/*
*********************************************************************************************************
*                                                uC/OS-II
*                                          The Real-Time Kernel
*
*                              (c) Copyright 2002, Micrium, Inc., Weston, FL
*                                           All Rights Reserved
*
*                                                TI MSP430
*
*
* File         : OS_CPU_C.C
* By           : Alley Zhou(zzy@lierda.com)
*                Jean J. Labrosse
* Compiler     : AQ430 for TI MSP430 V2.0.5.4
*********************************************************************************************************
*/

#define BANKED
//#define SMALL
#if !defined(BANKED) && !defined(SMALL)
#error it must define BANKED or SMALL
#endif
#if defined(BANKED) && defined(SMALL)
#error both BANKED and SMALL are defined 
#endif



#define  OS_CPU_GLOBALS
//#define CRGFLG (*((volatile unsigned char *)(0x0037)))
#include "includes.h"

/*
*********************************************************************************************************
*                                       OS INITIALIZATION HOOK
*                                            (BEGINNING)
*
* Description: This function is called by OSInit() at the beginning of OSInit().
*
* Arguments  : none
*
* Note(s)    : 1) Interrupts should be disabled during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0 && OS_VERSION > 203
void  OSInitHookBegin (void)
{
}
#endif

/*
*********************************************************************************************************
*                                       OS INITIALIZATION HOOK
*                                               (END)
*
* Description: This function is called by OSInit() at the end of OSInit().
*
* Arguments  : none
*
* Note(s)    : 1) Interrupts should be disabled during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0 && OS_VERSION > 203
void  OSInitHookEnd (void)
{
}
#endif

/*$PAGE*/
/*
*********************************************************************************************************
*                                          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.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0 
void  OSTaskCreateHook (OS_TCB *ptcb)
{
	ptcb = ptcb;                       /* Prevent compiler warning                                     */
}
#endif


/*
*********************************************************************************************************
*                                           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.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0 
void  OSTaskDelHook (OS_TCB *ptcb)
{
	ptcb = ptcb;                       /* Prevent compiler warning                                     */
}
#endif

/*
*********************************************************************************************************
*                                             IDLE TASK HOOK
*
* Description: This function is called by the idle task.  This hook has been added to allow you to do  
*              such things as STOP the CPU to conserve power.
*
* Arguments  : none
*
* Note(s)    : 1) Interrupts are enabled during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0 && OS_VERSION >= 251
void  OSTaskIdleHook (void)
{
	asm wai;/* Enter low power mode                              */   
}
#endif

/*
*********************************************************************************************************
*                                           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
*********************************************************************************************************
*/

#if OS_CPU_HOOKS_EN > 0 
void  OSTaskStatHook (void)
{
}
#endif

/*$PAGE*/
/*
*********************************************************************************************************
*                                        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
*                            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 *ptos, INT16U opt)
{
	INT16U  *stk;
#ifdef BANKED
	INT16U  RegPage;              /* uses to save the ppage  */ 
	INT16U *OffsetAddress;	 
#endif  

	stk = (INT16U *)ptos;         //load stack pointer
	*--stk = opt;                //opt the is one byte blank

#ifdef BANKED
	OffsetAddress = (INT16U *)&task;  /* 16 bit address*/
	RegPage = (INT8U)task;            /* PPAGE */
	*--stk = (INT16U)*OffsetAddress;     //pc for use of opt in task
	*--stk = (INT16U)*OffsetAddress;      //pc
#endif
#ifdef SMALL
	*--stk = (INT16U)(task);     //pc for use of opt in task
	*--stk = (INT16U)(task);      //pc
#endif

	*--stk = (INT16U)(0x1122);    //Y Register
	*--stk = (INT16U)(0x3344);    //X Register
	*--stk = (INT16U)pdata;	      //D Register:A,B
	*--stk = (INT16U)(0x00);	    //CCR,16 bits in S12X	
	/*((INT8U *)stk)--;            //CCR,8 bits in S12
	*(INT8U *)stk = (INT8U)(0x00); //CCR*/

#ifdef BANKED
	((INT8U *)stk)--;               // a byte need for PPAGE
	*(INT8U *)stk = RegPage;//PPAGE
#endif
	return((OS_STK *)stk);  
}

/*$PAGE*/
/*
*********************************************************************************************************
*                                           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).
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0
void  OSTaskSwHook (void)
{
}
#endif

/*
*********************************************************************************************************
*                                           OSTCBInit() HOOK
*
* Description: This function is called by OS_TCBInit() after setting up most of the TCB.
*
* Arguments  : ptcb    is a pointer to the TCB of the task being created.
*
* Note(s)    : 1) Interrupts may or may not be ENABLED during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0 && OS_VERSION > 203
void  OSTCBInitHook (OS_TCB *ptcb)
{
	ptcb = ptcb;                                           /* Prevent Compiler warning                 */
}
#endif


/*
*********************************************************************************************************
*                                               TICK HOOK
*
* Description: This function is called every tick.
*
* Arguments  : none
*
* Note(s)    : 1) Interrupts may or may not be ENABLED during this call.
*********************************************************************************************************
*/
#if OS_CPU_HOOKS_EN > 0
void  OSTimeTickHook (void)
{
}
#endif



#pragma CODE_SEG __NEAR_SEG NON_BANKED
void OSStartHighRdy(void)
{
	OSTaskSwHook();           //Call Hook function

	asm
	{
		ldx OSTCBCur;          // load the value in OSTCBCur or 
		lds 0,x;
		inc OSRunning;           //OSRunning = 1
#ifdef BANKED
		pula;
		staa PPAGE;
		nop ;                 //when PPAGE changed ,nop may be inserted
#endif
		rti;
	}
}

#pragma NO_RETURN
void OSIntCtxSw(void)
{
	OSTaskSwHook();   //Call Hook function
	OSTCBCur = OSTCBHighRdy; //change OSTCBCur and OSPrioCur
	OSPrioCur = OSPrioHighRdy;
	asm
	{
		ldx OSTCBCur;         //Get the new task's TCB's address
		lds 0,x;
#ifdef BANKED
		pula;
		staa PPAGE;
		nop;
#endif
		rti;
	}   
}


#pragma NO_RETURN
void interrupt OSCtxSw(void)     /*swi interrupt */
{
	asm
	{
#ifdef BANKED
		ldaa PPAGE;          //save page to statck
		psha;
		nop;
#endif
		ldx OSTCBCur;      //get the TCB's address
		sts 0,x; 
	}

	OSTaskSwHook(); //call Hook function
	OSTCBCur = OSTCBHighRdy;

	asm
	{
		ldx OSTCBCur;       //get the new task's TCB's address
		lds 0,x;

#ifdef BANKED
		pula;
		staa PPAGE;          //restore ppage stack
		nop;
#endif
		rti;
	}

}


#pragma NO_RETURN
void interrupt OSTickISR(void)
{
#ifdef BANKED
	asm
	{
		ldaa PPAGE;       //save ppage to stack
		psha;
	}
#endif

	OSIntEnter();
	OS_SAVE_SP();
	CRGFLG |= 0x80;   /* clear the rti interrupt flag */
	OSTimeTick();
	OSIntExit();     /* exit interrupt and task switch*/

	asm
	{
#ifdef BANKED
		pula;
		staa PPAGE;      /* restore ppage from stack */
		nop;
#endif
		rti;
	}
}