2 FreeRTOS V7.1.1 - Copyright (C) 2012 Real Time Engineers Ltd.
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5 ***************************************************************************
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7 * FreeRTOS tutorial books are available in pdf and paperback. *
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8 * Complete, revised, and edited pdf reference manuals are also *
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11 * Purchasing FreeRTOS documentation will not only help you, by *
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12 * ensuring you get running as quickly as possible and with an *
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13 * in-depth knowledge of how to use FreeRTOS, it will also help *
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14 * the FreeRTOS project to continue with its mission of providing *
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15 * professional grade, cross platform, de facto standard solutions *
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16 * for microcontrollers - completely free of charge! *
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18 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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20 * Thank you for using FreeRTOS, and thank you for your support! *
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22 ***************************************************************************
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25 This file is part of the FreeRTOS distribution.
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27 FreeRTOS is free software; you can redistribute it and/or modify it under
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28 the terms of the GNU General Public License (version 2) as published by the
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29 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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30 >>>NOTE<<< The modification to the GPL is included to allow you to
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31 distribute a combined work that includes FreeRTOS without being obliged to
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32 provide the source code for proprietary components outside of the FreeRTOS
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33 kernel. FreeRTOS is distributed in the hope that it will be useful, but
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34 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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35 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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36 more details. You should have received a copy of the GNU General Public
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37 License and the FreeRTOS license exception along with FreeRTOS; if not it
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38 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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39 by writing to Richard Barry, contact details for whom are available on the
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44 ***************************************************************************
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46 * Having a problem? Start by reading the FAQ "My application does *
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47 * not run, what could be wrong? *
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49 * http://www.FreeRTOS.org/FAQHelp.html *
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51 ***************************************************************************
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54 http://www.FreeRTOS.org - Documentation, training, latest information,
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55 license and contact details.
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57 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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58 including FreeRTOS+Trace - an indispensable productivity tool.
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60 Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
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61 the code with commercial support, indemnification, and middleware, under
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62 the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
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63 provide a safety engineered and independently SIL3 certified version under
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64 the SafeRTOS brand: http://www.SafeRTOS.com.
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68 * Creates eight tasks, each of which loops continuously performing a floating
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69 * point calculation - using single precision variables.
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71 * All the tasks run at the idle priority and never block or yield. This causes
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72 * all eight tasks to time slice with the idle task. Running at the idle priority
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73 * means that these tasks will get pre-empted any time another task is ready to run
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74 * or a time slice occurs. More often than not the pre-emption will occur mid
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75 * calculation, creating a good test of the schedulers context switch mechanism - a
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76 * calculation producing an unexpected result could be a symptom of a corruption in
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77 * the context of a task.
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83 /* Scheduler include files. */
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84 #include "FreeRTOS.h"
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87 /* Demo program include files. */
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90 #define mathSTACK_SIZE configMINIMAL_STACK_SIZE
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91 #define mathNUMBER_OF_TASKS ( 8 )
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93 /* Four tasks, each of which performs a different floating point calculation.
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94 Each of the four is created twice. */
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95 static portTASK_FUNCTION_PROTO( vCompetingMathTask1, pvParameters );
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96 static portTASK_FUNCTION_PROTO( vCompetingMathTask2, pvParameters );
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97 static portTASK_FUNCTION_PROTO( vCompetingMathTask3, pvParameters );
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98 static portTASK_FUNCTION_PROTO( vCompetingMathTask4, pvParameters );
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100 /* These variables are used to check that all the tasks are still running. If a
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101 task gets a calculation wrong it will
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102 stop incrementing its check variable. */
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103 static volatile unsigned short usTaskCheck[ mathNUMBER_OF_TASKS ] = { ( unsigned short ) 0 };
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105 /*-----------------------------------------------------------*/
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107 void vStartMathTasks( unsigned portBASE_TYPE uxPriority )
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109 xTaskCreate( vCompetingMathTask1, ( signed char * ) "Math1", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 0 ] ), uxPriority, NULL );
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110 xTaskCreate( vCompetingMathTask2, ( signed char * ) "Math2", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 1 ] ), uxPriority, NULL );
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111 xTaskCreate( vCompetingMathTask3, ( signed char * ) "Math3", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 2 ] ), uxPriority, NULL );
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112 xTaskCreate( vCompetingMathTask4, ( signed char * ) "Math4", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 3 ] ), uxPriority, NULL );
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113 xTaskCreate( vCompetingMathTask1, ( signed char * ) "Math5", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 4 ] ), uxPriority, NULL );
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114 xTaskCreate( vCompetingMathTask2, ( signed char * ) "Math6", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 5 ] ), uxPriority, NULL );
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115 xTaskCreate( vCompetingMathTask3, ( signed char * ) "Math7", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 6 ] ), uxPriority, NULL );
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116 xTaskCreate( vCompetingMathTask4, ( signed char * ) "Math8", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 7 ] ), uxPriority, NULL );
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118 /*-----------------------------------------------------------*/
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120 static portTASK_FUNCTION( vCompetingMathTask1, pvParameters )
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122 volatile float f1, f2, f3, f4;
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123 volatile unsigned short *pusTaskCheckVariable;
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124 volatile float fAnswer;
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125 short sError = pdFALSE;
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131 fAnswer = ( f1 + f2 ) * f3;
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133 /* The variable this task increments to show it is still running is passed in
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134 as the parameter. */
