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/*
FreeRTOS.org V5.2.0 - 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 (version 2) as published
by the Free Software Foundation and modified by the FreeRTOS exception.
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 is included to allow you 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.
***************************************************************************
* *
* 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. *
* *
***************************************************************************
1 tab == 4 spaces!
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.
*/
/*
Changes between V2.5.1 and V2.5.1
+ The memory pool has been defined within a struct to ensure correct memory
alignment on 32bit systems.
Changes between V2.6.1 and V3.0.0
+ An overflow check has been added to ensure the next free byte variable
does not wrap around.
*/
/*
* The simplest possible implementation of pvPortMalloc(). Note that this
* implementation does NOT allow allocated memory to be freed again.
*
* See heap_2.c and heap_3.c for alternative implementations, and the memory
* management pages of http://www.FreeRTOS.org for more information.
*/
#include <stdlib.h>
#include "FreeRTOS.h"
#include "task.h"
/* Setup the correct byte alignment mask for the defined byte alignment. */
#if portBYTE_ALIGNMENT == 8
#define heapBYTE_ALIGNMENT_MASK ( ( size_t ) 0x0007 )
#endif
#if portBYTE_ALIGNMENT == 4
#define heapBYTE_ALIGNMENT_MASK ( ( size_t ) 0x0003 )
#endif
#if portBYTE_ALIGNMENT == 2
#define heapBYTE_ALIGNMENT_MASK ( ( size_t ) 0x0001 )
#endif
#if portBYTE_ALIGNMENT == 1
#define heapBYTE_ALIGNMENT_MASK ( ( size_t ) 0x0000 )
#endif
#ifndef heapBYTE_ALIGNMENT_MASK
#error "Invalid portBYTE_ALIGNMENT definition"
#endif
/* Allocate the memory for the heap. The struct is used to force byte
alignment without using any non-portable code. */
static struct xRTOS_HEAP
{
unsigned portLONG ulDummy;
unsigned portCHAR ucHeap[ configTOTAL_HEAP_SIZE ];
} xHeap;
static size_t xNextFreeByte = ( size_t ) 0;
/*-----------------------------------------------------------*/
void *pvPortMalloc( size_t xWantedSize )
{
void *pvReturn = NULL;
/* Ensure that blocks are always aligned to the required number of bytes. */
#if portBYTE_ALIGNMENT != 1
if( xWantedSize & heapBYTE_ALIGNMENT_MASK )
{
/* Byte alignment required. */
xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & heapBYTE_ALIGNMENT_MASK ) );
}
#endif
vTaskSuspendAll();
{
/* Check there is enough room left for the allocation. */
if( ( ( xNextFreeByte + xWantedSize ) < configTOTAL_HEAP_SIZE ) &&
( ( xNextFreeByte + xWantedSize ) > xNextFreeByte ) )/* Check for overflow. */
{
/* Return the next free byte then increment the index past this
block. */
pvReturn = &( xHeap.ucHeap[ xNextFreeByte ] );
xNextFreeByte += xWantedSize;
}
}
xTaskResumeAll();
return pvReturn;
}
/*-----------------------------------------------------------*/
void vPortFree( void *pv )
{
/* Memory cannot be freed using this scheme. See heap_2.c and heap_3.c
for alternative implementations, and the memory management pages of
http://www.FreeRTOS.org for more information. */
( void ) pv;
}
/*-----------------------------------------------------------*/
void vPortInitialiseBlocks( void )
{
/* Only required when static memory is not cleared. */
xNextFreeByte = ( size_t ) 0;
}
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