os_core.c

一个著名的嵌入式实时操作系统源代码UCOS-

#if OS_TASK_PROFILE_EN > 0
                OSTCBHighRdy->OSTCBCtxSwCtr++;         /* Inc. # of context switches to this task      */
#endif
                OSCtxSwCtr++;                          /* Increment context switch counter             */
                OS_TASK_SW();                          /* Perform a context switch                     */
            }
        }
    }
    OS_EXIT_CRITICAL();
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                        COPY AN ASCII STRING
*
* Description: This function is called by other uC/OS-II services to copy an ASCII string from a 'source'
*              string to a 'destination' string.
*
* Arguments  : pdest    is a pointer to the string that will be receiving the copy.  Note that there MUST
*                       be sufficient space in the destination storage area to receive this string.
*
*              psrc     is a pointer to the source string.  The source string MUST NOT be greater than 
*                       254 characters.
*
* Returns    : The size of the string (excluding the NUL terminating character)
*
* Notes      : 1) This function is INTERNAL to uC/OS-II and your application should not call it.
*********************************************************************************************************
*/

#if (OS_EVENT_NAME_SIZE > 1) || (OS_FLAG_NAME_SIZE > 1) || (OS_MEM_NAME_SIZE > 1) || (OS_TASK_NAME_SIZE > 1)
INT8U  OS_StrCopy (char *pdest, char *psrc)
{
    INT8U  len;


    len = 0;
    while (*psrc != OS_ASCII_NUL) {
        *pdest++ = *psrc++;
        len++;
    }
    *pdest = OS_ASCII_NUL;
    return (len);
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
*                                DETERMINE THE LENGTH OF AN ASCII STRING
*
* Description: This function is called by other uC/OS-II services to determine the size of an ASCII string
*              (excluding the NUL character).
*
* Arguments  : psrc     is a pointer to the string for which we need to know the size.
*
* Returns    : The size of the string (excluding the NUL terminating character)
*
* Notes      : 1) This function is INTERNAL to uC/OS-II and your application should not call it.
*              2) The string to check must be less than 255 characters long.
*********************************************************************************************************
*/

#if (OS_EVENT_NAME_SIZE > 1) || (OS_FLAG_NAME_SIZE > 1) || (OS_MEM_NAME_SIZE > 1) || (OS_TASK_NAME_SIZE > 1)
INT8U  OS_StrLen (char *psrc)
{
    INT8U  len;


    len = 0;
    while (*psrc != OS_ASCII_NUL) {
        psrc++;
        len++;
    }
    return (len);
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
*                                              IDLE TASK
*
* Description: This task is internal to uC/OS-II and executes whenever no other higher priority tasks
*              executes because they are ALL waiting for event(s) to occur.
*
* Arguments  : none
*
* Returns    : none
*
* Note(s)    : 1) OSTaskIdleHook() is called after the critical section to ensure that interrupts will be
*                 enabled for at least a few instructions.  On some processors (ex. Philips XA), enabling
*                 and then disabling interrupts didn't allow the processor enough time to have interrupts
*                 enabled before they were disabled again.  uC/OS-II would thus never recognize
*                 interrupts.
*              2) This hook has been added to allow you to do such things as STOP the CPU to conserve 
*                 power.
*********************************************************************************************************
*/

void  OS_TaskIdle (void *parg)
{
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */
    OS_CPU_SR  cpu_sr;
    
    

    cpu_sr = 0;                                  /* Prevent compiler warning                           */
#endif    
    parg   = parg;                               /* Prevent compiler warning for not using 'parg'      */
    for (;;) {
        OS_ENTER_CRITICAL();
        OSIdleCtr++;
        OS_EXIT_CRITICAL();
        OSTaskIdleHook();                        /* Call user definable HOOK                           */
    }
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                            STATISTICS TASK
*
* Description: This task is internal to uC/OS-II and is used to compute some statistics about the
*              multitasking environment.  Specifically, OS_TaskStat() computes the CPU usage.
*              CPU usage is determined by:
*
*                                          OSIdleCtr
*                 OSCPUUsage = 100 * (1 - ------------)     (units are in %)
*                                         OSIdleCtrMax
*
* Arguments  : parg     this pointer is not used at this time.
*
* Returns    : none
*
* Notes      : 1) This task runs at a priority level higher than the idle task.  In fact, it runs at the
*                 next higher priority, OS_IDLE_PRIO-1.
*              2) You can disable this task by setting the configuration #define OS_TASK_STAT_EN to 0.
*              3) You MUST have at least a delay of 2/10 seconds to allow for the system to establish the 
*                 maximum value for the idle counter.
*********************************************************************************************************
*/

#if OS_TASK_STAT_EN > 0
void  OS_TaskStat (void *parg)
{
    INT32U     run;
    INT32U     max;
    INT8S      usage;
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */
    OS_CPU_SR  cpu_sr;



    cpu_sr = 0;                                  /* Prevent compiler warning                           */
#endif    
    parg   = parg;                               /* Prevent compiler warning for not using 'parg'      */
    while (OSStatRdy == FALSE) {
        OSTimeDly(2 * OS_TICKS_PER_SEC / 10);    /* Wait until statistic task is ready                 */
    }
    max = OSIdleCtrMax / 100L;
    for (;;) {
        OS_ENTER_CRITICAL();
        OSIdleCtrRun = OSIdleCtr;                /* Obtain the of the idle counter for the past second */
        run          = OSIdleCtr;
        OSIdleCtr    = 0L;                       /* Reset the idle counter for the next second         */
        OS_EXIT_CRITICAL();
        if (max > 0L) {
            usage = (INT8S)(100L - run / max);
            if (usage >= 0) {                    /* Make sure we don't have a negative percentage      */
                OSCPUUsage = usage;
            } else {
                OSCPUUsage = 0;
            }
        } else {
            OSCPUUsage = 0;
            max        = OSIdleCtrMax / 100L;
        }
        OSTaskStatHook();                        /* Invoke user definable hook                         */
#if (OS_TASK_STAT_STK_CHK_EN > 0) && (OS_TASK_CREATE_EXT_EN > 0)
        OS_TaskStatStkChk();                     /* Check the stacks for each task                     */
#endif
        OSTimeDly(OS_TICKS_PER_SEC / 10);        /* Accumulate OSIdleCtr for the next 1/10 second      */
    }
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
*                                      CHECK ALL TASK STACKS
*
* Description: This function is called by OS_TaskStat() to check the stacks of each active task.
*
* Arguments  : none
*
* Returns    : none
*********************************************************************************************************
*/

