2 FreeRTOS.org V5.0.0 - Copyright (C) 2003-2008 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify
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7 it under the terms of the GNU General Public License as published by
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8 the Free Software Foundation; either version 2 of the License, or
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9 (at your option) any later version.
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11 FreeRTOS.org is distributed in the hope that it will be useful,
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 GNU General Public License for more details.
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16 You should have received a copy of the GNU General Public License
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17 along with FreeRTOS.org; if not, write to the Free Software
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18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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20 A special exception to the GPL can be applied should you wish to distribute
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21 a combined work that includes FreeRTOS.org, without being obliged to provide
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22 the source code for any proprietary components. See the licensing section
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23 of http://www.FreeRTOS.org for full details of how and when the exception
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26 ***************************************************************************
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27 ***************************************************************************
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29 * SAVE TIME AND MONEY! We can port FreeRTOS.org to your own hardware, *
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30 * and even write all or part of your application on your behalf. *
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31 * See http://www.OpenRTOS.com for details of the services we provide to *
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32 * expedite your project. *
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34 ***************************************************************************
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35 ***************************************************************************
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37 Please ensure to read the configuration and relevant port sections of the
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38 online documentation.
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40 http://www.FreeRTOS.org - Documentation, latest information, license and
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43 http://www.SafeRTOS.com - A version that is certified for use in safety
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46 http://www.OpenRTOS.com - Commercial support, development, porting,
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47 licensing and training services.
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51 * Create a single persistent task which periodically dynamically creates another
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52 * two tasks. The original task is called the creator task, the two tasks it
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53 * creates are called suicidal tasks.
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55 * One of the created suicidal tasks kill one other suicidal task before killing
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56 * itself - leaving just the original task remaining.
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58 * The creator task must be spawned after all of the other demo application tasks
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59 * as it keeps a check on the number of tasks under the scheduler control. The
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60 * number of tasks it expects to see running should never be greater than the
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61 * number of tasks that were in existence when the creator task was spawned, plus
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62 * one set of four suicidal tasks. If this number is exceeded an error is flagged.
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64 * \page DeathC death.c
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65 * \ingroup DemoFiles
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71 + CreationCount sizes changed from unsigned portBASE_TYPE to
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72 unsigned portSHORT to minimize the risk of overflowing.
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74 + Reset of usLastCreationCount added
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77 + Changed the dummy calculation to use variables of type long, rather than
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78 float. This allows the file to be used with ports that do not support
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85 /* Scheduler include files. */
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86 #include "FreeRTOS.h"
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89 /* Demo program include files. */
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92 #define deathSTACK_SIZE ( configMINIMAL_STACK_SIZE + 60 )
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94 /* The task originally created which is responsible for periodically dynamically
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95 creating another four tasks. */
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96 static portTASK_FUNCTION_PROTO( vCreateTasks, pvParameters );
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98 /* The task function of the dynamically created tasks. */
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99 static portTASK_FUNCTION_PROTO( vSuicidalTask, pvParameters );
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101 /* A variable which is incremented every time the dynamic tasks are created. This
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102 is used to check that the task is still running. */
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103 static volatile unsigned portSHORT usCreationCount = 0;
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105 /* Used to store the number of tasks that were originally running so the creator
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106 task can tell if any of the suicidal tasks have failed to die.
