begriffs open source - cmsis-freertos/blob

1 /*

4

5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

6

7 This file is part of the FreeRTOS distribution.

8

9 FreeRTOS is free software; you can redistribute it and/or modify it under

10 the terms of the GNU General Public License (version 2) as published by the

11 Free Software Foundation >>>> AND MODIFIED BY <<<< the FreeRTOS exception.

12

13 ***************************************************************************

14 >>! NOTE: The modification to the GPL is included to allow you to !<<

15 >>! distribute a combined work that includes FreeRTOS without being !<<

16 >>! obliged to provide the source code for proprietary components !<<

17 >>! outside of the FreeRTOS kernel. !<<

18 ***************************************************************************

19

20 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY

21 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

22 FOR A PARTICULAR PURPOSE. Full license text is available on the following

23 link: http://www.freertos.org/a00114.html

24

25 ***************************************************************************

26 * *

27 * FreeRTOS provides completely free yet professionally developed, *

28 * robust, strictly quality controlled, supported, and cross *

29 * platform software that is more than just the market leader, it *

30 * is the industry's de facto standard. *

31 * *

32 * Help yourself get started quickly while simultaneously helping *

33 * to support the FreeRTOS project by purchasing a FreeRTOS *

34 * tutorial book, reference manual, or both: *

35 * http://www.FreeRTOS.org/Documentation *

36 * *

37 ***************************************************************************

38

39 http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading

40 the FAQ page "My application does not run, what could be wrong?". Have you

41 defined configASSERT()?

42

43 http://www.FreeRTOS.org/support - In return for receiving this top quality

44 embedded software for free we request you assist our global community by

45 participating in the support forum.

46

47 http://www.FreeRTOS.org/training - Investing in training allows your team to

48 be as productive as possible as early as possible. Now you can receive

49 FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers

50 Ltd, and the world's leading authority on the world's leading RTOS.

51

52 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,

53 including FreeRTOS+Trace - an indispensable productivity tool, a DOS

54 compatible FAT file system, and our tiny thread aware UDP/IP stack.

55

56 http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.

57 Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.

58

59 http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High

60 Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS

61 licenses offer ticketed support, indemnification and commercial middleware.

62

63 http://www.SafeRTOS.com - High Integrity Systems also provide a safety

64 engineered and independently SIL3 certified version for use in safety and

65 mission critical applications that require provable dependability.

66

67 1 tab == 4 spaces!

68 */

69

70 /**

71 * Create a single persistent task which periodically dynamically creates another

72 * four tasks. The original task is called the creator task, the four tasks it

73 * creates are called suicidal tasks.

74 *

75 * Two of the created suicidal tasks kill one other suicidal task before killing

76 * themselves - leaving just the original task remaining.

77 *

78 * The creator task must be spawned after all of the other demo application tasks

79 * as it keeps a check on the number of tasks under the scheduler control. The

80 * number of tasks it expects to see running should never be greater than the

81 * number of tasks that were in existence when the creator task was spawned, plus

82 * one set of four suicidal tasks. If this number is exceeded an error is flagged.

83 *

84 * \page DeathC death.c

85 * \ingroup DemoFiles

86 * <HR>

87 */

88

89 /*

90 Changes from V2.0.0

91

92 + Delay periods are now specified using variables and constants of

93 TickType_t rather than unsigned long.

94 */

95

96 #include <stdlib.h>

97

98 /* Scheduler include files. */

99 #include "FreeRTOS.h"

100 #include "task.h"

101

102 /* Demo program include files. */

103 #include "death.h"

104 #include "print.h"

105

106 #define deathSTACK_SIZE ( ( unsigned short ) 512 )

107

108 /* The task originally created which is responsible for periodically dynamically

109 creating another four tasks. */

110 static void vCreateTasks( void *pvParameters );

111

112 /* The task function of the dynamically created tasks. */

113 static void vSuicidalTask( void *pvParameters );

114

115 /* A variable which is incremented every time the dynamic tasks are created. This

116 is used to check that the task is still running. */

117 static volatile short sCreationCount = 0;

118

119 /* Used to store the number of tasks that were originally running so the creator

120 task can tell if any of the suicidal tasks have failed to die. */

121 static volatile unsigned portBASE_TYPE uxTasksRunningAtStart = 0;

122 static const unsigned portBASE_TYPE uxMaxNumberOfExtraTasksRunning = 5;

123

124 /* Used to store a handle to the tasks that should be killed by a suicidal task,

125 before it kills itself. */

126 TaskHandle_t xCreatedTask1, xCreatedTask2;

127

128 /*-----------------------------------------------------------*/

129

130 void vCreateSuicidalTasks( unsigned portBASE_TYPE uxPriority )

