2 * FreeRTOS Kernel V10.0.0
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3 * Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
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6 * this software and associated documentation files (the "Software"), to deal in
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7 * the Software without restriction, including without limitation the rights to
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8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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9 * the Software, and to permit persons to whom the Software is furnished to do so,
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10 * subject to the following conditions:
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12 * The above copyright notice and this permission notice shall be included in all
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13 * copies or substantial portions of the Software. If you wish to use our Amazon
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14 * FreeRTOS name, please do so in a fair use way that does not cause confusion.
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16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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18 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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19 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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20 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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23 * http://www.FreeRTOS.org
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24 * http://aws.amazon.com/freertos
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26 * 1 tab == 4 spaces!
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30 * A sample implementation of pvPortMalloc() that allows the heap to be defined
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31 * across multiple non-contigous blocks and combines (coalescences) adjacent
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32 * memory blocks as they are freed.
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34 * See heap_1.c, heap_2.c, heap_3.c and heap_4.c for alternative
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35 * implementations, and the memory management pages of http://www.FreeRTOS.org
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36 * for more information.
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40 * vPortDefineHeapRegions() ***must*** be called before pvPortMalloc().
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41 * pvPortMalloc() will be called if any task objects (tasks, queues, event
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42 * groups, etc.) are created, therefore vPortDefineHeapRegions() ***must*** be
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43 * called before any other objects are defined.
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45 * vPortDefineHeapRegions() takes a single parameter. The parameter is an array
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46 * of HeapRegion_t structures. HeapRegion_t is defined in portable.h as
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48 * typedef struct HeapRegion
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50 * uint8_t *pucStartAddress; << Start address of a block of memory that will be part of the heap.
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51 * size_t xSizeInBytes; << Size of the block of memory.
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54 * The array is terminated using a NULL zero sized region definition, and the
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55 * memory regions defined in the array ***must*** appear in address order from
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56 * low address to high address. So the following is a valid example of how
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57 * to use the function.
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59 * HeapRegion_t xHeapRegions[] =
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61 * { ( uint8_t * ) 0x80000000UL, 0x10000 }, << Defines a block of 0x10000 bytes starting at address 0x80000000
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62 * { ( uint8_t * ) 0x90000000UL, 0xa0000 }, << Defines a block of 0xa0000 bytes starting at address of 0x90000000
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63 * { NULL, 0 } << Terminates the array.
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66 * vPortDefineHeapRegions( xHeapRegions ); << Pass the array into vPortDefineHeapRegions().
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68 * Note 0x80000000 is the lower address so appears in the array first.
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73 /* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining
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74 all the API functions to use the MPU wrappers. That should only be done when
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75 task.h is included from an application file. */
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76 #define MPU_WRAPPERS_INCLUDED_FROM_API_FILE
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78 #include "FreeRTOS.h"
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81 #undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE
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83 #if( configSUPPORT_DYNAMIC_ALLOCATION == 0 )
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84 #error This file must not be used if configSUPPORT_DYNAMIC_ALLOCATION is 0
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87 /* Block sizes must not get too small. */
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88 #define heapMINIMUM_BLOCK_SIZE ( ( size_t ) ( xHeapStructSize << 1 ) )
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90 /* Assumes 8bit bytes! */
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91 #define heapBITS_PER_BYTE ( ( size_t ) 8 )
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93 /* Define the linked list structure. This is used to link free blocks in order
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94 of their memory address. */
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95 typedef struct A_BLOCK_LINK
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97 struct A_BLOCK_LINK *pxNextFreeBlock; /*<< The next free block in the list. */
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98 size_t xBlockSize; /*<< The size of the free block. */
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101 /*-----------------------------------------------------------*/
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104 * Inserts a block of memory that is being freed into the correct position in
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105 * the list of free memory blocks. The block being freed will be merged with
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106 * the block in front it and/or the block behind it if the memory blocks are
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107 * adjacent to each other.
