os_cpu_c.c

ucos-ii for gcc-elf-68k

/*
*********************************************************************************************************
*                                                uC/OS-II
*                                          The Real-Time Kernel
*
*                          (c) Copyright 1992-2003, Jean J. Labrosse, Weston, FL
*                                           All Rights Reserved
*                                      MC9S12DP256 Specific code
*                                       (MetroWerks C/C++ V4.2)
*
*
* File         : OS_CPU_C.C
* By   : Jean J. Labrosse
* Ported to MC9S12DP256 by Abderrahmane Assal
* Ported to GNU-M6811-GCC by Hansol Park
*********************************************************************************************************
*/

#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
*                            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)    : 1) XIRQ interrupts are disabled when your task starts executing. You can change this by 
*                 clearing BIT6 in the CCR.
*              2) The STOP instruction is disabled when your task starts executing.  You can change this
*                 by clearing BIT7 in the CCR.
*              3) The other interrupts (i.e. maskable interrupts) are enabled when your task starts
*                 executing.  You can change this by setting BIT4 in the CCR.
*              4) You can change pass the above options in the 'opt' argument.  You MUST only use the
*                 upper 8 bits of 'opt' because the lower bits are reserved by uC/OS-II.  If you make
*                 changes to the code below, you will need to ensure that it doesn't affect the behaviour
*                 of OSTaskIdle() and OSTaskStat().
*              5) Registers are initialized to make them easy to differentiate with a debugger.
*              6) Tasks do not have to be in NON-PAGED memory.That is why I added an extra byte in every task's 
*				  stack to save the PPAGE register that locate the memory page where the task is located. If a 
*                 context switch occurs, the proper page will be saved/restored by uC/OS-II.  This done automatically
*                 by the hardware provided that we add the option -CpPPAGE=0x30 as a compiler argument.  
*           
**********************************************************************************************************************
*/

void * near OSTaskStkInit (void (*task)(void *pd), void *pdata, OS_STK *ptos, INT16U opt)
{
    INT16U *wstk;
    INT8U  *bstk;
	INT8U regPage;						/* regPage is used to save the PAGE register                   */
    INT16U *OffsetAddress;
    opt     = opt;                     /* 'opt' is not used, prevent warning                           */
    wstk    = (INT16U *)ptos;          /* Load stack pointer                                           */
	// -1
    *--wstk = (INT16U)pdata;           /* Simulate call to function with argument                      */
	OffsetAddress = (INT16U*)&task;

	regPage = (INT8U)task;
	// -2
    *--wstk = (INT16U)*OffsetAddress;
	// -3
    *--wstk = (INT16U)*OffsetAddress;            /* Put pointer to task   on top of stack                        */
	// -4
    *--wstk = (INT16U)0x2222;          /* Y Register                                                   */
	// -5
    *--wstk = (INT16U)0x1111;          /* X Register                                                   */
	// -6
    *--wstk = (INT16U)0xBBAA;          /* D Register                                                   */
	// -7 					-> CCR Register
    bstk    = (INT8U *)wstk;           /* Convert WORD ptr to BYTE ptr to set CCR                      */
    *--bstk = 0x80;                    /* CCR Register (Disable STOP instruction)                      */

	#if defined( __BANKED__) || defined(__LARGE__)
    *--bstk = regPage;  			   /* Save the PPAGE register in case of banked memory model (see note 6)      */                   
    #endif                  
            return ((void *)bstk);             /* Return pointer to new top-of-stack                           */
}

/*$PAGE*/

/*
*********************************************************************************************************
*                                       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__("stop");
}
#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

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