/*
    FreeRTOS V7.5.0 - Copyright (C) 2013 Real Time Engineers Ltd.

    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!
*/

/* Scheduler includes. */
#include "FreeRTOS.h"
#include "task.h"

/*-----------------------------------------------------------
 * Implementation of functions defined in portable.h for the MSP430X port.
 *----------------------------------------------------------*/

/* Constants required for hardware setup.  The tick ISR runs off the ACLK,
not the MCLK. */
#define portACLK_FREQUENCY_HZ			( ( portTickType ) 32768 )
#define portINITIAL_CRITICAL_NESTING	( ( unsigned short ) 10 )
#define portFLAGS_INT_ENABLED			( ( portSTACK_TYPE ) 0x08 )

/* We require the address of the pxCurrentTCB variable, but don't want to know
any details of its type. */
typedef void tskTCB;
extern volatile tskTCB * volatile pxCurrentTCB;

/* Each task maintains a count of the critical section nesting depth.  Each
time a critical section is entered the count is incremented.  Each time a
critical section is exited the count is decremented - with interrupts only
being re-enabled if the count is zero.

usCriticalNesting will get set to zero when the scheduler starts, but must
not be initialised to zero as this will cause problems during the startup
sequence. */
volatile unsigned short usCriticalNesting = portINITIAL_CRITICAL_NESTING;
/*-----------------------------------------------------------*/


/*
 * Sets up the periodic ISR used for the RTOS tick.  This uses timer 0, but
 * could have alternatively used the watchdog timer or timer 1.
 */
void vPortSetupTimerInterrupt( void );
/*-----------------------------------------------------------*/

/*
 * Initialise the stack of a task to look exactly as if a call to
 * portSAVE_CONTEXT had been called.
 *
 * See the header file portable.h.
 */
portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
{
unsigned short *pusTopOfStack;
unsigned long *pulTopOfStack, ulTemp;

	/*
		Place a few bytes of known values on the bottom of the stack.
		This is just useful for debugging and can be included if required.

		*pxTopOfStack = ( portSTACK_TYPE ) 0x1111;
		pxTopOfStack--;
		*pxTopOfStack = ( portSTACK_TYPE ) 0x2222;
		pxTopOfStack--;
		*pxTopOfStack = ( portSTACK_TYPE ) 0x3333;
		pxTopOfStack--;
	*/

	/* Data types are need either 16 bits or 32 bits depending on the data 
	and code model used. */
	if( sizeof( pxCode ) == sizeof( unsigned short ) )
	{
		pusTopOfStack = ( unsigned short * ) pxTopOfStack;
		ulTemp = ( unsigned long ) pxCode;
		*pusTopOfStack = ( unsigned short ) ulTemp;
	}
	else
	{
		/* Make room for a 20 bit value stored as a 32 bit value. */
		pusTopOfStack = ( unsigned short * ) pxTopOfStack;		
		pusTopOfStack--;
		pulTopOfStack = ( unsigned long * ) pusTopOfStack;
		*pulTopOfStack = ( unsigned long ) pxCode;
	}

	pusTopOfStack--;
	*pusTopOfStack = portFLAGS_INT_ENABLED;
	pusTopOfStack -= ( sizeof( portSTACK_TYPE ) / 2 );
	
	/* From here on the size of stacked items depends on the memory model. */
	pxTopOfStack = ( portSTACK_TYPE * ) pusTopOfStack;

	/* Next the general purpose registers. */
	#ifdef PRELOAD_REGISTER_VALUES
		*pxTopOfStack = ( portSTACK_TYPE ) 0xffff;
		pxTopOfStack--;
		*pxTopOfStack = ( portSTACK_TYPE ) 0xeeee;
		pxTopOfStack--;
		*pxTopOfStack = ( portSTACK_TYPE ) 0xdddd;
		pxTopOfStack--;
		*pxTopOfStack = ( portSTACK_TYPE ) pvParameters;
		pxTopOfStack--;
		*pxTopOfStack = ( portSTACK_TYPE ) 0xbbbb;
		pxTopOfStack--;
		*pxTopOfStack = ( portSTACK_TYPE ) 0xaaaa;
		pxTopOfStack--;
		*pxTopOfStack = ( portSTACK_TYPE ) 0x9999;
		pxTopOfStack--;
		*pxTopOfStack = ( portSTACK_TYPE ) 0x8888;
		pxTopOfStack--;	
		*pxTopOfStack = ( portSTACK_TYPE ) 0x5555;
		pxTopOfStack--;
		*pxTopOfStack = ( portSTACK_TYPE ) 0x6666;
		pxTopOfStack--;
		*pxTopOfStack = ( portSTACK_TYPE ) 0x5555;
		pxTopOfStack--;
		*pxTopOfStack = ( portSTACK_TYPE ) 0x4444;
		pxTopOfStack--;
	#else
		pxTopOfStack -= 3;
		*pxTopOfStack = ( portSTACK_TYPE ) pvParameters;
		pxTopOfStack -= 9;
	#endif

	/* A variable is used to keep track of the critical section nesting.
	This variable has to be stored as part of the task context and is
	initially set to zero. */
	*pxTopOfStack = ( portSTACK_TYPE ) portNO_CRITICAL_SECTION_NESTING;	

	/* Return a pointer to the top of the stack we have generated so this can
	be stored in the task control block for the task. */
	return pxTopOfStack;
}
/*-----------------------------------------------------------*/

void vPortEndScheduler( void )
{
	/* It is unlikely that the MSP430 port will get stopped.  If required simply
	disable the tick interrupt here. */
}
/*-----------------------------------------------------------*/

/*
 * Hardware initialisation to generate the RTOS tick.
 */
void vPortSetupTimerInterrupt( void )
{
	vApplicationSetupTimerInterrupt();
}
/*-----------------------------------------------------------*/

#pragma vector=configTICK_VECTOR
interrupt void vTickISREntry( void )
{
extern void vPortTickISR( void );

	__bic_SR_register_on_exit( SCG1 + SCG0 + OSCOFF + CPUOFF );
	#if configUSE_PREEMPTION == 1
		extern void vPortPreemptiveTickISR( void );
		vPortPreemptiveTickISR();
	#else
		extern void vPortCooperativeTickISR( void );
		vPortCooperativeTickISR();
	#endif
}