/*
    FreeRTOS V7.5.3 - Copyright (C) 2013 Real Time Engineers Ltd. 
    All rights reserved

    VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

    ***************************************************************************
     *                                                                       *
     *    FreeRTOS provides completely free yet professionally developed,    *
     *    robust, strictly quality controlled, supported, and cross          *
     *    platform software that has become a de facto standard.             *
     *                                                                       *
     *    Help yourself get started quickly and support the FreeRTOS         *
     *    project by purchasing a FreeRTOS tutorial book, reference          *
     *    manual, or both from: http://www.FreeRTOS.org/Documentation        *
     *                                                                       *
     *    Thank you!                                                         *
     *                                                                       *
    ***************************************************************************

    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.

    >>! NOTE: The modification to the GPL is included to allow you to distribute
    >>! a combined work that includes FreeRTOS without being obliged to provide
    >>! the source code for proprietary components outside of the FreeRTOS
    >>! kernel.

    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.  Full license text is available from the following
    link: http://www.freertos.org/a00114.html

    1 tab == 4 spaces!

    ***************************************************************************
     *                                                                       *
     *    Having a problem?  Start by reading the FAQ "My application does   *
     *    not run, what could be wrong?"                                     *
     *                                                                       *
     *    http://www.FreeRTOS.org/FAQHelp.html                               *
     *                                                                       *
    ***************************************************************************

    http://www.FreeRTOS.org - Documentation, books, training, latest versions,
    license and Real Time Engineers Ltd. contact details.

    http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
    including FreeRTOS+Trace - an indispensable productivity tool, a DOS
    compatible FAT file system, and our tiny thread aware UDP/IP stack.

    http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
    Integrity Systems to sell under the OpenRTOS brand.  Low cost OpenRTOS
    licenses offer ticketed support, indemnification and middleware.

    http://www.SafeRTOS.com - High Integrity Systems also provide a safety
    engineered and independently SIL3 certified version for use in safety and
    mission critical applications that require provable dependability.

    1 tab == 4 spaces!
*/

#include <FreeRTOSConfig.h>

	RSEG    CODE:CODE(2)
	thumb

	EXTERN pxCurrentTCB
	EXTERN vTaskSwitchContext

	PUBLIC xPortPendSVHandler
	PUBLIC ulPortSetInterruptMask
	PUBLIC vPortClearInterruptMask
	PUBLIC vPortSVCHandler
	PUBLIC vPortStartFirstTask



/*-----------------------------------------------------------*/

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							


/*-----------------------------------------------------------*/

ulPortSetInterruptMask:
	mrs r0, basepri
	mov r1, #configMAX_SYSCALL_INTERRUPT_PRIORITY
	msr basepri, r1
	bx r14
	
/*-----------------------------------------------------------*/

vPortClearInterruptMask:
	msr basepri, r0
	bx r14

/*-----------------------------------------------------------*/

vPortSVCHandler:
	/* Get the location of the current TCB. */
	ldr	r3, =pxCurrentTCB
	ldr r1, [r3]
	ldr r0, [r1]
	/* Pop the core registers. */
	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. */
	cpsie i
	svc 0

	END