/*
    FreeRTOS V8.2.3 - Copyright (C) 2015 Real Time Engineers Ltd.
    All rights reserved

    VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

    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 on the following
    link: http://www.freertos.org/a00114.html

    ***************************************************************************
     *                                                                       *
     *    FreeRTOS provides completely free yet professionally developed,    *
     *    robust, strictly quality controlled, supported, and cross          *
     *    platform software that is more than just the market leader, it     *
     *    is the industry's de facto standard.                               *
     *                                                                       *
     *    Help yourself get started quickly while simultaneously helping     *
     *    to support the FreeRTOS project by purchasing a FreeRTOS           *
     *    tutorial book, reference manual, or both:                          *
     *    http://www.FreeRTOS.org/Documentation                              *
     *                                                                       *
    ***************************************************************************

    http://www.FreeRTOS.org/FAQHelp.html - Having a problem?  Start by reading
    the FAQ page "My application does not run, what could be wrong?".  Have you
    defined configASSERT()?

    http://www.FreeRTOS.org/support - In return for receiving this top quality
    embedded software for free we request you assist our global community by
    participating in the support forum.

    http://www.FreeRTOS.org/training - Investing in training allows your team to
    be as productive as possible as early as possible.  Now you can receive
    FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
    Ltd, and the world's leading authority on the world's leading RTOS.

    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.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
    Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.

    http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
    Integrity Systems ltd. to sell under the OpenRTOS brand.  Low cost OpenRTOS
    licenses offer ticketed support, indemnification and commercial 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!
*/

/*-----------------------------------------------------------
 * Implementation of functions defined in portable.h for the SH2A port.
 *----------------------------------------------------------*/

/* Scheduler includes. */
#include "FreeRTOS.h"
#include "task.h"

/* Library includes. */
#include "string.h"

/*-----------------------------------------------------------*/

/* The SR assigned to a newly created task.  The only important thing in this
value is for all interrupts to be enabled. */
#define portINITIAL_SR				( 0UL )

/* Dimensions the array into which the floating point context is saved.  
Allocate enough space for FPR0 to FPR15, FPUL and FPSCR, each of which is 4
bytes big.  If this number is changed then the 72 in portasm.src also needs
changing. */
#define portFLOP_REGISTERS_TO_STORE	( 18 )
#define portFLOP_STORAGE_SIZE 		( portFLOP_REGISTERS_TO_STORE * 4 )

/*-----------------------------------------------------------*/

/*
 * The TRAPA handler used to force a context switch.
 */
void vPortYield( void );

/*
 * Function to start the first task executing - defined in portasm.src.
 */
extern void vPortStartFirstTask( void );

/*
 * Obtains the current GBR value - defined in portasm.src.
 */
extern uint32_t ulPortGetGBR( void );

/*-----------------------------------------------------------*/

/* 
 * See header file for description. 
 */
StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
{
	/* Mark the end of the stack - used for debugging only and can be removed. */
	*pxTopOfStack = 0x11111111UL;
	pxTopOfStack--;
	*pxTopOfStack = 0x22222222UL;
	pxTopOfStack--;
	*pxTopOfStack = 0x33333333UL;
	pxTopOfStack--;

	/* SR. */
	*pxTopOfStack = portINITIAL_SR; 
	pxTopOfStack--;
	
	/* PC. */
	*pxTopOfStack = ( uint32_t ) pxCode;
	pxTopOfStack--;
	
	/* PR. */
	*pxTopOfStack = 15;
	pxTopOfStack--;
	
	/* 14. */
	*pxTopOfStack = 14;
	pxTopOfStack--;

	/* R13. */
	*pxTopOfStack = 13;
	pxTopOfStack--;

	/* R12. */
	*pxTopOfStack = 12;
	pxTopOfStack--;

	/* R11. */
	*pxTopOfStack = 11;
	pxTopOfStack--;

	/* R10. */
	*pxTopOfStack = 10;
	pxTopOfStack--;

	/* R9. */
	*pxTopOfStack = 9;
	pxTopOfStack--;

	/* R8. */
	*pxTopOfStack = 8;
	pxTopOfStack--;

	/* R7. */
	*pxTopOfStack = 7;
	pxTopOfStack--;

	/* R6. */
	*pxTopOfStack = 6;
	pxTopOfStack--;

