Source/portable/MPLAB/PIC24_dsPIC/port.c - third_party/github/FreeRTOS/FreeRTOS-Kernel - Git at Google

 /*
 	FreeRTOS.org V5.1.0 - Copyright (C) 2003-2008 Richard Barry.

 	This file is part of the FreeRTOS.org distribution.

 	FreeRTOS.org is free software; you can redistribute it and/or modify
 	it under the terms of the GNU General Public License as published by
 	the Free Software Foundation; either version 2 of the License, or
 	(at your option) any later version.

 	FreeRTOS.org 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.  See the
 	GNU General Public License for more details.

 	You should have received a copy of the GNU General Public License
 	along with FreeRTOS.org; if not, write to the Free Software
 	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 	A special exception to the GPL can be applied should you wish to distribute
 	a combined work that includes FreeRTOS.org, without being obliged to provide
 	the source code for any proprietary components.  See the licensing section
 	of http://www.FreeRTOS.org for full details of how and when the exception
 	can be applied.

     ***************************************************************************
     ***************************************************************************
     *                                                                         *
     * SAVE TIME AND MONEY!  We can port FreeRTOS.org to your own hardware,    *
     * and even write all or part of your application on your behalf.          *
     * See http://www.OpenRTOS.com for details of the services we provide to   *
     * expedite your project.                                                  *
     *                                                                         *
     ***************************************************************************
     ***************************************************************************

 	Please ensure to read the configuration and relevant port sections of the
 	online documentation.

 	http://www.FreeRTOS.org - Documentation, latest information, license and
 	contact details.

 	http://www.SafeRTOS.com - A version that is certified for use in safety
 	critical systems.

 	http://www.OpenRTOS.com - Commercial support, development, porting,
 	licensing and training services.
 */

 /*
 	Changes from V4.2.1

 	+ Introduced the configKERNEL_INTERRUPT_PRIORITY definition.
 */

 /*-----------------------------------------------------------
  * Implementation of functions defined in portable.h for the PIC24 port.
  *----------------------------------------------------------*/

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

 /* Hardware specifics. */
 #define portBIT_SET 1
 #define portTIMER_PRESCALE 8
 #define portINITIAL_SR	0

 /* Defined for backward compatability with project created prior to
 FreeRTOS.org V4.3.0. */
 #ifndef configKERNEL_INTERRUPT_PRIORITY
 	#define configKERNEL_INTERRUPT_PRIORITY 1
 #endif

 /* The program counter is only 23 bits. */
 #define portUNUSED_PR_BITS	0x7f

 /* Records the nesting depth of calls to portENTER_CRITICAL(). */
 unsigned portBASE_TYPE uxCriticalNesting = 0xef;

 #if configKERNEL_INTERRUPT_PRIORITY != 1
 	#error If configKERNEL_INTERRUPT_PRIORITY is not 1 then the #32 in the following macros needs changing to equal the portINTERRUPT_BITS value, which is ( configKERNEL_INTERRUPT_PRIORITY << 5 )
 #endif

 #ifdef MPLAB_PIC24_PORT

 	#define portRESTORE_CONTEXT()																						\
 		asm volatile(	"MOV	_pxCurrentTCB, W0		\n"	/* Restore the stack pointer for the task. */				\
 						"MOV	[W0], W15				\n"																\
 						"POP	W0						\n"	/* Restore the critical nesting counter for the task. */	\
 						"MOV	W0, _uxCriticalNesting	\n"																\
 						"POP	PSVPAG					\n"																\
 						"POP	CORCON					\n"																\
 						"POP	TBLPAG					\n"																\
 						"POP	RCOUNT					\n"	/* Restore the registers from the stack. */					\
 						"POP	W14						\n"																\
 						"POP.D	W12						\n"																\
 						"POP.D	W10						\n"																\
 						"POP.D	W8						\n"																\
 						"POP.D	W6						\n"																\
 						"POP.D	W4						\n"																\
 						"POP.D	W2						\n"																\
 						"POP.D	W0						\n"																\
 						"POP	SR						  " );

