mirror of
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296 lines
12 KiB
C
296 lines
12 KiB
C
/*
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FreeRTOS V8.2.0rc1 - Copyright (C) 2014 Real Time Engineers Ltd.
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All rights reserved
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VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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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 !<<
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>>! obliged to provide the source code for proprietary components !<<
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>>! outside of the FreeRTOS 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. Full license text is available on the following
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link: http://www.freertos.org/a00114.html
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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?". Have you defined configASSERT()? *
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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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***************************************************************************
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* *
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* FreeRTOS provides completely free yet professionally developed, *
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* robust, strictly quality controlled, supported, and cross *
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* platform software that is more than just the market leader, it *
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* is the industry's de facto standard. *
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* *
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* Help yourself get started quickly while simultaneously helping *
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* to support the FreeRTOS project by purchasing a FreeRTOS *
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* tutorial book, reference manual, or both: *
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* http://www.FreeRTOS.org/Documentation *
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* *
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***************************************************************************
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***************************************************************************
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* *
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* Investing in training allows your team to be as productive as *
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* possible as early as possible, lowering your overall development *
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* cost, and enabling you to bring a more robust product to market *
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* earlier than would otherwise be possible. Richard Barry is both *
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* the architect and key author of FreeRTOS, and so also the world's *
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* leading authority on what is the world's most popular real time *
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* kernel for deeply embedded MCU designs. Obtaining your training *
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* from Richard ensures your team will gain directly from his in-depth *
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* product knowledge and years of usage experience. Contact Real Time *
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* Engineers Ltd to enquire about the FreeRTOS Masterclass, presented *
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* by Richard Barry: http://www.FreeRTOS.org/contact
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* *
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***************************************************************************
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***************************************************************************
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* *
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* You are receiving this top quality software for free. Please play *
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* fair and reciprocate by reporting any suspected issues and *
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* participating in the community forum: *
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* http://www.FreeRTOS.org/support *
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* *
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* Thank you! *
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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, a DOS
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compatible FAT file system, and our tiny thread aware UDP/IP stack.
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http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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licenses offer ticketed support, indemnification and commercial middleware.
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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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1 tab == 4 spaces!
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*/
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/*-----------------------------------------------------------
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* Components that can be compiled to either ARM or THUMB mode are
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* contained in port.c The ISR routines, which can only be compiled
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* to ARM mode, are contained in this file.
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*----------------------------------------------------------*/
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/*
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Changes from V3.2.4
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+ The assembler statements are now included in a single asm block rather
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than each line having its own asm block.
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*/
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/* Scheduler includes. */
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#include "FreeRTOS.h"
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#include "task.h"
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#include "AT91SAM7X256.h"
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/* Constants required to handle interrupts. */
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#define portTIMER_MATCH_ISR_BIT ( ( uint8_t ) 0x01 )
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#define portCLEAR_VIC_INTERRUPT ( ( uint32_t ) 0 )
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/* Constants required to handle critical sections. */
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#define portNO_CRITICAL_NESTING ( ( uint32_t ) 0 )
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volatile uint32_t ulCriticalNesting = 9999UL;
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/*-----------------------------------------------------------*/
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/* ISR to handle manual context switches (from a call to taskYIELD()). */
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void vPortYieldProcessor( void ) __attribute__((interrupt("SWI"), naked));
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/*
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* The scheduler can only be started from ARM mode, hence the inclusion of this
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* function here.
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*/
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void vPortISRStartFirstTask( void );
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/*-----------------------------------------------------------*/
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void vPortISRStartFirstTask( void )
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{
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/* Simply start the scheduler. This is included here as it can only be
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called from ARM mode. */
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portRESTORE_CONTEXT();
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}
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/*-----------------------------------------------------------*/
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/*
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* Called by portYIELD() or taskYIELD() to manually force a context switch.
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*
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* When a context switch is performed from the task level the saved task
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* context is made to look as if it occurred from within the tick ISR. This
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* way the same restore context function can be used when restoring the context
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* saved from the ISR or that saved from a call to vPortYieldProcessor.
