heap_2.c

LPC2148 Demo compiled with winarm include make file to help you using opensource

/*
	FreeRTOS.org V4.3.1 - Copyright (C) 2003-2007 Richard Barry.

	This file is part of the FreeRTOS.org distribution.

	FreeRTOS.org is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	FreeRTOS.org 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
	along with FreeRTOS.org; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

	A special exception to the GPL can be applied should you wish to distribute
	a combined work that includes FreeRTOS.org, without being obliged to provide
	the source code for any proprietary components.  See the licensing section
	of http://www.FreeRTOS.org for full details of how and when the exception
	can be applied.

	***************************************************************************
	See http://www.FreeRTOS.org for documentation, latest information, license
	and contact details.  Please ensure to read the configuration and relevant
	port sections of the online documentation.

	Also see http://www.SafeRTOS.com for an IEC 61508 compliant version along
	with commercial development and support options.
	***************************************************************************
*/

/*
 * 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>

#include "FreeRTOS.h"
#include "task.h"

/* Setup the correct byte alignment mask for the defined byte alignment. */

#if portBYTE_ALIGNMENT == 8
	#define heapBYTE_ALIGNMENT_MASK ( ( size_t ) 0x0007 )
#endif

#if portBYTE_ALIGNMENT == 4
	#define heapBYTE_ALIGNMENT_MASK	( ( size_t ) 0x0003 )
#endif

#if portBYTE_ALIGNMENT == 2
	#define heapBYTE_ALIGNMENT_MASK	( ( size_t ) 0x0001 )
#endif

#if portBYTE_ALIGNMENT == 1
	#define heapBYTE_ALIGNMENT_MASK	( ( size_t ) 0x0000 )
#endif

#ifndef heapBYTE_ALIGNMENT_MASK
	#error "Invalid portBYTE_ALIGNMENT definition"
#endif

/* Allocate the memory for the heap.  The struct is used to force byte
alignment without using any non-portable code. */
static struct xRTOS_HEAP
{
	unsigned portLONG ulDummy;
	unsigned portCHAR 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 portSHORT  heapSTRUCT_SIZE	= ( sizeof( xBlockLink ) + ( 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;

/* 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;										\
}
/*-----------------------------------------------------------*/

#if ( INCLUDE_vPortUsedMem == 1 )

void vPortUsedMem(int *bytesFree, int *bytesUsed, int *blocksFree)  
{  
  xBlockLink *pxBlock = &xStart;  

  *bytesFree = 0;  
  *bytesUsed = 0;  
  *blocksFree = 0;

  vTaskSuspendAll();  

  while ((pxBlock) && (pxBlock != &xEnd))  
  {  
    *bytesFree += pxBlock->xBlockSize;  
    pxBlock = pxBlock->pxNextFreeBlock;  
    ++*blocksFree;
  }  

  xTaskResumeAll();  

  *bytesUsed = configTOTAL_HEAP_SIZE - *bytesFree;
}  

#endif
/*-----------------------------------------------------------*/

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 & heapBYTE_ALIGNMENT_MASK )
      {
        /* Byte alignment required. */
        xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & heapBYTE_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 portCHAR * ) 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 portCHAR * ) 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 ) );
        }
      }
    }
  }
  xTaskResumeAll();

  return pvReturn;
}
/*-----------------------------------------------------------*/

void vPortFree( void *pv )
{
unsigned portCHAR *puc = ( unsigned portCHAR * ) 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 ) );
		}
		xTaskResumeAll();
	}
}
/*-----------------------------------------------------------*/