	/* R5. */
	*pxTopOfStack = 5;
	pxTopOfStack--;

	/* R4. */
	*pxTopOfStack = ( uint32_t ) pvParameters;
	pxTopOfStack--;

	/* R3. */
	*pxTopOfStack = 3;
	pxTopOfStack--;

	/* R2. */
	*pxTopOfStack = 2;
	pxTopOfStack--;

	/* R1. */
	*pxTopOfStack = 1;
	pxTopOfStack--;
	
	/* R0 */
	*pxTopOfStack = 0;
	pxTopOfStack--;
	
	/* MACL. */
	*pxTopOfStack = 16;
	pxTopOfStack--;
	
	/* MACH. */
	*pxTopOfStack = 17;
	pxTopOfStack--;
	
	/* GBR. */
	*pxTopOfStack = ulPortGetGBR();
	
	/* GBR = global base register.
	   VBR = vector base register.
	   TBR = jump table base register.
	   R15 is the stack pointer. */

	return pxTopOfStack;
}
/*-----------------------------------------------------------*/

BaseType_t xPortStartScheduler( void )
{
extern void vApplicationSetupTimerInterrupt( void );

	/* Call an application function to set up the timer that will generate the
	tick interrupt.  This way the application can decide which peripheral to 
	use.  A demo application is provided to show a suitable example. */
	vApplicationSetupTimerInterrupt();

	/* Start the first task.  This will only restore the standard registers and
	not the flop registers.  This does not really matter though because the only
	flop register that is initialised to a particular value is fpscr, and it is
	only initialised to the current value, which will still be the current value
	when the first task starts executing. */
	trapa( portSTART_SCHEDULER_TRAP_NO );

	/* Should not get here. */
	return pdFAIL;
}
/*-----------------------------------------------------------*/

void vPortEndScheduler( void )
{
	/* Not implemented as there is nothing to return to. */
}
/*-----------------------------------------------------------*/

void vPortYield( void )
{
int32_t lInterruptMask;

	/* Ensure the yield trap runs at the same priority as the other interrupts
	that can cause a context switch. */
	lInterruptMask = get_imask();

	/* taskYIELD() can only be called from a task, not an interrupt, so the
	current interrupt mask can only be 0 or portKERNEL_INTERRUPT_PRIORITY and
	the mask can be set without risk of accidentally lowering the mask value. */	
	set_imask( portKERNEL_INTERRUPT_PRIORITY );
	
	trapa( portYIELD_TRAP_NO );
	
	/* Restore the interrupt mask to whatever it was previously (when the
	function was entered). */
	set_imask( ( int ) lInterruptMask );
}
/*-----------------------------------------------------------*/

BaseType_t xPortUsesFloatingPoint( TaskHandle_t xTask )
{
uint32_t *pulFlopBuffer;
BaseType_t xReturn;
extern void * volatile pxCurrentTCB;

	/* This function tells the kernel that the task referenced by xTask is
	going to use the floating point registers and therefore requires the
	floating point registers saved as part of its context. */

	/* Passing NULL as xTask is used to indicate that the calling task is the
	subject task - so pxCurrentTCB is the task handle. */
	if( xTask == NULL )
	{
		xTask = ( TaskHandle_t ) pxCurrentTCB;
	}

	/* Allocate a buffer large enough to hold all the flop registers. */
	pulFlopBuffer = ( uint32_t * ) pvPortMalloc( portFLOP_STORAGE_SIZE );
	
	if( pulFlopBuffer != NULL )
	{
		/* Start with the registers in a benign state. */
		memset( ( void * ) pulFlopBuffer, 0x00, portFLOP_STORAGE_SIZE );
		
		/* The first thing to get saved in the buffer is the FPSCR value -
		initialise this to the current FPSCR value. */
		*pulFlopBuffer = get_fpscr();
		
		/* Use the task tag to point to the flop buffer.  Pass pointer to just 
		above the buffer because the flop save routine uses a pre-decrement. */
		vTaskSetApplicationTaskTag( xTask, ( void * ) ( pulFlopBuffer + portFLOP_REGISTERS_TO_STORE ) );		
		xReturn = pdPASS;
	}
	else
	{
		xReturn = pdFAIL;
	}
	
	return xReturn;
}
/*-----------------------------------------------------------*/