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/*
FreeRTOS.org V5.1.2 - Copyright (C) 2003-2009 Richard Barry.
This file is part of the FreeRTOS.org distribution.
FreeRTOS.org is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FreeRTOS.org 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
along with FreeRTOS.org; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
A special exception to the GPL can be applied should you wish to distribute
a combined work that includes FreeRTOS.org, without being obliged to provide
the source code for any proprietary components. See the licensing section
of http://www.FreeRTOS.org for full details of how and when the exception
can be applied.
***************************************************************************
***************************************************************************
* *
* Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
* *
* This is a concise, step by step, 'hands on' guide that describes both *
* general multitasking concepts and FreeRTOS specifics. It presents and *
* explains numerous examples that are written using the FreeRTOS API. *
* Full source code for all the examples is provided in an accompanying *
* .zip file. *
* *
***************************************************************************
***************************************************************************
Please ensure to read the configuration and relevant port sections of the
online documentation.
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.
*/
/*
* Tests the floating point context save and restore mechanism.
*
* Two tasks are created - each of which is allocated a buffer of
* portNO_FLOP_REGISTERS_TO_SAVE 32bit variables into which the flop context
* of the task is saved when the task is switched out, and from which the
* flop context of the task is restored when the task is switch in. Prior to
* the tasks being created each position in the two buffers is filled with a
* unique value - this way the flop context of each task is different.
*
* The two test tasks never block so are always in either the Running or
* Ready state. They execute at the lowest priority so will get pre-empted
* regularly, although the yield frequently so will not get much execution
* time. The lack of execution time is not a problem as its only the
* switching in and out that is being tested.
*
* Whenever a task is moved from the Ready to the Running state its flop
* context will be loaded from the buffer, but while the task is in the
* Running state the buffer is not used and can contain any value - in this
* case and for test purposes the task itself clears the buffer to zero.
* The next time the task is moved out of the Running state into the
* Ready state the flop context will once more get saved to the buffer -
* overwriting the zeros.
*
* Therefore whenever the task is not in the Running state its buffer contains
* the most recent values of its floating point registers - the zeroing out
* of the buffer while the task was executing being used to ensure the values
* the buffer contains are not stale.
*
* When neither test task is in the Running state the buffers should contain
* the unique values allocated before the tasks were created. If so then
* the floating point context has been maintained. This check is performed
* by the 'check' task (defined in main.c) by calling
* xAreFlopRegisterTestsStillRunning().
*
* The test tasks also increment a value each time they execute.
* xAreFlopRegisterTestsStillRunning() also checks that this value has changed
* since it last ran to ensure the test tasks are still getting processing time.
*/
/* Standard includes files. */
#include <string.h>
/* Scheduler include files. */
#include "FreeRTOS.h"
#include "task.h"
/*-----------------------------------------------------------*/
#define flopNUMBER_OF_TASKS 2
#define flopSTART_VALUE ( 0x1 )
/*-----------------------------------------------------------*/
/* The two test tasks as described at the top of this file. */
static void vFlopTest1( void *pvParameters );
static void vFlopTest2( void *pvParameters );
/*-----------------------------------------------------------*/
/* Buffers into which the flop registers will be saved. There is a buffer for
both tasks. */
