OS_EXIT_CRITICAL();
                 *perr = OS_ERR_FLAG_WAIT_TYPE;
                 return ((OS_FLAGS)0);
        }
        pnode = (OS_FLAG_NODE *)pnode->OSFlagNodeNext; /* Point to next task waiting for event flag(s) */
    }
    OS_EXIT_CRITICAL();
    if (sched == OS_TRUE) {
        OS_Sched();
    }
    OS_ENTER_CRITICAL();
    flags_cur = pgrp->OSFlagFlags;
    OS_EXIT_CRITICAL();
    *perr     = OS_ERR_NONE;
    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.
*
*              perr          is a pointer to an error code returned to the called:
*                            OS_ERR_NONE                The call was successfull
*                            OS_ERR_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
OS_FLAGS  OSFlagQuery (OS_FLAG_GRP *pgrp, INT8U *perr)
{
    OS_FLAGS   flags;
#if OS_CRITICAL_METHOD == 3                       /* Allocate storage for CPU status register          */
    OS_CPU_SR  cpu_sr = 0;
#endif



#if OS_ARG_CHK_EN > 0
    if (perr == (INT8U *)0) {                     /* Validate 'perr'                                   */
        return ((OS_FLAGS)0);
    }
    if (pgrp == (OS_FLAG_GRP *)0) {               /* Validate 'pgrp'                                   */
        *perr = OS_ERR_FLAG_INVALID_PGRP;
        return ((OS_FLAGS)0);
    }
#endif
    if (pgrp->OSFlagType != OS_EVENT_TYPE_FLAG) { /* Validate event block type                         */
        *perr = OS_ERR_EVENT_TYPE;
        return ((OS_FLAGS)0);
    }
    OS_ENTER_CRITICAL();
    flags = pgrp->OSFlagFlags;
    OS_EXIT_CRITICAL();
    *perr = OS_ERR_NONE;
    return (flags);                               /* Return the current value of the event 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.
*********************************************************************************************************
*/

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;
    INT8U          y;


    OSTCBCur->OSTCBStat      |= OS_STAT_FLAG;
    OSTCBCur->OSTCBStatPend   = OS_STAT_PEND_OK;
    OSTCBCur->OSTCBDly        = timeout;              /* Store timeout in task's TCB                   */
#if OS_TASK_DEL_EN > 0
    OSTCBCur->OSTCBFlagNode   = pnode;                /* TCB to link to node                           */
#endif
    pnode->OSFlagNodeFlags    = flags;                /* Save the flags that we need to wait for       */
    pnode->OSFlagNodeWaitType = wait_type;            /* Save the type of wait we are doing            */
    pnode->OSFlagNodeTCB      = (void *)OSTCBCur;     /* Link to task's TCB                            */
    pnode->OSFlagNodeNext     = pgrp->OSFlagWaitList; /* Add node at beginning of event flag wait list */
    pnode->OSFlagNodePrev     = (void *)0;
    pnode->OSFlagNodeFlagGrp  = (void *)pgrp;         /* Link to Event Flag Group                      */
    pnode_next                = (OS_FLAG_NODE *)pgrp->OSFlagWaitList;
    if (pnode_next != (void *)0) {                    /* Is this the first NODE to insert?             */
        pnode_next->OSFlagNodePrev = pnode;           /* No, link in doubly linked list                */
    }
    pgrp->OSFlagWaitList = (void *)pnode;

    y            =  OSTCBCur->OSTCBY;                 /* Suspend current task until flag(s) received   */
    OSRdyTbl[y] &= ~OSTCBCur->OSTCBBitX;
    if (OSRdyTbl[y] == 0x00) {
        OSRdyGrp &= ~OSTCBCur->OSTCBBitY;
    }
}

