/*
    FreeRTOS V7.4.1 - Copyright (C) 2013 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 Real Time Engineers Ltd., 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, 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, and our new
    fully thread aware and reentrant UDP/IP stack.

    http://www.OpenRTOS.com - 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.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.
*/
	.extern pxCurrentTCB
	.extern vTaskISRHandler
	.extern vTaskSwitchContext
	.extern uxCriticalNesting
	.extern pulISRStack

	.global __FreeRTOS_interrupt_handler
	.global VPortYieldASM
	.global vStartFirstTask


.macro portSAVE_CONTEXT
	/* Make room for the context on the stack. */
	addik r1, r1, -132
	/* Save r31 so it can then be used. */
	swi r31, r1, 4
	/* Copy the msr into r31 - this is stacked later. */
	mfs r31, rmsr
	/* Stack general registers. */
	swi r30, r1, 12
	swi r29, r1, 16
	swi r28, r1, 20
	swi r27, r1, 24
	swi r26, r1, 28
	swi r25, r1, 32
	swi r24, r1, 36
	swi r23, r1, 40
	swi r22, r1, 44
	swi r21, r1, 48
	swi r20, r1, 52
	swi r19, r1, 56
	swi r18, r1, 60
	swi r17, r1, 64
	swi r16, r1, 68
	swi r15, r1, 72
	swi r13, r1, 80
	swi r12, r1, 84
	swi r11, r1, 88
	swi r10, r1, 92
	swi r9, r1, 96
	swi r8, r1, 100
	swi r7, r1, 104
	swi r6, r1, 108
	swi r5, r1, 112
	swi r4, r1, 116
	swi r3, r1, 120
	swi r2, r1, 124
	/* Stack the critical section nesting value. */
	lwi r3, r0, uxCriticalNesting
	swi r3, r1, 128
	/* Save the top of stack value to the TCB. */
	lwi r3, r0, pxCurrentTCB
	sw	r1, r0, r3
	
	.endm

.macro portRESTORE_CONTEXT
	/* Load the top of stack value from the TCB. */
	lwi r3, r0, pxCurrentTCB
	lw	r1, r0, r3	
	/* Restore the general registers. */
	lwi r31, r1, 4		
	lwi r30, r1, 12		
	lwi r29, r1, 16	
	lwi r28, r1, 20	
	lwi r27, r1, 24	
	lwi r26, r1, 28	
	lwi r25, r1, 32	
	lwi r24, r1, 36	
	lwi r23, r1, 40	
	lwi r22, r1, 44	
	lwi r21, r1, 48	
	lwi r20, r1, 52	
	lwi r19, r1, 56	
	lwi r18, r1, 60	
	lwi r17, r1, 64	
	lwi r16, r1, 68	
	lwi r15, r1, 72	
	lwi r14, r1, 76	
	lwi r13, r1, 80	
	lwi r12, r1, 84	
	lwi r11, r1, 88	
	lwi r10, r1, 92	
	lwi r9, r1, 96	
	lwi r8, r1, 100	
	lwi r7, r1, 104
	lwi r6, r1, 108
	lwi r5, r1, 112
	lwi r4, r1, 116
	lwi r2, r1, 124

	/* Load the critical nesting value. */
	lwi r3, r1, 128
	swi r3, r0, uxCriticalNesting

	/* Obtain the MSR value from the stack. */
	lwi r3, r1, 8

	/* Are interrupts enabled in the MSR?  If so return using an return from 
	interrupt instruction to ensure interrupts are enabled only once the task
	is running again. */
	andi r3, r3, 2
	beqid r3, 36
	or r0, r0, r0

	/* Reload the rmsr from the stack, clear the enable interrupt bit in the
	value before saving back to rmsr register, then return enabling interrupts
	as we return. */
	lwi r3, r1, 8
	andi r3, r3, ~2
	mts rmsr, r3
	lwi r3, r1, 120
	addik r1, r1, 132
	rtid r14, 0
	or r0, r0, r0

	/* Reload the rmsr from the stack, place it in the rmsr register, and
	return without enabling interrupts. */
	lwi r3, r1, 8
	mts rmsr, r3
	lwi r3, r1, 120
	addik r1, r1, 132
	rtsd r14, 0
	or r0, r0, r0

	.endm

	.text
	.align  2


__FreeRTOS_interrupt_handler:
	portSAVE_CONTEXT
	/* Entered via an interrupt so interrupts must be enabled in msr. */
	ori r31, r31, 2
	/* Stack msr. */
	swi r31, r1, 8
	/* Stack the return address.  As we entered via an interrupt we do
	not need to modify the return address prior to stacking. */
	swi r14, r1, 76
	/* Now switch to use the ISR stack. */
	lwi r3, r0, pulISRStack
	add r1, r3, r0
	bralid r15, vTaskISRHandler
	or r0, r0, r0
	portRESTORE_CONTEXT


VPortYieldASM:
	portSAVE_CONTEXT
	/* Stack msr. */
	swi r31, r1, 8
	/* Modify the return address so we return to the instruction after the
	exception. */
	addi r14, r14, 8
	swi r14, r1, 76
	/* Now switch to use the ISR stack. */
	lwi r3, r0, pulISRStack
	add r1, r3, r0
	bralid r15, vTaskSwitchContext
	or r0, r0, r0
	portRESTORE_CONTEXT

vStartFirstTask:
	portRESTORE_CONTEXT