portmacro.h

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/*
	FreeRTOS.org V5.2.0 - Copyright (C) 2003-2009 Richard Barry.

	This file is part of the FreeRTOS.org distribution.

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	under the terms of the GNU General Public License (version 2) as published
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	with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59 
	Temple Place, Suite 330, Boston, MA  02111-1307  USA.

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	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.


	***************************************************************************
	*                                                                         *
	* Get the FreeRTOS eBook!  See http://www.FreeRTOS.org/Documentation      *
	*                                                                         *
	* This is a concise, step by step, 'hands on' guide that describes both   *
	* general multitasking concepts and FreeRTOS specifics. It presents and   *
	* explains numerous examples that are written using the FreeRTOS API.     *
	* Full source code for all the examples is provided in an accompanying    *
	* .zip file.                                                              *
	*                                                                         *
	***************************************************************************

	1 tab == 4 spaces!

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

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

/* 
Changes from V3.0.0

Changes from V3.0.1
*/
#ifndef PORTMACRO_H
#define PORTMACRO_H

#if !defined(_SERIES) || _SERIES != 18
	#error "WizC supports FreeRTOS on the Microchip PIC18-series only"
#endif

#if !defined(QUICKCALL) || QUICKCALL != 1
	#error "QuickCall must be enabled (see ProjectOptions/Optimisations)"
#endif

#include <stddef.h>
#include <pic.h>

#define portCHAR		char
#define portFLOAT		float
#define portDOUBLE		portFLOAT
#define portLONG		long
#define portSHORT		short
#define portSTACK_TYPE	unsigned char
#define portBASE_TYPE	char

#if( configUSE_16_BIT_TICKS == 1 )
	typedef unsigned portSHORT portTickType;
	#define portMAX_DELAY ( portTickType )	( 0xFFFF )
#else
	typedef unsigned portLONG portTickType;
	#define portMAX_DELAY ( portTickType )	( 0xFFFFFFFF )
#endif

#define portBYTE_ALIGNMENT			1

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

/*
 * Constant used for context switch macro when we require the interrupt 
 * enable state to be forced when the interrupted task is switched back in.
 */
#define portINTERRUPTS_FORCED				(0x01)

/*
 * Constant used for context switch macro when we require the interrupt 
 * enable state to be unchanged when the interrupted task is switched back in.
 */
#define portINTERRUPTS_UNCHANGED			(0x00)

/* Initial interrupt enable state for newly created tasks.  This value is
 * used when a task switches in for the first time.
 */
#define portINTERRUPTS_INITIAL_STATE		(portINTERRUPTS_FORCED)

/*
 * Macros to modify the global interrupt enable bit in INTCON.
 */
#define portDISABLE_INTERRUPTS()	\
	do								\
	{								\
		bGIE=0;						\
	} while(bGIE)	// MicroChip recommends this check!
	
#define portENABLE_INTERRUPTS()		\
	do								\
	{								\
		bGIE=1;						\
	} while(0)

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

/*
 * Critical section macros.
 */
extern unsigned portCHAR ucCriticalNesting;

#define portNO_CRITICAL_SECTION_NESTING		( ( unsigned portCHAR ) 0 )

#define portENTER_CRITICAL()										\
	do																\
	{																\
		portDISABLE_INTERRUPTS();									\
																	\
		/*															\
		 * Now interrupts are disabled ucCriticalNesting			\
		 * can be accessed directly. Increment						\
		 * ucCriticalNesting to keep a count of how					\
		 * many times portENTER_CRITICAL() has been called. 		\
		 */															\
		ucCriticalNesting++;										\
	} while(0)

#define portEXIT_CRITICAL()											\
	do																\
	{																\
		if(ucCriticalNesting > portNO_CRITICAL_SECTION_NESTING)		\
		{															\
			/*														\
			 * Decrement the nesting count as we are leaving a		\
			 * critical section.									\
			 */														\
			ucCriticalNesting--;									\
		}															\
																	\
		/*															\
		 * If the nesting level has reached zero then				\
		 * interrupts should be re-enabled.							\
		 */															\
		if( ucCriticalNesting == portNO_CRITICAL_SECTION_NESTING )	\
		{															\
			portENABLE_INTERRUPTS();								\
		}															\
	} while(0)

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

/*
 * The minimal stacksize is calculated on the first reference of
 * portMINIMAL_STACK_SIZE. Some input to this calculation is
 * compiletime determined, other input is port-defined (see port.c)
 */
extern unsigned portSHORT usPortCALCULATE_MINIMAL_STACK_SIZE( void );
extern unsigned portSHORT usCalcMinStackSize;

#define portMINIMAL_STACK_SIZE					\
	((usCalcMinStackSize == 0)					\
		? usPortCALCULATE_MINIMAL_STACK_SIZE()	\
		: usCalcMinStackSize )

/*
 * WizC uses a downgrowing stack
 */
#define portSTACK_GROWTH			( -1 )

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

/*
 * Macro's that pushes all the registers that make up the context of a task onto
 * the stack, then saves the new top of stack into the TCB. TOSU and TBLPTRU
 * are only saved/restored on devices with more than 64kB (32k Words) ROM.
 * 
 * The stackpointer is helt by WizC in FSR2 and points to the first free byte.
 * WizC uses a "downgrowing" stack. There is no framepointer.
 *
 * We keep track of the interruptstatus using ucCriticalNesting. When this
 * value equals zero, interrupts have to be enabled upon exit from the
 * portRESTORE_CONTEXT macro.
 * 
 * If this is called from an ISR then the interrupt enable bits must have been 
 * set for the ISR to ever get called.  Therefore we want to save
 * ucCriticalNesting with value zero. This means the interrupts will again be
 * re-enabled when the interrupted task is switched back in.
 *
 * If this is called from a manual context switch (i.e. from a call to yield),
 * then we want to keep the current value of ucCritialNesting so it is restored
 * with its current value. This allows a yield from within a critical section.
 *
 * The compiler uses some locations at the bottom of RAM for temporary
 * storage. The compiler may also have been instructed to optimize
 * function-parameters and local variables to global storage. The compiler
 * uses an area called LocOpt for this wizC feature.
 * The total overheadstorage has to be saved in it's entirety as part of
 * a task context. These macro's store/restore from data address 0x0000 to
 * (OVERHEADPAGE0-LOCOPTSIZE+MAXLOCOPTSIZE - 1).
 * OVERHEADPAGE0, LOCOPTSIZE and MAXLOCOPTSIZE are compiler-generated
 * assembler definitions.
 */

#define	portSAVE_CONTEXT( ucInterruptForced )						\