2 FreeRTOS V7.4.2 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
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5 http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS tutorial books are available in pdf and paperback. *
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10 * Complete, revised, and edited pdf reference manuals are also *
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13 * Purchasing FreeRTOS documentation will not only help you, by *
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14 * ensuring you get running as quickly as possible and with an *
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15 * in-depth knowledge of how to use FreeRTOS, it will also help *
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16 * the FreeRTOS project to continue with its mission of providing *
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17 * professional grade, cross platform, de facto standard solutions *
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18 * for microcontrollers - completely free of charge! *
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20 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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22 * Thank you for using FreeRTOS, and thank you for your support! *
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24 ***************************************************************************
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27 This file is part of the FreeRTOS distribution.
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29 FreeRTOS is free software; you can redistribute it and/or modify it under
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30 the terms of the GNU General Public License (version 2) as published by the
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31 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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33 >>>>>>NOTE<<<<<< The modification to the GPL is included to allow you to
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34 distribute a combined work that includes FreeRTOS without being obliged to
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35 provide the source code for proprietary components outside of the FreeRTOS
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38 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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39 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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40 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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41 details. You should have received a copy of the GNU General Public License
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42 and the FreeRTOS license exception along with FreeRTOS; if not it can be
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43 viewed here: http://www.freertos.org/a00114.html and also obtained by
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44 writing to Real Time Engineers Ltd., contact details for whom are available
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45 on the FreeRTOS WEB site.
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49 ***************************************************************************
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51 * Having a problem? Start by reading the FAQ "My application does *
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52 * not run, what could be wrong?" *
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54 * http://www.FreeRTOS.org/FAQHelp.html *
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56 ***************************************************************************
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59 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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60 license and Real Time Engineers Ltd. contact details.
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62 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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63 including FreeRTOS+Trace - an indispensable productivity tool, and our new
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64 fully thread aware and reentrant UDP/IP stack.
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66 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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67 Integrity Systems, who sell the code with commercial support,
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68 indemnification and middleware, under the OpenRTOS brand.
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70 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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71 engineered and independently SIL3 certified version for use in safety and
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72 mission critical applications that require provable dependability.
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76 * Creates eight tasks, each of which loops continuously performing a
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77 * floating point calculation.
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79 * All the tasks run at the idle priority and never block or yield. This causes
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80 * all eight tasks to time slice with the idle task. Running at the idle priority
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81 * means that these tasks will get pre-empted any time another task is ready to run
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82 * or a time slice occurs. More often than not the pre-emption will occur mid
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83 * calculation, creating a good test of the schedulers context switch mechanism - a
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84 * calculation producing an unexpected result could be a symptom of a corruption in
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85 * the context of a task.
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87 * This file demonstrates the use of the task tag and traceTASK_SWITCHED_IN and
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88 * traceTASK_SWITCHED_OUT macros to save and restore the floating point context.
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94 /* Scheduler include files. */
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95 #include "FreeRTOS.h"
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98 /* Demo program include files. */
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101 /* Misc. definitions. */
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102 #define mathSTACK_SIZE configMINIMAL_STACK_SIZE
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103 #define mathNUMBER_OF_TASKS ( 8 )
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105 /* Four tasks, each of which performs a different floating point calculation.
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106 Each of the four is created twice. */
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107 static portTASK_FUNCTION_PROTO( vCompetingMathTask1, pvParameters );
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108 static portTASK_FUNCTION_PROTO( vCompetingMathTask2, pvParameters );
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109 static portTASK_FUNCTION_PROTO( vCompetingMathTask3, pvParameters );
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110 static portTASK_FUNCTION_PROTO( vCompetingMathTask4, pvParameters );
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112 /* These variables are used to check that all the tasks are still running. If a
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113 task gets a calculation wrong it will stop incrementing its check variable. */
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114 static volatile unsigned portSHORT usTaskCheck[ mathNUMBER_OF_TASKS ] = { ( unsigned portSHORT ) 0 };
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116 /* Buffers into which the flop registers will be saved. There is a buffer for
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117 each task created within this file. Zeroing out this array is the normal and
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118 safe option as this will cause the task to start with all zeros in its flop
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120 static unsigned portLONG ulFlopRegisters[ mathNUMBER_OF_TASKS ][ portNO_FLOP_REGISTERS_TO_SAVE ];
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122 /*-----------------------------------------------------------*/
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124 void vStartMathTasks( unsigned portBASE_TYPE uxPriority )
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126 xTaskHandle xTaskJustCreated;
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127 portBASE_TYPE x, y;
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129 /* Place known values into the buffers into which the flop registers are
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130 to be saved. This is for debug purposes only, it is not normally
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131 required. The last position in each array is left at zero as the status
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132 register will be loaded from there.
