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307 lines
12 KiB
C
307 lines
12 KiB
C
/*
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FreeRTOS V7.4.2 - Copyright (C) 2013 Real Time Engineers Ltd.
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FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
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http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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***************************************************************************
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* *
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* FreeRTOS tutorial books are available in pdf and paperback. *
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* Complete, revised, and edited pdf reference manuals are also *
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* available. *
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* *
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* Purchasing FreeRTOS documentation will not only help you, by *
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* ensuring you get running as quickly as possible and with an *
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* in-depth knowledge of how to use FreeRTOS, it will also help *
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* the FreeRTOS project to continue with its mission of providing *
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* professional grade, cross platform, de facto standard solutions *
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* for microcontrollers - completely free of charge! *
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* *
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* >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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* *
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* Thank you for using FreeRTOS, and thank you for your support! *
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* *
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***************************************************************************
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This file is part of the FreeRTOS distribution.
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FreeRTOS is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License (version 2) as published by the
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Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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>>>>>>NOTE<<<<<< The modification to the GPL is included to allow you to
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distribute a combined work that includes FreeRTOS without being obliged to
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provide the source code for proprietary components outside of the FreeRTOS
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kernel.
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FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details. You should have received a copy of the GNU General Public License
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and the FreeRTOS license exception along with FreeRTOS; if not it can be
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viewed here: http://www.freertos.org/a00114.html and also obtained by
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writing to Real Time Engineers Ltd., contact details for whom are available
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on the FreeRTOS WEB site.
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1 tab == 4 spaces!
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***************************************************************************
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* *
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* Having a problem? Start by reading the FAQ "My application does *
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* not run, what could be wrong?" *
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* *
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* http://www.FreeRTOS.org/FAQHelp.html *
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* *
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***************************************************************************
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http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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license and Real Time Engineers Ltd. contact details.
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http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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including FreeRTOS+Trace - an indispensable productivity tool, and our new
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fully thread aware and reentrant UDP/IP stack.
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http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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Integrity Systems, who sell the code with commercial support,
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indemnification and middleware, under the OpenRTOS brand.
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http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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engineered and independently SIL3 certified version for use in safety and
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mission critical applications that require provable dependability.
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*/
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/*-----------------------------------------------------------
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* Implementation of functions defined in portable.h for the Atmel ARM7 port.
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*----------------------------------------------------------*/
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/* Standard includes. */
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#include <stdlib.h>
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/* Scheduler includes. */
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#include "FreeRTOS.h"
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#include "task.h"
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/* Constants required to setup the initial stack. */
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#define portINITIAL_SPSR ( ( portSTACK_TYPE ) 0x1f ) /* System mode, ARM mode, interrupts enabled. */
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#define portTHUMB_MODE_BIT ( ( portSTACK_TYPE ) 0x20 )
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#define portINSTRUCTION_SIZE ( ( portSTACK_TYPE ) 4 )
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/* Constants required to setup the PIT. */
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#define portPIT_CLOCK_DIVISOR ( ( unsigned long ) 16 )
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#define portPIT_COUNTER_VALUE ( ( ( configCPU_CLOCK_HZ / portPIT_CLOCK_DIVISOR ) / 1000UL ) * portTICK_RATE_MS )
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/* Constants required to handle critical sections. */
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#define portNO_CRITICAL_NESTING ( ( unsigned long ) 0 )
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#define portINT_LEVEL_SENSITIVE 0
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#define portPIT_ENABLE ( ( unsigned short ) 0x1 << 24 )
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#define portPIT_INT_ENABLE ( ( unsigned short ) 0x1 << 25 )
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/*-----------------------------------------------------------*/
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/* Setup the PIT to generate the tick interrupts. */
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static void prvSetupTimerInterrupt( void );
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/* ulCriticalNesting will get set to zero when the first task starts. It
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cannot be initialised to 0 as this will cause interrupts to be enabled
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during the kernel initialisation process. */
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unsigned long ulCriticalNesting = ( unsigned long ) 9999;
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/*-----------------------------------------------------------*/
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/*
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* Initialise the stack of a task to look exactly as if a call to
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* portSAVE_CONTEXT had been called.
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*
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* See header file for description.