#if (OS_TASK_STAT_STK_CHK_EN > 0) && (OS_TASK_CREATE_EXT_EN > 0)
void  OS_TaskStatStkChk (void)
{
    OS_TCB      *ptcb;
    OS_STK_DATA  stk_data;
    INT8U        err;
    INT8U        prio;


    for (prio = 0; prio <= OS_IDLE_PRIO; prio++) {
        err = OSTaskStkChk(prio, &stk_data);
        if (err == OS_NO_ERR) {
            ptcb = OSTCBPrioTbl[prio];
            if (ptcb != (OS_TCB *)0) {                               /* Make sure task 'ptcb' is ...   */
                if (ptcb != (OS_TCB *)1) {                           /* ... still valid.               */
#if OS_TASK_PROFILE_EN > 0
                    #if OS_STK_GROWTH == 1
                    ptcb->OSTCBStkBase = ptcb->OSTCBStkBottom + ptcb->OSTCBStkSize;
                    #else
                    ptcb->OSTCBStkBase = ptcb->OSTCBStkBottom - ptcb->OSTCBStkSize;
                    #endif
                    ptcb->OSTCBStkUsed = (INT32U)stk_data.OSUsed;    /* Store the number of bytes used */
#endif
                }
            }
        }
    }
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
*                                            INITIALIZE TCB
*
* Description: This function is internal to uC/OS-II and is used to initialize a Task Control Block when
*              a task is created (see OSTaskCreate() and OSTaskCreateExt()).
*
* Arguments  : prio          is the priority of the task being created
*
*              ptos          is a pointer to the task's top-of-stack assuming that the CPU registers
*                            have been placed on the stack.  Note that the top-of-stack corresponds to a
*                            'high' memory location is OS_STK_GROWTH is set to 1 and a 'low' memory
*                            location if OS_STK_GROWTH is set to 0.  Note that stack growth is CPU
*                            specific.
*
*              pbos          is a pointer to the bottom of stack.  A NULL pointer is passed if called by
*                            'OSTaskCreate()'.
*
*              id            is the task's ID (0..65535)
*
*              stk_size      is the size of the stack (in 'stack units').  If the stack units are INT8Us
*                            then, 'stk_size' contains the number of bytes for the stack.  If the stack
*                            units are INT32Us then, the stack contains '4 * stk_size' bytes.  The stack
*                            units are established by the #define constant OS_STK which is CPU
*                            specific.  'stk_size' is 0 if called by 'OSTaskCreate()'.
*
*              pext          is a pointer to a user supplied memory area that is used to extend the task
*                            control block.  This allows you to store the contents of floating-point
*                            registers, MMU registers or anything else you could find useful during a
*                            context switch.  You can even assign a name to each task and store this name
*                            in this TCB extension.  A NULL pointer is passed if called by OSTaskCreate().
*
*              opt           options as passed to 'OSTaskCreateExt()' or,
*                            0 if called from 'OSTaskCreate()'.
*
* Returns    : OS_NO_ERR         if the call was successful
*              OS_NO_MORE_TCB    if there are no more free TCBs to be allocated and thus, the task cannot
*                                be created.
*
* Note       : This function is INTERNAL to uC/OS-II and your application should not call it.
*********************************************************************************************************
*/

INT8U  OS_TCBInit (INT8U prio, OS_STK *ptos, OS_STK *pbos, INT16U id, INT32U stk_size, void *pext, INT16U opt)
{
    OS_TCB    *ptcb;
#if OS_CRITICAL_METHOD == 3                                /* Allocate storage for CPU status register */
    OS_CPU_SR  cpu_sr;



    cpu_sr = 0;                                            /* Prevent compiler warning                 */
#endif    
    OS_ENTER_CRITICAL();
    ptcb = OSTCBFreeList;                                  /* Get a free TCB from the free TCB list    */
    if (ptcb != (OS_TCB *)0) {
        OSTCBFreeList        = ptcb->OSTCBNext;            /* Update pointer to free TCB list          */
        OS_EXIT_CRITICAL();
        ptcb->OSTCBStkPtr    = ptos;                       /* Load Stack pointer in TCB                */
        ptcb->OSTCBPrio      = prio;                       /* Load task priority into TCB              */
        ptcb->OSTCBStat      = OS_STAT_RDY;                /* Task is ready to run                     */
        ptcb->OSTCBPendTO    = FALSE;                      /* Clear the Pend timeout flag              */
        ptcb->OSTCBDly       = 0;                          /* Task is not delayed                      */

#if OS_TASK_CREATE_EXT_EN > 0
        ptcb->OSTCBExtPtr    = pext;                       /* Store pointer to TCB extension           */
        ptcb->OSTCBStkSize   = stk_size;                   /* Store stack size                         */
        ptcb->OSTCBStkBottom = pbos;                       /* Store pointer to bottom of stack         */
        ptcb->OSTCBOpt       = opt;                        /