/*
*********************************************************************************************************
*                                                uC/OS-II
*                                          The Real-Time Kernel
*                                            TASK MANAGEMENT
*
*                          (c) Copyright 1992-2002, Jean J. Labrosse, Weston, FL
*                                           All Rights Reserved
*
* File : OS_TASK.C
* By   : Jean J. Labrosse
*********************************************************************************************************
*/

#ifndef  OS_MASTER_FILE
#include "includes.h"
#endif

/*
*********************************************************************************************************
*                                        CHANGE PRIORITY OF A TASK
*
* Description: This function allows you to change the priority of a task dynamically.  Note that the new
*              priority MUST be available.
*
* Arguments  : oldp     is the old priority
*
*              newp     is the new priority
*
* Returns    : OS_NO_ERR        is the call was successful
*              OS_PRIO_INVALID  if the priority you specify is higher that the maximum allowed
*                               (i.e. >= OS_LOWEST_PRIO)
*              OS_PRIO_EXIST    if the new priority already exist.
*              OS_PRIO_ERR      there is no task with the specified OLD priority (i.e. the OLD task does
*                               not exist.
*********************************************************************************************************
*/

#if OS_TASK_CHANGE_PRIO_EN > 0
INT8U  OSTaskChangePrio (INT8U oldprio, INT8U newprio)
{
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */
    OS_CPU_SR    cpu_sr;
#endif

#if OS_EVENT_EN > 0
    OS_EVENT    *pevent;
#endif

    OS_TCB      *ptcb;
    INT8U        x;
    INT8U        y;
    INT8U        bitx;
    INT8U        bity;



#if OS_ARG_CHK_EN > 0
    if ((oldprio >= OS_LOWEST_PRIO && oldprio != OS_PRIO_SELF)  ||
         newprio >= OS_LOWEST_PRIO) 
    {
        return (OS_PRIO_INVALID);
    }
#endif
    OS_ENTER_CRITICAL();
    if (OSTCBPrioTbl[newprio] != (OS_TCB *)0)
    {                 /* New priority must not already exist */
        OS_EXIT_CRITICAL();
        return (OS_PRIO_EXIST);
    } else {
        OSTCBPrioTbl[newprio] = (OS_TCB *)1;                    /* Reserve the entry to prevent others */
        OS_EXIT_CRITICAL();
        y    = newprio >> 3;                                    /* Precompute to reduce INT. latency   */
        bity = OSMapTbl[y];
        x    = newprio & 0x07;
        bitx = OSMapTbl[x];
        OS_ENTER_CRITICAL();
        if (oldprio == OS_PRIO_SELF) 
        {                          /* See if changing self                */
            oldprio = OSTCBCur->OSTCBPrio;                      /* Yes, get priority                   */
        }
        ptcb = OSTCBPrioTbl[oldprio];
        if (ptcb != (OS_TCB *)0) {                              /* Task to change must exist           */
            OSTCBPrioTbl[oldprio] = (OS_TCB *)0;                /* Remove TCB from old priority        */
            if ((OSRdyTbl[ptcb->OSTCBY] & ptcb->OSTCBBitX) != 0x00) 
            {  /* If task is ready make it not */
                if ((OSRdyTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0x00) 
                {
                    OSRdyGrp &= ~ptcb->OSTCBBitY;
                }
                OSRdyGrp    |= bity;                            /* Make new priority ready to run      */
                OSRdyTbl[y] |= bitx;
#if OS_EVENT_EN > 0
            }
            else 
            {
                pevent = ptcb->OSTCBEventPtr;
                if (pevent != (OS_EVENT *)0) 
                {                  /* Remove from event wait list  */
                    if ((pevent->OSEventTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0) 
                    {
                        pevent->OSEventGrp &= ~ptcb->OSTCBBitY;
                    }
                    pevent->OSEventGrp    |= bity;              /* Add new priority to wait list       */
                    pevent->OSEventTbl[y] |= bitx;
                }
#endif
            }
            OSTCBPrioTbl[newprio] = ptcb;                       /* Place pointer to TCB @ new priority */
            ptcb->OSTCBPrio       = newprio;                    /* Set new task priority               */
            ptcb->OSTCBY          = y;
            ptcb->OSTCBX          = x;
            ptcb->OSTCBBitY       = bity;
            ptcb->OSTCBBitX       = bitx;
            OS_EXIT_CRITICAL();
            OS_Sched();                                         /* Run highest priority task ready     */
            return (OS_NO_ERR);
        } 
        else 
        {
            OSTCBPrioTbl[newprio] = (OS_TCB *)0;                /* Release the reserved prio.          */
            OS_EXIT_CRITICAL();
            return (OS_PRIO_ERR);                               /* Task to change didn't exist         */
        }
    }
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
*                                            CREATE A TASK
*
* Description: This function is used to have uC/OS-II manage the execution of a task.  Tasks can either
*              be created prior to the start of multitasking or by a running task.  A task cannot be
*              created by an ISR.
*
* Arguments  : task     is a pointer to the task's code
*
*              pdata    is a pointer to an optional data area which can be used to pass parameters to
*                       the task when the task first executes.  Where the task is concerned it thinks
*                       it was invoked and passed the argument 'pdata' as follows:
*
*                           void Task (void *pdata)
*                           {
*                               for (;;) {
*                                   Task code;
*                               }
*                           }
*
*              ptos     is a pointer to the task's top of stack.  If the configuration constant
*                       OS_STK_GROWTH is set to 1, the stack is assumed to grow downward (i.e. from high
*                       memory to low memory).  'pstk' will thus point to the highest (valid) memory
*                       location of the stack.  If OS_STK_GROWTH is set to 0, 'pstk' will point to the
*                       lowest memory location of the stack and the stack will grow with increasing
*                       memory locations.
*
*              prio     is the task's priority.  A unique priority MUST be assigned to each task and the
*                       lower the number, the higher the priority.
*
* Returns    : OS_NO_ERR        if the function was successful.
*              OS_PRIO_EXIT     if the task priority already exist
*                               (each task MUST have a unique priority).
*              OS_PRIO_INVALID  if the priority you specify is higher that the maximum allowed
*                               (i.e. >= OS_LOWEST_PRIO)
*********************************************************************************************************
*/

