μCOS-II中OS_FLAG.C源码中文注释版.doc

xilentz的网络文摘博客园 首页 新随笔 联系 订阅 管理 随笔 - 204 文章 - 0评论 - 10trackbacks - 0 OS_FLAG.C/* uC/OS-II* The Real-Time Kernel* EVENT FLAG MANAGEMENT* (c) Copyright 2001-2002, 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 局部定义*/ 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 didnt 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 无等待地获得事件标志组中的事件标志描述：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 如果等待事件不发生，调用事件并不挂起。与OSFlagPend()唯一不同点参数：pgrp：指向目标事件标志组的指针 flags：是一个位的模式显示要检查的位，比如：你要检测0位和1位，那么你将它 设置为0x03 wait_type ：标记你想全部检测还是只想检测其实一部分。你能标记如下参数：* OS_FLAG_WAIT_CLR_ALL 你将检测flags中全部的清零位* OS_FLAG_WAIT_CLR_ANY 你将检测flags中任何清零位* OS_FLAG_WAIT_SET_ALL 你将检测flags中全部的置一位* OS_FLAG_WAIT_SET_ANY 你将检测flags中任何置一位 如果想事件标志被调用函数清除的话，要加上OS_FLAG_CONSUME，比如：如果 想要组与后清除，那么将wait_type设置成OS_FLAG_WAIT_SET_ANY + OS_FLAG_CONSUME err 指向错误代码的指针，可以为：* OS_NO_ERR 无误* OS_ERR_EVENT_TYPE 没有指向任务事件标志组* OS_FLAG_ERR_WAIT_TYPE 你没有设置正确的 wait_type 参数* OS_FLAG_INVALID_PGRP 你传送了零指针而不是事件标志组操作* OS_FLAG_ERR_NOT_RDY 你等待的目标标志不合理返回：事件标志组的标志状态从任务和ISR中调用*/ #if OS_FLAG_ACCEPT_EN 0OS_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 0 if (pgrp = (OS_FLAG_GRP *)0) /* Validate pgrp */ *err = OS_FLAG_INVALID_PGRP; return (OS_FLAGS)0);/非空的pgrp if (pgrp-OSFlagType != OS_EVENT_TYPE_FLAG) /* Validate event block type */ *err = OS_ERR_EVENT_TYPE; return (OS_FLAGS)0);/合理的事件控制块类型 #endif if (wait_type & OS_FLAG_CONSUME) /* See if we need to consume the flags */ wait_type &= OS_FLAG_CONSUME; consume = TRUE; else consume = FALSE; /是否需要清除位/*$PAGE*/ *err = OS_NO_ERR; /* Assume NO error until proven otherwise. */初始化无错 OS_ENTER_CRITICAL(); switch (wait_type) case OS_FLAG_WAIT_SET_ALL: /* See if all required flags are set */ flags_rdy = pgrp-OSFlagFlags & flags; /* Extract only the bits we want */ if (flags_rdy = flags) /* Must match ALL the bits that we want */ /如果刚好是我们要的 if (consume = TRUE) /* See if we need to consume the flags */ pgrp-OSFlagFlags &= flags_rdy; /* Clear ONLY the flags that we wanted */ /是否要清除 else *err = OS_FLAG_ERR_NOT_RDY;/没有我们想要的，返回不合理 flags_cur = pgrp-OSFlagFlags; /* Will return the state of the group */ /返回标志 OS_EXIT_CRITICAL(); break; case OS_FLAG_WAIT_SET_ANY: flags_rdy = pgrp-OSFlagFlags & flags; /* Extract only the bits we want */ if (flags_rdy != (OS_FLAGS)0) /* See if any flag set */ /是否有标志置位 if (consume = TRUE) /* See if we need to consume the flags */ pgrp-OSFlagFlags &= flags_rdy; /* Clear ONLY the flags that we got */ /是否需要清除位 else /没有标志置位 *err = OS_FLAG_ERR_NOT_RDY; flags_cur = pgrp-OSFlagFlags; /* Will return the state of the group */ /返回组状态， OS_EXIT_CRITICAL(); break; #if OS_FLAG_WAIT_CLR_EN 0 case OS_FLAG_WAIT_CLR_ALL: /* See if all required flags are cleared */ flags_rdy = pgrp-OSFlagFlags & flags; /* Extract only the bits we want */ /设置位 if (flags_rdy = flags) /* Must match ALL the bits that we want */ /必须所有的位都匹配 if (consume = TRUE) /* See if we need to consume the flags */ pgrp-OSFlagFlags |= flags_rdy; /* Set ONLY the flags that we wanted */ /是否要设置位 else *err = OS_FLAG_ERR_NOT_RDY;/不是所有位都匹配 flags_cur = pgrp-OSFlagFlags; /* Will return the state of the group */ /返回标志组状态 OS_EXIT_CRITICAL(); break; case OS_FLAG_WAIT_CLR_ANY: 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;#endif default:/其它异常情况 OS_EXIT_CRITICAL(); flags_cur = (OS_FLAGS)0; *err = OS_FLAG_ERR_WAIT_TYPE; break; return (flags_cur);/返回状态#endif /*$PAGE*/ /* CREATE AN EVENT FLAG* Description: This function is called to create an event flag group.* Arguments : flags Contains the initial value to store in the event flag group.* err is a pointer to an error code which will be returned to your application:* OS_NO_ERR if the call was successful.* OS_ERR_CREATE_ISR if you attempted to create an Event Flag from an* ISR.* OS_FLAG_GRP_DEPLETED if there are no more event flag groups* Returns : A pointer to an event flag group or a NULL pointer if no more groups are available.* Called from: Task ONLY 建立一个事件标志组描述：建立一个事件标志组参数：flags：包含存储在事件标志组中的初始值 err：将返回到你应用程序的错误信息* OS_NO_ERR 如果成功* OS_ERR_CREATE_ISR 如果你想从ISR中建立* OS_FLAG_GRP_DEPLETED 如果没有多余的事件标志组了 */ OS_FLAG_GRP *OSFlagCreate (OS_FLAGS flags, INT8U *err)#if OS_CRITICAL_METHOD = 3 /* Allocate storage for CPU status register */ OS_CPU_SR cpu_sr;#endif OS_FLAG_GRP *pgrp; if (OSIntNesting 0) /* See if called from ISR . */ *err = OS_ERR_CREATE_ISR; /* . cant CREATE from an ISR */ return (OS_FLAG_GRP *)0);/不能从ISR中建立 OS_ENTER_CRITICAL(); pgrp = OSFlagFreeList; /* Get next free event flag */ /指向空链表的空地址 ，取得一个空闲事件标志 if (pgrp != (OS_FLAG_GRP *)0) /* See if we have event flag groups available */ /* Adjust free list */如果为0，表明没有空闲的事件标志组了 OSFlagFreeList = (OS_FLAG_GRP *)OSFlagFreeList-OSFlagWaitList; /调整系统的空闲事件标志组链表指针，使之指向新的表头 pgrp-OSFlagType = OS_EVENT_TYPE_FLAG; /* Set to event flag group type */ /分配它是事件标志组，确保能系统正常运行 pgrp-OSFlagFlags = flags; /* Set to desired initial value */ /将初始化值传入这个事件标志组 pgrp-OSFlagWaitList = (void *)0; /* Clear list of tasks waiting on flags */ /因为是刚刚建立的事件标志组，没有任何任务等待这个事件标志组， /所以等待任务链表指针初始化为0 OS_EXIT_CRITICAL(); *err = OS_NO_ERR; else /如果没有空闲的事件标志组了 OS_EXIT_CRITICAL(); *err = OS_FLAG_GRP_DEPLETED; return (pgrp); /* Return pointer to event flag group */ /返回刚刚建立的事件标志组指针，如果没有空闲的事件标志组， /将返回NULL指针 /*$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 didnt 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 0OS_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; /* . cant 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_wai