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109 static void prvInsertBlockIntoFreeList( BlockLink_t *pxBlockToInsert );
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111 /*-----------------------------------------------------------*/
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113 /* The size of the structure placed at the beginning of each allocated memory
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114 block must by correctly byte aligned. */
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115 static const size_t xHeapStructSize = ( sizeof( BlockLink_t ) + ( ( size_t ) ( portBYTE_ALIGNMENT - 1 ) ) ) & ~( ( size_t ) portBYTE_ALIGNMENT_MASK );
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117 /* Create a couple of list links to mark the start and end of the list. */
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118 static BlockLink_t xStart, *pxEnd = NULL;
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120 /* Keeps track of the number of free bytes remaining, but says nothing about
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122 static size_t xFreeBytesRemaining = 0U;
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123 static size_t xMinimumEverFreeBytesRemaining = 0U;
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125 /* Gets set to the top bit of an size_t type. When this bit in the xBlockSize
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126 member of an BlockLink_t structure is set then the block belongs to the
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127 application. When the bit is free the block is still part of the free heap
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129 static size_t xBlockAllocatedBit = 0;
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131 /*-----------------------------------------------------------*/
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133 void *pvPortMalloc( size_t xWantedSize )
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135 BlockLink_t *pxBlock, *pxPreviousBlock, *pxNewBlockLink;
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136 void *pvReturn = NULL;
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138 /* The heap must be initialised before the first call to
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139 prvPortMalloc(). */
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140 configASSERT( pxEnd );
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144 /* Check the requested block size is not so large that the top bit is
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145 set. The top bit of the block size member of the BlockLink_t structure
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146 is used to determine who owns the block - the application or the
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147 kernel, so it must be free. */
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148 if( ( xWantedSize & xBlockAllocatedBit ) == 0 )
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150 /* The wanted size is increased so it can contain a BlockLink_t
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151 structure in addition to the requested amount of bytes. */
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152 if( xWantedSize > 0 )
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154 xWantedSize += xHeapStructSize;
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156 /* Ensure that blocks are always aligned to the required number
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158 if( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) != 0x00 )
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160 /* Byte alignment required. */
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161 xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) );
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165 mtCOVERAGE_TEST_MARKER();
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170 mtCOVERAGE_TEST_MARKER();
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173 if( ( xWantedSize > 0 ) && ( xWantedSize <= xFreeBytesRemaining ) )
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175 /* Traverse the list from the start (lowest address) block until
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176 one of adequate size is found. */
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177 pxPreviousBlock = &xStart;
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178 pxBlock = xStart.pxNextFreeBlock;
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179 while( ( pxBlock->xBlockSize < xWantedSize ) && ( pxBlock->pxNextFreeBlock != NULL ) )
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181 pxPreviousBlock = pxBlock;
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182 pxBlock = pxBlock->pxNextFreeBlock;
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185 /* If the end marker was reached then a block of adequate size
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187 if( pxBlock != pxEnd )
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189 /* Return the memory space pointed to - jumping over the
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190 BlockLink_t structure at its start. */
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191 pvReturn = ( void * ) ( ( ( uint8_t * ) pxPreviousBlock->pxNextFreeBlock ) + xHeapStructSize );
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193 /* This block is being returned for use so must be taken out
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194 of the list of free blocks. */
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195 pxPreviousBlock->pxNextFreeBlock = pxBlock->pxNextFreeBlock;
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197 /* If the block is larger than required it can be split into
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199 if( ( pxBlock->xBlockSize - xWantedSize ) > heapMINIMUM_BLOCK_SIZE )
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201 /* This block is to be split into two. Create a new
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202 block following the number of bytes requested. The void
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203 cast is used to prevent byte alignment warnings from the
