333 lines
13 KiB
C
333 lines
13 KiB
C
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/*
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* FreeRTOS Kernel V10.2.1
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* Copyright (C) 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* http://www.FreeRTOS.org
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* http://aws.amazon.com/freertos
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*
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* 1 tab == 4 spaces!
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*/
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/*-----------------------------------------------------------
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* Implementation of functions defined in portable.h for the PIC32MX port.
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*----------------------------------------------------------*/
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#ifndef __XC
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#error This port is designed to work with XC32. Please update your C compiler version.
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#endif
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/* Scheduler include files. */
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#include "FreeRTOS.h"
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#include "task.h"
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/* Hardware specifics. */
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#define portTIMER_PRESCALE 8
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#define portPRESCALE_BITS 1
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/* Bits within various registers. */
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#define portIE_BIT ( 0x00000001 )
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#define portEXL_BIT ( 0x00000002 )
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/* Bits within the CAUSE register. */
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#define portCORE_SW_0 ( 0x00000100 )
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#define portCORE_SW_1 ( 0x00000200 )
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/* The EXL bit is set to ensure interrupts do not occur while the context of
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the first task is being restored. */
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#define portINITIAL_SR ( portIE_BIT | portEXL_BIT )
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/*
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By default port.c generates its tick interrupt from TIMER1. The user can
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override this behaviour by:
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1: Providing their own implementation of vApplicationSetupTickTimerInterrupt(),
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which is the function that configures the timer. The function is defined
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as a weak symbol in this file so if the same function name is used in the
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application code then the version in the application code will be linked
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into the application in preference to the version defined in this file.
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2: Define configTICK_INTERRUPT_VECTOR to the vector number of the timer used
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to generate the tick interrupt. For example, when timer 1 is used then
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configTICK_INTERRUPT_VECTOR is set to _TIMER_1_VECTOR.
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configTICK_INTERRUPT_VECTOR should be defined in FreeRTOSConfig.h.
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3: Define configCLEAR_TICK_TIMER_INTERRUPT() to clear the interrupt in the
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timer used to generate the tick interrupt. For example, when timer 1 is
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used configCLEAR_TICK_TIMER_INTERRUPT() is defined to
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IFS0CLR = _IFS0_T1IF_MASK.
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*/
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#ifndef configTICK_INTERRUPT_VECTOR
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#define configTICK_INTERRUPT_VECTOR _TIMER_1_VECTOR
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#define configCLEAR_TICK_TIMER_INTERRUPT() IFS0CLR = _IFS0_T1IF_MASK
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#else
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#ifndef configCLEAR_TICK_TIMER_INTERRUPT
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#error If configTICK_INTERRUPT_VECTOR is defined in application code then configCLEAR_TICK_TIMER_INTERRUPT must also be defined in application code.
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#endif
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#endif
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/* Let the user override the pre-loading of the initial RA with the address of
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prvTaskExitError() in case it messes up unwinding of the stack in the
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debugger - in which case configTASK_RETURN_ADDRESS can be defined as 0 (NULL). */
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#ifdef configTASK_RETURN_ADDRESS
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#define portTASK_RETURN_ADDRESS configTASK_RETURN_ADDRESS
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#else
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#define portTASK_RETURN_ADDRESS prvTaskExitError
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#endif
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/* Set configCHECK_FOR_STACK_OVERFLOW to 3 to add ISR stack checking to task
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stack checking. A problem in the ISR stack will trigger an assert, not call the
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stack overflow hook function (because the stack overflow hook is specific to a
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task stack, not the ISR stack). */
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#if( configCHECK_FOR_STACK_OVERFLOW > 2 )
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/* Don't use 0xa5 as the stack fill bytes as that is used by the kernerl for
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the task stacks, and so will legitimately appear in many positions within
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the ISR stack. */
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#define portISR_STACK_FILL_BYTE 0xee
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static const uint8_t ucExpectedStackBytes[] = {
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portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, \
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portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, \
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portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, \
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portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, \
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portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE, portISR_STACK_FILL_BYTE }; \
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#define portCHECK_ISR_STACK() configASSERT( ( memcmp( ( void * ) xISRStack, ( void * ) ucExpectedStackBytes, sizeof( ucExpectedStackBytes ) ) == 0 ) )
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#else
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/* Define the function away. */
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#define portCHECK_ISR_STACK()
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#endif /* configCHECK_FOR_STACK_OVERFLOW > 2 */
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/*-----------------------------------------------------------*/
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/*
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* Place the prototype here to ensure the interrupt vector is correctly installed.
