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/*
FreeRTOS.org V5.1.1 - Copyright (C) 2003-2008 Richard Barry.
This file is part of the FreeRTOS.org distribution.
FreeRTOS.org is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FreeRTOS.org is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with FreeRTOS.org; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
A special exception to the GPL can be applied should you wish to distribute
a combined work that includes FreeRTOS.org, without being obliged to provide
the source code for any proprietary components. See the licensing section
of http://www.FreeRTOS.org for full details of how and when the exception
can be applied.
***************************************************************************
***************************************************************************
* *
* SAVE TIME AND MONEY! We can port FreeRTOS.org to your own hardware, *
* and even write all or part of your application on your behalf. *
* See http://www.OpenRTOS.com for details of the services we provide to *
* expedite your project. *
* *
***************************************************************************
***************************************************************************
Please ensure to read the configuration and relevant port sections of the
online documentation.
http://www.FreeRTOS.org - Documentation, latest information, license and
contact details.
http://www.SafeRTOS.com - A version that is certified for use in safety
critical systems.
http://www.OpenRTOS.com - Commercial support, development, porting,
licensing and training services.
*/
/*
Changes from V1.00:
+ pxPortInitialiseStack() now initialises the stack of new tasks to the
same format used by the compiler. This allows the compiler generated
interrupt mechanism to be used for context switches.
Changes from V2.6.1
+ Move usPortCheckFreeStackSpace() to tasks.c.
*/
#include <dos.h>
#include <stdlib.h>
#include "FreeRTOS.h"
/*-----------------------------------------------------------*/
/* See header file for description. */
portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
{
portSTACK_TYPE DS_Reg = 0;
/* Place a few bytes of known values on the bottom of the stack.
This is just useful for debugging. */
*pxTopOfStack = 0x1111;
pxTopOfStack--;
*pxTopOfStack = 0x2222;
pxTopOfStack--;
*pxTopOfStack = 0x3333;
pxTopOfStack--;
*pxTopOfStack = 0x4444;
pxTopOfStack--;
*pxTopOfStack = 0x5555;
pxTopOfStack--;
/*lint -e950 -e611 -e923 Lint doesn't like this much - but nothing I can do about it. */
/* We are going to start the scheduler using a return from interrupt
instruction to load the program counter, so first there would be the
function call with parameters preamble. */
*pxTopOfStack = FP_SEG( pvParameters );
pxTopOfStack--;
*pxTopOfStack = FP_OFF( pvParameters );
pxTopOfStack--;
*pxTopOfStack = FP_SEG( pxCode );
pxTopOfStack--;
*pxTopOfStack = FP_OFF( pxCode );
pxTopOfStack--;
/* Next the status register and interrupt return address. */
*pxTopOfStack = portINITIAL_SW;
pxTopOfStack--;
*pxTopOfStack = FP_SEG( pxCode );
pxTopOfStack--;
*pxTopOfStack = FP_OFF( pxCode );
pxTopOfStack--;
/* The remaining registers would be pushed on the stack by our context
switch function. These are loaded with values simply to make debugging
easier. */
*pxTopOfStack = ( portSTACK_TYPE ) 0xAAAA; /* AX */
pxTopOfStack--;
*pxTopOfStack = ( portSTACK_TYPE ) 0xBBBB; /* BX */
pxTopOfStack--;
*pxTopOfStack = ( portSTACK_TYPE ) 0xCCCC; /* CX */
pxTopOfStack--;
*pxTopOfStack = ( portSTACK_TYPE ) 0xDDDD; /* DX */
pxTopOfStack--;
*pxTopOfStack = ( portSTACK_TYPE ) 0xEEEE; /* ES */
pxTopOfStack--;
/* We need the true data segment. */
__asm{ MOV DS_Reg, DS };
*pxTopOfStack = DS_Reg; /* DS */
pxTopOfStack--;
*pxTopOfStack = ( portSTACK_TYPE ) 0x0123; /* SI */
pxTopOfStack--;
*pxTopOfStack = ( portSTACK_TYPE ) 0xDDDD; /* DI */
pxTopOfStack--;
*pxTopOfStack = ( portSTACK_TYPE ) 0xBBBB; /* BP */
/*lint +e950 +e611 +e923 */
return pxTopOfStack;
}
/*-----------------------------------------------------------*/
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