/*
    FreeRTOS V7.6.0 - Copyright (C) 2013 Real Time Engineers Ltd. 
    All rights reserved

    VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

    ***************************************************************************
     *                                                                       *
     *    FreeRTOS provides completely free yet professionally developed,    *
     *    robust, strictly quality controlled, supported, and cross          *
     *    platform software that has become a de facto standard.             *
     *                                                                       *
     *    Help yourself get started quickly and support the FreeRTOS         *
     *    project by purchasing a FreeRTOS tutorial book, reference          *
     *    manual, or both from: http://www.FreeRTOS.org/Documentation        *
     *                                                                       *
     *    Thank you!                                                         *
     *                                                                       *
    ***************************************************************************

    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.  Full license text is available from the following
    link: http://www.freertos.org/a00114.html

    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, books, training, latest versions,
    license and Real Time Engineers Ltd. contact details.

    http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
    including FreeRTOS+Trace - an indispensable productivity tool, a DOS
    compatible FAT file system, and our tiny thread aware UDP/IP stack.

    http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
    Integrity Systems to sell under the OpenRTOS brand.  Low cost OpenRTOS
    licenses offer ticketed support, indemnification and middleware.

    http://www.SafeRTOS.com - High Integrity Systems also provide a safety
    engineered and independently SIL3 certified version for use in safety and
    mission critical applications that require provable dependability.

    1 tab == 4 spaces!
*/
#include "msp430.h"
#include "FreeRTOSConfig.h"
#include "data_model.h"

	IMPORT xTaskIncrementTick
	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	#xTaskIncrementTick
	cmp.w   #0x0, R12
    jeq     SkipContextSwitch
    calla   #vTaskSwitchContext
SkipContextSwitch:
	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