_CLR_ANY You will check ANY bit in 'mask' to be clear (0)
* OS_FLAG_WAIT_SET_ALL You will check ALL bits in 'mask' to be set (1)
* OS_FLAG_WAIT_SET_ANY You will check ANY bit in 'mask' to be set (1)
*
* timeout is the desired amount of time that the task will wait for the event flag
* bit(s) to be set.
*
* Returns : none
*
* Called by : OSFlagPend() OS_FLAG.C
*
* Note(s) : This function is INTERNAL to uC/OS-II and your application should not call it.
*********************************************************************************************************
*/
//OS_FLAG.C文件中的OSFlagPend（）调用
static void OS_FlagBlock (OS_FLAG_GRP *pgrp, OS_FLAG_NODE *pnode, OS_FLAGS flags, INT8U wait_type, INT16U timeout)
{OS_FLAG_NODE *pnode_next;OSTCBCur->OSTCBStat |= OS_STAT_FLAG; //TCB的状态为OS_STAT_FLAGOSTCBCur->OSTCBDly = timeout; /* Store timeout in task's TCB *///OSTCBDly 为timeout
#if OS_TASK_DEL_EN > 0OSTCBCur->OSTCBFlagNode = pnode; /* TCB to link to node */】/*以下几行代码都是将pnode设置为链表的新的头节点*/
#endif pnode->OSFlagNodeFlags = flags; /* Save the flags that we need to wait for *///获得flags存到pnodepnode->OSFlagNodeWaitType = wait_type; /* Save the type of wait we are doing *///赋值wait_type为等待状态pnode->OSFlagNodeTCB = (void *)OSTCBCur; /* Link to task's TCB *///和TCB建立联系pnode->OSFlagNodeNext = pgrp->OSFlagWaitList; /* Add node at beginning of event flag wait list *///设置下一个节点的值pnode->OSFlagNodePrev = (void *)0;pnode->OSFlagNodeFlagGrp = (void *)pgrp; /* Link to Event Flag Group *///链接到事件组pnode_next = pgrp->OSFlagWaitList;if (pnode_next != (void *)0) { /* Is this the first NODE to insert? */pnode_next->OSFlagNodePrev = pnode; /* No, link in doubly linked list */} //空地址，只有一个节点（就是本节点），如果非空，那么将该链表的头节点改为现在这个节点pgrp->OSFlagWaitList = (void *)pnode;/* Suspend current task until flag(s) received */if ((OSRdyTbl[OSTCBCur->OSTCBY] &= ~OSTCBCur->OSTCBBitX) == 0) {OSRdyGrp &= ~OSTCBCur->OSTCBBitY;}//挂起现在的任务直到收到任务
}/*$PAGE*/
/*
*********************************************************************************************************
* INITIALIZE THE EVENT FLAG MODULE
*
* Description: This function is called by uC/OS-II to initialize the event flag module. Your application
* MUST NOT call this function. In other words, this function is internal to uC/OS-II.
*
* Arguments : none
*
* Returns : none
*
* WARNING : You MUST NOT call this function from your code. This is an INTERNAL function to uC/OS-II.
*********************************************************************************************************
*/
//该功能用来初始化事件标志模块
void OS_FlagInit (void)
{
#if OS_MAX_FLAGS == 1OSFlagFreeList = (OS_FLAG_GRP *)&OSFlagTbl[0]; /* Only ONE event flag group! */// 只有一个事件标志组，空闲列表指针指向标志表中第0号内容OSFlagFreeList->OSFlagType = OS_EVENT_TYPE_UNUSED;//将标志类型设置为未使用类型OSFlagFreeList->OSFlagWaitList = (void *)0;//*将等待列表指针置为空*/
#endif#if OS_MAX_FLAGS >= 2INT8U i;OS_FLAG_GRP *pgrp1;// 第一个指向事件标志组的指针OS_FLAG_GRP *pgrp2;// 第一个指向事件标志组的指针pgrp1 = &OSFlagTbl[0];pgrp2 = &OSFlagTbl[1];for (i = 0; i < (OS_MAX_FLAGS - 1); i++) { /* Init. list of free EVENT FLAGS */pgrp1->OSFlagType = OS_EVENT_TYPE_UNUSED;pgrp1->OSFlagWaitList = (void *)pgrp2;pgrp1++;pgrp2++;}//遍历该表，初始化所有的事件标志pgrp1->OSFlagWaitList = (void *)0;OSFlagFreeList = (OS_FLAG_GRP *)&OSFlagTbl[0];#endif
}/*$PAGE*/
/*
*********************************************************************************************************
* MAKE TASK READY-TO-RUN, EVENT(s) OCCURRED
*
* Description: This function is internal to uC/OS-II and is used to make a task ready-to-run because the
* desired event flag bits have been set.