/*$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.
*********************************************************************************************************
*/

void  OS_FlagInit (void)
{
#if OS_MAX_FLAGS == 1
    OSFlagFreeList                 = (OS_FLAG_GRP *)&OSFlagTbl[0];  /* Only ONE event flag group!      */
    OSFlagFreeList->OSFlagType     = OS_EVENT_TYPE_UNUSED;
    OSFlagFreeList->OSFlagWaitList = (void *)0;
    OSFlagFreeList->OSFlagFlags    = (OS_FLAGS)0;
#if OS_FLAG_NAME_SIZE > 1
    OSFlagFreeList->OSFlagName[0]  = '?';
    OSFlagFreeList->OSFlagName[1]  = OS_ASCII_NUL;
#endif
#endif

#if OS_MAX_FLAGS >= 2
    INT16U       i;
    OS_FLAG_GRP *pgrp1;
    OS_FLAG_GRP *pgrp2;


    OS_MemClr((INT8U *)&OSFlagTbl[0], sizeof(OSFlagTbl));           /* Clear the flag group table      */
    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;
#if OS_FLAG_NAME_SIZE > 1
        pgrp1->OSFlagName[0]  = '?';                                /* Unknown name                    */
        pgrp1->OSFlagName[1]  = OS_ASCII_NUL;
#endif
        pgrp1++;
        pgrp2++;
    }
    pgrp1->OSFlagType     = OS_EVENT_TYPE_UNUSED;
    pgrp1->OSFlagWaitList = (void *)0;
#if OS_FLAG_NAME_SIZE > 1
    pgrp1->OSFlagName[0]  = '?';                                    /* Unknown name                    */
    pgrp1->OSFlagName[1]  = OS_ASCII_NUL;
#endif
    OSFlagFreeList        = &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    : OS_TRUE       If the task has been placed in the ready list and thus needs scheduling
*              OS_FALSE      The task is still not ready to run and thus scheduling is not necessary
*
* 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.
*********************************************************************************************************
*/

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             */
    ptcb->OSTCBDly       = 0;
    ptcb->OSTCBFlagsRdy  = flags_rdy;
    ptcb->OSTCBStat     &= ~(INT8U)OS_STAT_FLAG;
    ptcb->OSTCBStatPend  = OS_STAT_PEND_OK;
    if (ptcb->OSTCBStat == OS_STAT_RDY) {                  /* Task now ready?                          */
        OSRdyGrp               |= ptcb->OSTCBBitY;         /* Put task into ready list                 */
        OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
        sched                   = OS_TRUE;
    } else {
        sched                   = OS_FALSE;
    }
    OS_FlagUnlink(pnode);
    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.
*********************************************************************************************************
*/

void  OS_FlagUnlink (OS_FLAG_NODE *pnode)
{
#if OS_TASK_DEL_EN > 0
    OS_TCB       *ptcb;
#endif
    OS_FLAG_GRP  *pgrp;
    OS_FLAG_NODE *pnode_prev;
    OS_FLAG_NODE *pnode_next;


    pnode_prev = (OS_FLAG_NODE *)pnode->OSFlagNodePrev;
    pnode_next = (OS_FLAG_NODE *)pnode->OSFlagNodeNext;
    if (pnode_prev == (OS_FLAG_NODE *)0) {                      /* Is it first node in wait list?      */
        pgrp                 = (OS_FLAG_GRP *)pnode->OSFlagNodeFlagGrp;
        pgrp->OSFlagWaitList = (void *)pnode_next;              /*      Update list for new 1st node   */
        if (pnode_next != (OS_FLAG_NODE *)0) {
            pnode_next->OSFlagNodePrev = (OS_FLAG_NODE *)0;     /*      Link new 1st node PREV to NULL */
        }
    } else {                                                    /* No,  A node somewhere in the list   */
        pnode_prev->OSFlagNodeNext = pnode_next;                /*      Link around the node to unlink */
        if (pnode_next != (OS_FLAG_NODE *)0) {                  /*      Was this the LAST node?        */
            pnode_next->OSFlagNodePrev = pnode_prev;            /*      No, Link around current node   */
        }
    }
#if OS_TASK_DEL_EN > 0
    ptcb                = (OS_TCB *)pnode->OSFlagNodeTCB;
    ptcb->OSTCBFlagNode = (OS_FLAG_NODE *)0;
#endif
}
#endif