FreeRTOS/Source/portable/MemMang/heap_1.c

   1 /*
   2     FreeRTOS V6.0.5 - Copyright (C) 2010 Real Time Engineers Ltd.
   3
   4     ***************************************************************************
   5     *                                                                         *
   6     * If you are:                                                             *
   7     *                                                                         *
   8     *    + New to FreeRTOS,                                                   *
   9     *    + Wanting to learn FreeRTOS or multitasking in general quickly       *
  10     *    + Looking for basic training,                                        *
  11     *    + Wanting to improve your FreeRTOS skills and productivity           *
  12     *                                                                         *
  13     * then take a look at the FreeRTOS eBook                                  *
  14     *                                                                         *
  15     *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
  16     *                  http://www.FreeRTOS.org/Documentation                  *
  17     *                                                                         *
  18     * A pdf reference manual is also available.  Both are usually delivered   *
  19     * to your inbox within 20 minutes to two hours when purchased between 8am *
  20     * and 8pm GMT (although please allow up to 24 hours in case of            *
  21     * exceptional circumstances).  Thank you for your support!                *
  22     *                                                                         *
  23     ***************************************************************************
  24
  25     This file is part of the FreeRTOS distribution.
  26
  27     FreeRTOS is free software; you can redistribute it and/or modify it under
  28     the terms of the GNU General Public License (version 2) as published by the
  29     Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
  30     ***NOTE*** The exception to the GPL is included to allow you to distribute
  31     a combined work that includes FreeRTOS without being obliged to provide the
  32     source code for proprietary components outside of the FreeRTOS kernel.
  33     FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
  34     ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  35     FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  36     more details. You should have received a copy of the GNU General Public
  37     License and the FreeRTOS license exception along with FreeRTOS; if not it
  38     can be viewed here: http://www.freertos.org/a00114.html and also obtained
  39     by writing to Richard Barry, contact details for whom are available on the
  40     FreeRTOS WEB site.
  41
  42     1 tab == 4 spaces!
  43
  44     http://www.FreeRTOS.org - Documentation, latest information, license and
  45     contact details.
  46
  47     http://www.SafeRTOS.com - A version that is certified for use in safety
  48     critical systems.
  49
  50     http://www.OpenRTOS.com - Commercial support, development, porting,
  51     licensing and training services.
  52 */
  53
  54
  55 /*
  56  * The simplest possible implementation of pvPortMalloc().  Note that this
  57  * implementation does NOT allow allocated memory to be freed again.
  58  *
  59  * See heap_2.c and heap_3.c for alternative implementations, and the memory
  60  * management pages of http://www.FreeRTOS.org for more information.
  61  */
  62 #include <stdlib.h>
  63
  64 /* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining
  65 all the API functions to use the MPU wrappers.  That should only be done when
  66 task.h is included from an application file. */
  67 #define MPU_WRAPPERS_INCLUDED_FROM_API_FILE
  68
  69 #include "FreeRTOS.h"
  70 #include "task.h"
  71
  72 #undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE
  73
  74 /* Allocate the memory for the heap.  The struct is used to force byte
  75 alignment without using any non-portable code. */
  76 static union xRTOS_HEAP
  77 {
  78         #if portBYTE_ALIGNMENT == 8
  79                 volatile portDOUBLE dDummy;
  80         #else
  81                 volatile unsigned long ulDummy;
  82         #endif
  83         unsigned char ucHeap[ configTOTAL_HEAP_SIZE ];
  84 } xHeap;
  85
  86 static size_t xNextFreeByte = ( size_t ) 0;
  87 /*-----------------------------------------------------------*/
  88
  89 void *pvPortMalloc( size_t xWantedSize )
  90 {
  91 void *pvReturn = NULL;
  92
  93         /* Ensure that blocks are always aligned to the required number of bytes. */
  94         #if portBYTE_ALIGNMENT != 1
  95                 if( xWantedSize & portBYTE_ALIGNMENT_MASK )
  96                 {
  97                         /* Byte alignment required. */
  98                         xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) );
  99                 }
 100         #endif
 101
 102         vTaskSuspendAll();
 103         {
 104                 /* Check there is enough room left for the allocation. */
 105                 if( ( ( xNextFreeByte + xWantedSize ) < configTOTAL_HEAP_SIZE ) &&
 106                         ( ( xNextFreeByte + xWantedSize ) > xNextFreeByte )     )/* Check for overflow. */
 107                 {
 108                         /* Return the next free byte then increment the index past this
 109                         block. */
 110                         pvReturn = &( xHeap.ucHeap[ xNextFreeByte ] );
 111                         xNextFreeByte += xWantedSize;
 112                 }
 113         }
 114         xTaskResumeAll();
 115
 116         #if( configUSE_MALLOC_FAILED_HOOK == 1 )
 117         {
 118                 if( pvReturn == NULL )
 119                 {
 120                         extern void vApplicationMallocFailedHook( void );
 121                         vApplicationMallocFailedHook();
 122                 }
 123         }
 124         #endif
 125
 126         return pvReturn;
 127 }
 128 /*-----------------------------------------------------------*/
 129
 130 void vPortFree( void *pv )
 131 {
 132         /* Memory cannot be freed using this scheme.  See heap_2.c and heap_3.c
 133         for alternative implementations, and the memory management pages of
 134         http://www.FreeRTOS.org for more information. */
 135         ( void ) pv;
 136 }
 137 /*-----------------------------------------------------------*/
 138
 139 void vPortInitialiseBlocks( void )
 140 {
 141         /* Only required when static memory is not cleared. */
 142         xNextFreeByte = ( size_t ) 0;
 143 }
 144 /*-----------------------------------------------------------*/
 145
 146 size_t xPortGetFreeHeapSize( void )
 147 {
 148         return ( configTOTAL_HEAP_SIZE - xNextFreeByte );
 149 }
 150
 151
 152