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*/
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void vPortYieldProcessor( void )
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{
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/* Within an IRQ ISR the link register has an offset from the true return
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address, but an SWI ISR does not. Add the offset manually so the same
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ISR return code can be used in both cases. */
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__asm volatile ( "ADD LR, LR, #4" );
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/* Perform the context switch. First save the context of the current task. */
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portSAVE_CONTEXT();
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/* Find the highest priority task that is ready to run. */
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vTaskSwitchContext();
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/* Restore the context of the new task. */
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portRESTORE_CONTEXT();
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}
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/*-----------------------------------------------------------*/
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/*
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* The ISR used for the scheduler tick depends on whether the cooperative or
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* the preemptive scheduler is being used.
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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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void vNonPreemptiveTick( void ) __attribute__ ((interrupt ("IRQ")));
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void vNonPreemptiveTick( void )
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{
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uint32_t 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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/* The preemptive scheduler is defined as "naked" as the full context is
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saved on entry as part of the context switch. */
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void vPreemptiveTick( void ) __attribute__((naked));
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void vPreemptiveTick( void )
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{
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/* Save the context of the current task. */
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portSAVE_CONTEXT();
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/* Increment the tick count - this may wake a task. */
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if( xTaskIncrementTick() != pdFALSE )
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{
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/* Find the highest priority task that is ready to run. */
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vTaskSwitchContext();
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}
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/* End the interrupt in the AIC. */
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AT91C_BASE_AIC->AIC_EOICR = AT91C_BASE_PITC->PITC_PIVR;
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portRESTORE_CONTEXT();
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}
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#endif
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/*-----------------------------------------------------------*/
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/*
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* The interrupt management utilities can only be called from ARM mode. When
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* THUMB_INTERWORK is defined the utilities are defined as functions here to
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* ensure a switch to ARM mode. When THUMB_INTERWORK is not defined then
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* the utilities are defined as macros in portmacro.h - as per other ports.
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*/
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void vPortDisableInterruptsFromThumb( void ) __attribute__ ((naked));
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void vPortEnableInterruptsFromThumb( void ) __attribute__ ((naked));
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void vPortDisableInterruptsFromThumb( void )
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{
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__asm volatile (
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"STMDB SP!, {R0} \n\t" /* Push R0. */
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"MRS R0, CPSR \n\t" /* Get CPSR. */
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"ORR R0, R0, #0xC0 \n\t" /* Disable IRQ, FIQ. */
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"MSR CPSR, R0 \n\t" /* Write back modified value. */
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"LDMIA SP!, {R0} \n\t" /* Pop R0. */
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"BX R14" ); /* Return back to thumb. */
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}
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void vPortEnableInterruptsFromThumb( void )
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{
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__asm volatile (
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"STMDB SP!, {R0} \n\t" /* Push R0. */
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"MRS R0, CPSR \n\t" /* Get CPSR. */
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"BIC R0, R0, #0xC0 \n\t" /* Enable IRQ, FIQ. */
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"MSR CPSR, R0 \n\t" /* Write back modified value. */
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"LDMIA SP!, {R0} \n\t" /* Pop R0. */
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"BX R14" ); /* Return back to thumb. */
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}
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/* The code generated by the GCC compiler uses the stack in different ways at
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different optimisation levels. The interrupt flags can therefore not always
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be saved to the stack. Instead the critical section nesting level is stored
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in a variable, which is then saved as part of the stack context. */
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void vPortEnterCritical( void )
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{
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/* Disable interrupts as per portDISABLE_INTERRUPTS(); */
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__asm volatile (
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"STMDB SP!, {R0} \n\t" /* Push R0. */
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"MRS R0, CPSR \n\t" /* Get CPSR. */
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"ORR R0, R0, #0xC0 \n\t" /* Disable IRQ, FIQ. */
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"MSR CPSR, R0 \n\t" /* Write back modified value. */
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"LDMIA SP!, {R0}" ); /* Pop R0. */
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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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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 interrupts as per portEXIT_CRITICAL(). */
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__asm volatile (
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"STMDB SP!, {R0} \n\t" /* Push R0. */
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"MRS R0, CPSR \n\t" /* Get CPSR. */
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"BIC R0, R0, #0xC0 \n\t" /* Enable IRQ, FIQ. */
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"MSR CPSR, R0 \n\t" /* Write back modified value. */
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"LDMIA SP!, {R0}" ); /* Pop R0. */
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}
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}
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}
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