/*
	FreeRTOS V3.2.0 - Copyright (C) 2003 - 2005 Richard Barry.

	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 as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	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.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with FreeRTOS; 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, 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.

	***************************************************************************
	See http://www.FreeRTOS.org for documentation, latest information, license 
	and contact details.  Please ensure to read the configuration and relevant 
	port sections of the online documentation.
	***************************************************************************
*/


#ifndef PORTMACRO_H
#define PORTMACRO_H

/*-----------------------------------------------------------
 * Port specific definitions.  
 *
 * The settings in this file configure FreeRTOS correctly for the
 * given hardware and compiler.
 *
 * These settings should not be altered.
 *-----------------------------------------------------------
 */

/* Type definitions. */
#define portCHAR		char
#define portFLOAT		float
#define portDOUBLE		double
#define portLONG		long
#define portSHORT		short
#define portSTACK_TYPE	unsigned portLONG
#define portBASE_TYPE	long

#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
/*-----------------------------------------------------------*/	

/* Hardware specifics. */
#define portSTACK_GROWTH			( -1 )
#define portTICK_RATE_MS			( ( portTickType ) 1000 / configTICK_RATE_HZ )		
#define portBYTE_ALIGNMENT			4
#define portYIELD()					asm volatile ( "SWI" );	

/*
 * These define the timer to use for generating the tick interrupt.
 * They are put in this file so they can be shared between "port.c"
 * and "portisr.c".
 */
#define portTIMER_REG_BASE_PTR		AT91C_BASE_TC0
#define portTIMER_CLK_ENABLE_BIT	AT91C_PS_TC0
#define portTIMER_AIC_CHANNEL		( ( unsigned portLONG ) 4 )
/*-----------------------------------------------------------*/	

/* Task utilities. */

/*
 * portRESTORE_CONTEXT, portRESTORE_CONTEXT, portENTER_SWITCHING_ISR
 * and portEXIT_SWITCHING_ISR can only be called from ARM mode, but
 * are included here for efficiency.  An attempt to call one from
 * THUMB mode code will result in a compile time error.
 */

#define portRESTORE_CONTEXT()											\
{																		\
extern volatile void * volatile pxCurrentTCB;							\
extern volatile unsigned portLONG ulCriticalNesting;					\
																		\
	/* Set the LR to the task stack. */									\
	asm volatile ( "LDR		R0, %0" : : "m" (pxCurrentTCB) );			\
	asm volatile ( "LDR		LR, [R0]" );								\
																		\
	/* The critical nesting depth is the first item on the stack. */	\
	/* Load it into the ulCriticalNesting variable. */					\
	asm volatile ( "LDR		R0, =ulCriticalNesting" );					\
	asm volatile ( "LDMFD	LR!, {R1}" );								\
	asm volatile ( "STR		R1, [R0]" );								\
																		\
	/* Get the SPSR from the stack. */									\
	asm volatile ( "LDMFD	LR!, {R0}" );								\
	asm volatile ( "MSR		SPSR, R0" );								\
																		\
	/* Restore all system mode registers for the task. */				\
	asm volatile ( "LDMFD	LR, {R0-R14}^" );							\
	asm volatile ( "NOP" );												\
																		\
	/* Restore the return address. */									\
	asm volatile ( "LDR		LR, [LR, #+60]" );							\
																		\
	/* And return - correcting the offset in the LR to obtain the */	\
	/* correct address. */												\
	asm volatile ( "SUBS	PC, LR, #4" );								\
	( void ) ulCriticalNesting;											\
}
/*-----------------------------------------------------------*/

#define portSAVE_CONTEXT()												\
{																		\
extern volatile void * volatile pxCurrentTCB;							\
extern volatile unsigned portLONG ulCriticalNesting;					\
																		\
	/* Push R0 as we are going to use the register. */					\
	asm volatile ( "STMDB	SP!, {R0}" );								\
																		\
	/* Set R0 to point to the task stack pointer. */					\
	asm volatile ( "STMDB	SP,{SP}^" );								\
	asm volatile ( "SUB		SP, SP, #4" );								\
	asm volatile ( "LDMIA	SP!,{R0}" );								\
																		\
	/* Push the return address onto the stack. */						\
	asm volatile ( "STMDB	R0!, {LR}" );								\
																		\
	/* Now we have saved LR we can use it instead of R0. */				\
	asm volatile ( "MOV		LR, R0" );									\
																		\
	/* Pop R0 so we can save it onto the system mode stack. */			\
	asm volatile ( "LDMIA	SP!, {R0}" );								\
																		\
	/* Push all the system mode registers onto the task stack. */		\
	asm volatile ( "STMDB	LR,{R0-LR}^");								\
	asm volatile ( "SUB		LR, LR, #60" );								\
																		\
	/* Push the SPSR onto the task stack. */							\
	asm volatile ( "MRS		R0, SPSR" );								\
	asm volatile ( "STMDB	LR!, {R0}" );								\
																		\
	asm volatile ( "LDR		R0, =ulCriticalNesting " );					\
	asm volatile ( "LDR		R0, [R0]" );								\
	asm volatile ( "STMDB	LR!, {R0}" );								\
																		\
	/* Store the new top of stack for the task. */						\
	asm volatile ( "LDR		R0, %0" : : "m" (pxCurrentTCB) );			\
	asm volatile ( "STR		LR, [R0]" );								\
	( void ) ulCriticalNesting;											\
}

