Source/portable/CCS4/MSP430X/portext.asm

;
;    FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
;
;    ***************************************************************************
;    *                                                                         *
;    * If you are:                                                             *
;    *                                                                         *
;    *    + New to FreeRTOS,                                                   *
;    *    + Wanting to learn FreeRTOS or multitasking in general quickly       *
;    *    + Looking for basic training,                                        *
;    *    + Wanting to improve your FreeRTOS skills and productivity           *
;    *                                                                         *
;    * then take a look at the FreeRTOS books - available as PDF or paperback  *
;    *                                                                         *
;    *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
;    *                  http://www.FreeRTOS.org/Documentation                  *
;    *                                                                         *
;    * A pdf reference manual is also available.  Both are usually delivered   *
;    * to your inbox within 20 minutes to two hours when purchased between 8am *
;    * and 8pm GMT (although please allow up to 24 hours in case of            *
;    * exceptional circumstances).  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 exception 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!
;
;    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.

; * The definition of the "register test" tasks, as described at the top of
; * main.c

	.include data_model.h

	.global vTaskIncrementTick
	.global vTaskSwitchContext
	.global vPortSetupTimerInterrupt
	.global pxCurrentTCB
	.global usCriticalNesting

	.def vPortPreemptiveTickISR
	.def vPortCooperativeTickISR
	.def vPortYield
	.def 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
	ret_x
	.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.
;*/
	
	.text
	.align 2
	
vPortPreemptiveTickISR: .asmfunc
	
	; 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
				
	call_x	#vTaskIncrementTick
	call_x	#vTaskSwitchContext
		
	portRESTORE_CONTEXT
	.endasmfunc
;-----------------------------------------------------------

	.align 2
	
vPortCooperativeTickISR: .asmfunc
	
	; 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
				
	call_x	#vTaskIncrementTick
		
	portRESTORE_CONTEXT
	
	.endasmfunc
;-----------------------------------------------------------

;
; Manual context switch called by the portYIELD() macro.
;

	.align 2

vPortYield: .asmfunc

	; 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.
	call_x	#vTaskSwitchContext		

	; Restore the context of the new task.
	portRESTORE_CONTEXT
	.endasmfunc
;-----------------------------------------------------------


;
; Start off the scheduler by initialising the RTOS tick timer, then restoring
; the context of the first task.
;

	.align 2
	
xPortStartScheduler: .asmfunc

	; Setup the hardware to generate the tick.  Interrupts are disabled
	; when this function is called.
	call_x	#vPortSetupTimerInterrupt

	; Restore the context of the first task that is going to run.
	portRESTORE_CONTEXT
	.endasmfunc
;-----------------------------------------------------------
      		
	.end