387 lines
14 KiB
C
387 lines
14 KiB
C
/*
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FreeRTOS V7.5.2 - Copyright (C) 2013 Real Time Engineers Ltd.
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VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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***************************************************************************
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* *
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* FreeRTOS provides completely free yet professionally developed, *
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* robust, strictly quality controlled, supported, and cross *
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* platform software that has become a de facto standard. *
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* *
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* Help yourself get started quickly and support the FreeRTOS *
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* project by purchasing a FreeRTOS tutorial book, reference *
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* manual, or both from: http://www.FreeRTOS.org/Documentation *
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* *
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* Thank you! *
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* *
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***************************************************************************
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This file is part of the FreeRTOS distribution.
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FreeRTOS is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License (version 2) as published by the
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Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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>>! NOTE: The modification to the GPL is included to allow you to distribute
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>>! a combined work that includes FreeRTOS without being obliged to provide
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>>! the source code for proprietary components outside of the FreeRTOS
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>>! kernel.
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FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. Full license text is available from the following
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link: http://www.freertos.org/a00114.html
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1 tab == 4 spaces!
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***************************************************************************
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* *
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* Having a problem? Start by reading the FAQ "My application does *
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* not run, what could be wrong?" *
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* *
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* http://www.FreeRTOS.org/FAQHelp.html *
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* *
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***************************************************************************
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http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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license and Real Time Engineers Ltd. contact details.
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http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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compatible FAT file system, and our tiny thread aware UDP/IP stack.
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http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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licenses offer ticketed support, indemnification and middleware.
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http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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engineered and independently SIL3 certified version for use in safety and
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mission critical applications that require provable dependability.
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1 tab == 4 spaces!
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*/
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/*
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* A sample implementation of pvPortMalloc() and vPortFree() that combines
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* (coalescences) adjacent memory blocks as they are freed, and in so doing
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* limits memory fragmentation.
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*
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* See heap_1.c, heap_2.c and heap_3.c for alternative implementations, and the
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* memory management pages of http://www.FreeRTOS.org for more information.
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*/
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#include <stdlib.h>
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/* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining
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all the API functions to use the MPU wrappers. That should only be done when
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task.h is included from an application file. */
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#define MPU_WRAPPERS_INCLUDED_FROM_API_FILE
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#include "FreeRTOS.h"
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#include "task.h"
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#undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE
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/* Block sizes must not get too small. */
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#define heapMINIMUM_BLOCK_SIZE ( ( size_t ) ( heapSTRUCT_SIZE * 2 ) )
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/* Assumes 8bit bytes! */
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#define heapBITS_PER_BYTE ( ( size_t ) 8 )
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/* A few bytes might be lost to byte aligning the heap start address. */
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#define heapADJUSTED_HEAP_SIZE ( configTOTAL_HEAP_SIZE - portBYTE_ALIGNMENT )
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/* Allocate the memory for the heap. */
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static unsigned char ucHeap[ configTOTAL_HEAP_SIZE ];
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/* Define the linked list structure. This is used to link free blocks in order
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of their memory address. */
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typedef struct A_BLOCK_LINK
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{
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struct A_BLOCK_LINK *pxNextFreeBlock; /*<< The next free block in the list. */
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size_t xBlockSize; /*<< The size of the free block. */
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} xBlockLink;
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/*-----------------------------------------------------------*/
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/*
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* Inserts a block of memory that is being freed into the correct position in
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* the list of free memory blocks. The block being freed will be merged with
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* the block in front it and/or the block behind it if the memory blocks are
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* adjacent to each other.
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*/
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static void prvInsertBlockIntoFreeList( xBlockLink *pxBlockToInsert );
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/*
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* Called automatically to setup the required heap structures the first time
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* pvPortMalloc() is called.
