FreeRTOS/Source/portable/Renesas/SH2A_FPU/port.c - third_party/github/FreeRTOS/FreeRTOS-Kernel - Git at Google

 /*
     FreeRTOS V7.5.2 - 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!
 */

 /*-----------------------------------------------------------
  * 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 unsigned long ulPortGetGBR( void );

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

 /*
  * See header file for description.
  */
 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE 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 = ( 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 )
 {
 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 )
 {
 long 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 );
 }
 /*-----------------------------------------------------------*/

 portBASE_TYPE xPortUsesFloatingPoint( xTaskHandle xTask )
 {
 unsigned long *pulFlopBuffer;
 portBASE_TYPE 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 = ( xTaskHandle ) pxCurrentTCB;
 	}

 	/* Allocate a buffer large enough to hold all the flop registers. */
 	pulFlopBuffer = ( unsigned long * ) 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;
 }
 /*-----------------------------------------------------------*/
	/*
	FreeRTOS V7.5.2 - 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!
	*/

	/*-----------------------------------------------------------
	* 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 unsigned long ulPortGetGBR( void );

	/-----------------------------------------------------------/

	/*
	* See header file for description.
	*/
	portSTACK_TYPE pxPortInitialiseStack( portSTACK_TYPE pxTopOfStack, pdTASK_CODE 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 = ( 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 )
	{
	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 )
	{
	long 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 );
	}
	/-----------------------------------------------------------/

	portBASE_TYPE xPortUsesFloatingPoint( xTaskHandle xTask )
	{
	unsigned long *pulFlopBuffer;
	portBASE_TYPE 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 = ( xTaskHandle ) pxCurrentTCB;
	}

	/* Allocate a buffer large enough to hold all the flop registers. */
	pulFlopBuffer = ( unsigned long * ) 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;
	}
	/-----------------------------------------------------------/