/*
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    ***************************************************************************
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    ***************************************************************************

    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.

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    1 tab == 4 spaces!

    ***************************************************************************
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*/

/*
	Changes from V3.2.3
	
	+ Modified portENTER_SWITCHING_ISR() to allow use with GCC V4.0.1.

	Changes from V3.2.4

	+ Removed the use of the %0 parameter within the assembler macros and 
	  replaced them with hard coded registers.  This will ensure the
	  assembler does not select the link register as the temp register as
	  was occasionally happening previously.

	+ The assembler statements are now included in a single asm block rather
	  than each line having its own asm block.

	Changes from V4.5.0

	+ Removed the portENTER_SWITCHING_ISR() and portEXIT_SWITCHING_ISR() macros
	  and replaced them with portYIELD_FROM_ISR() macro.  Application code 
	  should now make use of the portSAVE_CONTEXT() and portRESTORE_CONTEXT()
	  macros as per the V4.5.1 demo code.
*/

#ifndef PORTMACRO_H
#define PORTMACRO_H

#ifdef __cplusplus
extern "C" {
#endif

/*-----------------------------------------------------------
 * 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			8
#define portYIELD()					asm volatile ( "SWI 0" )
#define portNOP()					asm volatile ( "NOP" )

/*
 * 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, =pxCurrentTCB								\n\t"	\
	"LDR		R0, [R0]										\n\t"	\
	"LDR		LR, [R0]										\n\t"	\
																		\
	/* The critical nesting depth is the first item on the stack. */	\
	/* Load it into the ulCriticalNesting variable. */					\
	"LDR		R0, =ulCriticalNesting							\n\t"	\
	"LDMFD	LR!, {R1}											\n\t"	\
	"STR		R1, [R0]										\n\t"	\
																		\
	/* Get the SPSR from the stack. */									\
	"LDMFD	LR!, {R0}											\n\t"	\
	"MSR		SPSR, R0										\n\t"	\
																		\
	/* Restore all system mode registers for the task. */				\
	"LDMFD	LR, {R0-R14}^										\n\t"	\
	"NOP														\n\t"	\
																		\
	/* Restore the return address. */									\
	"LDR		LR, [LR, #+60]									\n\t"	\
																		\
	/* And return - correcting the offset in the LR to obtain the */	\
	/* correct address. */												\
	"SUBS	PC, LR, #4											\n\t"	\
	);																	\
	( void ) ulCriticalNesting;											\
	( void ) pxCurrentTCB;												\
}
/*-----------------------------------------------------------*/

#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}											\n\t"	\
																		\
	/* Set R0 to point to the task stack pointer. */					\
	"STMDB	SP,{SP}^											\n\t"	\
	"NOP														\n\t"	\
	"SUB	SP, SP, #4											\n\t"	\
	"LDMIA	SP!,{R0}											\n\t"	\
																		\
	/* Push the return address onto the stack. */						\
	"STMDB	R0!, {LR}											\n\t"	\
																		\
	/* Now we have saved LR we can use it instead of R0. */				\
	"MOV	LR, R0												\n\t"	\
																		\
	/* Pop R0 so we can save it onto the system mode stack. */			\
	"LDMIA	SP!, {R0}											\n\t"	\
																		\
	/* Push all the system mode registers onto the task stack. */		\
	"STMDB	LR,{R0-LR}^											\n\t"	\
	"NOP														\n\t"	\
	"SUB	LR, LR, #60											\n\t"	\
																		\
	/* Push the SPSR onto the task stack. */							\
	"MRS	R0, SPSR											\n\t"	\
	"STMDB	LR!, {R0}											\n\t"	\
																		\
	"LDR	R0, =ulCriticalNesting								\n\t"	\
	"LDR	R0, [R0]											\n\t"	\
	"STMDB	LR!, {R0}											\n\t"	\
																		\
	/* Store the new top of stack for the task. */						\
	"LDR	R0, =pxCurrentTCB									\n\t"	\
	"LDR	R0, [R0]											\n\t"	\
	"STR	LR, [R0]											\n\t"	\
	);																	\
	( void ) ulCriticalNesting;											\
	( void ) pxCurrentTCB;												\
}

#define portYIELD_FROM_ISR() vTaskSwitchContext()

/* 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}		\n\t"	/* Push R0.						*/	\
			"MRS	R0, CPSR		\n\t"	/* Get CPSR.					*/	\
			"ORR	R0, R0, #0xC0	\n\t"	/* Disable IRQ, FIQ.			*/	\
			"MSR	CPSR, R0		\n\t"	/* Write back modified value.	*/	\
			"LDMIA	SP!, {R0}			" )	/* Pop R0.						*/
			
	#define portENABLE_INTERRUPTS()												\
		asm volatile (															\
			"STMDB	SP!, {R0}		\n\t"	/* Push R0.						*/	\
			"MRS	R0, CPSR		\n\t"	/* Get CPSR.					*/	\
			"BIC	R0, R0, #0xC0	\n\t"	/* Enable IRQ, FIQ.				*/	\
			"MSR	CPSR, R0		\n\t"	/* Write back modified value.	*/	\
			"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 )

#ifdef __cplusplus
}
#endif

#endif /* PORTMACRO_H */