2 FreeRTOS V6.0.0 - Copyright (C) 2009 Real Time Engineers Ltd.
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4 ***************************************************************************
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8 * + New to FreeRTOS, *
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9 * + Wanting to learn FreeRTOS or multitasking in general quickly *
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10 * + Looking for basic training, *
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11 * + Wanting to improve your FreeRTOS skills and productivity *
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13 * then take a look at the FreeRTOS eBook *
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15 * "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
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16 * http://www.FreeRTOS.org/Documentation *
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18 * A pdf reference manual is also available. Both are usually delivered *
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19 * to your inbox within 20 minutes to two hours when purchased between 8am *
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20 * and 8pm GMT (although please allow up to 24 hours in case of *
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21 * exceptional circumstances). Thank you for your support! *
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23 ***************************************************************************
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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 exception to the GPL is included to allow you to distribute
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31 a combined work that includes FreeRTOS without being obliged to provide the
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32 source code for proprietary components outside of the FreeRTOS kernel.
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33 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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34 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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35 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 http://www.FreeRTOS.org - Documentation, latest information, license and
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47 http://www.SafeRTOS.com - A version that is certified for use in safety
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50 http://www.OpenRTOS.com - Commercial support, development, porting,
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51 licensing and training services.
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55 * Creates eight tasks, each of which loops continuously performing a
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56 * floating point calculation.
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58 * All the tasks run at the idle priority and never block or yield. This causes
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59 * all eight tasks to time slice with the idle task. Running at the idle priority
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60 * means that these tasks will get pre-empted any time another task is ready to run
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61 * or a time slice occurs. More often than not the pre-emption will occur mid
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62 * calculation, creating a good test of the schedulers context switch mechanism - a
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63 * calculation producing an unexpected result could be a symptom of a corruption in
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64 * the context of a task.
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66 * This file demonstrates the use of the task tag and traceTASK_SWITCHED_IN and
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67 * traceTASK_SWITCHED_OUT macros to save and restore the floating point context.
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73 /* Scheduler include files. */
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74 #include "FreeRTOS.h"
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77 /* Demo program include files. */
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80 /* Misc. definitions. */
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81 #define mathSTACK_SIZE configMINIMAL_STACK_SIZE
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82 #define mathNUMBER_OF_TASKS ( 8 )
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84 /* Four tasks, each of which performs a different floating point calculation.
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85 Each of the four is created twice. */
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86 static portTASK_FUNCTION_PROTO( vCompetingMathTask1, pvParameters );
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87 static portTASK_FUNCTION_PROTO( vCompetingMathTask2, pvParameters );
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88 static portTASK_FUNCTION_PROTO( vCompetingMathTask3, pvParameters );
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89 static portTASK_FUNCTION_PROTO( vCompetingMathTask4, pvParameters );
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91 /* These variables are used to check that all the tasks are still running. If a
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92 task gets a calculation wrong it will stop incrementing its check variable. */
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93 static volatile unsigned short usTaskCheck[ mathNUMBER_OF_TASKS ] = { ( unsigned short ) 0 };
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95 /* Buffers into which the flop registers will be saved. There is a buffer for
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96 each task created within this file. Zeroing out this array is the normal and
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97 safe option as this will cause the task to start with all zeros in its flop
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99 static portDOUBLE dFlopRegisters[ mathNUMBER_OF_TASKS ][ portNO_FLOP_REGISTERS_TO_SAVE ];
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101 /*-----------------------------------------------------------*/
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103 void vStartMathTasks( unsigned portBASE_TYPE uxPriority )
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105 xTaskHandle xTaskJustCreated;
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106 portBASE_TYPE x, y;
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108 /* Place known values into the buffers into which the flop registers are
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109 to be saved. This is for debug purposes only, it is not normally
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110 required. The last position in each array is left at zero as the status
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111 register will be loaded from there.
