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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33 #define portINITIAL_FORMAT_VECTOR ( ( StackType_t ) 0x4000 )
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35 /* Supervisor mode set. */
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36 #define portINITIAL_STATUS_REGISTER ( ( StackType_t ) 0x2000)
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38 /* The clock prescale into the timer peripheral. */
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39 #define portPRESCALE_VALUE ( ( uint8_t ) 10 )
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41 /* The clock frequency into the RTC. */
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42 #define portRTC_CLOCK_HZ ( ( uint32_t ) 1000 )
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44 asm void interrupt VectorNumber_VL1swi vPortYieldISR( void );
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45 static void prvSetupTimerInterrupt( void );
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47 /* Used to keep track of the number of nested calls to taskENTER_CRITICAL(). This
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48 will be set to 0 prior to the first task being started. */
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49 static uint32_t ulCriticalNesting = 0x9999UL;
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51 /*-----------------------------------------------------------*/
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53 StackType_t *pxPortInitialiseStack( StackType_t * pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
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56 uint32_t ulOriginalA5;
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58 __asm{ MOVE.L A5, ulOriginalA5 };
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61 *pxTopOfStack = (StackType_t) 0xDEADBEEF;
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64 /* Exception stack frame starts with the return address. */
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65 *pxTopOfStack = ( StackType_t ) pxCode;
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68 *pxTopOfStack = ( portINITIAL_FORMAT_VECTOR << 16UL ) | ( portINITIAL_STATUS_REGISTER );
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71 *pxTopOfStack = ( StackType_t ) 0x0; /*FP*/
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72 pxTopOfStack -= 14; /* A5 to D0. */
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74 /* Parameter in A0. */
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75 *( pxTopOfStack + 8 ) = ( StackType_t ) pvParameters;
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77 /* A5 must be maintained as it is resurved by the compiler. */
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78 *( pxTopOfStack + 13 ) = ulOriginalA5;
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80 return pxTopOfStack;
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82 /*-----------------------------------------------------------*/
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84 BaseType_t xPortStartScheduler( void )
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86 extern void vPortStartFirstTask( void );
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88 ulCriticalNesting = 0UL;
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90 /* Configure a timer to generate the tick interrupt. */
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91 prvSetupTimerInterrupt();
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93 /* Start the first task executing. */
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94 vPortStartFirstTask();
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98 /*-----------------------------------------------------------*/
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100 static void prvSetupTimerInterrupt( void )
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102 /* Prescale by 1 - ie no prescale. */
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105 /* Compare match value. */
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106 RTCMOD = portRTC_CLOCK_HZ / configTICK_RATE_HZ;
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108 /* Enable the RTC to generate interrupts - interrupts are already disabled
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109 when this code executes. */
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112 /*-----------------------------------------------------------*/
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114 void vPortEndScheduler( void )
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116 /* Not implemented as there is nothing to return to. */
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118 /*-----------------------------------------------------------*/
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120 void vPortEnterCritical( void )
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122 if( ulCriticalNesting == 0UL )
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124 /* Guard against context switches being pended simultaneously with a
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125 critical section being entered. */
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128 portDISABLE_INTERRUPTS();
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129 if( INTC_FRC == 0UL )
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134 portENABLE_INTERRUPTS();
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138 ulCriticalNesting++;
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140 /*-----------------------------------------------------------*/
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142 void vPortExitCritical( void )
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144 ulCriticalNesting--;
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145 if( ulCriticalNesting == 0 )
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147 portENABLE_INTERRUPTS();
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150 /*-----------------------------------------------------------*/
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152 void vPortYieldHandler( void )
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154 uint32_t ulSavedInterruptMask;
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156 ulSavedInterruptMask = portSET_INTERRUPT_MASK_FROM_ISR();
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158 /* Note this will clear all forced interrupts - this is done for speed. */
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160 vTaskSwitchContext();
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162 portCLEAR_INTERRUPT_MASK_FROM_ISR( ulSavedInterruptMask );
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164 /*-----------------------------------------------------------*/
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166 void interrupt VectorNumber_Vrtc vPortTickISR( void )
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168 uint32_t ulSavedInterruptMask;
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170 /* Clear the interrupt. */
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171 RTCSC |= RTCSC_RTIF_MASK;
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173 /* Increment the RTOS tick. */
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174 ulSavedInterruptMask = portSET_INTERRUPT_MASK_FROM_ISR();
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176 if( xTaskIncrementTick() != pdFALSE )
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181 portCLEAR_INTERRUPT_MASK_FROM_ISR( ulSavedInterruptMask );
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