/*
	FreeRTOS.org V5.1.2 - Copyright (C) 2003-2009 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.

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

	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.
*/

/*
	Change from V4.2.1:

	+ Introduced usage of configKERNEL_INTERRUPT_PRIORITY macro to set the
	  interrupt priority used by the kernel.
*/

#include <FreeRTOSConfig.h>

/* For backward compatibility, ensure configKERNEL_INTERRUPT_PRIORITY is
defined.  The value zero should also ensure backward compatibility.
FreeRTOS.org versions prior to V4.3.0 did not include this definition. */
#ifndef configKERNEL_INTERRUPT_PRIORITY
	#define configKERNEL_INTERRUPT_PRIORITY 0
#endif

	
	RSEG    CODE:CODE(2)
	thumb

	EXTERN vPortYieldFromISR
	EXTERN pxCurrentTCB
	EXTERN vTaskSwitchContext

	PUBLIC vSetMSP
	PUBLIC xPortPendSVHandler
	PUBLIC vPortSetInterruptMask
	PUBLIC vPortClearInterruptMask
	PUBLIC vPortSVCHandler
	PUBLIC vPortStartFirstTask


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

vSetMSP
	msr msp, r0
	bx lr
	
/*-----------------------------------------------------------*/

xPortPendSVHandler:
	mrs r0, psp						
	ldr	r3, =pxCurrentTCB			/* Get the location of the current TCB. */
	ldr	r2, [r3]						

	stmdb r0!, {r4-r11}				/* Save the remaining registers. */
	str r0, [r2]					/* Save the new top of stack into the first member of the TCB. */

	stmdb sp!, {r3, r14}
	mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY
	msr basepri, r0
	bl vTaskSwitchContext			
	mov r0, #0
	msr basepri, r0
	ldmia sp!, {r3, r14}

	ldr r1, [r3]					
	ldr r0, [r1]					/* The first item in pxCurrentTCB is the task top of stack. */
	ldmia r0!, {r4-r11}				/* Pop the registers. */
	msr psp, r0						
	bx r14							


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

vPortSetInterruptMask:
	push { r0 }
	mov R0, #configMAX_SYSCALL_INTERRUPT_PRIORITY
	msr BASEPRI, R0
	pop { R0 }

	bx r14
	
/*-----------------------------------------------------------*/

vPortClearInterruptMask:
	PUSH { r0 }
	MOV R0, #0
	MSR BASEPRI, R0
	POP	 { R0 }

	bx r14

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

vPortSVCHandler;
	ldr	r3, =pxCurrentTCB
	ldr r1, [r3]
	ldr r0, [r1]
	ldmia r0!, {r4-r11}
	msr psp, r0
	mov r0, #0
	msr	basepri, r0
	orr r14, r14, #13
	bx r14

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

vPortStartFirstTask
	/* Use the NVIC offset register to locate the stack. */
	ldr r0, =0xE000ED08
	ldr r0, [r0]
	ldr r0, [r0]
	/* Set the msp back to the start of the stack. */
	msr msp, r0
	/* Call SVC to start the first task. */
	svc 0

	END
	