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134 It is intended that these values can be viewed being loaded into the
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135 flop registers when a task is started - however the Insight debugger
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136 does not seem to want to show the flop register values. */
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137 for( x = 0; x < mathNUMBER_OF_TASKS; x++ )
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139 for( y = 0; y < ( portNO_FLOP_REGISTERS_TO_SAVE - 1 ); y++ )
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141 ulFlopRegisters[ x ][ y ] = ( x + 1 );
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145 /* Create the first task - passing it the address of the check variable
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146 that it is going to increment. This check variable is used as an
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147 indication that the task is still running. */
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148 xTaskCreate( vCompetingMathTask1, ( signed portCHAR * ) "Math1", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 0 ] ), uxPriority, &xTaskJustCreated );
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150 /* The task tag value is a value that can be associated with a task, but
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151 is not used by the scheduler itself. Its use is down to the application so
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152 it makes a convenient place in this case to store the pointer to the buffer
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153 into which the flop context of the task will be stored. The first created
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154 task uses ulFlopRegisters[ 0 ], the second ulFlopRegisters[ 1 ], etc. */
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155 vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( ulFlopRegisters[ 0 ][ 0 ] ) );
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157 /* Create another 7 tasks, allocating a buffer for each. */
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158 xTaskCreate( vCompetingMathTask2, ( signed portCHAR * ) "Math2", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 1 ] ), uxPriority, &xTaskJustCreated );
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159 vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( ulFlopRegisters[ 1 ][ 0 ] ) );
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161 xTaskCreate( vCompetingMathTask3, ( signed portCHAR * ) "Math3", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 2 ] ), uxPriority, &xTaskJustCreated );
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162 vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( ulFlopRegisters[ 2 ][ 0 ] ) );
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164 xTaskCreate( vCompetingMathTask4, ( signed portCHAR * ) "Math4", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 3 ] ), uxPriority, &xTaskJustCreated );
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165 vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( ulFlopRegisters[ 3 ][ 0 ] ) );
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167 xTaskCreate( vCompetingMathTask1, ( signed portCHAR * ) "Math5", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 4 ] ), uxPriority, &xTaskJustCreated );
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168 vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( ulFlopRegisters[ 4 ][ 0 ] ) );
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170 xTaskCreate( vCompetingMathTask2, ( signed portCHAR * ) "Math6", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 5 ] ), uxPriority, &xTaskJustCreated );
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171 vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( ulFlopRegisters[ 5 ][ 0 ] ) );
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173 xTaskCreate( vCompetingMathTask3, ( signed portCHAR * ) "Math7", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 6 ] ), uxPriority, &xTaskJustCreated );
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174 vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( ulFlopRegisters[ 6 ][ 0 ] ) );
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176 xTaskCreate( vCompetingMathTask4, ( signed portCHAR * ) "Math8", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 7 ] ), uxPriority, &xTaskJustCreated );
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177 vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( ulFlopRegisters[ 7 ][ 0 ] ) );
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179 /*-----------------------------------------------------------*/
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181 static portTASK_FUNCTION( vCompetingMathTask1, pvParameters )
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183 volatile portFLOAT ff1, ff2, ff3, ff4;
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184 volatile unsigned portSHORT *pusTaskCheckVariable;
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185 volatile portFLOAT fAnswer;
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186 portSHORT sError = pdFALSE;
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192 fAnswer = ( ff1 + ff2 ) * ff3;
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194 /* The variable this task increments to show it is still running is passed in
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195 as the parameter. */
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196 pusTaskCheckVariable = ( unsigned portSHORT * ) pvParameters;
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198 /* Keep performing a calculation and checking the result against a constant. */
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205 ff4 = ( ff1 + ff2 ) * ff3;
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207 #if configUSE_PREEMPTION == 0
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211 /* If the calculation does not match the expected constant, stop the
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212 increment of the check variable. */
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213 if( fabs( ff4 - fAnswer ) > 0.001F )
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218 if( sError == pdFALSE )
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220 /* If the calculation has always been correct, increment the check
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221 variable so we know this task is still running okay. */
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222 ( *pusTaskCheckVariable )++;
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225 #if configUSE_PREEMPTION == 0
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231 /*-----------------------------------------------------------*/
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233 static portTASK_FUNCTION( vCompetingMathTask2, pvParameters )
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235 volatile portFLOAT ff1, ff2, ff3, ff4;
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236 volatile unsigned portSHORT *pusTaskCheckVariable;
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237 volatile portFLOAT fAnswer;
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238 portSHORT sError = pdFALSE;
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244 fAnswer = ( ff1 / ff2 ) * ff3;
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247 /* The variable this task increments to show it is still running is passed in
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248 as the parameter. */
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249 pusTaskCheckVariable = ( unsigned portSHORT * ) pvParameters;
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251 /* Keep performing a calculation and checking the result against a constant. */
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258 ff4 = ( ff1 / ff2 ) * ff3;
