portext.asm

FreeRTOS - V5.1.1 Last Update: Nov 20 2008 http://sourceforge.net/projects/freertos/

/*
	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.
*/

#include "FreeRTOSConfig.h"
#include "portasm.h"


.CODE

/*
 * The RTOS tick ISR.
 *
 * If the cooperative scheduler is in use this simply increments the tick 
 * count.
 *
 * If the preemptive scheduler is in use a context switch can also occur.
 */
_vTickISR:
		portSAVE_CONTEXT
				
		call	#_vTaskIncrementTick

		#if configUSE_PREEMPTION == 1
			call	#_vTaskSwitchContext
		#endif
		
		portRESTORE_CONTEXT
/*-----------------------------------------------------------*/


/*
 * Manual context switch called by the portYIELD() macro.
 */                
_vPortYield::

		/* Mimic an interrupt by pushing the SR. */
		push	SR			

		/* Now the SR is stacked we can disable interrupts. */
		dint			
				
		/* Save the context of the current task. */
		portSAVE_CONTEXT			

		/* Switch to the highest priority task that is ready to run. */
		call	#_vTaskSwitchContext		

		/* Restore the context of the new task. */
		portRESTORE_CONTEXT
/*-----------------------------------------------------------*/


/*
 * Start off the scheduler by initialising the RTOS tick timer, then restoring
 * the context of the first task.
 */
_xPortStartScheduler::

		/* Setup the hardware to generate the tick.  Interrupts are disabled 
		when this function is called. */
		call	#_prvSetupTimerInterrupt

		/* Restore the context of the first task that is going to run. */
		portRESTORE_CONTEXT
/*-----------------------------------------------------------*/          
      		

		/* Place the tick ISR in the correct vector. */
		.VECTORS
		
		.KEEP
		
		ORG		TIMERA0_VECTOR
		DW		_vTickISR
		


		END