/***********************************************************************************************
 *                                               uC/OS-II
 *                                         The Real-Time Kernel
 * File         : os_cpu_c.c
 * For          : uC/OS Real-time multitasking kernel for the Nios2 SoftCore Processor
 * Written by   : IS
 * Based on     : Nios port done by JS
 *
 * Functions defined in this module:
 *
 ***********************************************************************************************/

#include <reent.h>
#include <string.h>

#define  OS_CPU_GLOBALS
#include "includes.h"                   // Standard includes for uC/OS-II

extern void OSStartTsk;                 // The entry point for all tasks.

/***********************************************************************************************
 *                                        INITIALIZE A TASK'S STACK
 *
 * Description: This function is called by either OSTaskCreate() or OSTaskCreateExt() to
 *              initialize the stack frame of the task being created.  This function is
 *              highly processor specific.
 *
 * What it does: It builds up initial stack for a task.
 *
 * Arguments  : task          is a pointer to the task code
 *
 *              pdata         is a pointer to a user supplied data area that will be passed to the task
 *                            when the task first executes.
 *
 *              ptos          is a pointer to the top of stack.  It is assumed that 'ptos' points to
 *                            a 'free' entry on the task stack.  If OS_STK_GROWTH is set to 1 then
 *                            'ptos' will contain the HIGHEST valid address of the stack.  Similarly, if
 *                            OS_STK_GROWTH is set to 0, the 'ptos' will contains the LOWEST valid address
 *                            of the stack.
 *
 *              opt           specifies options that can be used to alter the behavior of OSTaskStkInit().
 *                            (see uCOS_II.H for OS_TASK_OPT_???).
 *
 * Returns    : Always returns the location of the new top-of-stack' once the processor registers have
 *              been placed on the stack in the proper order.
 *
 ***********************************************************************************************/

OS_STK *OSTaskStkInit(void (*task)(void *pd), void *pdata, OS_STK *pstk, INT16U opt)
{
   INT32U   *frame_pointer;
   INT32U   *stk;

   struct _reent* impure_ptr;   

   /* 
    * create and initialise the impure pointer used for Newlib thread local storage.
    */

   impure_ptr = (struct _reent*)((((INT32U)(pstk)) & ~0x3) - sizeof(struct _reent));

   _REENT_INIT_PTR (impure_ptr);
     
   /* 
    * create a stack frame at the top of the stack (leaving space for the 
    * reentrant data structure).
    */

   frame_pointer = (INT32U*) impure_ptr;
   stk = frame_pointer - DEFAULT_STACK_FRAME;

   /* Now fill the stack frame. */

   *(stk + 13) = (INT32U)task;            /* return address (ra) */
   *(stk + 12) = (INT32U) pdata;          /* first register argument (r4) */

   *(stk + 11) = (INT32U) impure_ptr;     /* value of _impure_ptr for this thread */
   *(stk + 10) = 1;                       /* disable interrupts */
   *(stk + 1)  = (INT32U) frame_pointer;  /* frame pointer (fp) */
   *(stk)      = (INT32U) &OSStartTsk;    /* exception return address (ea) */  

   return((OS_STK *)stk);
}

#if OS_CPU_HOOKS_EN
/*
*********************************************************************************************************
*                                          TASK CREATION HOOK
*
* Description: This function is called when a task is created.
*
* Arguments  : ptcb   is a pointer to the task control block of the task being created.
*
* Note(s)    : 1) Interrupts are disabled during this call.
*********************************************************************************************************
*/
void OSTaskCreateHook (OS_TCB *ptcb)
{
    OSView_TaskCreateHook(ptcb);
}


/*
*********************************************************************************************************
*                                           TASK DELETION HOOK
*
* Description: This function is called when a task is deleted.
*
* Arguments  : ptcb   is a pointer to the task control block of the task being deleted.
*
* Note(s)    : 1) Interrupts are disabled during this call.
*********************************************************************************************************
*/
void OSTaskDelHook (OS_TCB *ptcb)
{
    ptcb = ptcb;                       /* Prevent compiler warning                                     */
}

/*
*********************************************************************************************************
*                                           TASK SWITCH HOOK
*
* Description: This function is called when a task switch is performed.  This allows you to perform other
*              operations during a context switch.
*
* Arguments  : none
*
* Note(s)    : 1) Interrupts are disabled during this call.
*              2) It is assumed that the global pointer 'OSTCBHighRdy' points to the TCB of the task that
*                 will be 'switched in' (i.e. the highest priority task) and, 'OSTCBCur' points to the
*                 task being switched out (i.e. the preempted task).
*********************************************************************************************************
*/
void OSTaskSwHook (void)
{
    OSView_TaskSwHook();
}

/*
*********************************************************************************************************
*                                           STATISTIC TASK HOOK
*
* Description: This function is called every second by uC/OS-II's statistics task.  This allows your
*              application to add functionality to the statistics task.
*
* Arguments  : none
*********************************************************************************************************
*/
void OSTaskStatHook (void)
{
}

/*
*********************************************************************************************************
*                                               TICK HOOK
*
* Description: This function is called every tick.
*
* Arguments  : none
*
* Note(s)    : 1) Interrupts may or may not be ENABLED during this call.
*********************************************************************************************************
*/
void OSTimeTickHook (void)
{
    OSView_TickHook();
}

void          OSInitHookBegin(void)
{
}

void          OSInitHookEnd(void)
{
}

void          OSTaskIdleHook(void)
{
}

void          OSTCBInitHook(OS_TCB *ptcb)
{
}

#endif