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*/
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portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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{
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portSTACK_TYPE *pxOriginalTOS;
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pxOriginalTOS = pxTopOfStack;
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/* To ensure asserts in tasks.c don't fail, although in this case the assert
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is not really required. */
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pxTopOfStack--;
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/* Setup the initial stack of the task. The stack is set exactly as
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expected by the portRESTORE_CONTEXT() macro. */
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/* First on the stack is the return address - which in this case is the
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start of the task. The offset is added to make the return address appear
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as it would within an IRQ ISR. */
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*pxTopOfStack = ( portSTACK_TYPE ) pxCode + portINSTRUCTION_SIZE;
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0xaaaaaaaa; /* R14 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) pxOriginalTOS; /* Stack used when task starts goes in R13. */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x12121212; /* R12 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x11111111; /* R11 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x10101010; /* R10 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x09090909; /* R9 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x08080808; /* R8 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x07070707; /* R7 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x06060606; /* R6 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x05050505; /* R5 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x04040404; /* R4 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x03030303; /* R3 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x02020202; /* R2 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x01010101; /* R1 */
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pxTopOfStack--;
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/* When the task starts is will expect to find the function parameter in
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R0. */
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*pxTopOfStack = ( portSTACK_TYPE ) pvParameters; /* R0 */
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pxTopOfStack--;
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/* The status register is set for system mode, with interrupts enabled. */
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*pxTopOfStack = ( portSTACK_TYPE ) portINITIAL_SPSR;
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if( ( ( unsigned long ) pxCode & 0x01UL ) != 0x00UL )
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{
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/* We want the task to start in thumb mode. */
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*pxTopOfStack |= portTHUMB_MODE_BIT;
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}
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pxTopOfStack--;
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/* Interrupt flags cannot always be stored on the stack and will
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instead be stored in a variable, which is then saved as part of the
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tasks context. */
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*pxTopOfStack = portNO_CRITICAL_NESTING;
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return pxTopOfStack;
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}
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/*-----------------------------------------------------------*/
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portBASE_TYPE xPortStartScheduler( void )
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{
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extern void vPortStartFirstTask( void );
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/* Start the timer that generates the tick ISR. Interrupts are disabled
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here already. */
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prvSetupTimerInterrupt();
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/* Start the first task. */
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vPortStartFirstTask();
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/* Should not get here! */
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return 0;
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}
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/*-----------------------------------------------------------*/
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void vPortEndScheduler( void )
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{
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/* It is unlikely that the ARM port will require this function as there
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is nothing to return to. */
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}
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/*-----------------------------------------------------------*/
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#if configUSE_PREEMPTION == 0
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/* The cooperative scheduler requires a normal IRQ service routine to
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simply increment the system tick. */
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static __arm __irq void vPortNonPreemptiveTick( void );
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static __arm __irq void vPortNonPreemptiveTick( void )
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{
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unsigned long ulDummy;
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/* Increment the tick count - which may wake some tasks but as the
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preemptive scheduler is not being used any woken task is not given
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processor time no matter what its priority. */
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xTaskIncrementTick();
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/* Clear the PIT interrupt. */
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ulDummy = AT91C_BASE_PITC->PITC_PIVR;
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/* End the interrupt in the AIC. */
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AT91C_BASE_AIC->AIC_EOICR = ulDummy;
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}
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#else
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/* Currently the IAR port requires the preemptive tick function to be
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defined in an asm file. */
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#endif
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/*-----------------------------------------------------------*/
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static void prvSetupTimerInterrupt( void )
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{
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AT91PS_PITC pxPIT = AT91C_BASE_PITC;
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/* Setup the AIC for PIT interrupts. The interrupt routine chosen depends
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on whether the preemptive or cooperative scheduler is being used. */
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#if configUSE_PREEMPTION == 0
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AT91F_AIC_ConfigureIt( AT91C_BASE_AIC, AT91C_ID_SYS, AT91C_AIC_PRIOR_HIGHEST, portINT_LEVEL_SENSITIVE, ( void (*)(void) ) vPortNonPreemptiveTick );
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#else
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extern void ( vPortPreemptiveTick )( void );
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AT91F_AIC_ConfigureIt( AT91C_BASE_AIC, AT91C_ID_SYS, AT91C_AIC_PRIOR_HIGHEST, portINT_LEVEL_SENSITIVE, ( void (*)(void) ) vPortPreemptiveTick );
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#endif
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/* Configure the PIT period. */
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pxPIT->PITC_PIMR = portPIT_ENABLE | portPIT_INT_ENABLE | portPIT_COUNTER_VALUE;
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/* Enable the interrupt. Global interrupts are disables at this point so
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this is safe. */
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AT91F_AIC_EnableIt( AT91C_BASE_AIC, AT91C_ID_SYS );
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}
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/*-----------------------------------------------------------*/
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void vPortEnterCritical( void )
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{
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/* Disable interrupts first! */
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__disable_interrupt();
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/* Now interrupts are disabled ulCriticalNesting can be accessed
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directly. Increment ulCriticalNesting to keep a count of how many times
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portENTER_CRITICAL() has been called. */
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ulCriticalNesting++;
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}
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/*-----------------------------------------------------------*/
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void vPortExitCritical( void )
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{
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if( ulCriticalNesting > portNO_CRITICAL_NESTING )
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{
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/* Decrement the nesting count as we are leaving a critical section. */
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ulCriticalNesting--;
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/* If the nesting level has reached zero then interrupts should be
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re-enabled. */
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if( ulCriticalNesting == portNO_CRITICAL_NESTING )
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{
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__enable_interrupt();
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}
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}
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}
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/*-----------------------------------------------------------*/
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