/*-----------------------------------------------------------
 * ISR entry and exit macros.  These are only required if a task switch
 * is required from the ISR.
 *----------------------------------------------------------*/

#define portENTER_SWITCHING_ISR()										\
	/* Save the context of the interrupted task. */						\
	portSAVE_CONTEXT();													\
																		\
	/* We don't know the stack requirements for the ISR, so the frame */\
	/* pointer will be set to the top of the task stack, and the stack*/\
	/* pointer left where it is.  The IRQ stack will get used for any */\
	/* functions calls made by this ISR. */								\
	asm volatile ( "MOV		R11, LR" );									\
	{

#define portEXIT_SWITCHING_ISR( SwitchRequired )						\
		/* If a switch is required then we just need to call */			\
		/* vTaskSwitchContext() as the context has already been */		\
		/* saved. */													\
		if( SwitchRequired )											\
		{																\
			vTaskSwitchContext();										\
		}																\
	}																	\
	/* Restore the context of which ever task is now the highest */		\
	/* priority that is ready to run. */								\
	portRESTORE_CONTEXT();
/*-----------------------------------------------------------*/	

/* Critical section handling. */

/*
 * The interrupt management utilities can only be called from ARM mode.  When
 * THUMB_INTERWORK is defined the utilities are defined as functions in 
 * portISR.c to ensure a switch to ARM mode.  When THUMB_INTERWORK is not 
 * defined then the utilities are defined as macros here - as per other ports.
 */

#ifdef THUMB_INTERWORK

	extern void vPortDisableInterruptsFromThumb( void ) __attribute__ ((naked));
	extern void vPortEnableInterruptsFromThumb( void ) __attribute__ ((naked));

	#define portDISABLE_INTERRUPTS()	vPortDisableInterruptsFromThumb()
	#define portENABLE_INTERRUPTS()		vPortEnableInterruptsFromThumb()
	
#else

	#define portDISABLE_INTERRUPTS()																\
		asm volatile ( "STMDB	SP!, {R0}" );		/* Push R0.									*/	\
		asm volatile ( "MRS		R0, CPSR" );		/* Get CPSR.								*/	\
		asm volatile ( "ORR		R0, R0, #0xC0" );	/* Disable IRQ, FIQ.						*/	\
		asm volatile ( "MSR		CPSR, R0" );		/* Write back modified value.				*/	\
		asm volatile ( "LDMIA	SP!, {R0}" )		/* Pop R0.									*/
			
	#define portENABLE_INTERRUPTS()																	\
		asm volatile ( "STMDB	SP!, {R0}" );		/* Push R0.									*/	\
		asm volatile ( "MRS		R0, CPSR" );		/* Get CPSR.								*/	\
		asm volatile ( "BIC		R0, R0, #0xC0" );	/* Enable IRQ, FIQ.							*/	\
		asm volatile ( "MSR		CPSR, R0" );		/* Write back modified value.				*/	\
		asm volatile ( "LDMIA	SP!, {R0}" )		/* Pop R0. */

#endif /* THUMB_INTERWORK */

extern void vPortEnterCritical( void );
extern void vPortExitCritical( void );

#define portENTER_CRITICAL()		vPortEnterCritical();
#define portEXIT_CRITICAL()			vPortExitCritical();

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

/* Task function macros as described on the FreeRTOS.org WEB site. */
#define portTASK_FUNCTION_PROTO( vFunction, pvParameters ) void vFunction( void *pvParameters )
#define portTASK_FUNCTION( vFunction, pvParameters ) void vFunction( void *pvParameters )

#endif /* PORTMACRO_H */