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135 pusTaskCheckVariable = ( unsigned short * ) pvParameters;
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137 /* Keep performing a calculation and checking the result against a constant. */
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144 f4 = ( f1 + f2 ) * f3;
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146 #if configUSE_PREEMPTION == 0
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150 /* If the calculation does not match the expected constant, stop the
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151 increment of the check variable. */
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152 if( fabs( f4 - fAnswer ) > 0.001F )
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157 if( sError == pdFALSE )
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159 /* If the calculation has always been correct, increment the check
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160 variable so we know this task is still running okay. */
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161 ( *pusTaskCheckVariable )++;
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164 #if configUSE_PREEMPTION == 0
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170 /*-----------------------------------------------------------*/
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172 static portTASK_FUNCTION( vCompetingMathTask2, pvParameters )
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174 volatile float f1, f2, f3, f4;
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175 volatile unsigned short *pusTaskCheckVariable;
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176 volatile float fAnswer;
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177 short sError = pdFALSE;
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183 fAnswer = ( f1 / f2 ) * f3;
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186 /* The variable this task increments to show it is still running is passed in
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187 as the parameter. */
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188 pusTaskCheckVariable = ( unsigned short * ) pvParameters;
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190 /* Keep performing a calculation and checking the result against a constant. */
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197 f4 = ( f1 / f2 ) * f3;
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199 #if configUSE_PREEMPTION == 0
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203 /* If the calculation does not match the expected constant, stop the
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204 increment of the check variable. */
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205 if( fabs( f4 - fAnswer ) > 0.001F )
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210 if( sError == pdFALSE )
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212 /* If the calculation has always been correct, increment the check
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213 variable so we know
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214 this task is still running okay. */
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215 ( *pusTaskCheckVariable )++;
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218 #if configUSE_PREEMPTION == 0
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223 /*-----------------------------------------------------------*/
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225 static portTASK_FUNCTION( vCompetingMathTask3, pvParameters )
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227 volatile float *pfArray, fTotal1, fTotal2, fDifference, fPosition;
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228 volatile unsigned short *pusTaskCheckVariable;
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229 const size_t xArraySize = 10;
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231 short sError = pdFALSE;
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233 /* The variable this task increments to show it is still running is passed in
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234 as the parameter. */
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235 pusTaskCheckVariable = ( unsigned short * ) pvParameters;
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237 pfArray = ( float * ) pvPortMalloc( xArraySize * sizeof( float ) );
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239 /* Keep filling an array, keeping a running total of the values placed in the
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240 array. Then run through the array adding up all the values. If the two totals
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241 do not match, stop the check variable from incrementing. */
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248 for( xPosition = 0; xPosition < xArraySize; xPosition++ )
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250 pfArray[ xPosition ] = fPosition + 5.5F;
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251 fTotal1 += fPosition + 5.5F;
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254 #if configUSE_PREEMPTION == 0
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258 for( xPosition = 0; xPosition < xArraySize; xPosition++ )
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260 fTotal2 += pfArray[ xPosition ];
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263 fDifference = fTotal1 - fTotal2;
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264 if( fabs( fDifference ) > 0.001F )
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269 #if configUSE_PREEMPTION == 0
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273 if( sError == pdFALSE )
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275 /* If the calculation has always been correct, increment the check
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276 variable so we know this task is still running okay. */
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277 ( *pusTaskCheckVariable )++;
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281 /*-----------------------------------------------------------*/
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283 static portTASK_FUNCTION( vCompetingMathTask4, pvParameters )
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285 volatile float *pfArray, fTotal1, fTotal2, fDifference, fPosition;
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286 volatile unsigned short *pusTaskCheckVariable;
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287 const size_t xArraySize = 10;
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289 short sError = pdFALSE;
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291 /* The variable this task increments to show it is still running is passed in
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292 as the parameter. */
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293 pusTaskCheckVariable = ( unsigned short * ) pvParameters;
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295 pfArray = ( float * ) pvPortMalloc( xArraySize * sizeof( float ) );
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297 /* Keep filling an array, keeping a running total of the values placed in the
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298 array. Then run through the array adding up all the values. If the two totals
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299 do not match, stop the check variable from incrementing. */
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306 for( xPosition = 0; xPosition < xArraySize; xPosition++ )
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308 pfArray[ xPosition ] = fPosition * 12.123F;
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309 fTotal1 += fPosition * 12.123F;
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312 #if configUSE_PREEMPTION == 0
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316 for( xPosition = 0; xPosition < xArraySize; xPosition++ )
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318 fTotal2 += pfArray[ xPosition ];
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321 fDifference = fTotal1 - fTotal2;
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322 if( fabs( fDifference ) > 0.001F )
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327 #if configUSE_PREEMPTION == 0
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331 if( sError == pdFALSE )
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333 /* If the calculation has always been correct, increment the check
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334 variable so we know this task is still running okay. */
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335 ( *pusTaskCheckVariable )++;
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339 /*-----------------------------------------------------------*/
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341 /* This is called to check that all the created tasks are still running. */
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342 portBASE_TYPE xAreMathsTaskStillRunning( void )
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344 /* Keep a history of the check variables so we know if they have been incremented
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345 since the last call. */
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346 static unsigned short usLastTaskCheck[ mathNUMBER_OF_TASKS ] = { ( unsigned short ) 0 };
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347 portBASE_TYPE xReturn = pdTRUE, xTask;
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349 /* Check the maths tasks are still running by ensuring their check variables
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350 are still incrementing. */
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351 for( xTask = 0; xTask < mathNUMBER_OF_TASKS; xTask++ )
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353 if( usTaskCheck[ xTask ] == usLastTaskCheck[ xTask ] )
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355 /* The check has not incremented so an error exists. */
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359 usLastTaskCheck[ xTask ] = usTaskCheck[ xTask ];
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