 #endif /* MPLAB_PIC24_PORT */

 #ifdef MPLAB_DSPIC_PORT

 	#define portRESTORE_CONTEXT()																						\
 		asm volatile(	"MOV	_pxCurrentTCB, W0		\n"	/* Restore the stack pointer for the task. */				\
 						"MOV	[W0], W15				\n"																\
 						"POP	W0						\n"	/* Restore the critical nesting counter for the task. */	\
 						"MOV	W0, _uxCriticalNesting	\n"																\
 						"POP	PSVPAG					\n"																\
 						"POP	CORCON					\n"																\
 						"POP	DOENDH					\n"																\
 						"POP	DOENDL					\n"																\
 						"POP	DOSTARTH				\n"																\
 						"POP	DOSTARTL				\n"																\
 						"POP	DCOUNT					\n"																\
 						"POP	ACCBU					\n"																\
 						"POP	ACCBH					\n"																\
 						"POP	ACCBL					\n"																\
 						"POP	ACCAU					\n"																\
 						"POP	ACCAH					\n"																\
 						"POP	ACCAL					\n"																\
 						"POP	TBLPAG					\n"																\
 						"POP	RCOUNT					\n"	/* Restore the registers from the stack. */					\
 						"POP	W14						\n"																\
 						"POP.D	W12						\n"																\
 						"POP.D	W10						\n"																\
 						"POP.D	W8						\n"																\
 						"POP.D	W6						\n"																\
 						"POP.D	W4						\n"																\
 						"POP.D	W2						\n"																\
 						"POP.D	W0						\n"																\
 						"POP	SR						  " );

 #endif /* MPLAB_DSPIC_PORT */

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

 /*
  * See header file for description.
  */
 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
 {
 unsigned portSHORT usCode;
 portBASE_TYPE i;

 const portSTACK_TYPE xInitialStack[] =
 {
 	0x1111,	/* W1 */
 	0x2222, /* W2 */
 	0x3333, /* W3 */
 	0x4444, /* W4 */
 	0x5555, /* W5 */
 	0x6666, /* W6 */
 	0x7777, /* W7 */
 	0x8888, /* W8 */
 	0x9999, /* W9 */
 	0xaaaa, /* W10 */
 	0xbbbb, /* W11 */
 	0xcccc, /* W12 */
 	0xdddd, /* W13 */
 	0xeeee, /* W14 */
 	0xcdce, /* RCOUNT */
 	0xabac, /* TBLPAG */

 	/* dsPIC specific registers. */
 	#ifdef MPLAB_DSPIC_PORT
 		0x0202, /* ACCAL */
 		0x0303, /* ACCAH */
 		0x0404, /* ACCAU */
 		0x0505, /* ACCBL */
 		0x0606, /* ACCBH */
 		0x0707, /* ACCBU */
 		0x0808, /* DCOUNT */
 		0x090a, /* DOSTARTL */
 		0x1010, /* DOSTARTH */
 		0x1110, /* DOENDL */
 		0x1212, /* DOENDH */
 	#endif
 };

 	/* Setup the stack as if a yield had occurred.

 	Save the low bytes of the program counter. */
 	usCode = ( unsigned portSHORT ) pxCode;
 	*pxTopOfStack = ( portSTACK_TYPE ) usCode;
 	pxTopOfStack++;

 	/* Save the high byte of the program counter.  This will always be zero
 	here as it is passed in a 16bit pointer.  If the address is greater than
 	16 bits then the pointer will point to a jump table. */
 	*pxTopOfStack = ( portSTACK_TYPE ) 0;
 	pxTopOfStack++;

 	/* Status register with interrupts enabled. */
 	*pxTopOfStack = portINITIAL_SR;
 	pxTopOfStack++;

 	/* Parameters are passed in W0. */
 	*pxTopOfStack = ( portSTACK_TYPE ) pvParameters;
 	pxTopOfStack++;

 	for( i = 0; i < ( sizeof( xInitialStack ) / sizeof( portSTACK_TYPE ) ); i++ )
 	{
 		*pxTopOfStack = xInitialStack[ i ];
 		pxTopOfStack++;
 	}

 	*pxTopOfStack = CORCON;
 	pxTopOfStack++;
 	*pxTopOfStack = PSVPAG;
 	pxTopOfStack++;

