FreeRTOS-Kernel/Source/portable/GCC/ARM7_LPC2000/portmacro.h

/*
	FreeRTOS.org V4.4.0 - Copyright (C) 2003-2007 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.

	***************************************************************************
	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.

	Also see http://www.SafeRTOS.com for an IEC 61508 compliant version along
	with commercial development and support options.
	***************************************************************************
*/

/*
	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.
*/

#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	portLONG

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

/* Architecture specifics. */
#define portSTACK_GROWTH			( -1 )
#define portTICK_RATE_MS			( ( portTickType ) 1000 / configTICK_RATE_HZ )		
#define portBYTE_ALIGNMENT			4
#define portNOP()					asm volatile ( "NOP" );
/*-----------------------------------------------------------*/	


/* Scheduler 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;												\
}


/*-----------------------------------------------------------
 * 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 ( "SUB		R11, LR, #4" );							\
	{

#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();

#define portYIELD()					asm volatile ( "SWI" );	
/*-----------------------------------------------------------*/


/* Critical section management. */

/*
 * 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 )

#endif /* PORTMACRO_H */