FreeRTOS-Kernel/Source/portable/IAR/MSP430X/portext.s43

/*
    FreeRTOS V7.0.2 - Copyright (C) 2011 Real Time Engineers Ltd.
	

    ***************************************************************************
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     *    for microcontrollers - completely free of charge!                  *
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    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.

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*/
#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
		
	/* The last thing on the stack will be the status register.
	Ensure the power down bits are clear ready for the next
	time this power down register is popped from the stack. */
	bic.w   #0xf0, 0( sp )
		
	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). */
	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