#if OS_TASK_CREATE_EN > 0
INT8U  OSTaskCreate (void (*task)(void *pd), void *pdata, OS_STK *ptos, INT8U prio)
{
#if OS_CRITICAL_METHOD == 3                  /* Allocate storage for CPU status register               */
    OS_CPU_SR  cpu_sr;
#endif
    OS_STK    *psp;
    INT8U      err;


#if OS_ARG_CHK_EN > 0
    if (prio > OS_LOWEST_PRIO) 
		{             /* Make sure priority is within allowable range           */
        return (OS_PRIO_INVALID);
        }
#endif
    OS_ENTER_CRITICAL();
    if (OSTCBPrioTbl[prio] == (OS_TCB *)0) 
    { /* Make sure task doesn't already exist at this priority  */
        OSTCBPrioTbl[prio] = (OS_TCB *)1;    /* Reserve the priority to prevent others from doing ...  */
                                             /* ... the same thing until task is created.              */
        OS_EXIT_CRITICAL();
        psp = (OS_STK *)OSTaskStkInit(task, pdata, ptos, 0);    /* Initialize the task's stack         */
        err = OS_TCBInit(prio, psp, (OS_STK *)0, 0, 0, (void *)0, 0);
        if (err == OS_NO_ERR) 
        {
            OS_ENTER_CRITICAL();
            OSTaskCtr++;                                        /* Increment the #tasks counter        */
            OS_EXIT_CRITICAL();
            if (OSRunning == TRUE) 
            {         /* Find highest priority task if multitasking has started */
                OS_Sched();
            }
        } 
        else 
        {
            OS_ENTER_CRITICAL();
            OSTCBPrioTbl[prio] = (OS_TCB *)0;/* Make this priority available to others                 */
            OS_EXIT_CRITICAL();
        }
        return (err);
    }
    OS_EXIT_CRITICAL();
    return (OS_PRIO_EXIST);
}