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Show/hide line numbers heap_1.c Source File

heap_1.c

00001 /*
00002     FreeRTOS V6.0.3 - Copyright (C) 2010 Real Time Engineers Ltd.
00003 
00004     ***************************************************************************
00005     *                                                                         *
00006     * If you are:                                                             *
00007     *                                                                         *
00008     *    + New to FreeRTOS,                                                   *
00009     *    + Wanting to learn FreeRTOS or multitasking in general quickly       *
00010     *    + Looking for basic training,                                        *
00011     *    + Wanting to improve your FreeRTOS skills and productivity           *
00012     *                                                                         *
00013     * then take a look at the FreeRTOS eBook                                  *
00014     *                                                                         *
00015     *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
00016     *                  http://www.FreeRTOS.org/Documentation                  *
00017     *                                                                         *
00018     * A pdf reference manual is also available.  Both are usually delivered   *
00019     * to your inbox within 20 minutes to two hours when purchased between 8am *
00020     * and 8pm GMT (although please allow up to 24 hours in case of            *
00021     * exceptional circumstances).  Thank you for your support!                *
00022     *                                                                         *
00023     ***************************************************************************
00024 
00025     This file is part of the FreeRTOS distribution.
00026 
00027     FreeRTOS is free software; you can redistribute it and/or modify it under
00028     the terms of the GNU General Public License (version 2) as published by the
00029     Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
00030     ***NOTE*** The exception to the GPL is included to allow you to distribute
00031     a combined work that includes FreeRTOS without being obliged to provide the
00032     source code for proprietary components outside of the FreeRTOS kernel.
00033     FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
00034     ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
00035     FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
00036     more details. You should have received a copy of the GNU General Public 
00037     License and the FreeRTOS license exception along with FreeRTOS; if not it 
00038     can be viewed here: http://www.freertos.org/a00114.html and also obtained 
00039     by writing to Richard Barry, contact details for whom are available on the
00040     FreeRTOS WEB site.
00041 
00042     1 tab == 4 spaces!
00043 
00044     http://www.FreeRTOS.org - Documentation, latest information, license and
00045     contact details.
00046 
00047     http://www.SafeRTOS.com - A version that is certified for use in safety
00048     critical systems.
00049 
00050     http://www.OpenRTOS.com - Commercial support, development, porting,
00051     licensing and training services.
00052 */
00053 
00054 
00055 /*
00056  * The simplest possible implementation of pvPortMalloc().  Note that this
00057  * implementation does NOT allow allocated memory to be freed again.
00058  *
00059  * See heap_2.c and heap_3.c for alternative implementations, and the memory
00060  * management pages of http://www.FreeRTOS.org for more information.
00061  */
00062 
00063 #include <stdlib.h>
00064 
00065 /* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining
00066 all the API functions to use the MPU wrappers.  That should only be done when
00067 task.h is included from an application file. */
00068 #define MPU_WRAPPERS_INCLUDED_FROM_API_FILE
00069 
00070 #include "FreeRTOS.h"
00071 #include "task.h"
00072 
00073 #undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE
00074 
00075 /* Allocate the memory for the heap.  The struct is used to force byte
00076 alignment without using any non-portable code. */
00077 static union xRTOS_HEAP
00078 {
00079     #if portBYTE_ALIGNMENT == 8
00080         volatile portDOUBLE dDummy;
00081     #else
00082         volatile unsigned long ulDummy;
00083     #endif    
00084     unsigned char ucHeap[ configTOTAL_HEAP_SIZE ];
00085 } xHeap;
00086 
00087 static size_t xNextFreeByte = ( size_t ) 0;
00088 /*-----------------------------------------------------------*/
00089 
00090 void *pvPortMalloc( size_t xWantedSize )
00091 {
00092 void *pvReturn = NULL; 
00093 
00094     /* Ensure that blocks are always aligned to the required number of bytes. */
00095     #if portBYTE_ALIGNMENT != 1
00096         if( xWantedSize & portBYTE_ALIGNMENT_MASK )
00097         {
00098             /* Byte alignment required. */
00099             xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) );
00100         }
00101     #endif
00102 
00103     vTaskSuspendAll();
00104     {
00105         /* Check there is enough room left for the allocation. */
00106         if( ( ( xNextFreeByte + xWantedSize ) < configTOTAL_HEAP_SIZE ) &&
00107             ( ( xNextFreeByte + xWantedSize ) > xNextFreeByte )    )/* Check for overflow. */
00108         {
00109             /* Return the next free byte then increment the index past this
00110             block. */
00111             pvReturn = &( xHeap.ucHeap[ xNextFreeByte ] );
00112             xNextFreeByte += xWantedSize;            
00113         }    
00114     }
00115     xTaskResumeAll();
00116     
00117     #if( configUSE_MALLOC_FAILED_HOOK == 1 )
00118     {
00119         if( pvReturn == NULL )
00120         {
00121             extern void vApplicationMallocFailedHook( void );
00122             vApplicationMallocFailedHook();
00123         }
00124     }
00125     #endif    
00126 
00127     return pvReturn;
00128 }
00129 /*-----------------------------------------------------------*/
00130 
00131 void vPortFree( void *pv )
00132 {
00133     /* Memory cannot be freed using this scheme.  See heap_2.c and heap_3.c 
00134     for alternative implementations, and the memory management pages of 
00135     http://www.FreeRTOS.org for more information. */
00136     ( void ) pv;
00137 }
00138 /*-----------------------------------------------------------*/
00139 
00140 void vPortInitialiseBlocks( void )
00141 {
00142     /* Only required when static memory is not cleared. */
00143     xNextFreeByte = ( size_t ) 0;
00144 }
00145 /*-----------------------------------------------------------*/
00146 
00147 size_t xPortGetFreeHeapSize( void )
00148 {
00149     return ( configTOTAL_HEAP_SIZE - xNextFreeByte );
00150 }
00151 
00152 
00153