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* Note that because the interrupt is written in assembly, the IPL setting in the
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* following line of code has no effect. The interrupt priority is set by the
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* call to ConfigIntTimer1() in vApplicationSetupTickTimerInterrupt().
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*/
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extern void __attribute__( (interrupt(IPL1AUTO), vector( configTICK_INTERRUPT_VECTOR ))) vPortTickInterruptHandler( void );
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/*
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* The software interrupt handler that performs the yield. Note that, because
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* the interrupt is written in assembly, the IPL setting in the following line of
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* code has no effect. The interrupt priority is set by the call to
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* mConfigIntCoreSW0() in xPortStartScheduler().
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*/
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void __attribute__( (interrupt(IPL1AUTO), vector(_CORE_SOFTWARE_0_VECTOR))) vPortYieldISR( void );
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/*
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* Used to catch tasks that attempt to return from their implementing function.
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*/
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static void prvTaskExitError( void );
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/*-----------------------------------------------------------*/
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/* Records the interrupt nesting depth. This is initialised to one as it is
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decremented to 0 when the first task starts. */
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volatile UBaseType_t uxInterruptNesting = 0x01;
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/* Stores the task stack pointer when a switch is made to use the system stack. */
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UBaseType_t uxSavedTaskStackPointer = 0;
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/* The stack used by interrupt service routines that cause a context switch. */
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__attribute__ ((aligned(8))) StackType_t xISRStack[ configISR_STACK_SIZE ] = { 0 };
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/* The top of stack value ensures there is enough space to store 6 registers on
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the callers stack, as some functions seem to want to do this. */
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const StackType_t * const xISRStackTop = &( xISRStack[ ( configISR_STACK_SIZE & ~portBYTE_ALIGNMENT_MASK ) - 8 ] );
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/*-----------------------------------------------------------*/
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/*
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* See header file for description.
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*/
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StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
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{
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/* Ensure byte alignment is maintained when leaving this function. */
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pxTopOfStack--;
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*pxTopOfStack = (StackType_t) 0xDEADBEEF;
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pxTopOfStack--;
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*pxTopOfStack = (StackType_t) 0x12345678; /* Word to which the stack pointer will be left pointing after context restore. */
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pxTopOfStack--;
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*pxTopOfStack = (StackType_t) _CP0_GET_CAUSE();
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pxTopOfStack--;
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*pxTopOfStack = (StackType_t) portINITIAL_SR;/* CP0_STATUS */
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pxTopOfStack--;
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*pxTopOfStack = (StackType_t) pxCode; /* CP0_EPC */
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pxTopOfStack--;
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*pxTopOfStack = (StackType_t) portTASK_RETURN_ADDRESS; /* ra */
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pxTopOfStack -= 15;
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*pxTopOfStack = (StackType_t) pvParameters; /* Parameters to pass in. */
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pxTopOfStack -= 15;
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return pxTopOfStack;
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}
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/*-----------------------------------------------------------*/
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static void prvTaskExitError( void )
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{
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/* A function that implements a task must not exit or attempt to return to
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its caller as there is nothing to return to. If a task wants to exit it
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should instead call vTaskDelete( NULL ).
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Artificially force an assert() to be triggered if configASSERT() is
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defined, then stop here so application writers can catch the error. */
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configASSERT( uxSavedTaskStackPointer == 0UL );
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portDISABLE_INTERRUPTS();
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for( ;; );
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}
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/*-----------------------------------------------------------*/
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/*
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* Setup a timer for a regular tick. This function uses peripheral timer 1.
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* The function is declared weak so an application writer can use a different
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* timer by redefining this implementation. If a different timer is used then
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* configTICK_INTERRUPT_VECTOR must also be defined in FreeRTOSConfig.h to
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* ensure the RTOS provided tick interrupt handler is installed on the correct
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* vector number. When Timer 1 is used the vector number is defined as
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* _TIMER_1_VECTOR.
