/*
*********************************************************************************************************
*                                               uC/OS-II
*                                         The Real-Time Kernel
*
*                        (c) Copyright 1992-1998, Jean J. Labrosse, Plantation, FL
*                                          All Rights Reserved
*                        (c) Copyright ARM Limited 1999.  All rights reserved.
*
*                                          ARM Specific code
*
*
* File : OS_CPU_C.C
*********************************************************************************************************
*/

#define  OS_CPU_GLOBALS
#include "ucos_ii.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
*                            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.
*
* Note(s)    : Interrupts are enabled when your task starts executing. You can change this by setting the
*              PSW to 0x0002 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!
*********************************************************************************************************
*/

#if 0
void OSStartHighRdy (void)
{
	OS_STK*	pstk;	//R4
	int	temp=0;		//R5
	OSTaskSwHook();
	pstk=OSTCBHighRdy->OSTCBStkPtr;
	asm("MOV	R5,SP");
	asm("LDMIA	SP!{R4}");
	asm("MOV	SP,R4");
 
    OSRunning = TRUE;
 
    //Restore all processor registers from the  task's stack;     
 
    //Execute a return from interrupt instruction;                           
 
}
 
void OSCtxSw(void)
 
{
 
    保存處理器寄存器;
 
    將當前任務的堆棧指針保存到當前任務的OS_TCB中:
 
        OSTCBCur->OSTCBStkPtr = Stack pointer;
 
    調用用戶定義的OSTaskSwHook();
 
    OSTCBCur  = OSTCBHighRdy;
 
    OSPrioCur = OSPrioHighRdy;
 
    得到需要恢復的任務的堆棧指針:
 
        Stack pointer = OSTCBHighRdy->OSTCBStkPtr;
 
    將所有處理器寄存器從新任務的堆棧中恢復出來;
 
    執行中斷返回指令;
 
}
 


void OSIntCtxSw(void)
 
{ 
	OSIntExit();

	OSIntCtxSw()過程中壓入堆棧的多余內容;

	將當前任務堆棧指針保存到當前任務的OS_TCB中:

	OSTCBCur->OSTCBStkPtr = 堆棧指針;

	調用用戶定義的OSTaskSwHook();

	OSTCBCur  = OSTCBHighRdy;

	OSPrioCur = OSPrioHighRdy;

	得到需要恢復的任務的堆棧指針:

	堆棧指針 = OSTCBHighRdy->OSTCBStkPtr;

	將所有處理器寄存器從新任務的堆棧中恢復出來;

	執行中斷返回指令;
 
}
 
void OSTickISR(void)
 
{
 
   保存處理器寄存器;
 
   調用OSIntEnter()或者直接將 OSIntNesting加1;
 
 
 
   調用OSTimeTick();
 
 
 
   調用OSIntExit();
 
   恢復處理器寄存器;
 
   執行中斷返回指令;
 
}
#endif

OS_STK       *OSTaskStkInit(void (*task)(void *p_arg), void *p_arg, OS_STK *ptos, INT16U opt)
//void *OSTaskStkInit (void (*task)(void *pd), void *pdata, void *ptos, INT16U opt)
{
	//unsigned int *stk;
	OS_STK* stk;

	opt    = opt;                           /* 'opt' is not used, prevent warning                      */
	stk    = (unsigned int *)ptos;          /* Load stack pointer                                      */

	/* build a context for the new task */
	//*--stk = (unsigned int) task;       /* pc */
	*stk = (unsigned int) task;       /* pc */	//the ptos is the empty stack 
	*--stk = (unsigned int) task;       /* lr */