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205 pxNewBlockLink = ( void * ) ( ( ( uint8_t * ) pxBlock ) + xWantedSize );
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207 /* Calculate the sizes of two blocks split from the
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209 pxNewBlockLink->xBlockSize = pxBlock->xBlockSize - xWantedSize;
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210 pxBlock->xBlockSize = xWantedSize;
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212 /* Insert the new block into the list of free blocks. */
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213 prvInsertBlockIntoFreeList( ( pxNewBlockLink ) );
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217 mtCOVERAGE_TEST_MARKER();
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220 xFreeBytesRemaining -= pxBlock->xBlockSize;
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222 if( xFreeBytesRemaining < xMinimumEverFreeBytesRemaining )
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224 xMinimumEverFreeBytesRemaining = xFreeBytesRemaining;
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228 mtCOVERAGE_TEST_MARKER();
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231 /* The block is being returned - it is allocated and owned
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232 by the application and has no "next" block. */
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233 pxBlock->xBlockSize |= xBlockAllocatedBit;
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234 pxBlock->pxNextFreeBlock = NULL;
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238 mtCOVERAGE_TEST_MARKER();
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243 mtCOVERAGE_TEST_MARKER();
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248 mtCOVERAGE_TEST_MARKER();
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251 traceMALLOC( pvReturn, xWantedSize );
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253 ( void ) xTaskResumeAll();
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255 #if( configUSE_MALLOC_FAILED_HOOK == 1 )
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257 if( pvReturn == NULL )
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259 extern void vApplicationMallocFailedHook( void );
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260 vApplicationMallocFailedHook();
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264 mtCOVERAGE_TEST_MARKER();
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271 /*-----------------------------------------------------------*/
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273 void vPortFree( void *pv )
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275 uint8_t *puc = ( uint8_t * ) pv;
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276 BlockLink_t *pxLink;
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280 /* The memory being freed will have an BlockLink_t structure immediately
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282 puc -= xHeapStructSize;
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284 /* This casting is to keep the compiler from issuing warnings. */
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285 pxLink = ( void * ) puc;
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287 /* Check the block is actually allocated. */
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288 configASSERT( ( pxLink->xBlockSize & xBlockAllocatedBit ) != 0 );
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289 configASSERT( pxLink->pxNextFreeBlock == NULL );
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291 if( ( pxLink->xBlockSize & xBlockAllocatedBit ) != 0 )
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293 if( pxLink->pxNextFreeBlock == NULL )
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295 /* The block is being returned to the heap - it is no longer
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297 pxLink->xBlockSize &= ~xBlockAllocatedBit;
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301 /* Add this block to the list of free blocks. */
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302 xFreeBytesRemaining += pxLink->xBlockSize;
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303 traceFREE( pv, pxLink->xBlockSize );
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304 prvInsertBlockIntoFreeList( ( ( BlockLink_t * ) pxLink ) );
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306 ( void ) xTaskResumeAll();
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310 mtCOVERAGE_TEST_MARKER();
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315 mtCOVERAGE_TEST_MARKER();
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319 /*-----------------------------------------------------------*/
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321 size_t xPortGetFreeHeapSize( void )
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323 return xFreeBytesRemaining;
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325 /*-----------------------------------------------------------*/
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327 size_t xPortGetMinimumEverFreeHeapSize( void )
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329 return xMinimumEverFreeBytesRemaining;
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331 /*-----------------------------------------------------------*/
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333 static void prvInsertBlockIntoFreeList( BlockLink_t *pxBlockToInsert )
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335 BlockLink_t *pxIterator;
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338 /* Iterate through the list until a block is found that has a higher address
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339 than the block being inserted. */
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340 for( pxIterator = &xStart; pxIterator->pxNextFreeBlock < pxBlockToInsert; pxIterator = pxIterator->pxNextFreeBlock )
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342 /* Nothing to do here, just iterate to the right position. */
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345 /* Do the block being inserted, and the block it is being inserted after
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346 make a contiguous block of memory? */
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347 puc = ( uint8_t * ) pxIterator;