*
* Arguments : pnode is a pointer to a structure which contains data about the task waiting for
* event flag bit(s) to be set.
*
* flags_rdy contains the bit pattern of the event flags that cause the task to become
* ready-to-run.
*
* Returns : none
*
* Called by : OSFlagsPost() OS_FLAG.C
*
* Note(s) : 1) This function assumes that interrupts are disabled.
* 2) This function is INTERNAL to uC/OS-II and your application should not call it.
*********************************************************************************************************
*///是否可以使任务变为就绪态
static BOOLEAN OS_FlagTaskRdy (OS_FLAG_NODE *pnode, OS_FLAGS flags_rdy)
{OS_TCB *ptcb;BOOLEAN sched;ptcb = (OS_TCB *)pnode->OSFlagNodeTCB; /* Point to TCB of waiting task *///指向TCBptcb->OSTCBDly = 0;//等待时间设置为0ptcb->OSTCBFlagsRdy = flags_rdy;// //OSTCBFlagsRdy块中设置为flags_rdyptcb->OSTCBStat &= ~OS_STAT_FLAG;//OSTCBStat设置为0if (ptcb->OSTCBStat == OS_STAT_RDY) { /* Put task into ready list *///如果OSTCBStat为就绪状态OSRdyGrp |= ptcb->OSTCBBitY;OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;//设置对应的优先级sched = TRUE;//调度开启} else {sched = FALSE;}OS_FlagUnlink(pnode);//删除节点return (sched);
}/*$PAGE*/
/*
*********************************************************************************************************
* UNLINK EVENT FLAG NODE FROM WAITING LIST
*
* Description: This function is internal to uC/OS-II and is used to unlink an event flag node from a
* list of tasks waiting for the event flag.
*
* Arguments : pnode is a pointer to a structure which contains data about the task waiting for
* event flag bit(s) to be set.
*
* Returns : none
*
* Called by : OS_FlagTaskRdy() OS_FLAG.C
* OSFlagPend() OS_FLAG.C
* OSTaskDel() OS_TASK.C
*
* Note(s) : 1) This function assumes that interrupts are disabled.
* 2) This function is INTERNAL to uC/OS-II and your application should not call it.
*********************************************************************************************************
*/
//待事件标志任务列表中解除事件标志节点
void OS_FlagUnlink (OS_FLAG_NODE *pnode)
{OS_TCB *ptcb;OS_FLAG_GRP *pgrp;OS_FLAG_NODE *pnode_prev;OS_FLAG_NODE *pnode_next;pnode_prev = pnode->OSFlagNodePrev;//前一个节点指针pnode_next = pnode->OSFlagNodeNext;//后一个节点指针if (pnode_prev == (OS_FLAG_NODE *)0) { /* Is it first node in wait list? *////如果前一个节点为空。那么pnode指向的是等待列表的首节点（相当于删除首节点）pgrp = pnode->OSFlagNodeFlagGrp; /* Yes, Point to event flag group *///指向所在的组pgrp->OSFlagWaitList = (void *)pnode_next; /* Update list for new 1st node *///指向下一个节点 if (pnode_next != (OS_FLAG_NODE *)0) { pnode_next->OSFlagNodePrev = (OS_FLAG_NODE *)0; /* Link new 1st node PREV to NULL *///判断下一个节点是否有效，有效把前一个节点设置为0}} else { /* No, A node somewhere in the list */pnode_prev->OSFlagNodeNext = pnode_next; /* Link around the node to unlink *///指向下一个节点if (pnode_next != (OS_FLAG_NODE *)0) { /* Was this the LAST node? */pnode_next->OSFlagNodePrev = pnode_prev; /* No, Link around current node *///如果下一个节点有效，链接当前节点}}ptcb = (OS_TCB *)pnode->OSFlagNodeTCB;//点指向的TCB节点赋给ptcb指针*/
#if OS_TASK_DEL_EN > 0ptcb->OSTCBFlagNode = (void *)0;//OSTCBFlagNode赋值为0
#endif
}
#endif
