os_core.c

UCOS最小系统。能在单片机上闪烁LED。支持2个led闪烁。

/*
*********************************************************************************************************
*                              FIND HIGHEST PRIORITY TASK READY TO RUN
*
* Description: This function is called by other uC/OS-II services to determine the highest priority task
*              that is ready to run.  The global variable 'OSPrioHighRdy' is changed accordingly.
*
* Arguments  : none
*
* Returns    : none
*
* Notes      : 1) This function is INTERNAL to uC/OS-II and your application should not call it.
*              2) Interrupts are assumed to be disabled when this function is called.
*********************************************************************************************************
*/

static  void  OS_SchedNew (void)
{
#if OS_LOWEST_PRIO <= 63                         /* See if we support up to 64 tasks                   */
    INT8U   y;


    y             = OSUnMapTbl[OSRdyGrp];
    OSPrioHighRdy = (INT8U)((y << 3) + OSUnMapTbl[OSRdyTbl[y]]);
#else                                            /* We support up to 256 tasks                         */
    INT8U   y;
    INT16U *ptbl;


    if ((OSRdyGrp & 0xFF) != 0) {
        y = OSUnMapTbl[OSRdyGrp & 0xFF];
    } else {
        y = OSUnMapTbl[(OSRdyGrp >> 8) & 0xFF] + 8;
    }
    ptbl = &OSRdyTbl[y];
    if ((*ptbl & 0xFF) != 0) {
        OSPrioHighRdy = (INT8U)((y << 4) + OSUnMapTbl[(*ptbl & 0xFF)]);
    } else {
        OSPrioHighRdy = (INT8U)((y << 4) + OSUnMapTbl[(*ptbl >> 8) & 0xFF] + 8);
    }
#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  OSTaskIdle (void *p_arg) reentrant
{
    p_arg=p_arg;                                 /* Prevent compiler warning for not using 'parg'      */
    for (;;) {
        OS_ENTER_CRITICAL();
        OSIdleCtr++;
        OS_EXIT_CRITICAL();
    }
}
/*$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_TASK_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.
*********************************************************************************************************
*/



void OSInit (void) reentrant
{
    INT16U i;


    OSTime        = 0L;                                    /* Clear the 32-bit system clock            */
    OSIntNesting  = 0;                                     /* Clear the interrupt nesting counter      */
    OSLockNesting = 0;                                     /* Clear the scheduling lock counter        */
#if OS_TASK_CREATE_EN  || OS_TASK_CREATE_EXT_EN || OS_TASK_DEL_EN
    OSTaskCtr     = 0;                                     /* Clear the number of tasks                */
#endif
    OSRunning     = FALSE;                                 /* Indicate that multitasking not started   */
    OSIdleCtr     = 0L;                                    /* Clear the 32-bit idle counter            */
#if OS_TASK_STAT_EN && OS_TASK_CREATE_EXT_EN
    OSIdleCtrRun  = 0L;
    OSIdleCtrMax  = 0L;
    OSStatRdy     = FALSE;                                 /* Statistic task is not ready              */
#endif
    OSCtxSwCtr    = 0;                                     /* Clear the context switch counter         */
    OSRdyGrp      = 0;                                     /* Clear the ready list                     */
    for (i = 0; i < OS_RDY_TBL_SIZE; i++) {
        OSRdyTbl[i] = 0;
    }
                
    OSPrioCur     = 0;
    OSPrioHighRdy = 0;                                           
    OSTCBHighRdy  = (OS_TCB *)0;                                 /* TCB Initialization                 */
    OSTCBCur      = (OS_TCB *)0;
    OSTCBList     = (OS_TCB *)0;
    for (i = 0; i < (OS_LOWEST_PRIO + 1); i++) {                 /* Clear the priority table           */
        OSTCBPrioTbl[i] = (OS_TCB *)0;
    }
    for (i = 0; i < (OS_MAX_TASKS + OS_N_SYS_TASKS - 1); i++) {  /* Init. list of free TCBs            */
        OSTCBTbl[i].OSTCBNext = &OSTCBTbl[i + 1];
    }
    OSTCBTbl[OS_MAX_TASKS + OS_N_SYS_TASKS - 1].OSTCBNext = (OS_TCB *)0;    /* Last OS_TCB             */
    OSTCBFreeList                                         = &OSTCBTbl[0];

#if OS_Q_EN && (OS_MAX_QS >= 2)
    OSQInit();                                             /* Initialize the message queue structures  */
#endif

#if OS_MEM_EN && OS_MAX_MEM_PART >= 2
    OSMemInit();                                           /* Initialize the memory manager            */
#endif    

#if OS_STK_GROWTH == 1
    OSTaskCreate(OSTaskIdle, (void *)0, &OSTaskIdleStk[OS_TASK_IDLE_STK_SIZE - 1], OS_IDLE_PRIO);
#else
    OSTaskCreate(OSTaskIdle, (void *)0, &OSTaskIdleStk[0], OS_IDLE_PRIO);
#endif

//OS_InitTaskIdle();

}
/*$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_ERR_NONE         if the call was successful
*              OS_ERR_TASK_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 OSTCBInit (INT8U prio, OS_STK *ptos, OS_STK *pbos, INT16U id, INT16U stk_size, void *pext, INT16U opt) reentrant
{
    OS_TCB *ptcb;


    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      = (INT8U)prio;                /* Load task priority into TCB              */
        ptcb->OSTCBStat      = OS_STAT_RDY;                /* Task is ready to run                     */
        ptcb->OSTCBDly       = 0;                          /* Task is not delayed                      */

#if OS_TASK_CREATE_EXT_EN        
        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;                        /* Store task options                       */
        ptcb->OSTCBId        = id;                         /* Store task ID                            */
#else
        pext                 = pext;                       /* Prevent compiler warning if not used     */
        stk_size             = stk_size;
        pbos                 = pbos;
        opt                  = opt;
        id                   = id;
#endif

#if OS_TASK_DEL_EN        
        ptcb->OSTCBDelReq    = OS_NO_ERR;
#endif

        ptcb->OSTCBY         = prio >> 3;                  /* Pre-compute X, Y, BitX and BitY          */
        ptcb->OSTCBBitY      = OSMapTbl[ptcb->OSTCBY];
        ptcb->OSTCBX         = prio & 0x07;
        ptcb->OSTCBBitX      = OSMapTbl[ptcb->OSTCBX];

#if     OS_MBOX_EN || (OS_Q_EN && (OS_MAX_QS >= 2)) || OS_SEM_EN
        ptcb->OSTCBEventPtr  = (OS_EVENT *)0;              /* Task is not pending on an event          */
#endif

#if     OS_MBOX_EN || (OS_Q_EN && (OS_MAX_QS >= 2))
        ptcb->OSTCBMsg       = (void *)0;                  /* No message received                      */
#endif

        OS_ENTER_CRITICAL();
        OSTCBPrioTbl[prio]   = ptcb;
        ptcb->OSTCBNext      = OSTCBList;                  /* Link into TCB chain                      */
        ptcb->OSTCBPrev      = (OS_TCB *)0;
        if (OSTCBList != (OS_TCB *)0) {
            OSTCBList->OSTCBPrev = ptcb;
        }
        OSTCBList               = ptcb;
        OSRdyGrp               |= ptcb->OSTCBBitY;         /* Make task ready to run                   */
        OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
        OS_EXIT_CRITICAL();
        return (OS_NO_ERR);
    } else {
        OS_EXIT_CRITICAL();
        return (OS_NO_MORE_TCB);
    }
}