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260 #if configUSE_PREEMPTION == 0
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264 /* If the calculation does not match the expected constant, stop the
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265 increment of the check variable. */
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266 if( fabs( ff4 - fAnswer ) > 0.001F )
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271 if( sError == pdFALSE )
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273 /* If the calculation has always been correct, increment the check
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274 variable so we know
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275 this task is still running okay. */
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276 ( *pusTaskCheckVariable )++;
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279 #if configUSE_PREEMPTION == 0
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284 /*-----------------------------------------------------------*/
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286 static portTASK_FUNCTION( vCompetingMathTask3, pvParameters )
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288 volatile portFLOAT *pfArray, fTotal1, fTotal2, fDifference;
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289 volatile unsigned portSHORT *pusTaskCheckVariable;
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290 const size_t xArraySize = 10;
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292 portSHORT sError = pdFALSE;
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294 /* The variable this task increments to show it is still running is passed in
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295 as the parameter. */
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296 pusTaskCheckVariable = ( unsigned portSHORT * ) pvParameters;
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298 pfArray = ( portFLOAT * ) pvPortMalloc( xArraySize * sizeof( portFLOAT ) );
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300 /* Keep filling an array, keeping a running total of the values placed in the
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301 array. Then run through the array adding up all the values. If the two totals
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302 do not match, stop the check variable from incrementing. */
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308 for( xPosition = 0; xPosition < xArraySize; xPosition++ )
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310 pfArray[ xPosition ] = ( portFLOAT ) xPosition + 5.5F;
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311 fTotal1 += ( portFLOAT ) xPosition + 5.5F;
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314 #if configUSE_PREEMPTION == 0
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318 for( xPosition = 0; xPosition < xArraySize; xPosition++ )
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320 fTotal2 += pfArray[ xPosition ];
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323 fDifference = fTotal1 - fTotal2;
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324 if( fabs( fDifference ) > 0.001F )
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329 #if configUSE_PREEMPTION == 0
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333 if( sError == pdFALSE )
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335 /* If the calculation has always been correct, increment the check
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336 variable so we know this task is still running okay. */
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337 ( *pusTaskCheckVariable )++;
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341 /*-----------------------------------------------------------*/
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343 static portTASK_FUNCTION( vCompetingMathTask4, pvParameters )
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345 volatile portFLOAT *pfArray, fTotal1, fTotal2, fDifference;
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346 volatile unsigned portSHORT *pusTaskCheckVariable;
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347 const size_t xArraySize = 10;
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349 portSHORT sError = pdFALSE;
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351 /* The variable this task increments to show it is still running is passed in
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352 as the parameter. */
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353 pusTaskCheckVariable = ( unsigned portSHORT * ) pvParameters;
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355 pfArray = ( portFLOAT * ) pvPortMalloc( xArraySize * sizeof( portFLOAT ) );
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357 /* Keep filling an array, keeping a running total of the values placed in the
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358 array. Then run through the array adding up all the values. If the two totals
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359 do not match, stop the check variable from incrementing. */
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365 for( xPosition = 0; xPosition < xArraySize; xPosition++ )
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367 pfArray[ xPosition ] = ( portFLOAT ) xPosition * 12.123F;
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368 fTotal1 += ( portFLOAT ) xPosition * 12.123F;
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371 #if configUSE_PREEMPTION == 0
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375 for( xPosition = 0; xPosition < xArraySize; xPosition++ )
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377 fTotal2 += pfArray[ xPosition ];
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380 fDifference = fTotal1 - fTotal2;
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381 if( fabs( fDifference ) > 0.001F )
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386 #if configUSE_PREEMPTION == 0
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390 if( sError == pdFALSE )
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392 /* If the calculation has always been correct, increment the check
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393 variable so we know this task is still running okay. */
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394 ( *pusTaskCheckVariable )++;
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398 /*-----------------------------------------------------------*/
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400 /* This is called to check that all the created tasks are still running. */
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401 portBASE_TYPE xAreMathsTaskStillRunning( void )
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403 /* Keep a history of the check variables so we know if they have been incremented
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404 since the last call. */
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405 static unsigned portSHORT usLastTaskCheck[ mathNUMBER_OF_TASKS ] = { ( unsigned portSHORT ) 0 };
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406 portBASE_TYPE xReturn = pdTRUE, xTask;
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408 /* Check the maths tasks are still running by ensuring their check variables
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409 are still incrementing. */
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410 for( xTask = 0; xTask < mathNUMBER_OF_TASKS; xTask++ )
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412 if( usTaskCheck[ xTask ] == usLastTaskCheck[ xTask ] )
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414 /* The check has not incremented so an error exists. */
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418 usLastTaskCheck[ xTask ] = usTaskCheck[ xTask ];
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