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Diffstat (limited to 'libraries/FreeRTOS/utility/heap_2.c')
| -rwxr-xr-x | libraries/FreeRTOS/utility/heap_2.c | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/libraries/FreeRTOS/utility/heap_2.c b/libraries/FreeRTOS/utility/heap_2.c new file mode 100755 index 0000000..d135d8f --- /dev/null +++ b/libraries/FreeRTOS/utility/heap_2.c @@ -0,0 +1,278 @@ +/* + FreeRTOS V7.0.1 - 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. +*/ + +/* + * A sample implementation of pvPortMalloc() and vPortFree() that permits + * allocated blocks to be freed, but does not combine adjacent free blocks + * into a single larger block. + * + * See heap_1.c and heap_3.c for alternative implementations, and the memory + * management pages of http://www.FreeRTOS.org for more information. + */ +#include <stdlib.h> + +/* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining +all the API functions to use the MPU wrappers. That should only be done when +task.h is included from an application file. */ +#define MPU_WRAPPERS_INCLUDED_FROM_API_FILE + +#include "FreeRTOS.h" +#include "task.h" + +#undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE + +/* Allocate the memory for the heap. The struct is used to force byte +alignment without using any non-portable code. */ +static union xRTOS_HEAP +{ + #if portBYTE_ALIGNMENT == 8 + volatile portDOUBLE dDummy; + #else + volatile unsigned long ulDummy; + #endif + unsigned char ucHeap[ configTOTAL_HEAP_SIZE ]; +} xHeap; + +/* Define the linked list structure. This is used to link free blocks in order +of their size. */ +typedef struct A_BLOCK_LINK +{ + struct A_BLOCK_LINK *pxNextFreeBlock; /*<< The next free block in the list. */ + size_t xBlockSize; /*<< The size of the free block. */ +} xBlockLink; + + +static const unsigned short heapSTRUCT_SIZE = ( sizeof( xBlockLink ) + portBYTE_ALIGNMENT - ( sizeof( xBlockLink ) % portBYTE_ALIGNMENT ) ); +#define heapMINIMUM_BLOCK_SIZE ( ( size_t ) ( heapSTRUCT_SIZE * 2 ) ) + +/* Create a couple of list links to mark the start and end of the list. */ +static xBlockLink xStart, xEnd; + +/* Keeps track of the number of free bytes remaining, but says nothing about +fragmentation. */ +static size_t xFreeBytesRemaining = configTOTAL_HEAP_SIZE; + +/* STATIC FUNCTIONS ARE DEFINED AS MACROS TO MINIMIZE THE FUNCTION CALL DEPTH. */ + +/* + * Insert a block into the list of free blocks - which is ordered by size of + * the block. Small blocks at the start of the list and large blocks at the end + * of the list. + */ +#define prvInsertBlockIntoFreeList( pxBlockToInsert ) \ +{ \ +xBlockLink *pxIterator; \ +size_t xBlockSize; \ + \ + xBlockSize = pxBlockToInsert->xBlockSize; \ + \ + /* Iterate through the list until a block is found that has a larger size */ \ + /* than the block we are inserting. */ \ + for( pxIterator = &xStart; pxIterator->pxNextFreeBlock->xBlockSize < xBlockSize; pxIterator = pxIterator->pxNextFreeBlock ) \ + { \ + /* There is nothing to do here - just iterate to the correct position. */ \ + } \ + \ + /* Update the list to include the block being inserted in the correct */ \ + /* position. */ \ + pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock; \ + pxIterator->pxNextFreeBlock = pxBlockToInsert; \ +} +/*-----------------------------------------------------------*/ + +#define prvHeapInit() \ +{ \ +xBlockLink *pxFirstFreeBlock; \ + \ + /* xStart is used to hold a pointer to the first item in the list of free */ \ + /* blocks. The void cast is used to prevent compiler warnings. */ \ + xStart.pxNextFreeBlock = ( void * ) xHeap.ucHeap; \ + xStart.xBlockSize = ( size_t ) 0; \ + \ + /* xEnd is used to mark the end of the list of free blocks. */ \ + xEnd.xBlockSize = configTOTAL_HEAP_SIZE; \ + xEnd.pxNextFreeBlock = NULL; \ + \ + /* To start with there is a single free block that is sized to take up the \ + entire heap space. */ \ + pxFirstFreeBlock = ( void * ) xHeap.ucHeap; \ + pxFirstFreeBlock->xBlockSize = configTOTAL_HEAP_SIZE; \ + pxFirstFreeBlock->pxNextFreeBlock = &xEnd; \ +} +/*-----------------------------------------------------------*/ + +void *pvPortMalloc( size_t xWantedSize ) +{ +xBlockLink *pxBlock, *pxPreviousBlock, *pxNewBlockLink; +static portBASE_TYPE xHeapHasBeenInitialised = pdFALSE; +void *pvReturn = NULL; + + vTaskSuspendAll(); + { + /* If this is the first call to malloc then the heap will require + initialisation to setup the list of free blocks. */ + if( xHeapHasBeenInitialised == pdFALSE ) + { + prvHeapInit(); + xHeapHasBeenInitialised = pdTRUE; + } + + /* The wanted size is increased so it can contain a xBlockLink + structure in addition to the requested amount of bytes. */ + if( xWantedSize > 0 ) + { + xWantedSize += heapSTRUCT_SIZE; + + /* Ensure that blocks are always aligned to the required number of bytes. */ + if( xWantedSize & portBYTE_ALIGNMENT_MASK ) + { + /* Byte alignment required. */ + xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) ); + } + } + + if( ( xWantedSize > 0 ) && ( xWantedSize < configTOTAL_HEAP_SIZE ) ) + { + /* Blocks are stored in byte order - traverse the list from the start + (smallest) block until one of adequate size is found. */ + pxPreviousBlock = &xStart; + pxBlock = xStart.pxNextFreeBlock; + while( ( pxBlock->xBlockSize < xWantedSize ) && ( pxBlock->pxNextFreeBlock ) ) + { + pxPreviousBlock = pxBlock; + pxBlock = pxBlock->pxNextFreeBlock; + } + + /* If we found the end marker then a block of adequate size was not found. */ + if( pxBlock != &xEnd ) + { + /* Return the memory space - jumping over the xBlockLink structure + at its start. */ + pvReturn = ( void * ) ( ( ( unsigned char * ) pxPreviousBlock->pxNextFreeBlock ) + heapSTRUCT_SIZE ); + + /* This block is being returned for use so must be taken our of the + list of free blocks. */ + pxPreviousBlock->pxNextFreeBlock = pxBlock->pxNextFreeBlock; + + /* If the block is larger than required it can be split into two. */ + if( ( pxBlock->xBlockSize - xWantedSize ) > heapMINIMUM_BLOCK_SIZE ) + { + /* This block is to be split into two. Create a new block + following the number of bytes requested. The void cast is + used to prevent byte alignment warnings from the compiler. */ + pxNewBlockLink = ( void * ) ( ( ( unsigned char * ) pxBlock ) + xWantedSize ); + + /* Calculate the sizes of two blocks split from the single + block. */ + pxNewBlockLink->xBlockSize = pxBlock->xBlockSize - xWantedSize; + pxBlock->xBlockSize = xWantedSize; + + /* Insert the new block into the list of free blocks. */ + prvInsertBlockIntoFreeList( ( pxNewBlockLink ) ); + } + + xFreeBytesRemaining -= pxBlock->xBlockSize; + } + } + } + xTaskResumeAll(); + + #if( configUSE_MALLOC_FAILED_HOOK == 1 ) + { + if( pvReturn == NULL ) + { + extern void vApplicationMallocFailedHook( void ); + vApplicationMallocFailedHook(); + } + } + #endif + + return pvReturn; +} +/*-----------------------------------------------------------*/ + +void vPortFree( void *pv ) +{ +unsigned char *puc = ( unsigned char * ) pv; +xBlockLink *pxLink; + + if( pv ) + { + /* The memory being freed will have an xBlockLink structure immediately + before it. */ + puc -= heapSTRUCT_SIZE; + + /* This casting is to keep the compiler from issuing warnings. */ + pxLink = ( void * ) puc; + + vTaskSuspendAll(); + { + /* Add this block to the list of free blocks. */ + prvInsertBlockIntoFreeList( ( ( xBlockLink * ) pxLink ) ); + xFreeBytesRemaining += pxLink->xBlockSize; + } + xTaskResumeAll(); + } +} +/*-----------------------------------------------------------*/ + +size_t xPortGetFreeHeapSize( void ) +{ + return xFreeBytesRemaining; +} +/*-----------------------------------------------------------*/ + +void vPortInitialiseBlocks( void ) +{ + /* This just exists to keep the linker quiet. */ +} |