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113 It is intended that these values can be viewed being loaded into the
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114 flop registers when a task is started - however the Insight debugger
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115 does not seem to want to show the flop register values. */
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116 for( x = 0; x < mathNUMBER_OF_TASKS; x++ )
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118 for( y = 0; y < ( portNO_FLOP_REGISTERS_TO_SAVE - 1 ); y++ )
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120 dFlopRegisters[ x ][ y ] = ( x + 1 );
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124 /* Create the first task - passing it the address of the check variable
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125 that it is going to increment. This check variable is used as an
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126 indication that the task is still running. */
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127 xTaskCreate( vCompetingMathTask1, ( signed char * ) "Math1", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 0 ] ), uxPriority, &xTaskJustCreated );
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129 /* The task tag value is a value that can be associated with a task, but
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130 is not used by the scheduler itself. Its use is down to the application so
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131 it makes a convenient place in this case to store the pointer to the buffer
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132 into which the flop context of the task will be stored. The first created
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133 task uses dFlopRegisters[ 0 ], the second dFlopRegisters[ 1 ], etc. */
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134 vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( dFlopRegisters[ 0 ][ 0 ] ) );
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136 /* Create another 7 tasks, allocating a buffer for each. */
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137 xTaskCreate( vCompetingMathTask2, ( signed char * ) "Math2", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 1 ] ), uxPriority, &xTaskJustCreated );
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138 vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( dFlopRegisters[ 1 ][ 0 ] ) );
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140 xTaskCreate( vCompetingMathTask3, ( signed char * ) "Math3", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 2 ] ), uxPriority, &xTaskJustCreated );
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141 vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( dFlopRegisters[ 2 ][ 0 ] ) );
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143 xTaskCreate( vCompetingMathTask4, ( signed char * ) "Math4", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 3 ] ), uxPriority, &xTaskJustCreated );
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144 vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( dFlopRegisters[ 3 ][ 0 ] ) );
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146 xTaskCreate( vCompetingMathTask1, ( signed char * ) "Math5", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 4 ] ), uxPriority, &xTaskJustCreated );
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147 vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( dFlopRegisters[ 4 ][ 0 ] ) );
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149 xTaskCreate( vCompetingMathTask2, ( signed char * ) "Math6", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 5 ] ), uxPriority, &xTaskJustCreated );
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150 vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( dFlopRegisters[ 5 ][ 0 ] ) );
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152 xTaskCreate( vCompetingMathTask3, ( signed char * ) "Math7", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 6 ] ), uxPriority, &xTaskJustCreated );
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153 vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( dFlopRegisters[ 6 ][ 0 ] ) );
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155 xTaskCreate( vCompetingMathTask4, ( signed char * ) "Math8", mathSTACK_SIZE, ( void * ) &( usTaskCheck[ 7 ] ), uxPriority, &xTaskJustCreated );
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156 vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( dFlopRegisters[ 7 ][ 0 ] ) );
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158 /*-----------------------------------------------------------*/
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160 static portTASK_FUNCTION( vCompetingMathTask1, pvParameters )
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162 volatile portDOUBLE df1, df2, df3, df4;
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163 volatile unsigned short *pusTaskCheckVariable;
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164 volatile portDOUBLE dAnswer;
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165 short sError = pdFALSE;
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171 dAnswer = ( df1 + df2 ) * df3;
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173 /* The variable this task increments to show it is still running is passed in
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174 as the parameter. */
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175 pusTaskCheckVariable = ( unsigned short * ) pvParameters;
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177 /* Keep performing a calculation and checking the result against a constant. */
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184 df4 = ( df1 + df2 ) * df3;
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186 #if configUSE_PREEMPTION == 0
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190 /* If the calculation does not match the expected constant, stop the
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191 increment of the check variable. */
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192 if( fabs( df4 - dAnswer ) > 0.001 )
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197 if( sError == pdFALSE )
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199 /* If the calculation has always been correct, increment the check
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200 variable so we know this task is still running okay. */
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201 ( *pusTaskCheckVariable )++;
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204 #if configUSE_PREEMPTION == 0
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210 /*-----------------------------------------------------------*/
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212 static portTASK_FUNCTION( vCompetingMathTask2, pvParameters )
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214 volatile portDOUBLE df1, df2, df3, df4;
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215 volatile unsigned short *pusTaskCheckVariable;
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216 volatile portDOUBLE dAnswer;
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217 short sError = pdFALSE;
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223 dAnswer = ( df1 / df2 ) * df3;
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226 /* The variable this task increments to show it is still running is passed in
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227 as the parameter. */
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228 pusTaskCheckVariable = ( unsigned short * ) pvParameters;
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230 /* Keep performing a calculation and checking the result against a constant. */
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237 df4 = ( df1 / df2 ) * df3;
