1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
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 ();
}
}
/*-----------------------------------------------------------*/
|
