/*
********************************************************************************
*                               uC/OS-II
*                          The Real-Time Kernel
* 
*                         ATmega103 Specific code
*
* File:			OS_CPU_C.C
* By:			Ole Saether
* Modified by:	Joerg Meyer
* Revision:		0
*
*
*
********************************************************************************
*/

#define  OS_CPU_GLOBALS
#include "includes.h"

/*
********************************************************************************
*                     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.
*
* 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
*			the highest valid address on 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.
*
* Note(s):
*	Interrupts are enabled when your task starts executing. You can change this 
* 	by setting the SREG to 0x00 instead. In this case, interrupts would be 
*	disabled upon task startup. The application code would be responsible for 
*	enabling interrupts at the beginning of the task code. You will need to 
*	modify OSTaskIdle() and OSTaskStat() so that they enable interrupts. Failure
*	to do this will make your system crash! The AVR return stack is placed 64 
*	bytes above the start of the (512 byte) stack. This provides 32 levels of 
*	function call nesting which should be more than enough for most applications
*	(see the "read.me" file for more info).
*
********************************************************************************
*/
OS_STK *OSTaskStkInit (void (*task)(void *pd),
						 void *pdata, OS_STK *ptos, INT16U opt){

    INT8U  *stk;
    INT8U  *stks;		// Temp. variable used for setting up AVR hardware stack
    INT16U tmp;


    opt     = opt;			// 'opt' is not used, prevent warning
    stk     = (INT8U *)ptos;		// Wandlung von ptos in Bytezeiger
	// AVR return stack ("hardware stack")
    stks    = (INT8U *)(ptos)-(OS_TASK_DEF_STK_SIZE-32);

	// the function address has an extra level of indirection. Fetch the
    // actual address and assign it back to task. - NOTE: assume task
    // remains in R16/17.
    //    
    tmp = *(INT16U const *)task;
    /*
	// IIC uebergibt die Funktionsadresse nicht direkt, sondern indirekt als
	// Zeiger, infolgedessen muss die Adresse erst aus _func_lit geholt werden
	// r16, 17 ist erstes Argument, hier also task
	asm("MOV      R30, R16\n");	// L-Teil
	asm("MOV      R31, R17\n");	// H-Teil
	asm("LPM\n");				// Umschalten auf constant data
	asm("MOV      R16,R0\n");	// solange _func_lit am Anfang des Flashs liegt
	asm("ADIW     R30, 0x1\n");	// ist eine Uebertragsbehandlung nicht notwendig
	asm("LPM\n");
	asm("MOV      R17, R0\n");
    tmp     = (INT16U)task;
	*/
    
	// 36 Bytes
    *stks-- = (INT8U)tmp;	//Put task start address on top of hardware stack
    *stks-- = (INT8U)(tmp >> 8);

    *stk-- = (INT8U)0x00;		// R0  = 0x00
    *stk-- = (INT8U)0x01; 
    *stk-- = (INT8U)0x02;
    *stk-- = (INT8U)0x03;
    *stk-- = (INT8U)0x04;
    *stk-- = (INT8U)0x05;
    *stk-- = (INT8U)0x06;
    *stk-- = (INT8U)0x07;
    *stk-- = (INT8U)0x08;
    *stk-- = (INT8U)0x09;
    *stk-- = (INT8U)0x10;
    *stk-- = (INT8U)0x11;
    *stk-- = (INT8U)0x12;
    *stk-- = (INT8U)0x13;
    *stk-- = (INT8U)0x14;
    *stk-- = (INT8U)0x15;
    tmp    = (INT16U)pdata;
    *stk-- = (INT8U)tmp;	//Simulate call to function with argument
    *stk-- = (INT8U)(tmp >> 8);
    *stk-- = (INT8U)0x18;
    *stk-- = (INT8U)0x19;
    *stk-- = (INT8U)0x20;
    *stk-- = (INT8U)0x21;
    *stk-- = (INT8U)0x22;
    *stk-- = (INT8U)0x23;
    *stk-- = (INT8U)0x24;
    *stk-- = (INT8U)0x25;
    *stk-- = (INT8U)0x26;
    *stk-- = (INT8U)0x27;
	// the heap pointer Y=R29:R28 will not be stored
    *stk-- = (INT8U)0x30;
    *stk-- = (INT8U)0x31;
    *stk-- = (INT8U)0x3B;
    *stk-- = (INT8U)0x80;	//SREG = Interrupts enabled

    tmp    = (INT16U)(stks);
    *stk-- = (INT8U)(tmp >> 8);
    *stk   = (INT8U)(tmp);
    return ((void *)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)
{
    ptcb = ptcb;		// Prevent compiler warning
}


/*
********************************************************************************
*                      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)
{
}

/*
********************************************************************************
*                       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)
{
}
#endif

//*****************************************************************************
//			TickISR
//*****************************************************************************
// Init Timer/Counter2 fuer Takterzeugung
void TC2_Init (void){	
	/* Only uses TIMER2 overflow for tick interrupt. Timer compare
     * can also be used.
     */
	TIMSK &= ~(BIT(TOIE2)/* | BIT(OCIE2) */);	//disable TC2 interrupts
	TCCR2 = 0x05;		// interner Takt, /1024
	TCNT2 = 256-39; 	// Counter ruecksetzen, 10ms @ 4MHz
	// OCR2 = 180;			// OutputCompareRegister
	TIMSK |= BIT(TOIE2);	// enable OVF-interrupt
	                                                                                                                                //TIMSK |= OCIE2;		// enable COMP-interrupt
	
    SEI();	// enable global interrupt     
}

//*****************************************************************************
// Interrupt Timer/Counter0 Overflow
// OVF_Takt:  4MHz / 1024 / 39 = 10ms
#pragma interrupt_handler OSTickISR:11

	// Funktion siehe OS_CPU_A.S
/*
void TC2_OVF (void){		//overflow interrupt vector


}
*/