os_cpu_c.c

KeilC下philips932MCU的ucos2源代码

/*
*********************************************************************************************************
*                                               uC/OS-II
*                                         The Real-Time Kernel
*
*                        (c) Copyright 1992-1998, Jean J. Labrosse, Plantation, FL
*                                          All Rights Reserved
*
*
*                                       80x86/80x88 Specific code
*                                          LARGE MEMORY MODEL
*
* File : OS_CPU_C.C
* By   : Jean J. Labrosse
*********************************************************************************************************
*/

#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
*                            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!
*********************************************************************************************************
*/

void *OSTaskStkInit (void (*task)(void *pd), void *vpdata, void *ptos, INT16U opt) reentrant
{
    OS_STK *stk;
   

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

    /*任务入口地址设置，低字节在前*/
	*stk++ = 15;							/*设置任务堆栈已使用的字节数，不算此计数字节及模拟栈指针*/
	*stk++ = (INT8U)((INT16U)task&0x00ff);           
	*stk++ = (INT8U)((INT16U)task>>8);

    *stk++ = 00;	/* PSW ，使用Keil C51的大模式*/         
    *stk++ = 00;    /* ACC */      
    *stk++ = 00;    /* B   */      
    *stk++ = 00;    /* DPL */ 
	*stk++ = 00;    /* DPH */      
    *stk++ = 00;    /* R0  */ 
	*stk++ = 00;    /* R1  */      
    *stk++ = 00;    /* R2  */ 
	*stk++ = 00;    /* R3  */      
    *stk++ = 00;    /* R4  */ 
	*stk++ = 00;    /* R5  */      
    *stk++ = 00;    /* R6  */ 
	*stk++ = 00;    /* R7  */ 
    
	/*使用任务堆栈的末地址作为本任务系统模拟堆，模拟堆是向下增长的*/ 
    *stk++ = (INT8U)((INT16U)vpdata>>8);          /*C_XBP，模拟栈高8位地址*/
	*stk   = (INT8U)((INT16U)vpdata&0x00ff);      /*C_XBP+1，模拟栈低8位地址*/         
    return (ptos);						          /*返回任务堆栈指针起始地址，以使任务切换时能够找到它*/
}


/*$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) reentrant
{
    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) reentrant
{
    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) reentrant
{
}

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

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