	*--stk = 0;                         /* r12 */
	*--stk = 0;                         /* r11 */
	*--stk = 0;                         /* r10 */
	*--stk = 0;                         /* r9 */
	*--stk = 0;                         /* r8 */
	*--stk = 0;                         /* r7 */
	*--stk = 0;                         /* r6 */
	*--stk = 0;                         /* r5 */
	*--stk = 0;                         /* r4 */
	*--stk = 0;                         /* r3 */
	*--stk = 0;                         /* r2 */
	*--stk = 0;                         /* r1 */
	*--stk = (unsigned int) p_arg;      /* r0 */
	//*--stk = (SYS32MODE|0x0);			/* cpsr  IRQ, FIQ disable*/
	*--stk = (SYS32MODE|0x0);			/* spsr  IRQ, FIQ disable */


	return ((OS_STK*)stk);
}

/*$PAGE*/
#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)
{
}

#if OS_VERSION >= 204
void OSInitHookBegin(void)
{
	
}

void OSInitHookEnd(void)
{
	
}
#endif

#if OS_VERSION >= 204
void OSTCBInitHook(OS_TCB *ptcb)
{
	
}
#endif

#if OS_VERSION >= 251
void OSTaskIdleHook(void)
{
	
}
#endif

#endif	//HOOK EN

#if 0
#define BUILD_DATE "Date: " __DATE__ "\n"

/*
 * Initialize an ARM Target board
 */
void
 ARMTargetInit(void)
{
    /* ---- Tell the world who we are ---------------------------------- */
    uHALr_printf("uCOS-II Running on a") ;
#if defined(EBSA285)
    uHALr_printf("n EBSA-285 (21285 evaluation board)\n") ;
#elif defined(BRUTUS) 
    uHALr_printf(" Brutus (SA-1100 verification platform)\n") ;
#elif defined(INTEGRATOR) 
    uHALr_printf("n Integrator board\n") ;
#elif defined(PROSPECTOR) 
    uHALr_printf(" Prospector board\n") ;
#elif defined(SAMSUNG)
	uHALr_printf(" SAMSUNG board\n");
#else
    uHALr_printf("n unknown ARM board\n") ;
#endif
    uHALr_printf(uHAL_VERSION_STRING); 
    uHALr_printf("\n") ;
    uHALr_printf(BUILD_DATE);
    uHALr_printf("\n") ;

#ifdef DEBUG
    uHALr_printf("Initialising target\n");
#endif

    /* ---- disable the MMU        ------------------------------------- */
    uHALr_ResetMMU();

    /* ---- disable interrupts (IRQs) --------------------------------- */
    ARMDisableInt();

    /* ---- soft vectors ---------------------------------------------- */
#ifdef DEBUG
    uHALr_printf("Setting up soft vectors\n");
#endif
    /* Define pre & post-process routines for Interrupt */
    uHALir_DefineIRQ((void *)IrqStart, (void *)IrqFinish, (void *) 0);
    uHALr_InitInterrupts();

#ifdef DEBUG
    uHALr_printf("Timer init\n");
#endif
    uHALr_InitTimers();

#ifdef DEBUG
    uHALr_printf("targetInit() complete\n");
#endif
}                               /* targetInit */

/* start the ARM target running */
void
 ARMTargetStart(void)
{
#ifdef DEBUG
    uHALr_printf("Starting target\n") ;
#endif

    /* request the system timer */
    if (uHALr_RequestSystemTimer(
                                 (void *) OSTimeTick,
                                 (const unsigned char *)"uCOS-II") <= 0)
        uHALr_printf("Timer/IRQ busy\n");

    /* Start system timer & enable the interrupt. */
    uHALr_InstallSystemTimer();
}

extern void IRQContextSwap(void);   /* post DispatchIRQ processing (the _real_ one) */

/* just 'notice' that we need to change context */
int need_to_swap_context = 0 ;
void OSIntCtxSw(void) {
    need_to_swap_context = 1;
}

/* This is what uCOS does at the start of an IRQ */
void IrqStart(void)
{
    /* increment nesting counter */
    OSIntNesting++;
}

/* This is what uCOS does at the end of an IRQ */
void *IrqFinish(void)
{
    OSIntExit() ;
    if (need_to_swap_context) {
//        need_to_swap_context = 0 ;
        return ((void *)IRQContextSwap) ;
    } else {
        return (void *)0;
    }
}
#endif