/*
 * FreeRTOS Kernel <DEVELOPMENT BRANCH>
 * Copyright (C) 2021 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * https://www.FreeRTOS.org
 * https://github.com/FreeRTOS
 *
 * 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"

/* Hardware specifics. */
#include <machine.h>

/*-----------------------------------------------------------*/

/* Tasks should start with interrupts enabled and in Supervisor mode, therefore
PSW is set with U and I set, and PM and IPL clear. */
#define portINITIAL_PSW	 ( ( StackType_t ) 0x00030000 )
#define portINITIAL_FPSW	( ( StackType_t ) 0x00000100 )

/*-----------------------------------------------------------*/

/*
 * Function to start the first task executing - written in asm code as direct
 * access to registers is required.
 */
extern void prvStartFirstTask( void );

/*
 * The tick ISR handler.  The peripheral used is configured by the application
 * via a hook/callback function.
 */
__interrupt void vTickISR( void );

/*-----------------------------------------------------------*/

extern void *pxCurrentTCB;

/*-----------------------------------------------------------*/

/*
 * See header file for description.
 */
StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
{
	/* R0 is not included as it is the stack pointer. */

	*pxTopOfStack = 0x00;
	pxTopOfStack--;
 	*pxTopOfStack = portINITIAL_PSW;
	pxTopOfStack--;
	*pxTopOfStack = ( StackType_t ) pxCode;

	/* When debugging it can be useful if every register is set to a known
	value.  Otherwise code space can be saved by just setting the registers
	that need to be set. */
	#ifdef USE_FULL_REGISTER_INITIALISATION
	{
		pxTopOfStack--;
		*pxTopOfStack = 0xffffffff;	/* r15. */
		pxTopOfStack--;
		*pxTopOfStack = 0xeeeeeeee;
		pxTopOfStack--;
		*pxTopOfStack = 0xdddddddd;
		pxTopOfStack--;
		*pxTopOfStack = 0xcccccccc;
		pxTopOfStack--;
		*pxTopOfStack = 0xbbbbbbbb;
		pxTopOfStack--;
		*pxTopOfStack = 0xaaaaaaaa;
		pxTopOfStack--;
		*pxTopOfStack = 0x99999999;
		pxTopOfStack--;
		*pxTopOfStack = 0x88888888;
		pxTopOfStack--;
		*pxTopOfStack = 0x77777777;
		pxTopOfStack--;
		*pxTopOfStack = 0x66666666;
		pxTopOfStack--;
		*pxTopOfStack = 0x55555555;
		pxTopOfStack--;
		*pxTopOfStack = 0x44444444;
		pxTopOfStack--;
		*pxTopOfStack = 0x33333333;
		pxTopOfStack--;
		*pxTopOfStack = 0x22222222;
		pxTopOfStack--;
	}
	#else
	{
		pxTopOfStack -= 15;
	}
	#endif

	*pxTopOfStack = ( StackType_t ) pvParameters; /* R1 */
	pxTopOfStack--;
	*pxTopOfStack = portINITIAL_FPSW;
	pxTopOfStack--;
	*pxTopOfStack = 0x11111111; /* Accumulator 0. */
	pxTopOfStack--;
	*pxTopOfStack = 0x22222222; /* Accumulator 0. */
	pxTopOfStack--;
	*pxTopOfStack = 0x33333333; /* Accumulator 0. */
	pxTopOfStack--;
	*pxTopOfStack = 0x44444444; /* Accumulator 1. */
	pxTopOfStack--;
	*pxTopOfStack = 0x55555555; /* Accumulator 1. */
	pxTopOfStack--;
	*pxTopOfStack = 0x66666666; /* Accumulator 1. */

	return pxTopOfStack;
}
/*-----------------------------------------------------------*/

BaseType_t xPortStartScheduler( void )
{
extern void vApplicationSetupTimerInterrupt( void );

	/* Use pxCurrentTCB just so it does not get optimised away. */
	if( pxCurrentTCB != NULL )
	{
		/* 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();

		/* Enable the software interrupt. */
		_IEN( _ICU_SWINT ) = 1;

		/* Ensure the software interrupt is clear. */
		_IR( _ICU_SWINT ) = 0;

		/* Ensure the software interrupt is set to the kernel priority. */
		_IPR( _ICU_SWINT ) = configKERNEL_INTERRUPT_PRIORITY;

		/* Start the first task. */
		prvStartFirstTask();
	}

	/* Should not get here. */
	return pdFAIL;
}
/*-----------------------------------------------------------*/

#pragma vector = configTICK_VECTOR
__interrupt void vTickISR( void )
{
	/* Re-enable interrupts. */
	__enable_interrupt();

	/* Increment the tick, and perform any processing the new tick value
	necessitates. */
	__set_interrupt_level( configMAX_SYSCALL_INTERRUPT_PRIORITY );
	{
		if( xTaskIncrementTick() != pdFALSE )
		{
			taskYIELD();
		}
	}
	__set_interrupt_level( configKERNEL_INTERRUPT_PRIORITY );
}
/*-----------------------------------------------------------*/

void vPortEndScheduler( void )
{
	/* Not implemented in ports where there is nothing to return to.
	Artificially force an assert. */
	configASSERT( pxCurrentTCB == NULL );
}
/*-----------------------------------------------------------*/