 	/* Finally the critical nesting depth. */
 	*pxTopOfStack = 0x00;
 	pxTopOfStack++;

 	return pxTopOfStack;
 }
 /*-----------------------------------------------------------*/

 portBASE_TYPE xPortStartScheduler( void )
 {
 	/* Setup a timer for the tick ISR. */
 	prvSetupTimerInterrupt();

 	/* Restore the context of the first task to run. */
 	portRESTORE_CONTEXT();

 	/* Simulate the end of the yield function. */
 	asm volatile ( "return" );

 	/* Should not reach here. */
 	return pdTRUE;
 }
 /*-----------------------------------------------------------*/

 void vPortEndScheduler( void )
 {
 	/* It is unlikely that the scheduler for the PIC port will get stopped
 	once running.  If required disable the tick interrupt here, then return
 	to xPortStartScheduler(). */
 }
 /*-----------------------------------------------------------*/

 /*
  * Setup a timer for a regular tick.
  */
 static void prvSetupTimerInterrupt( void )
 {
 const unsigned portLONG ulCompareMatch = ( configCPU_CLOCK_HZ / portTIMER_PRESCALE ) / configTICK_RATE_HZ;

 	/* Prescale of 8. */
 	T1CON = 0;
 	TMR1 = 0;

 	PR1 = ( unsigned portSHORT ) ulCompareMatch;

 	/* Setup timer 1 interrupt priority. */
 	IPC0bits.T1IP = configKERNEL_INTERRUPT_PRIORITY;

 	/* Clear the interrupt as a starting condition. */
 	IFS0bits.T1IF = 0;

 	/* Enable the interrupt. */
 	IEC0bits.T1IE = 1;

 	/* Setup the prescale value. */
 	T1CONbits.TCKPS0 = 1;
 	T1CONbits.TCKPS1 = 0;

 	/* Start the timer. */
 	T1CONbits.TON = 1;
 }
 /*-----------------------------------------------------------*/

 void vPortEnterCritical( void )
 {
 	portDISABLE_INTERRUPTS();
 	uxCriticalNesting++;
 }
 /*-----------------------------------------------------------*/

 void vPortExitCritical( void )
 {
 	uxCriticalNesting--;
 	if( uxCriticalNesting == 0 )
 	{
 		portENABLE_INTERRUPTS();
 	}
 }
 /*-----------------------------------------------------------*/

 void __attribute__((__interrupt__, auto_psv)) _T1Interrupt( void )
 {
 	/* Clear the timer interrupt. */
 	IFS0bits.T1IF = 0;

 	vTaskIncrementTick();

 	#if configUSE_PREEMPTION == 1
 		portYIELD();
 	#endif
 }
	/*
	FreeRTOS.org V5.1.0 - Copyright (C) 2003-2008 Richard Barry.

	This file is part of the FreeRTOS.org distribution.

	FreeRTOS.org is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	FreeRTOS.org 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. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with FreeRTOS.org; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

	A special exception to the GPL can be applied should you wish to distribute
	a combined work that includes FreeRTOS.org, without being obliged to provide
	the source code for any proprietary components. See the licensing section
	of http://www.FreeRTOS.org for full details of how and when the exception
	can be applied.

	***************************************************************************
	***************************************************************************
	* *
	* SAVE TIME AND MONEY! We can port FreeRTOS.org to your own hardware, *
	* and even write all or part of your application on your behalf. *
	* See http://www.OpenRTOS.com for details of the services we provide to *
	* expedite your project. *
	* *
	***************************************************************************
	***************************************************************************

	Please ensure to read the configuration and relevant port sections of the
	online documentation.

	http://www.FreeRTOS.org - Documentation, latest information, license and
	contact details.

	http://www.SafeRTOS.com - A version that is certified for use in safety
	critical systems.

	http://www.OpenRTOS.com - Commercial support, development, porting,
	licensing and training services.
	*/

	/*
	Changes from V4.2.1

	+ Introduced the configKERNEL_INTERRUPT_PRIORITY definition.
	*/

	/*-----------------------------------------------------------
	* Implementation of functions defined in portable.h for the PIC24 port.
	----------------------------------------------------------/

