portasm.s79

FreeRTOS is a portable, open source, mini Real Time Kernel - a free to download and royalty free RTO

;/*
;	FreeRTOS.org V5.2.0 - Copyright (C) 2003-2009 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 (version 2) as published
;	by the Free Software Foundation and modified by the FreeRTOS exception.
;
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;	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.
;
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;	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.
;
;
;	***************************************************************************
;	*                                                                         *
;	* Get the FreeRTOS eBook!  See http://www.FreeRTOS.org/Documentation      *
;	*                                                                         *
;	* This is a concise, step by step, 'hands on' guide that describes both   *
;	* general multitasking concepts and FreeRTOS specifics. It presents and   *
;	* explains numerous examples that are written using the FreeRTOS API.     *
;	* Full source code for all the examples is provided in an accompanying    *
;	* .zip file.                                                              *
;	*                                                                         *
;	***************************************************************************
;
;	1 tab == 4 spaces!
;
;	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.
;*/

	RSEG ICODE:CODE
	CODE32

	EXTERN vPortPreemptiveTick
	EXTERN vTaskSwitchContext

	PUBLIC vPortYieldProcessor
	PUBLIC vPortStartFirstTask

#include "ISR_Support.h"

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Starting the first task is just a matter of restoring the context that
; was created by pxPortInitialiseStack().
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
vPortStartFirstTask:
	portRESTORE_CONTEXT

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Manual context switch function.  This is the SWI hander.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
vPortYieldProcessor:
	ADD		LR, LR, #4			; Add 4 to the LR to make the LR appear exactly
								; as if the context was saved during and IRQ
								; handler.
								
	portSAVE_CONTEXT			; Save the context of the current task...
	LDR R0, =vTaskSwitchContext	; before selecting the next task to execute.
	mov     lr, pc
	BX R0
	portRESTORE_CONTEXT			; Restore the context of the selected task.



	END