/* | |
FreeRTOS V7.1.0 - Copyright (C) 2011 Real Time Engineers Ltd. | |
*************************************************************************** | |
* * | |
* FreeRTOS tutorial books are available in pdf and paperback. * | |
* Complete, revised, and edited pdf reference manuals are also * | |
* available. * | |
* * | |
* Purchasing FreeRTOS documentation will not only help you, by * | |
* ensuring you get running as quickly as possible and with an * | |
* in-depth knowledge of how to use FreeRTOS, it will also help * | |
* the FreeRTOS project to continue with its mission of providing * | |
* professional grade, cross platform, de facto standard solutions * | |
* for microcontrollers - completely free of charge! * | |
* * | |
* >>> See http://www.FreeRTOS.org/Documentation for details. <<< * | |
* * | |
* Thank you for using FreeRTOS, and thank you for your support! * | |
* * | |
*************************************************************************** | |
This file is part of the FreeRTOS distribution. | |
FreeRTOS is free software; you can redistribute it and/or modify it under | |
the terms of the GNU General Public License (version 2) as published by the | |
Free Software Foundation AND MODIFIED BY the FreeRTOS exception. | |
>>>NOTE<<< The modification to the GPL is included to allow you to | |
distribute a combined work that includes FreeRTOS without being obliged to | |
provide the source code for proprietary components outside of the FreeRTOS | |
kernel. FreeRTOS is distributed in the hope that it will be useful, but | |
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY | |
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
more details. You should have received a copy of the GNU General Public | |
License and the FreeRTOS license exception along with FreeRTOS; if not it | |
can be viewed here: http://www.freertos.org/a00114.html and also obtained | |
by writing to Richard Barry, contact details for whom are available on the | |
FreeRTOS WEB site. | |
1 tab == 4 spaces! | |
http://www.FreeRTOS.org - Documentation, latest information, license and | |
contact details. | |
http://www.SafeRTOS.com - A version that is certified for use in safety | |
critical systems. | |
http://www.OpenRTOS.com - Commercial support, development, porting, | |
licensing and training services. | |
*/ | |
/** | |
* Create a single persistent task which periodically dynamically creates another | |
* two tasks. The original task is called the creator task, the two tasks it | |
* creates are called suicidal tasks. | |
* | |
* One of the created suicidal tasks kill one other suicidal task before killing | |
* itself - leaving just the original task remaining. | |
* | |
* The creator task must be spawned after all of the other demo application tasks | |
* as it keeps a check on the number of tasks under the scheduler control. The | |
* number of tasks it expects to see running should never be greater than the | |
* number of tasks that were in existence when the creator task was spawned, plus | |
* one set of four suicidal tasks. If this number is exceeded an error is flagged. | |
* | |
* \page DeathC death.c | |
* \ingroup DemoFiles | |
* <HR> | |
*/ | |
/* | |
Changes from V3.0.0 | |
+ CreationCount sizes changed from unsigned portBASE_TYPE to | |
unsigned short to minimize the risk of overflowing. | |
+ Reset of usLastCreationCount added | |
Changes from V3.1.0 | |
+ Changed the dummy calculation to use variables of type long, rather than | |
float. This allows the file to be used with ports that do not support | |
floating point. | |
*/ | |
#include <stdlib.h> | |
/* Scheduler include files. */ | |
#include "FreeRTOS.h" | |
#include "task.h" | |
/* Demo program include files. */ | |
#include "death.h" | |
#define deathSTACK_SIZE ( configMINIMAL_STACK_SIZE + 60 ) | |
/* The task originally created which is responsible for periodically dynamically | |
creating another four tasks. */ | |
static portTASK_FUNCTION_PROTO( vCreateTasks, pvParameters ); | |
/* The task function of the dynamically created tasks. */ | |
static portTASK_FUNCTION_PROTO( vSuicidalTask, pvParameters ); | |
/* A variable which is incremented every time the dynamic tasks are created. This | |
is used to check that the task is still running. */ | |
static volatile unsigned short usCreationCount = 0; | |
/* Used to store the number of tasks that were originally running so the creator | |
task can tell if any of the suicidal tasks have failed to die. | |
*/ | |
static volatile unsigned portBASE_TYPE uxTasksRunningAtStart = 0; | |
/* Tasks are deleted by the idle task. Under heavy load the idle task might | |