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

	/* Hardware specifics. */
	#define portBIT_SET 1
	#define portTIMER_PRESCALE 8
	#define portINITIAL_SR 0

	/* Defined for backward compatability with project created prior to
	FreeRTOS.org V4.3.0. */
	#ifndef configKERNEL_INTERRUPT_PRIORITY
	#define configKERNEL_INTERRUPT_PRIORITY 1
	#endif

	/* The program counter is only 23 bits. */
	#define portUNUSED_PR_BITS 0x7f

	/* Records the nesting depth of calls to portENTER_CRITICAL(). */
	unsigned portBASE_TYPE uxCriticalNesting = 0xef;

	#if configKERNEL_INTERRUPT_PRIORITY != 1
	#error If configKERNEL_INTERRUPT_PRIORITY is not 1 then the #32 in the following macros needs changing to equal the portINTERRUPT_BITS value, which is ( configKERNEL_INTERRUPT_PRIORITY << 5 )
	#endif

	#ifdef MPLAB_PIC24_PORT

	#define portRESTORE_CONTEXT() \
	asm volatile( "MOV _pxCurrentTCB, W0 \n" /* Restore the stack pointer for the task. */ \
	"MOV [W0], W15 \n" \
	"POP W0 \n" /* Restore the critical nesting counter for the task. */ \
	"MOV W0, _uxCriticalNesting \n" \
	"POP PSVPAG \n" \
	"POP CORCON \n" \
	"POP TBLPAG \n" \
	"POP RCOUNT \n" /* Restore the registers from the stack. */ \
	"POP W14 \n" \
	"POP.D W12 \n" \
	"POP.D W10 \n" \
	"POP.D W8 \n" \
	"POP.D W6 \n" \
	"POP.D W4 \n" \
	"POP.D W2 \n" \
	"POP.D W0 \n" \
	"POP SR " );

	#endif /* MPLAB_PIC24_PORT */

	#ifdef MPLAB_DSPIC_PORT

	#define portRESTORE_CONTEXT() \
	asm volatile( "MOV _pxCurrentTCB, W0 \n" /* Restore the stack pointer for the task. */ \
	"MOV [W0], W15 \n" \
	"POP W0 \n" /* Restore the critical nesting counter for the task. */ \
	"MOV W0, _uxCriticalNesting \n" \
	"POP PSVPAG \n" \
	"POP CORCON \n" \
	"POP DOENDH \n" \
	"POP DOENDL \n" \
	"POP DOSTARTH \n" \
	"POP DOSTARTL \n" \
	"POP DCOUNT \n" \
	"POP ACCBU \n" \
	"POP ACCBH \n" \
	"POP ACCBL \n" \
	"POP ACCAU \n" \
	"POP ACCAH \n" \
	"POP ACCAL \n" \
	"POP TBLPAG \n" \
	"POP RCOUNT \n" /* Restore the registers from the stack. */ \
	"POP W14 \n" \
	"POP.D W12 \n" \
	"POP.D W10 \n" \
	"POP.D W8 \n" \
	"POP.D W6 \n" \
	"POP.D W4 \n" \
	"POP.D W2 \n" \
	"POP.D W0 \n" \
	"POP SR " );

	#endif /* MPLAB_DSPIC_PORT */

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

	/*
	* See header file for description.
	*/
	portSTACK_TYPE pxPortInitialiseStack( portSTACK_TYPE pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
	{
	unsigned portSHORT usCode;
	portBASE_TYPE i;

	const portSTACK_TYPE xInitialStack[] =
	{
	0x1111, /* W1 */
	0x2222, /* W2 */
	0x3333, /* W3 */
	0x4444, /* W4 */
	0x5555, /* W5 */
	0x6666, /* W6 */
	0x7777, /* W7 */
	0x8888, /* W8 */
	0x9999, /* W9 */
	0xaaaa, /* W10 */
	0xbbbb, /* W11 */
	0xcccc, /* W12 */
	0xdddd, /* W13 */
	0xeeee, /* W14 */
	0xcdce, /* RCOUNT */
	0xabac, /* TBLPAG */

	/* dsPIC specific registers. */
	#ifdef MPLAB_DSPIC_PORT
	0x0202, /* ACCAL */
	0x0303, /* ACCAH */
	0x0404, /* ACCAU */
	0x0505, /* ACCBL */
	0x0606, /* ACCBH */
	0x0707, /* ACCBU */
	0x0808, /* DCOUNT */
	0x090a, /* DOSTARTL */
	0x1010, /* DOSTARTH */
	0x1110, /* DOENDL */
	0x1212, /* DOENDH */
	#endif
	};

	/* Setup the stack as if a yield had occurred.

