diff options
Diffstat (limited to 'FreeRTOS/Source/portable/MemMang/heap_2.c')
| -rw-r--r-- | FreeRTOS/Source/portable/MemMang/heap_2.c | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/FreeRTOS/Source/portable/MemMang/heap_2.c b/FreeRTOS/Source/portable/MemMang/heap_2.c new file mode 100644 index 0000000..9f8de5c --- /dev/null +++ b/FreeRTOS/Source/portable/MemMang/heap_2.c @@ -0,0 +1,278 @@ +/*
+ FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
+
+ ***************************************************************************
+ * *
+ * If you are: *
+ * *
+ * + New to FreeRTOS, *
+ * + Wanting to learn FreeRTOS or multitasking in general quickly *
+ * + Looking for basic training, *
+ * + Wanting to improve your FreeRTOS skills and productivity *
+ * *
+ * then take a look at the FreeRTOS books - available as PDF or paperback *
+ * *
+ * "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
+ * http://www.FreeRTOS.org/Documentation *
+ * *
+ * A pdf reference manual is also available. Both are usually delivered *
+ * to your inbox within 20 minutes to two hours when purchased between 8am *
+ * and 8pm GMT (although please allow up to 24 hours in case of *
+ * exceptional circumstances). 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 exception 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. */
+}
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