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*/
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static void prvHeapInit( void );
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/*-----------------------------------------------------------*/
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/* The size of the structure placed at the beginning of each allocated memory
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block must by correctly byte aligned. */
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static const unsigned short heapSTRUCT_SIZE = ( ( sizeof ( xBlockLink ) + ( portBYTE_ALIGNMENT - 1 ) ) & ~portBYTE_ALIGNMENT_MASK );
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/* Ensure the pxEnd pointer will end up on the correct byte alignment. */
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static const size_t xTotalHeapSize = ( ( size_t ) heapADJUSTED_HEAP_SIZE ) & ( ( size_t ) ~portBYTE_ALIGNMENT_MASK );
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/* Create a couple of list links to mark the start and end of the list. */
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static xBlockLink xStart, *pxEnd = NULL;
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/* Keeps track of the number of free bytes remaining, but says nothing about
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fragmentation. */
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static size_t xFreeBytesRemaining = ( ( size_t ) heapADJUSTED_HEAP_SIZE ) & ( ( size_t ) ~portBYTE_ALIGNMENT_MASK );
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/* Gets set to the top bit of an size_t type. When this bit in the xBlockSize
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member of an xBlockLink structure is set then the block belongs to the
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application. When the bit is free the block is still part of the free heap
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space. */
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static size_t xBlockAllocatedBit = 0;
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/*-----------------------------------------------------------*/
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void *pvPortMalloc( size_t xWantedSize )
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{
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xBlockLink *pxBlock, *pxPreviousBlock, *pxNewBlockLink;
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void *pvReturn = NULL;
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vTaskSuspendAll();
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{
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/* If this is the first call to malloc then the heap will require
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initialisation to setup the list of free blocks. */
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if( pxEnd == NULL )
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{
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prvHeapInit();
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}
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/* Check the requested block size is not so large that the top bit is
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set. The top bit of the block size member of the xBlockLink structure
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is used to determine who owns the block - the application or the
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kernel, so it must be free. */
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if( ( xWantedSize & xBlockAllocatedBit ) == 0 )
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{
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/* The wanted size is increased so it can contain a xBlockLink
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structure in addition to the requested amount of bytes. */
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if( xWantedSize > 0 )
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{
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xWantedSize += heapSTRUCT_SIZE;
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/* Ensure that blocks are always aligned to the required number
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of bytes. */
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if( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) != 0x00 )
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{
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/* Byte alignment required. */
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xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) );
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}
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}
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if( ( xWantedSize > 0 ) && ( xWantedSize <= xFreeBytesRemaining ) )
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{
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/* Traverse the list from the start (lowest address) block until
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one of adequate size is found. */
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pxPreviousBlock = &xStart;
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pxBlock = xStart.pxNextFreeBlock;
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while( ( pxBlock->xBlockSize < xWantedSize ) && ( pxBlock->pxNextFreeBlock != NULL ) )
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{
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pxPreviousBlock = pxBlock;
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pxBlock = pxBlock->pxNextFreeBlock;
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}
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/* If the end marker was reached then a block of adequate size
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was not found. */
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if( pxBlock != pxEnd )
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{
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/* Return the memory space pointed to - jumping over the
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xBlockLink structure at its start. */
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pvReturn = ( void * ) ( ( ( unsigned char * ) pxPreviousBlock->pxNextFreeBlock ) + heapSTRUCT_SIZE );
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/* This block is being returned for use so must be taken out
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of the list of free blocks. */
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pxPreviousBlock->pxNextFreeBlock = pxBlock->pxNextFreeBlock;
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/* If the block is larger than required it can be split into
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two. */
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if( ( pxBlock->xBlockSize - xWantedSize ) > heapMINIMUM_BLOCK_SIZE )
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{
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/* This block is to be split into two. Create a new
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block following the number of bytes requested. The void
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cast is used to prevent byte alignment warnings from the
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compiler. */
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pxNewBlockLink = ( void * ) ( ( ( unsigned char * ) pxBlock ) + xWantedSize );
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/* Calculate the sizes of two blocks split from the
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single block. */
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pxNewBlockLink->xBlockSize = pxBlock->xBlockSize - xWantedSize;
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pxBlock->xBlockSize = xWantedSize;
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/* Insert the new block into the list of free blocks. */
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prvInsertBlockIntoFreeList( ( pxNewBlockLink ) );
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}
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xFreeBytesRemaining -= pxBlock->xBlockSize;
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/* The block is being returned - it is allocated and owned
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by the application and has no "next" block. */
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pxBlock->xBlockSize |= xBlockAllocatedBit;
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pxBlock->pxNextFreeBlock = NULL;
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}
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}
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}
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}
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xTaskResumeAll();
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#if( configUSE_MALLOC_FAILED_HOOK == 1 )
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{
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if( pvReturn == NULL )
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{
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extern void vApplicationMallocFailedHook( void );
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vApplicationMallocFailedHook();
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}
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}
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#endif
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return pvReturn;
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}
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/*-----------------------------------------------------------*/
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void vPortFree( void *pv )
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{
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unsigned char *puc = ( unsigned char * ) pv;
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xBlockLink *pxLink;
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if( pv != NULL )
