os_cpu_c.c

embed in keil

/*********************************************************************************************************\
*                                               uC/OS-II                                                  *
*                                         The Real-Time Kernel                                            *
*                                                                                                         *
*                        (c) Copyright 1992-1999, Jean J. Labrosse, Weston, FL                            *
*                                          All Rights Reserved                                            *
*                                                                                                         *
*                                       Intel 80C52 Specific code                                         *
*                                          LARGE MEMORY MODEL                                             *
*                                                                                                         *
*                             (IAR Systems Embedded Workbench 2.2 Compiler)                               *
*                                                                                                         *
* File : OS_CPU_C.C                                                                                       *
* By   : Jean J. Labrosse                                                                                 *
*                                                                                                         *
* Ported to the IAR Systems compiler by: A. Fuentes ([e-mail])                         *
\*********************************************************************************************************/
#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                                                *
*                                                                                                         *
*              pfdata        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.                                              *
*                                                                                                         *
\*********************************************************************************************************/
pOS_STK OSTaskStkInit(void (*task)(void *), void *pfdata, pOS_STK ptos, INT16U opt)
{
/*<---[ Variables used in this function: ]-------------------------------------------------------------->*/

 pOS_STK     stk;                      /* Used to access the task' stack in xdata memory                 */

 INT8U      *data_ptr;                 /* Pointer variable to convert 'pfdata' to a 16-bit value         */
 INT8U code *task_ptr;                 /* Pointer variable to convert 'task' to a 16-bit value           */
 
 INT16U  xsp;                          /* 16-bit pointer to the base of the task'stack                   */
 INT16U  ptr;                          /* 16-bit pointer to the task parameter area passed at creation   */
 INT8U   tsk_h;                        /* Upper 8-bits of the task pointer                               */
 INT8U   tsk_l;                        /* Lower 8-bits of the task pointer                               */
  
/*<---[ End of variable declaration ]------------------------------------------------------------------->*/

 opt = opt;                                      /* 'opt' is not used, prevent warning                   */
 stk = ptos;                                     /* Load stack pointer                                   */
 xsp = (INT16U)(stk + 1);                        /* Store the base of 'xstack' for later use             */

 task_ptr = (INT8U code *)task;                  /* ... Convert 'task' pointer to 16-bit value           */ 
 tsk_l    = *task_ptr++;                         /* Get lower 8 bits of 'task'                           */
 tsk_h    = *task_ptr;                           /* Get upper 8 bits of 'task'                           */
*++stk    = tsk_h;                               /* Place upper 8 bits of 'task' on stack                */
*++stk    = tsk_l;                               /* Place lower 8 bits of 'task' on stack                */

*++stk = 0x00;                                   /* Make room to store the PSW                           */
*++stk = 0xAC;                                   /* Make room to store the ACC                           */
*++stk = 0x0B;                                   /* Make room to store the B register                    */
*++stk = 0x00;                                   /* Make room to store the R0 register                   */
*++stk = 0x01;                                   /* Make room to store the R1 register                   */
*++stk = 0x02;                                   /* Make room to store the R2 register                   */
*++stk = 0x03;                                   /* Make room to store the R3 register                   */
*++stk = 0x04;                                   /* Make room to store the R4 register                   */

 data_ptr = (INT8U *)pfdata;                     /* Point to task parameter data                         */
 ptr      = (INT16U)data_ptr;                    /* ... Convert 'pfdata' pointer to 16-bit value         */
*++stk = (INT8U)(ptr & 0x00FF);                  /* Place lower bits of 'pfdata' on stack (passed in R5) */
*++stk = (INT8U)((ptr >> 8) & 0x00FF);           /* Place upper bits of 'pfdata' on stack (passed in R6) */
*++stk = 0x01;                                   /* Place pointer type (always 01)        (passed in R7) */

*++stk = 0x00;                                   /* Make room to store DPH                               */
*++stk = 0x00;                                   /* Make room to store DPL                               */

*++stk = (INT8U)((xsp >> 8) & 0x00FF);           /* Place pointer high to base of 'xstack'               */
*++stk = (INT8U)(xsp & 0x00FF);                  /* Place pointer low to base of 'xstack'                */

*++stk = 0x11;                                   /* Place number of bytes stacked (17)                   */
 return((pOS_STK)stk);                           /* Return pointer to task's top-of-stack                */
}
/*********************************************************************************************************\
*                                         SYSTEM INITIALIZATION HOOK                                      *
*                                                                                                         *
* Description: This function kernel initialisation starts.                                                *
*                                                                                                         *
* Arguments  : void.                                                                                      *
*                                                                                                         *
* Note(s)    : 1) Interrupts are disabled during this call.                                               *
\*********************************************************************************************************/
void OSInitHookBegin(void)
{
/*<---[ Variables used in this function: ]-------------------------------------------------------------->*/

/*<---[ End of variable declaration ]------------------------------------------------------------------->*/
}
/*********************************************************************************************************\
*                                      INITIALIZATION COMPLETE HOOK                                       *
*                                                                                                         *
* Description: This function is called when kernel initialisation is completed.                           *
*                                                                                                         *
* Arguments  : void                                                                                       *
*                                                                                                         *
* Note(s)    : 1) Interrupts are disabled during this call.                                               *
\*********************************************************************************************************/
void OSInitHookEnd(void)
{