heap_2.c

Revision 14, 9.6 kB (checked in by phil, 15 years ago)
added unmodified FreeRTOS package V5.4.1 with only web srv demo source for LPC2368 for CrossWorks?

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1	/*
2	FreeRTOS V5.4.1 - Copyright (C) 2009 Real Time Engineers Ltd.
3
4	This file is part of the FreeRTOS distribution.
5
6	FreeRTOS is free software; you can redistribute it and/or modify it under
7	the terms of the GNU General Public License (version 2) as published by the
8	Free Software Foundation and modified by the FreeRTOS exception.
9	NOTE The exception to the GPL is included to allow you to distribute a
10	combined work that includes FreeRTOS without being obliged to provide the
11	source code for proprietary components outside of the FreeRTOS kernel.
12	Alternative commercial license and support terms are also available upon
13	request. See the licensing section of http://www.FreeRTOS.org for full
14	license details.
15
16	FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
17	ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
18	FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
19	more details.
20
21	You should have received a copy of the GNU General Public License along
22	with FreeRTOS; if not, write to the Free Software Foundation, Inc., 59
23	Temple Place, Suite 330, Boston, MA 02111-1307 USA.
24
25
26	***************************************************************************
27	* *
28	* Looking for a quick start? Then check out the FreeRTOS eBook! *
29	* See http://www.FreeRTOS.org/Documentation for details *
30	* *
31	***************************************************************************
32
33	1 tab == 4 spaces!
34
35	Please ensure to read the configuration and relevant port sections of the
36	online documentation.
37
38	http://www.FreeRTOS.org - Documentation, latest information, license and
39	contact details.
40
41	http://www.SafeRTOS.com - A version that is certified for use in safety
42	critical systems.
43
44	http://www.OpenRTOS.com - Commercial support, development, porting,
45	licensing and training services.
46	*/
47
48	/*
49	* A sample implementation of pvPortMalloc() and vPortFree() that permits
50	* allocated blocks to be freed, but does not combine adjacent free blocks
51	* into a single larger block.
52	*
53	* See heap_1.c and heap_3.c for alternative implementations, and the memory
54	* management pages of http://www.FreeRTOS.org for more information.
55	*/
56	#include <stdlib.h>
57
58	#include "FreeRTOS.h"
59	#include "task.h"
60
61	/* Setup the correct byte alignment mask for the defined byte alignment. */
62
63	#if portBYTE_ALIGNMENT == 8
64	#define heapBYTE_ALIGNMENT_MASK ( ( size_t ) 0x0007 )
65	#endif
66
67	#if portBYTE_ALIGNMENT == 4
68	#define heapBYTE_ALIGNMENT_MASK ( ( size_t ) 0x0003 )
69	#endif
70
71	#if portBYTE_ALIGNMENT == 2
72	#define heapBYTE_ALIGNMENT_MASK ( ( size_t ) 0x0001 )
73	#endif
74
75	#if portBYTE_ALIGNMENT == 1
76	#define heapBYTE_ALIGNMENT_MASK ( ( size_t ) 0x0000 )
77	#endif
78
79	#ifndef heapBYTE_ALIGNMENT_MASK
80	#error "Invalid portBYTE_ALIGNMENT definition"
81	#endif
82
83	/* Allocate the memory for the heap. The struct is used to force byte
84	alignment without using any non-portable code. */
85	static union xRTOS_HEAP
86	{
87	#if portBYTE_ALIGNMENT == 8
88	volatile portDOUBLE dDummy;
89	#else
90	volatile unsigned portLONG ulDummy;
91	#endif
92	unsigned portCHAR ucHeap[ configTOTAL_HEAP_SIZE ];
93	} xHeap;
94
95	/* Define the linked list structure. This is used to link free blocks in order
96	of their size. */
97	typedef struct A_BLOCK_LINK
98	{
99	struct A_BLOCK_LINK pxNextFreeBlock; /<< The next free block in the list. */
100	size_t xBlockSize; /<< The size of the free block. /
101	} xBlockLink;
102
103
104	static const unsigned portSHORT heapSTRUCT_SIZE = ( sizeof( xBlockLink ) + portBYTE_ALIGNMENT - ( sizeof( xBlockLink ) % portBYTE_ALIGNMENT ) );
105	#define heapMINIMUM_BLOCK_SIZE ( ( size_t ) ( heapSTRUCT_SIZE * 2 ) )
106
107	/* Create a couple of list links to mark the start and end of the list. */
108	static xBlockLink xStart, xEnd;
109
110	/* STATIC FUNCTIONS ARE DEFINED AS MACROS TO MINIMIZE THE FUNCTION CALL DEPTH. */
111
112	/*
113	* Insert a block into the list of free blocks - which is ordered by size of
114	* the block. Small blocks at the start of the list and large blocks at the end
115	* of the list.
116	*/
117	#define prvInsertBlockIntoFreeList( pxBlockToInsert ) \
118	{ \
119	xBlockLink *pxIterator; \
120	size_t xBlockSize; \
121	\
122	xBlockSize = pxBlockToInsert->xBlockSize; \
123	\
124	/* Iterate through the list until a block is found that has a larger size */ \
125	/* than the block we are inserting. */ \
126	for( pxIterator = &xStart; pxIterator->pxNextFreeBlock->xBlockSize < xBlockSize; pxIterator = pxIterator->pxNextFreeBlock ) \
127	{ \