static volatile unsigned portLONG ulFlopRegisters[ flopNUMBER_OF_TASKS ][ portNO_FLOP_REGISTERS_TO_SAVE ];
/* Variables that are incremented by the tasks to indicate that they are still
running. */
static volatile unsigned portLONG ulFlop1CycleCount = 0, ulFlop2CycleCount = 0;
/*-----------------------------------------------------------*/
void vStartFlopRegTests( void )
{
xTaskHandle xTaskJustCreated;
unsigned portBASE_TYPE x, y, z = flopSTART_VALUE;
/* Fill the arrays into which the flop registers are to be saved with
known values. These are the values that will be written to the flop
registers when the tasks start, and as the tasks do not perform any
flop operations the values should never change. Each position in the
buffer contains a different value so the flop context of each task
will be different. */
for( x = 0; x < flopNUMBER_OF_TASKS; x++ )
{
for( y = 0; y < ( portNO_FLOP_REGISTERS_TO_SAVE - 1); y++ )
{
ulFlopRegisters[ x ][ y ] = z;
z++;
}
}
/* Create the first task. */
xTaskCreate( vFlopTest1, ( signed portCHAR * ) "flop1", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY, &xTaskJustCreated );
/* The task tag value is a value that can be associated with a task, but
is not used by the scheduler itself. Its use is down to the application so
it makes a convenient place in this case to store the pointer to the buffer
into which the flop context of the task will be stored. The first created
task uses ulFlopRegisters[ 0 ], the second ulFlopRegisters[ 1 ]. */
vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( ulFlopRegisters[ 0 ][ 0 ] ) );
/* Do the same for the second task. */
xTaskCreate( vFlopTest2, ( signed portCHAR * ) "flop2", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY, &xTaskJustCreated );
vTaskSetApplicationTaskTag( xTaskJustCreated, ( void * ) &( ulFlopRegisters[ 1 ][ 0 ] ) );
}
/*-----------------------------------------------------------*/
static void vFlopTest1( void *pvParameters )
{
/* Just to remove compiler warning. */
( void ) pvParameters;
for( ;; )
{
/* The values from the buffer should have now been written to the flop
registers. Clear the buffer to ensure the same values then get written
back the next time the task runs. Being preempted during this memset
could cause the test to fail, hence the critical section. */
portENTER_CRITICAL();
memset( ( void * ) ulFlopRegisters[ 0 ], 0x00, ( portNO_FLOP_REGISTERS_TO_SAVE * sizeof( unsigned portBASE_TYPE ) ) );
portEXIT_CRITICAL();
/* We don't have to do anything other than indicate that we are
still running. */
ulFlop1CycleCount++;
taskYIELD();
}
}
/*-----------------------------------------------------------*/
static void vFlopTest2( void *pvParameters )
{
/* Just to remove compiler warning. */
( void ) pvParameters;
for( ;; )
{
/* The values from the buffer should have now been written to the flop
registers. Clear the buffer to ensure the same values then get written
back the next time the task runs. */
portENTER_CRITICAL();
memset( ( void * ) ulFlopRegisters[ 1 ], 0x00, ( portNO_FLOP_REGISTERS_TO_SAVE * sizeof( unsigned portBASE_TYPE ) ) );
portEXIT_CRITICAL();
/* We don't have to do anything other than indicate that we are
still running. */
ulFlop2CycleCount++;
taskYIELD();
}
}
/*-----------------------------------------------------------*/
portBASE_TYPE xAreFlopRegisterTestsStillRunning( void )
{
portBASE_TYPE xReturn = pdPASS;
unsigned portBASE_TYPE x, y, z = flopSTART_VALUE;
static unsigned portLONG ulLastFlop1CycleCount = 0, ulLastFlop2CycleCount = 0;
/* Called from the 'check' task.
The flop tasks cannot be currently running, check their saved registers
are as expected. The tests tasks do not perform any flop operations so
their registers should be as per their initial setting. */
for( x = 0; x < flopNUMBER_OF_TASKS; x++ )
{
for( y = 0; y < ( portNO_FLOP_REGISTERS_TO_SAVE - 1 ); y++ )
{
if( ulFlopRegisters[ x ][ y ] != z )
{
xReturn = pdFAIL;
break;
}
z++;
}
}
/* Check both tasks have actually been swapped in and out since this function
last executed. */
if( ulFlop1CycleCount == ulLastFlop1CycleCount )
{
xReturn = pdFAIL;
}
if( ulFlop2CycleCount == ulLastFlop2CycleCount )
{
xReturn = pdFAIL;
}
ulLastFlop1CycleCount = ulFlop1CycleCount;
ulLastFlop2CycleCount = ulFlop2CycleCount;
return xReturn;
}
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