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{
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/* The memory being freed will have an xBlockLink structure immediately
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before it. */
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puc -= heapSTRUCT_SIZE;
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/* This casting is to keep the compiler from issuing warnings. */
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pxLink = ( void * ) puc;
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/* Check the block is actually allocated. */
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configASSERT( ( pxLink->xBlockSize & xBlockAllocatedBit ) != 0 );
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configASSERT( pxLink->pxNextFreeBlock == NULL );
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if( ( pxLink->xBlockSize & xBlockAllocatedBit ) != 0 )
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{
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if( pxLink->pxNextFreeBlock == NULL )
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{
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/* The block is being returned to the heap - it is no longer
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allocated. */
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pxLink->xBlockSize &= ~xBlockAllocatedBit;
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vTaskSuspendAll();
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{
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/* Add this block to the list of free blocks. */
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xFreeBytesRemaining += pxLink->xBlockSize;
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prvInsertBlockIntoFreeList( ( ( xBlockLink * ) pxLink ) );
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}
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xTaskResumeAll();
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}
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}
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}
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}
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/*-----------------------------------------------------------*/
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size_t xPortGetFreeHeapSize( void )
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{
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return xFreeBytesRemaining;
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}
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/*-----------------------------------------------------------*/
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void vPortInitialiseBlocks( void )
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{
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/* This just exists to keep the linker quiet. */
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}
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/*-----------------------------------------------------------*/
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static void prvHeapInit( void )
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{
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xBlockLink *pxFirstFreeBlock;
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unsigned char *pucHeapEnd, *pucAlignedHeap;
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/* Ensure the heap starts on a correctly aligned boundary. */
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pucAlignedHeap = ( unsigned char * ) ( ( ( portPOINTER_SIZE_TYPE ) &ucHeap[ portBYTE_ALIGNMENT ] ) & ( ( portPOINTER_SIZE_TYPE ) ~portBYTE_ALIGNMENT_MASK ) );
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/* xStart is used to hold a pointer to the first item in the list of free
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blocks. The void cast is used to prevent compiler warnings. */
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xStart.pxNextFreeBlock = ( void * ) pucAlignedHeap;
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xStart.xBlockSize = ( size_t ) 0;
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/* pxEnd is used to mark the end of the list of free blocks and is inserted
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at the end of the heap space. */
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pucHeapEnd = pucAlignedHeap + xTotalHeapSize;
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pucHeapEnd -= heapSTRUCT_SIZE;
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pxEnd = ( void * ) pucHeapEnd;
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configASSERT( ( ( ( unsigned long ) pxEnd ) & ( ( unsigned long ) portBYTE_ALIGNMENT_MASK ) ) == 0UL );
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pxEnd->xBlockSize = 0;
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pxEnd->pxNextFreeBlock = NULL;
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/* To start with there is a single free block that is sized to take up the
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entire heap space, minus the space taken by pxEnd. */
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pxFirstFreeBlock = ( void * ) pucAlignedHeap;
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pxFirstFreeBlock->xBlockSize = xTotalHeapSize - heapSTRUCT_SIZE;
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pxFirstFreeBlock->pxNextFreeBlock = pxEnd;
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/* The heap now contains pxEnd. */
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xFreeBytesRemaining -= heapSTRUCT_SIZE;
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/* Work out the position of the top bit in a size_t variable. */
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xBlockAllocatedBit = ( ( size_t ) 1 ) << ( ( sizeof( size_t ) * heapBITS_PER_BYTE ) - 1 );
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}
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/*-----------------------------------------------------------*/
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static void prvInsertBlockIntoFreeList( xBlockLink *pxBlockToInsert )
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{
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xBlockLink *pxIterator;
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unsigned char *puc;
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/* Iterate through the list until a block is found that has a higher address
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than the block being inserted. */
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for( pxIterator = &xStart; pxIterator->pxNextFreeBlock < pxBlockToInsert; pxIterator = pxIterator->pxNextFreeBlock )
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{
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/* Nothing to do here, just iterate to the right position. */
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}
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/* Do the block being inserted, and the block it is being inserted after
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make a contiguous block of memory? */
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puc = ( unsigned char * ) pxIterator;
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if( ( puc + pxIterator->xBlockSize ) == ( unsigned char * ) pxBlockToInsert )
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{
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pxIterator->xBlockSize += pxBlockToInsert->xBlockSize;
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pxBlockToInsert = pxIterator;
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}
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/* Do the block being inserted, and the block it is being inserted before
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make a contiguous block of memory? */
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puc = ( unsigned char * ) pxBlockToInsert;
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if( ( puc + pxBlockToInsert->xBlockSize ) == ( unsigned char * ) pxIterator->pxNextFreeBlock )
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{
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if( pxIterator->pxNextFreeBlock != pxEnd )
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{
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/* Form one big block from the two blocks. */
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pxBlockToInsert->xBlockSize += pxIterator->pxNextFreeBlock->xBlockSize;
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pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock->pxNextFreeBlock;
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}
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else
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{
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pxBlockToInsert->pxNextFreeBlock = pxEnd;
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}
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}
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else
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{
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pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock;
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}
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/* If the block being inserted plugged a gab, so was merged with the block
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before and the block after, then it's pxNextFreeBlock pointer will have
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already been set, and should not be set here as that would make it point
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to itself. */
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if( pxIterator != pxBlockToInsert )
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{
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pxIterator->pxNextFreeBlock = pxBlockToInsert;
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}
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}
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