not get much processing time, so it would be legitimate for several tasks to | |
remain undeleted for a short period. */ | |
static const unsigned portBASE_TYPE uxMaxNumberOfExtraTasksRunning = 2; | |
/* Used to store a handle to the task that should be killed by a suicidal task, | |
before it kills itself. */ | |
xTaskHandle xCreatedTask; | |
/*-----------------------------------------------------------*/ | |
void vCreateSuicidalTasks( unsigned portBASE_TYPE uxPriority ) | |
{ | |
unsigned portBASE_TYPE *puxPriority; | |
/* Create the Creator tasks - passing in as a parameter the priority at which | |
the suicidal tasks should be created. */ | |
puxPriority = ( unsigned portBASE_TYPE * ) pvPortMalloc( sizeof( unsigned portBASE_TYPE ) ); | |
*puxPriority = uxPriority; | |
xTaskCreate( vCreateTasks, ( signed char * ) "CREATOR", deathSTACK_SIZE, ( void * ) puxPriority, uxPriority, NULL ); | |
/* Record the number of tasks that are running now so we know if any of the | |
suicidal tasks have failed to be killed. */ | |
uxTasksRunningAtStart = ( unsigned portBASE_TYPE ) uxTaskGetNumberOfTasks(); | |
/* FreeRTOS.org versions before V3.0 started the idle-task as the very | |
first task. The idle task was then already included in uxTasksRunningAtStart. | |
From FreeRTOS V3.0 on, the idle task is started when the scheduler is | |
started. Therefore the idle task is not yet accounted for. We correct | |
this by increasing uxTasksRunningAtStart by 1. */ | |
uxTasksRunningAtStart++; | |
/* From FreeRTOS version 7.0.0 can optionally create a timer service task. | |
If this is done, then uxTasksRunningAtStart needs incrementing again as that | |
too is created when the scheduler is started. */ | |
#if configUSE_TIMERS == 1 | |
uxTasksRunningAtStart++; | |
#endif | |
} | |
/*-----------------------------------------------------------*/ | |
static portTASK_FUNCTION( vSuicidalTask, pvParameters ) | |
{ | |
volatile long l1, l2; | |
xTaskHandle xTaskToKill; | |
const portTickType xDelay = ( portTickType ) 200 / portTICK_RATE_MS; | |
if( pvParameters != NULL ) | |
{ | |
/* This task is periodically created four times. Two created tasks are | |
passed a handle to the other task so it can kill it before killing itself. | |
The other task is passed in null. */ | |
xTaskToKill = *( xTaskHandle* )pvParameters; | |
} | |
else | |
{ | |
xTaskToKill = NULL; | |
} | |
for( ;; ) | |
{ | |
/* Do something random just to use some stack and registers. */ | |
l1 = 2; | |
l2 = 89; | |
l2 *= l1; | |
vTaskDelay( xDelay ); | |
if( xTaskToKill != NULL ) | |
{ | |
/* Make sure the other task has a go before we delete it. */ | |
vTaskDelay( ( portTickType ) 0 ); | |
/* Kill the other task that was created by vCreateTasks(). */ | |
vTaskDelete( xTaskToKill ); | |
/* Kill ourselves. */ | |
vTaskDelete( NULL ); | |
} | |
} | |
}/*lint !e818 !e550 Function prototype must be as per standard for task functions. */ | |
/*-----------------------------------------------------------*/ | |
static portTASK_FUNCTION( vCreateTasks, pvParameters ) | |
{ | |
const portTickType xDelay = ( portTickType ) 1000 / portTICK_RATE_MS; | |
unsigned portBASE_TYPE uxPriority; | |
uxPriority = *( unsigned portBASE_TYPE * ) pvParameters; | |
vPortFree( pvParameters ); | |
for( ;; ) | |
{ | |
/* Just loop round, delaying then creating the four suicidal tasks. */ | |
vTaskDelay( xDelay ); | |
xCreatedTask = NULL; | |
xTaskCreate( vSuicidalTask, ( signed char * ) "SUICID1", configMINIMAL_STACK_SIZE, NULL, uxPriority, &xCreatedTask ); | |
xTaskCreate( vSuicidalTask, ( signed char * ) "SUICID2", configMINIMAL_STACK_SIZE, &xCreatedTask, uxPriority, NULL ); | |
++usCreationCount; | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
/* This is called to check that the creator task is still running and that there | |
are not any more than four extra tasks. */ | |
portBASE_TYPE xIsCreateTaskStillRunning( void ) | |
{ | |
static unsigned short usLastCreationCount = 0xfff; | |
portBASE_TYPE xReturn = pdTRUE; | |
static unsigned portBASE_TYPE uxTasksRunningNow; | |
if( usLastCreationCount == usCreationCount ) | |
{ | |
xReturn = pdFALSE; | |
} | |
else | |
{ | |
usLastCreationCount = usCreationCount; | |
} | |
uxTasksRunningNow = ( unsigned portBASE_TYPE ) uxTaskGetNumberOfTasks(); | |
if( uxTasksRunningNow < uxTasksRunningAtStart ) | |
{ | |
xReturn = pdFALSE; | |
} | |
else if( ( uxTasksRunningNow - uxTasksRunningAtStart ) > uxMaxNumberOfExtraTasksRunning ) | |
{ | |
xReturn = pdFALSE; | |
} | |
else | |
{ | |
/* Everything is okay. */ | |
} | |
return xReturn; | |
} | |