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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Source/] [portable/] [MemMang/] [heap_2.c] - Blame information for rev 843

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1 572 jeremybenn
/*
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    FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
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    ***************************************************************************
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    *                                                                         *
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    * If you are:                                                             *
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    *                                                                         *
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    *    + New to FreeRTOS,                                                   *
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    *    + Wanting to learn FreeRTOS or multitasking in general quickly       *
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    *    + Looking for basic training,                                        *
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    *    + Wanting to improve your FreeRTOS skills and productivity           *
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    *                                                                         *
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    * then take a look at the FreeRTOS books - available as PDF or paperback  *
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    *                                                                         *
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    *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
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    *                  http://www.FreeRTOS.org/Documentation                  *
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    *                                                                         *
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    * A pdf reference manual is also available.  Both are usually delivered   *
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    * to your inbox within 20 minutes to two hours when purchased between 8am *
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    * and 8pm GMT (although please allow up to 24 hours in case of            *
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    * exceptional circumstances).  Thank you for your support!                *
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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 exception 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 the
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    source code for proprietary components outside of the FreeRTOS kernel.
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    FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
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    more details. You should have received a copy of the GNU General Public
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    License and the FreeRTOS license exception along with FreeRTOS; if not it
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    can be viewed here: http://www.freertos.org/a00114.html and also obtained
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    by writing to Richard Barry, contact details for whom are available on the
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    FreeRTOS WEB site.
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    1 tab == 4 spaces!
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    http://www.FreeRTOS.org - Documentation, latest information, license and
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    contact details.
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    http://www.SafeRTOS.com - A version that is certified for use in safety
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    critical systems.
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    http://www.OpenRTOS.com - Commercial support, development, porting,
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    licensing and training services.
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*/
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/*
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 * A sample implementation of pvPortMalloc() and vPortFree() that permits
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 * allocated blocks to be freed, but does not combine adjacent free blocks
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 * into a single larger block.
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 *
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 * See heap_1.c and heap_3.c for alternative implementations, and the memory
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 * 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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/* Allocate the memory for the heap.  The struct is used to force byte
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alignment without using any non-portable code. */
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static union xRTOS_HEAP
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{
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        #if portBYTE_ALIGNMENT == 8
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                volatile portDOUBLE dDummy;
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        #else
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                volatile unsigned long ulDummy;
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        #endif
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        unsigned char ucHeap[ configTOTAL_HEAP_SIZE ];
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} xHeap;
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/* Define the linked list structure.  This is used to link free blocks in order
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of their size. */
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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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static const unsigned short  heapSTRUCT_SIZE    = ( sizeof( xBlockLink ) + portBYTE_ALIGNMENT - ( sizeof( xBlockLink ) % portBYTE_ALIGNMENT ) );
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#define heapMINIMUM_BLOCK_SIZE  ( ( size_t ) ( heapSTRUCT_SIZE * 2 ) )
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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, xEnd;
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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 = configTOTAL_HEAP_SIZE;
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/* STATIC FUNCTIONS ARE DEFINED AS MACROS TO MINIMIZE THE FUNCTION CALL DEPTH. */
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/*
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 * Insert a block into the list of free blocks - which is ordered by size of
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 * the block.  Small blocks at the start of the list and large blocks at the end
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 * of the list.
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 */
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#define prvInsertBlockIntoFreeList( pxBlockToInsert )                                                           \
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{                                                                                                                                                                       \
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xBlockLink *pxIterator;                                                                                                                         \
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size_t xBlockSize;                                                                                                                                      \
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                                                                                                                                                                        \
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        xBlockSize = pxBlockToInsert->xBlockSize;                                                                               \
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                                                                                                                                                                        \
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        /* Iterate through the list until a block is found that has a larger size */    \
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        /* than the block we are inserting. */                                                                                  \
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        for( pxIterator = &xStart; pxIterator->pxNextFreeBlock->xBlockSize < xBlockSize; pxIterator = pxIterator->pxNextFreeBlock )     \
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        {                                                                                                                                                               \
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                /* There is nothing to do here - just iterate to the correct position. */       \
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        }                                                                                                                                                               \
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                                                                                                                                                                        \
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        /* Update the list to include the block being inserted in the correct */                \
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        /* position. */                                                                                                                                 \
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        pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock;                                 \
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        pxIterator->pxNextFreeBlock = pxBlockToInsert;                                                                  \
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}
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/*-----------------------------------------------------------*/
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#define prvHeapInit()                                                                                                                           \
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{                                                                                                                                                                       \
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xBlockLink *pxFirstFreeBlock;                                                                                                           \
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                                                                                                                                                                        \
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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 * ) xHeap.ucHeap;                                                               \
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        xStart.xBlockSize = ( size_t ) 0;                                                                                                \
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                                                                                                                                                                        \
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        /* xEnd is used to mark the end of the list of free blocks. */                                  \
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        xEnd.xBlockSize = configTOTAL_HEAP_SIZE;                                                                                \
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        xEnd.pxNextFreeBlock = NULL;                                                                                                    \
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                                                                                                                                                                        \
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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. */                                                                                                                   \
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        pxFirstFreeBlock = ( void * ) xHeap.ucHeap;                                                                             \
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        pxFirstFreeBlock->xBlockSize = configTOTAL_HEAP_SIZE;                                                   \
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        pxFirstFreeBlock->pxNextFreeBlock = &xEnd;                                                                              \
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}
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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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static portBASE_TYPE xHeapHasBeenInitialised = pdFALSE;
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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( xHeapHasBeenInitialised == pdFALSE )
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                {
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                        prvHeapInit();
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                        xHeapHasBeenInitialised = pdTRUE;
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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 of bytes. */
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                        if( xWantedSize & portBYTE_ALIGNMENT_MASK )
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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 < configTOTAL_HEAP_SIZE ) )
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                {
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                        /* Blocks are stored in byte order - traverse the list from the start
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                        (smallest) block until 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 ) )
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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 we found the end marker then a block of adequate size was not found. */
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                        if( pxBlock != &xEnd )
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                        {
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                                /* Return the memory space - jumping over the xBlockLink structure
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                                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 our of the
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                                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 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 block
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                                        following the number of bytes requested. The void cast is
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                                        used to prevent byte alignment warnings from the compiler. */
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                                        pxNewBlockLink = ( void * ) ( ( ( unsigned char * ) pxBlock ) + xWantedSize );
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                                        /* Calculate the sizes of two blocks split from the single
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                                        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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                        }
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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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244
void vPortFree( void *pv )
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{
246
unsigned char *puc = ( unsigned char * ) pv;
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xBlockLink *pxLink;
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249
        if( pv )
250
        {
251
                /* The memory being freed will have an xBlockLink structure immediately
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                before it. */
253
                puc -= heapSTRUCT_SIZE;
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255
                /* This casting is to keep the compiler from issuing warnings. */
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                pxLink = ( void * ) puc;
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258
                vTaskSuspendAll();
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                {
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                        /* Add this block to the list of free blocks. */
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                        prvInsertBlockIntoFreeList( ( ( xBlockLink * ) pxLink ) );
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                        xFreeBytesRemaining += pxLink->xBlockSize;
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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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269
size_t xPortGetFreeHeapSize( void )
270
{
271
        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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