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108 static volatile unsigned portBASE_TYPE uxTasksRunningAtStart = 0;
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110 /* Tasks are deleted by the idle task. Under heavy load the idle task might
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111 not get much processing time, so it would be legitimate for several tasks to
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112 remain undeleted for a short period. */
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113 static const unsigned portBASE_TYPE uxMaxNumberOfExtraTasksRunning = 2;
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115 /* Used to store a handle to the task that should be killed by a suicidal task,
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116 before it kills itself. */
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117 xTaskHandle xCreatedTask;
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119 /*-----------------------------------------------------------*/
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121 void vCreateSuicidalTasks( unsigned portBASE_TYPE uxPriority )
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123 unsigned portBASE_TYPE *puxPriority;
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125 /* Create the Creator tasks - passing in as a parameter the priority at which
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126 the suicidal tasks should be created. */
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127 puxPriority = ( unsigned portBASE_TYPE * ) pvPortMalloc( sizeof( unsigned portBASE_TYPE ) );
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128 *puxPriority = uxPriority;
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130 xTaskCreate( vCreateTasks, ( signed portCHAR * ) "CREATOR", deathSTACK_SIZE, ( void * ) puxPriority, uxPriority, NULL );
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132 /* Record the number of tasks that are running now so we know if any of the
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133 suicidal tasks have failed to be killed. */
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134 uxTasksRunningAtStart = ( unsigned portBASE_TYPE ) uxTaskGetNumberOfTasks();
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136 /* FreeRTOS.org versions before V3.0 started the idle-task as the very
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137 first task. The idle task was then already included in uxTasksRunningAtStart.
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138 From FreeRTOS V3.0 on, the idle task is started when the scheduler is
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139 started. Therefore the idle task is not yet accounted for. We correct
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140 this by increasing uxTasksRunningAtStart by 1. */
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141 uxTasksRunningAtStart++;
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143 /*-----------------------------------------------------------*/
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145 static portTASK_FUNCTION( vSuicidalTask, pvParameters )
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147 volatile portLONG l1, l2;
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148 xTaskHandle xTaskToKill;
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149 const portTickType xDelay = ( portTickType ) 200 / portTICK_RATE_MS;
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151 if( pvParameters != NULL )
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153 /* This task is periodically created four times. Two created tasks are
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154 passed a handle to the other task so it can kill it before killing itself.
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155 The other task is passed in null. */
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156 xTaskToKill = *( xTaskHandle* )pvParameters;
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160 xTaskToKill = NULL;
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165 /* Do something random just to use some stack and registers. */
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169 vTaskDelay( xDelay );
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171 if( xTaskToKill != NULL )
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173 /* Make sure the other task has a go before we delete it. */
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174 vTaskDelay( ( portTickType ) 0 );
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176 /* Kill the other task that was created by vCreateTasks(). */
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177 vTaskDelete( xTaskToKill );
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179 /* Kill ourselves. */
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180 vTaskDelete( NULL );
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183 }/*lint !e818 !e550 Function prototype must be as per standard for task functions. */
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184 /*-----------------------------------------------------------*/
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186 static portTASK_FUNCTION( vCreateTasks, pvParameters )
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188 const portTickType xDelay = ( portTickType ) 1000 / portTICK_RATE_MS;
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189 unsigned portBASE_TYPE uxPriority;
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191 uxPriority = *( unsigned portBASE_TYPE * ) pvParameters;
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192 vPortFree( pvParameters );
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196 /* Just loop round, delaying then creating the four suicidal tasks. */
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197 vTaskDelay( xDelay );
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199 xCreatedTask = NULL;
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201 xTaskCreate( vSuicidalTask, ( signed portCHAR * ) "SUICID1", configMINIMAL_STACK_SIZE, NULL, uxPriority, &xCreatedTask );
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202 xTaskCreate( vSuicidalTask, ( signed portCHAR * ) "SUICID2", configMINIMAL_STACK_SIZE, &xCreatedTask, uxPriority, NULL );
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207 /*-----------------------------------------------------------*/
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209 /* This is called to check that the creator task is still running and that there
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210 are not any more than four extra tasks. */
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211 portBASE_TYPE xIsCreateTaskStillRunning( void )
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213 static portSHORT usLastCreationCount = -1;
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214 portBASE_TYPE xReturn = pdTRUE;
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215 static unsigned portBASE_TYPE uxTasksRunningNow;
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217 if( usLastCreationCount == usCreationCount )
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223 usLastCreationCount = usCreationCount;
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226 uxTasksRunningNow = ( unsigned portBASE_TYPE ) uxTaskGetNumberOfTasks();
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228 if( uxTasksRunningNow < uxTasksRunningAtStart )
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232 else if( ( uxTasksRunningNow - uxTasksRunningAtStart ) > uxMaxNumberOfExtraTasksRunning )
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238 /* Everything is okay. */
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