/*
    FreeRTOS V7.6.0 - 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 vPortYieldFromISR
	EXTERN pxCurrentTCB
	EXTERN vTaskSwitchContext

	PUBLIC vSetMSP
	PUBLIC xPortPendSVHandler
	PUBLIC vPortSVCHandler
	PUBLIC vPortStartFirstTask
	PUBLIC ulSetInterruptMaskFromISR
	PUBLIC vClearInterruptMaskFromISR

/*-----------------------------------------------------------*/

vSetMSP
	msr msp, r0
	bx lr

/*-----------------------------------------------------------*/

xPortPendSVHandler:
	mrs r0, psp

	ldr	r3, =pxCurrentTCB	/* Get the location of the current TCB. */
	ldr	r2, [r3]

	subs r0, r0, #32		/* Make space for the remaining low registers. */
	str r0, [r2]			/* Save the new top of stack. */
	stmia r0!, {r4-r7}		/* Store the low registers that are not saved automatically. */
	mov r4, r8				/* Store the high registers. */
	mov r5, r9
	mov r6, r10
	mov r7, r11
	stmia r0!, {r4-r7}

	push {r3, r14}
	cpsid i
	bl vTaskSwitchContext
	cpsie i
	pop {r2, r3}			/* lr goes in r3. r2 now holds tcb pointer. */

	ldr r1, [r2]
	ldr r0, [r1]			/* The first item in pxCurrentTCB is the task top of stack. */
	adds r0, r0, #16		/* Move to the high registers. */
	ldmia r0!, {r4-r7}		/* Pop the high registers. */
	mov r8, r4
	mov r9, r5
	mov r10, r6
	mov r11, r7

	msr psp, r0				/* Remember the new top of stack for the task. */

	subs r0, r0, #32		/* Go back for the low registers that are not automatically restored. */
	ldmia r0!, {r4-r7}		/* Pop low registers.  */

	bx r3

/*-----------------------------------------------------------*/

vPortSVCHandler;
	/* This function is no longer used, but retained for backward
	compatibility. */
	bx lr

/*-----------------------------------------------------------*/

vPortStartFirstTask
	/* The MSP stack is not reset as, unlike on M3/4 parts, there is no vector
	table offset register that can be used to locate the initial stack value.
	Not all M0 parts have the application vector table at address 0. */

	ldr	r3, =pxCurrentTCB	/* Obtain location of pxCurrentTCB. */
	ldr r1, [r3]
	ldr r0, [r1]			/* The first item in pxCurrentTCB is the task top of stack. */
	adds r0, #32			/* Discard everything up to r0. */
	msr psp, r0				/* This is now the new top of stack to use in the task. */
	movs r0, #2				/* Switch to the psp stack. */
	msr CONTROL, r0
	pop {r0-r5}				/* Pop the registers that are saved automatically. */
	mov lr, r5				/* lr is now in r5. */
	cpsie i					/* The first task has its context and interrupts can be enabled. */
	pop {pc}				/* Finally, pop the PC to jump to the user defined task code. */

/*-----------------------------------------------------------*/

ulSetInterruptMaskFromISR
	mrs r0, PRIMASK
	cpsid i
	bx lr

/*-----------------------------------------------------------*/

vClearInterruptMaskFromISR
	msr PRIMASK, r0
	bx lr

	END