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239 #if configUSE_PREEMPTION == 0
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243 /* If the calculation does not match the expected constant, stop the
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244 increment of the check variable. */
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245 if( fabs( df4 - dAnswer ) > 0.001 )
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250 if( sError == pdFALSE )
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252 /* If the calculation has always been correct, increment the check
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253 variable so we know
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254 this task is still running okay. */
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255 ( *pusTaskCheckVariable )++;
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258 #if configUSE_PREEMPTION == 0
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263 /*-----------------------------------------------------------*/
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265 static portTASK_FUNCTION( vCompetingMathTask3, pvParameters )
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267 volatile portDOUBLE *pdArray, dTotal1, dTotal2, dDifference;
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268 volatile unsigned short *pusTaskCheckVariable;
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269 const size_t xArraySize = 10;
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271 short sError = pdFALSE;
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273 /* The variable this task increments to show it is still running is passed in
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274 as the parameter. */
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275 pusTaskCheckVariable = ( unsigned short * ) pvParameters;
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277 pdArray = ( portDOUBLE * ) pvPortMalloc( xArraySize * sizeof( portDOUBLE ) );
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279 /* Keep filling an array, keeping a running total of the values placed in the
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280 array. Then run through the array adding up all the values. If the two totals
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281 do not match, stop the check variable from incrementing. */
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287 for( xPosition = 0; xPosition < xArraySize; xPosition++ )
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289 pdArray[ xPosition ] = ( portDOUBLE ) xPosition + 5.5;
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290 dTotal1 += ( portDOUBLE ) xPosition + 5.5;
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293 #if configUSE_PREEMPTION == 0
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297 for( xPosition = 0; xPosition < xArraySize; xPosition++ )
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299 dTotal2 += pdArray[ xPosition ];
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302 dDifference = dTotal1 - dTotal2;
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303 if( fabs( dDifference ) > 0.001 )
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308 #if configUSE_PREEMPTION == 0
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312 if( sError == pdFALSE )
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314 /* If the calculation has always been correct, increment the check
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315 variable so we know this task is still running okay. */
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316 ( *pusTaskCheckVariable )++;
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320 /*-----------------------------------------------------------*/
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322 static portTASK_FUNCTION( vCompetingMathTask4, pvParameters )
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324 volatile portDOUBLE *pdArray, dTotal1, dTotal2, dDifference;
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325 volatile unsigned short *pusTaskCheckVariable;
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326 const size_t xArraySize = 10;
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328 short sError = pdFALSE;
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330 /* The variable this task increments to show it is still running is passed in
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331 as the parameter. */
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332 pusTaskCheckVariable = ( unsigned short * ) pvParameters;
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334 pdArray = ( portDOUBLE * ) pvPortMalloc( xArraySize * sizeof( portDOUBLE ) );
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336 /* Keep filling an array, keeping a running total of the values placed in the
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337 array. Then run through the array adding up all the values. If the two totals
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338 do not match, stop the check variable from incrementing. */
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344 for( xPosition = 0; xPosition < xArraySize; xPosition++ )
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346 pdArray[ xPosition ] = ( portDOUBLE ) xPosition * 12.123;
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347 dTotal1 += ( portDOUBLE ) xPosition * 12.123;
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350 #if configUSE_PREEMPTION == 0
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354 for( xPosition = 0; xPosition < xArraySize; xPosition++ )
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356 dTotal2 += pdArray[ xPosition ];
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359 dDifference = dTotal1 - dTotal2;
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360 if( fabs( dDifference ) > 0.001 )
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365 #if configUSE_PREEMPTION == 0
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369 if( sError == pdFALSE )
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371 /* If the calculation has always been correct, increment the check
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372 variable so we know this task is still running okay. */
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373 ( *pusTaskCheckVariable )++;
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377 /*-----------------------------------------------------------*/
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379 /* This is called to check that all the created tasks are still running. */
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380 portBASE_TYPE xAreMathsTaskStillRunning( void )
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382 /* Keep a history of the check variables so we know if they have been incremented
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383 since the last call. */
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384 static unsigned short usLastTaskCheck[ mathNUMBER_OF_TASKS ] = { ( unsigned short ) 0 };
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385 portBASE_TYPE xReturn = pdTRUE, xTask;
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387 /* Check the maths tasks are still running by ensuring their check variables
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388 are still incrementing. */
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389 for( xTask = 0; xTask < mathNUMBER_OF_TASKS; xTask++ )
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391 if( usTaskCheck[ xTask ] == usLastTaskCheck[ xTask ] )
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393 /* The check has not incremented so an error exists. */
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397 usLastTaskCheck[ xTask ] = usTaskCheck[ xTask ];
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