131 {

132 unsigned portBASE_TYPE *puxPriority;

133

134 /* Create the Creator tasks - passing in as a parameter the priority at which

135 the suicidal tasks should be created. */

136 puxPriority = ( unsigned portBASE_TYPE * ) pvPortMalloc( sizeof( unsigned portBASE_TYPE ) );

137 *puxPriority = uxPriority;

138

139 xTaskCreate( vCreateTasks, "CREATOR", deathSTACK_SIZE, ( void * ) puxPriority, uxPriority, NULL );

140

141 /* Record the number of tasks that are running now so we know if any of the

142 suicidal tasks have failed to be killed. */

143 uxTasksRunningAtStart = uxTaskGetNumberOfTasks();

144 }

145 /*-----------------------------------------------------------*/

146

147 static void vSuicidalTask( void *pvParameters )

148 {

149 portDOUBLE d1, d2;

150 TaskHandle_t xTaskToKill;

151 const TickType_t xDelay = ( TickType_t ) 500 / portTICK_PERIOD_MS;

152

153 if( pvParameters != NULL )

154 {

155 /* This task is periodically created four times. Tow created tasks are

156 passed a handle to the other task so it can kill it before killing itself.

157 The other task is passed in null. */

158 xTaskToKill = *( TaskHandle_t* )pvParameters;

159 }

160 else

161 {

162 xTaskToKill = NULL;

163 }

164

165 for( ;; )

166 {

167 /* Do something random just to use some stack and registers. */

168 d1 = 2.4;

169 d2 = 89.2;

170 d2 *= d1;

171 vTaskDelay( xDelay );

172

173 if( xTaskToKill != NULL )

174 {

175 /* Make sure the other task has a go before we delete it. */

176 vTaskDelay( ( TickType_t ) 0 );

177 /* Kill the other task that was created by vCreateTasks(). */

178 vTaskDelete( xTaskToKill );

179 /* Kill ourselves. */

180 vTaskDelete( NULL );

181 }

182 }

183 }/*lint !e818 !e550 Function prototype must be as per standard for task functions. */

184 /*-----------------------------------------------------------*/

185

186 static void vCreateTasks( void *pvParameters )

187 {

188 const TickType_t xDelay = ( TickType_t ) 1000 / portTICK_PERIOD_MS;

189 unsigned portBASE_TYPE uxPriority;

190 const char * const pcTaskStartMsg = "Create task started.\r\n";

191

192 /* Queue a message for printing to say the task has started. */

193 vPrintDisplayMessage( &pcTaskStartMsg );

194

195 uxPriority = *( unsigned portBASE_TYPE * ) pvParameters;

196 vPortFree( pvParameters );

197

198 for( ;; )

199 {

200 /* Just loop round, delaying then creating the four suicidal tasks. */

201 vTaskDelay( xDelay );

202

203 xTaskCreate( vSuicidalTask, "SUICIDE1", deathSTACK_SIZE, NULL, uxPriority, &xCreatedTask1 );

204 xTaskCreate( vSuicidalTask, "SUICIDE2", deathSTACK_SIZE, &xCreatedTask1, uxPriority, NULL );

205

206 xTaskCreate( vSuicidalTask, "SUICIDE1", deathSTACK_SIZE, NULL, uxPriority, &xCreatedTask2 );

207 xTaskCreate( vSuicidalTask, "SUICIDE2", deathSTACK_SIZE, &xCreatedTask2, uxPriority, NULL );

208

209 ++sCreationCount;

210 }

211 }

212 /*-----------------------------------------------------------*/

213

214 /* This is called to check that the creator task is still running and that there

215 are not any more than four extra tasks. */

216 portBASE_TYPE xIsCreateTaskStillRunning( void )

217 {

218 static short sLastCreationCount = 0;

219 short sReturn = pdTRUE;

220 unsigned portBASE_TYPE uxTasksRunningNow;

221

222 if( sLastCreationCount == sCreationCount )

223 {

224 sReturn = pdFALSE;

225 }

226

227 uxTasksRunningNow = uxTaskGetNumberOfTasks();

228

229 if( uxTasksRunningNow < uxTasksRunningAtStart )

230 {

231 sReturn = pdFALSE;

232 }

233 else if( ( uxTasksRunningNow - uxTasksRunningAtStart ) > uxMaxNumberOfExtraTasksRunning )

234 {

235 sReturn = pdFALSE;

236 }

237 else

238 {

239 /* Everything is okay. */

240 }

241

242 return sReturn;

243 }

244

245