2 * FreeRTOS Kernel V10.3.0
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3 * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
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6 * this software and associated documentation files (the "Software"), to deal in
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7 * the Software without restriction, including without limitation the rights to
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8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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9 * the Software, and to permit persons to whom the Software is furnished to do so,
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10 * subject to the following conditions:
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12 * The above copyright notice and this permission notice shall be included in all
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13 * copies or substantial portions of the Software.
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15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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17 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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18 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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19 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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20 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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22 * http://www.FreeRTOS.org
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23 * http://aws.amazon.com/freertos
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25 * 1 tab == 4 spaces!
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28 /* Kernel includes. */
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29 #include "FreeRTOS.h"
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32 #define portINITIAL_FORMAT_VECTOR ( ( StackType_t ) 0x4000 )
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34 /* Supervisor mode set. */
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35 #define portINITIAL_STATUS_REGISTER ( ( StackType_t ) 0x2000)
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37 /* Used to keep track of the number of nested calls to taskENTER_CRITICAL(). This
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38 will be set to 0 prior to the first task being started. */
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39 static uint32_t ulCriticalNesting = 0x9999UL;
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41 /*-----------------------------------------------------------*/
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43 StackType_t *pxPortInitialiseStack( StackType_t * pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
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45 *pxTopOfStack = ( StackType_t ) pvParameters;
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48 *pxTopOfStack = (StackType_t) 0xDEADBEEF;
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51 /* Exception stack frame starts with the return address. */
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52 *pxTopOfStack = ( StackType_t ) pxCode;
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55 *pxTopOfStack = ( portINITIAL_FORMAT_VECTOR << 16UL ) | ( portINITIAL_STATUS_REGISTER );
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58 *pxTopOfStack = ( StackType_t ) 0x0; /*FP*/
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59 pxTopOfStack -= 14; /* A5 to D0. */
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61 return pxTopOfStack;
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63 /*-----------------------------------------------------------*/
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65 BaseType_t xPortStartScheduler( void )
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67 extern void vPortStartFirstTask( void );
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69 ulCriticalNesting = 0UL;
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71 /* Configure the interrupts used by this port. */
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72 vApplicationSetupInterrupts();
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74 /* Start the first task executing. */
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75 vPortStartFirstTask();
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79 /*-----------------------------------------------------------*/
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81 void vPortEndScheduler( void )
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83 /* Not implemented as there is nothing to return to. */
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85 /*-----------------------------------------------------------*/
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87 void vPortEnterCritical( void )
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89 if( ulCriticalNesting == 0UL )
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91 /* Guard against context switches being pended simultaneously with a
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92 critical section being entered. */
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95 portDISABLE_INTERRUPTS();
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96 if( MCF_INTC0_INTFRCL == 0UL )
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101 portENABLE_INTERRUPTS();
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105 ulCriticalNesting++;
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107 /*-----------------------------------------------------------*/
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109 void vPortExitCritical( void )
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111 ulCriticalNesting--;
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112 if( ulCriticalNesting == 0 )
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114 portENABLE_INTERRUPTS();
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117 /*-----------------------------------------------------------*/
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119 void vPortYieldHandler( void )
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121 uint32_t ulSavedInterruptMask;
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123 ulSavedInterruptMask = portSET_INTERRUPT_MASK_FROM_ISR();
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124 /* Note this will clear all forced interrupts - this is done for speed. */
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125 MCF_INTC0_INTFRCL = 0;
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126 vTaskSwitchContext();
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127 portCLEAR_INTERRUPT_MASK_FROM_ISR( ulSavedInterruptMask );
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