	Save the low bytes of the program counter. */
	usCode = ( unsigned portSHORT ) pxCode;
	*pxTopOfStack = ( portSTACK_TYPE ) usCode;
	pxTopOfStack++;

	/* Save the high byte of the program counter. This will always be zero
	here as it is passed in a 16bit pointer. If the address is greater than
	16 bits then the pointer will point to a jump table. */
	*pxTopOfStack = ( portSTACK_TYPE ) 0;
	pxTopOfStack++;

	/* Status register with interrupts enabled. */
	*pxTopOfStack = portINITIAL_SR;
	pxTopOfStack++;

	/* Parameters are passed in W0. */
	*pxTopOfStack = ( portSTACK_TYPE ) pvParameters;
	pxTopOfStack++;

	for( i = 0; i < ( sizeof( xInitialStack ) / sizeof( portSTACK_TYPE ) ); i++ )
	{
	*pxTopOfStack = xInitialStack[ i ];
	pxTopOfStack++;
	}

	*pxTopOfStack = CORCON;
	pxTopOfStack++;
	*pxTopOfStack = PSVPAG;
	pxTopOfStack++;

	/* Finally the critical nesting depth. */
	*pxTopOfStack = 0x00;
	pxTopOfStack++;

	return pxTopOfStack;
	}
	/-----------------------------------------------------------/

	portBASE_TYPE xPortStartScheduler( void )
	{
	/* Setup a timer for the tick ISR. */
	prvSetupTimerInterrupt();

	/* Restore the context of the first task to run. */
	portRESTORE_CONTEXT();

	/* Simulate the end of the yield function. */
	asm volatile ( "return" );

	/* Should not reach here. */
	return pdTRUE;
	}
	/-----------------------------------------------------------/

	void vPortEndScheduler( void )
	{
	/* It is unlikely that the scheduler for the PIC port will get stopped
	once running. If required disable the tick interrupt here, then return
	to xPortStartScheduler(). */
	}
	/-----------------------------------------------------------/

	/*
	* Setup a timer for a regular tick.
	*/
	static void prvSetupTimerInterrupt( void )
	{
	const unsigned portLONG ulCompareMatch = ( configCPU_CLOCK_HZ / portTIMER_PRESCALE ) / configTICK_RATE_HZ;

	/* Prescale of 8. */
	T1CON = 0;
	TMR1 = 0;

	PR1 = ( unsigned portSHORT ) ulCompareMatch;

	/* Setup timer 1 interrupt priority. */
	IPC0bits.T1IP = configKERNEL_INTERRUPT_PRIORITY;

	/* Clear the interrupt as a starting condition. */
	IFS0bits.T1IF = 0;

	/* Enable the interrupt. */
	IEC0bits.T1IE = 1;

	/* Setup the prescale value. */
	T1CONbits.TCKPS0 = 1;
	T1CONbits.TCKPS1 = 0;

	/* Start the timer. */
	T1CONbits.TON = 1;
	}
	/-----------------------------------------------------------/

	void vPortEnterCritical( void )
	{
	portDISABLE_INTERRUPTS();
	uxCriticalNesting++;
	}
	/-----------------------------------------------------------/

	void vPortExitCritical( void )
	{
	uxCriticalNesting--;
	if( uxCriticalNesting == 0 )
	{
	portENABLE_INTERRUPTS();
	}
	}
	/-----------------------------------------------------------/

	void __attribute__((__interrupt__, auto_psv)) _T1Interrupt( void )
	{
	/* Clear the timer interrupt. */
	IFS0bits.T1IF = 0;

	vTaskIncrementTick();

	#if configUSE_PREEMPTION == 1
	portYIELD();
	#endif
	}