/*
    FreeRTOS V7.3.0 - Copyright (C) 2012 Real Time Engineers Ltd.

    FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME.  PLEASE VISIT 
    http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

    ***************************************************************************
     *                                                                       *
     *    FreeRTOS tutorial books are available in pdf and paperback.        *
     *    Complete, revised, and edited pdf reference manuals are also       *
     *    available.                                                         *
     *                                                                       *
     *    Purchasing FreeRTOS documentation will not only help you, by       *
     *    ensuring you get running as quickly as possible and with an        *
     *    in-depth knowledge of how to use FreeRTOS, it will also help       *
     *    the FreeRTOS project to continue with its mission of providing     *
     *    professional grade, cross platform, de facto standard solutions    *
     *    for microcontrollers - completely free of charge!                  *
     *                                                                       *
     *    >>> See http://www.FreeRTOS.org/Documentation for details. <<<     *
     *                                                                       *
     *    Thank you for using FreeRTOS, and thank you for your support!      *
     *                                                                       *
    ***************************************************************************


    This file is part of the FreeRTOS distribution.

    FreeRTOS 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.
    >>>NOTE<<< The modification to the GPL is included to allow you to
    distribute a combined work that includes FreeRTOS without being obliged to
    provide the source code for proprietary components outside of the FreeRTOS
    kernel.  FreeRTOS 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 and the FreeRTOS license exception along with FreeRTOS; if not it
    can be viewed here: http://www.freertos.org/a00114.html and also obtained
    by writing to Richard Barry, contact details for whom are available on the
    FreeRTOS WEB site.

    1 tab == 4 spaces!
    
    ***************************************************************************
     *                                                                       *
     *    Having a problem?  Start by reading the FAQ "My application does   *
     *    not run, what could be wrong?"                                     *
     *                                                                       *
     *    http://www.FreeRTOS.org/FAQHelp.html                               *
     *                                                                       *
    ***************************************************************************

    
    http://www.FreeRTOS.org - Documentation, training, latest versions, license 
    and contact details.  
    
    http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
    including FreeRTOS+Trace - an indispensable productivity tool.

    Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell 
    the code with commercial support, indemnification, and middleware, under 
    the OpenRTOS brand: http://www.OpenRTOS.com.  High Integrity Systems also
    provide a safety engineered and independently SIL3 certified version under 
    the SafeRTOS brand: http://www.SafeRTOS.com.
*/
#include "msp430.h"
#include "FreeRTOSConfig.h"
#include "data_model.h"

	IMPORT vTaskIncrementTick
	IMPORT vTaskSwitchContext
	IMPORT vPortSetupTimerInterrupt
	IMPORT pxCurrentTCB
	IMPORT usCriticalNesting

	EXPORT vPortTickISR
	EXPORT vPortYield
	EXPORT xPortStartScheduler

portSAVE_CONTEXT macro

	/* Save the remaining registers. */
	pushm_x	#12, r15
	mov.w	&usCriticalNesting, r14
	push_x r14
	mov_x	&pxCurrentTCB, r12
	mov_x	sp, 0( r12 )
	endm
/*-----------------------------------------------------------*/
		
portRESTORE_CONTEXT macro

	mov_x	&pxCurrentTCB, r12
	mov_x	@r12, sp
	pop_x	r15
	mov.w	r15, &usCriticalNesting
	popm_x	#12, r15
	pop.w	sr
	reta
	endm
/*-----------------------------------------------------------*/


/*
 * 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.
 */

	RSEG CODE
	EVEN

vPortTickISR:

	/* The sr is not saved in portSAVE_CONTEXT() because vPortYield() needs
	to save it manually before it gets modified (interrupts get disabled).
	Entering through this interrupt means the SR is already on the stack, but
	this keeps the stack frames identical. */
	push.w sr
	portSAVE_CONTEXT

	calla	#vTaskIncrementTick

	#if configUSE_PREEMPTION == 1
		calla	#vTaskSwitchContext
	#endif

	portRESTORE_CONTEXT
/*-----------------------------------------------------------*/

/*
 * Manual context switch called by the portYIELD() macro.
 */
 	EVEN

vPortYield:

	/* The sr needs saving before it is modified. */
	push.w	sr

	/* Now the SR is stacked we can disable interrupts. */
	dint
	nop

	/* Save the context of the current task. */
	portSAVE_CONTEXT

	/* Select the next task to run. */
	calla	#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.
 */
 	EVEN

xPortStartScheduler:

	/* Setup the hardware to generate the tick.  Interrupts are disabled
	when this function is called. */
	calla	#vPortSetupTimerInterrupt

	/* Restore the context of the first task that is going to run. */
	portRESTORE_CONTEXT
/*-----------------------------------------------------------*/

	END