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Diffstat (limited to 'openpicc/os/core/MemMang/heap_2.c')
| -rw-r--r-- | openpicc/os/core/MemMang/heap_2.c | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/openpicc/os/core/MemMang/heap_2.c b/openpicc/os/core/MemMang/heap_2.c new file mode 100644 index 0000000..0b74d44 --- /dev/null +++ b/openpicc/os/core/MemMang/heap_2.c @@ -0,0 +1,255 @@ +/* + FreeRTOS.org V4.2.1 - 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; \ +} +/*-----------------------------------------------------------*/ + +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 (); + } +} + +/*-----------------------------------------------------------*/ |