FreeRTOS/Source/portable/IAR/RL78/port.c

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    This file is part of the FreeRTOS distribution.

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*/

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

/* The critical nesting value is initialised to a non zero value to ensure
interrupts don't accidentally become enabled before the scheduler is started. */
#define portINITIAL_CRITICAL_NESTING  ( ( unsigned short ) 10 )

/* Initial PSW value allocated to a newly created task.
 *   1100011000000000
 *   ||||||||-------------- Fill byte
 *   |||||||--------------- Carry Flag cleared
 *   |||||----------------- In-service priority Flags set to low level
 *   ||||------------------ Register bank Select 0 Flag cleared
 *   |||------------------- Auxiliary Carry Flag cleared
 *   ||-------------------- Register bank Select 1 Flag cleared
 *   |--------------------- Zero Flag set
 *   ---------------------- Global Interrupt Flag set (enabled)
 */
#define portPSW		  ( 0xc6UL )

/* The address of the pxCurrentTCB variable, but don't know or need to know 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 that could cause problems during the startup
sequence. */
volatile unsigned short usCriticalNesting = portINITIAL_CRITICAL_NESTING;

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

/*
 * Sets up the periodic ISR used for the RTOS tick using the interval timer.
 * The application writer can define configSETUP_TICK_INTERRUPT() (in
 * FreeRTOSConfig.h) such that their own tick interrupt configuration is used
 * in place of prvSetupTimerInterrupt().
 */
static void prvSetupTimerInterrupt( void );
#ifndef configSETUP_TICK_INTERRUPT
	/* The user has not provided their own tick interrupt configuration so use
    the definition in this file (which uses the interval timer). */
	#define configSETUP_TICK_INTERRUPT() prvSetupTimerInterrupt()
#endif /* configSETUP_TICK_INTERRUPT */

/*
 * Defined in portasm.s87, this function starts the scheduler by loading the
 * context of the first task to run.
 */
extern void vPortStartFirstTask( 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 long *pulLocal;

	#if __DATA_MODEL__ == __DATA_MODEL_FAR__
	{
		/* Parameters are passed in on the stack, and written using a 32bit value
		hence a space is left for the second two bytes. */
		pxTopOfStack--;

		/* Write in the parameter value. */
		pulLocal =  ( unsigned long * ) pxTopOfStack;
		*pulLocal = ( unsigned long ) pvParameters;
		pxTopOfStack--;

		/* These values are just spacers.  The return address of the function
		would normally be written here. */
		*pxTopOfStack = ( portSTACK_TYPE ) 0xcdcd;
		pxTopOfStack--;
		*pxTopOfStack = ( portSTACK_TYPE ) 0xcdcd;
		pxTopOfStack--;

		/* The start address / PSW value is also written in as a 32bit value,
		so leave a space for the second two bytes. */
		pxTopOfStack--;

		/* Task function start address combined with the PSW. */
		pulLocal = ( unsigned long * ) pxTopOfStack;
		*pulLocal = ( ( ( unsigned long ) pxCode ) | ( portPSW << 24UL ) );
		pxTopOfStack--;

		/* An initial value for the AX register. */
		*pxTopOfStack = ( portSTACK_TYPE ) 0x1111;
		pxTopOfStack--;
	}
	#else
	{
		/* Task function address is written to the stack first.  As it is
		written as a 32bit value a space is left on the stack for the second
		two bytes. */
		pxTopOfStack--;

		/* Task function start address combined with the PSW. */
		pulLocal = ( unsigned long * ) pxTopOfStack;
		*pulLocal = ( ( ( unsigned long ) pxCode ) | ( portPSW << 24UL ) );
		pxTopOfStack--;

		/* The parameter is passed in AX. */
		*pxTopOfStack = ( portSTACK_TYPE ) pvParameters;
		pxTopOfStack--;
	}
	#endif

	/* An initial value for the HL register. */
	*pxTopOfStack = ( portSTACK_TYPE ) 0x2222;
	pxTopOfStack--;

	/* CS and ES registers. */
	*pxTopOfStack = ( portSTACK_TYPE ) 0x0F00;
	pxTopOfStack--;

	/* The remaining general purpose registers DE and BC */
	*pxTopOfStack = ( portSTACK_TYPE ) 0xDEDE;
	pxTopOfStack--;
	*pxTopOfStack = ( portSTACK_TYPE ) 0xBCBC;
	pxTopOfStack--;

	/* Finally the critical section nesting count is set to zero when the task
	first starts. */
	*pxTopOfStack = ( portSTACK_TYPE ) portNO_CRITICAL_SECTION_NESTING;

	/* Return a pointer to the top of the stack that has been generated so it
	can	be stored in the task control block for the task. */
	return pxTopOfStack;
}
/*-----------------------------------------------------------*/

portBASE_TYPE xPortStartScheduler( void )
{
	/* Setup the hardware to generate the tick.  Interrupts are disabled when
	this function is called. */
	configSETUP_TICK_INTERRUPT();

	/* Restore the context of the first task that is going to run. */
	vPortStartFirstTask();

	/* Execution should not reach here as the tasks are now running!
	prvSetupTimerInterrupt() is called here to prevent the compiler outputting
	a warning about a statically declared function not being referenced in the
	case that the application writer has provided their own tick interrupt
	configuration routine (and defined configSETUP_TICK_INTERRUPT() such that
	their own routine will be called in place of prvSetupTimerInterrupt()). */
	prvSetupTimerInterrupt();
	return pdTRUE;
}
/*-----------------------------------------------------------*/

void vPortEndScheduler( void )
{
	/* It is unlikely that the RL78 port will get stopped. */
}
/*-----------------------------------------------------------*/

static void prvSetupTimerInterrupt( void )
{
const unsigned short usClockHz = 15000UL; /* Internal clock. */
const unsigned short usCompareMatch = ( usClockHz / configTICK_RATE_HZ ) + 1UL;

	/* Use the internal 15K clock. */
	OSMC = ( unsigned char ) 0x16;

	#ifdef RTCEN
	{
		/* Supply the interval timer clock. */
		RTCEN = ( unsigned char ) 1U;

		/* Disable INTIT interrupt. */
		ITMK = ( unsigned char ) 1;

		/* Disable ITMC operation. */
		ITMC = ( unsigned char ) 0x0000;

		/* Clear INIT interrupt. */
		ITIF = ( unsigned char ) 0;

		/* Set interval and enable interrupt operation. */
		ITMC = usCompareMatch | 0x8000U;

		/* Enable INTIT interrupt. */
		ITMK = ( unsigned char ) 0;
	}
	#endif

	#ifdef TMKAEN
	{
		/* Supply the interval timer clock. */
		TMKAEN = ( unsigned char ) 1U;

		/* Disable INTIT interrupt. */
		TMKAMK = ( unsigned char ) 1;

		/* Disable ITMC operation. */
		ITMC = ( unsigned char ) 0x0000;

		/* Clear INIT interrupt. */
		TMKAIF = ( unsigned char ) 0;

		/* Set interval and enable interrupt operation. */
		ITMC = usCompareMatch | 0x8000U;

		/* Enable INTIT interrupt. */
		TMKAMK = ( unsigned char ) 0;
	}
	#endif
}
/*-----------------------------------------------------------*/