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*/
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__attribute__(( weak )) void vApplicationSetupTickTimerInterrupt( void )
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{
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const uint32_t ulCompareMatch = ( (configPERIPHERAL_CLOCK_HZ / portTIMER_PRESCALE) / configTICK_RATE_HZ ) - 1;
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T1CON = 0x0000;
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T1CONbits.TCKPS = portPRESCALE_BITS;
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PR1 = ulCompareMatch;
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IPC1bits.T1IP = configKERNEL_INTERRUPT_PRIORITY;
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/* Clear the interrupt as a starting condition. */
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IFS0bits.T1IF = 0;
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/* Enable the interrupt. */
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IEC0bits.T1IE = 1;
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/* Start the timer. */
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T1CONbits.TON = 1;
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}
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/*-----------------------------------------------------------*/
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void vPortEndScheduler(void)
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{
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/* Not implemented in ports where there is nothing to return to.
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Artificially force an assert. */
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configASSERT( uxInterruptNesting == 1000UL );
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}
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/*-----------------------------------------------------------*/
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BaseType_t xPortStartScheduler( void )
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{
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extern void vPortStartFirstTask( void );
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extern void *pxCurrentTCB;
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#if ( configCHECK_FOR_STACK_OVERFLOW > 2 )
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{
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/* Fill the ISR stack to make it easy to asses how much is being used. */
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memset( ( void * ) xISRStack, portISR_STACK_FILL_BYTE, sizeof( xISRStack ) );
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}
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#endif /* configCHECK_FOR_STACK_OVERFLOW > 2 */
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/* Clear the software interrupt flag. */
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IFS0CLR = _IFS0_CS0IF_MASK;
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/* Set software timer priority. */
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IPC0CLR = _IPC0_CS0IP_MASK;
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IPC0SET = ( configKERNEL_INTERRUPT_PRIORITY << _IPC0_CS0IP_POSITION );
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/* Enable software interrupt. */
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IEC0CLR = _IEC0_CS0IE_MASK;
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IEC0SET = 1 << _IEC0_CS0IE_POSITION;
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/* Setup the timer to generate the tick. Interrupts will have been
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disabled by the time we get here. */
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vApplicationSetupTickTimerInterrupt();
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/* Kick off the highest priority task that has been created so far.
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Its stack location is loaded into uxSavedTaskStackPointer. */
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uxSavedTaskStackPointer = *( UBaseType_t * ) pxCurrentTCB;
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vPortStartFirstTask();
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/* Should never get here as the tasks will now be executing! Call the task
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exit error function to prevent compiler warnings about a static function
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not being called in the case that the application writer overrides this
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functionality by defining configTASK_RETURN_ADDRESS. */
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prvTaskExitError();
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return pdFALSE;
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}
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/*-----------------------------------------------------------*/
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void vPortIncrementTick( void )
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{
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UBaseType_t uxSavedStatus;
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uxSavedStatus = uxPortSetInterruptMaskFromISR();
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{
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if( xTaskIncrementTick() != pdFALSE )
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{
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/* Pend a context switch. */
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_CP0_BIS_CAUSE( portCORE_SW_0 );
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}
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}
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vPortClearInterruptMaskFromISR( uxSavedStatus );
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/* Look for the ISR stack getting near or past its limit. */
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portCHECK_ISR_STACK();
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/* Clear timer interrupt. */
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configCLEAR_TICK_TIMER_INTERRUPT();
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}
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/*-----------------------------------------------------------*/
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UBaseType_t uxPortSetInterruptMaskFromISR( void )
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{
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UBaseType_t uxSavedStatusRegister;
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__builtin_disable_interrupts();
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uxSavedStatusRegister = _CP0_GET_STATUS() | 0x01;
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/* This clears the IPL bits, then sets them to
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configMAX_SYSCALL_INTERRUPT_PRIORITY. This function should not be called
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from an interrupt that has a priority above
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configMAX_SYSCALL_INTERRUPT_PRIORITY so, when used correctly, the action
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can only result in the IPL being unchanged or raised, and therefore never
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lowered. */
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_CP0_SET_STATUS( ( ( uxSavedStatusRegister & ( ~portALL_IPL_BITS ) ) ) | ( configMAX_SYSCALL_INTERRUPT_PRIORITY << portIPL_SHIFT ) );
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return uxSavedStatusRegister;
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}
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/*-----------------------------------------------------------*/
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void vPortClearInterruptMaskFromISR( UBaseType_t uxSavedStatusRegister )
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{
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_CP0_SET_STATUS( uxSavedStatusRegister );
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}
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/*-----------------------------------------------------------*/
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