128	/* There is nothing to do here - just iterate to the correct position. */ \
129	} \
130	\
131	/* Update the list to include the block being inserted in the correct */ \
132	/* position. */ \
133	pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock; \
134	pxIterator->pxNextFreeBlock = pxBlockToInsert; \
135	}
136	/-----------------------------------------------------------/
137
138	#define prvHeapInit() \
139	{ \
140	xBlockLink *pxFirstFreeBlock; \
141	\
142	/* xStart is used to hold a pointer to the first item in the list of free */ \
143	/* blocks. The void cast is used to prevent compiler warnings. */ \
144	xStart.pxNextFreeBlock = ( void * ) xHeap.ucHeap; \
145	xStart.xBlockSize = ( size_t ) 0; \
146	\
147	/* xEnd is used to mark the end of the list of free blocks. */ \
148	xEnd.xBlockSize = configTOTAL_HEAP_SIZE; \
149	xEnd.pxNextFreeBlock = NULL; \
150	\
151	/* To start with there is a single free block that is sized to take up the \
152	entire heap space. */ \
153	pxFirstFreeBlock = ( void * ) xHeap.ucHeap; \
154	pxFirstFreeBlock->xBlockSize = configTOTAL_HEAP_SIZE; \
155	pxFirstFreeBlock->pxNextFreeBlock = &xEnd; \
156	}
157	/-----------------------------------------------------------/
158
159	void *pvPortMalloc( size_t xWantedSize )
160	{
161	xBlockLink pxBlock, pxPreviousBlock, *pxNewBlockLink;
162	static portBASE_TYPE xHeapHasBeenInitialised = pdFALSE;
163	void *pvReturn = NULL;
164
165	vTaskSuspendAll();
166	{
167	/* If this is the first call to malloc then the heap will require
168	initialisation to setup the list of free blocks. */
169	if( xHeapHasBeenInitialised == pdFALSE )
170	{
171	prvHeapInit();
172	xHeapHasBeenInitialised = pdTRUE;
173	}
174
175	/* The wanted size is increased so it can contain a xBlockLink
176	structure in addition to the requested amount of bytes. */
177	if( xWantedSize > 0 )
178	{
179	xWantedSize += heapSTRUCT_SIZE;
180
181	/* Ensure that blocks are always aligned to the required number of bytes. */
182	if( xWantedSize & heapBYTE_ALIGNMENT_MASK )
183	{
184	/* Byte alignment required. */
185	xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & heapBYTE_ALIGNMENT_MASK ) );
186	}
187	}
188
189	if( ( xWantedSize > 0 ) && ( xWantedSize < configTOTAL_HEAP_SIZE ) )
190	{
191	/* Blocks are stored in byte order - traverse the list from the start
192	(smallest) block until one of adequate size is found. */
193	pxPreviousBlock = &xStart;
194	pxBlock = xStart.pxNextFreeBlock;
195	while( ( pxBlock->xBlockSize < xWantedSize ) && ( pxBlock->pxNextFreeBlock ) )
196	{
197	pxPreviousBlock = pxBlock;
198	pxBlock = pxBlock->pxNextFreeBlock;
199	}
200
201	/* If we found the end marker then a block of adequate size was not found. */
202	if( pxBlock != &xEnd )
203	{
204	/* Return the memory space - jumping over the xBlockLink structure
205	at its start. */
206	pvReturn = ( void * ) ( ( ( unsigned portCHAR * ) pxPreviousBlock->pxNextFreeBlock ) + heapSTRUCT_SIZE );
207
208	/* This block is being returned for use so must be taken our of the
209	list of free blocks. */
210	pxPreviousBlock->pxNextFreeBlock = pxBlock->pxNextFreeBlock;
211
212	/* If the block is larger than required it can be split into two. */
213	if( ( pxBlock->xBlockSize - xWantedSize ) > heapMINIMUM_BLOCK_SIZE )
214	{
215	/* This block is to be split into two. Create a new block
216	following the number of bytes requested. The void cast is
217	used to prevent byte alignment warnings from the compiler. */
218	pxNewBlockLink = ( void * ) ( ( ( unsigned portCHAR * ) pxBlock ) + xWantedSize );
219
220	/* Calculate the sizes of two blocks split from the single
221	block. */
222	pxNewBlockLink->xBlockSize = pxBlock->xBlockSize - xWantedSize;
223	pxBlock->xBlockSize = xWantedSize;
224
225	/* Insert the new block into the list of free blocks. */
226	prvInsertBlockIntoFreeList( ( pxNewBlockLink ) );
227	}
228	}
229	}
230	}
231	xTaskResumeAll();
232
233	#if( configUSE_MALLOC_FAILED_HOOK == 1 )
234	{
235	if( pvReturn == NULL )
236	{
237	extern void vApplicationMallocFailedHook( void );
238	vApplicationMallocFailedHook();
239	}
240	}
241	#endif
242
243	return pvReturn;
244	}
245	/-----------------------------------------------------------/
246
247	void vPortFree( void *pv )
248	{
249	unsigned portCHAR puc = ( unsigned portCHAR ) pv;
250	xBlockLink *pxLink;
251
252	if( pv )
253	{
254	/* The memory being freed will have an xBlockLink structure immediately
255	before it. */
256	puc -= heapSTRUCT_SIZE;
257
258	/* This casting is to keep the compiler from issuing warnings. */
259	pxLink = ( void * ) puc;
260
261	vTaskSuspendAll();
262	{
263	/* Add this block to the list of free blocks. */
264	prvInsertBlockIntoFreeList( ( ( xBlockLink * ) pxLink ) );
265	}
266	xTaskResumeAll();
267	}
268	}
269	/-----------------------------------------------------------/
270

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