FreeRTOS-Kernel/Source/portable/Renesas/SH2A_FPU/port.c

/*
    FreeRTOS V6.0.2 - Copyright (C) 2009 Real Time Engineers Ltd.

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    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
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*/

/*-----------------------------------------------------------
 * Implementation of functions defined in portable.h for the SH2A port.
 *----------------------------------------------------------*/

/* Scheduler includes. */
#include "FreeRTOS.h"
#include "task.h"

#define portINITIAL_SR		0UL /* No interrupts masked. */


/*-----------------------------------------------------------*/

/*
 * Setup a peripheral timer to generate the RTOS tick interrupt.
 */
static void prvSetupTimerInterrupt( void );

/*
 * 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 unsigned long ulPortGetGBR( void );

/*-----------------------------------------------------------*/

/* 
 * See header file for description. 
 */
portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
{
*pxTopOfStack = 0x11111111UL;
pxTopOfStack--;
*pxTopOfStack = 0x22222222UL;
pxTopOfStack--;
*pxTopOfStack = 0x33333333UL;
pxTopOfStack--;

	/* SR. */
	*pxTopOfStack = portINITIAL_SR; 
	pxTopOfStack--;
	
	/* PC. */
	*pxTopOfStack = ( unsigned long ) 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 = ( unsigned long ) 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;
}
/*-----------------------------------------------------------*/

portBASE_TYPE xPortStartScheduler( void )
{
	/* Start the tick interrupt. */
	prvSetupTimerInterrupt();
	
	/* Start the first task. */
	trapa( 32 );

	/* Should not get here. */
	return pdFAIL;
}
/*-----------------------------------------------------------*/

void vPortEndScheduler( void )
{
	/* Not implemented as there is nothing to return to. */
}
/*-----------------------------------------------------------*/

void vPortTickInterrupt( void )
{
	vTaskIncrementTick();
	#if configUSE_PREEMPTION == 1
		vTaskSwitchContext();
	#endif
}
/*-----------------------------------------------------------*/

static void prvSetupTimerInterrupt( void )
{
extern void vApplicationSetupTimerInterrupt( void );

	/* Call an application function to set up the timer.  This way the application
	can decide which peripheral to use.  A demo application is provided to show a
	suitable example. */
	vApplicationSetupTimerInterrupt();
}
/*-----------------------------------------------------------*/