/*
*********************************************************************************************************
*                                              uC/OS-II
*                                        The Real-Time Kernel
*
*                    Copyright 1992-2020 Silicon Laboratories Inc. www.silabs.com
*
*                                 SPDX-License-Identifier: APACHE-2.0
*
*               This software is subject to an open source license and is distributed by
*                Silicon Laboratories Inc. pursuant to the terms of the Apache License,
*                    Version 2.0 available at www.apache.org/licenses/LICENSE-2.0.
*
*********************************************************************************************************
*/


/*
*********************************************************************************************************
*
*                                            TASK MANAGEMENT
*
* Filename : os_task.c
* Version  : V2.93.00
*********************************************************************************************************
*/

#ifndef  OS_MASTER_FILE
#include <ucos_ii.h>
#endif

/*
*********************************************************************************************************
*                                            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
*
*              p_arg    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 'p_arg' as follows:
*
*                           void Task (void *p_arg)
*                           {
*                               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 *p_arg, 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, p_arg, 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);
}
#endif