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348 if( ( puc + pxIterator->xBlockSize ) == ( uint8_t * ) pxBlockToInsert )
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350 pxIterator->xBlockSize += pxBlockToInsert->xBlockSize;
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351 pxBlockToInsert = pxIterator;
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355 mtCOVERAGE_TEST_MARKER();
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358 /* Do the block being inserted, and the block it is being inserted before
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359 make a contiguous block of memory? */
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360 puc = ( uint8_t * ) pxBlockToInsert;
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361 if( ( puc + pxBlockToInsert->xBlockSize ) == ( uint8_t * ) pxIterator->pxNextFreeBlock )
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363 if( pxIterator->pxNextFreeBlock != pxEnd )
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365 /* Form one big block from the two blocks. */
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366 pxBlockToInsert->xBlockSize += pxIterator->pxNextFreeBlock->xBlockSize;
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367 pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock->pxNextFreeBlock;
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371 pxBlockToInsert->pxNextFreeBlock = pxEnd;
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376 pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock;
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379 /* If the block being inserted plugged a gab, so was merged with the block
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380 before and the block after, then it's pxNextFreeBlock pointer will have
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381 already been set, and should not be set here as that would make it point
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383 if( pxIterator != pxBlockToInsert )
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385 pxIterator->pxNextFreeBlock = pxBlockToInsert;
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389 mtCOVERAGE_TEST_MARKER();
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392 /*-----------------------------------------------------------*/
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394 void vPortDefineHeapRegions( const HeapRegion_t * const pxHeapRegions )
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396 BlockLink_t *pxFirstFreeBlockInRegion = NULL, *pxPreviousFreeBlock;
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397 size_t xAlignedHeap;
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398 size_t xTotalRegionSize, xTotalHeapSize = 0;
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399 BaseType_t xDefinedRegions = 0;
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401 const HeapRegion_t *pxHeapRegion;
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403 /* Can only call once! */
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404 configASSERT( pxEnd == NULL );
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406 pxHeapRegion = &( pxHeapRegions[ xDefinedRegions ] );
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408 while( pxHeapRegion->xSizeInBytes > 0 )
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410 xTotalRegionSize = pxHeapRegion->xSizeInBytes;
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412 /* Ensure the heap region starts on a correctly aligned boundary. */
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413 xAddress = ( size_t ) pxHeapRegion->pucStartAddress;
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414 if( ( xAddress & portBYTE_ALIGNMENT_MASK ) != 0 )
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416 xAddress += ( portBYTE_ALIGNMENT - 1 );
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417 xAddress &= ~portBYTE_ALIGNMENT_MASK;
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419 /* Adjust the size for the bytes lost to alignment. */
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420 xTotalRegionSize -= xAddress - ( size_t ) pxHeapRegion->pucStartAddress;
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423 xAlignedHeap = xAddress;
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425 /* Set xStart if it has not already been set. */
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426 if( xDefinedRegions == 0 )
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428 /* xStart is used to hold a pointer to the first item in the list of
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429 free blocks. The void cast is used to prevent compiler warnings. */
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430 xStart.pxNextFreeBlock = ( BlockLink_t * ) xAlignedHeap;
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431 xStart.xBlockSize = ( size_t ) 0;
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435 /* Should only get here if one region has already been added to the
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437 configASSERT( pxEnd != NULL );
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439 /* Check blocks are passed in with increasing start addresses. */
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440 configASSERT( xAddress > ( size_t ) pxEnd );
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443 /* Remember the location of the end marker in the previous region, if
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445 pxPreviousFreeBlock = pxEnd;
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447 /* pxEnd is used to mark the end of the list of free blocks and is
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448 inserted at the end of the region space. */
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449 xAddress = xAlignedHeap + xTotalRegionSize;
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450 xAddress -= xHeapStructSize;
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451 xAddress &= ~portBYTE_ALIGNMENT_MASK;
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452 pxEnd = ( BlockLink_t * ) xAddress;
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453 pxEnd->xBlockSize = 0;
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454 pxEnd->pxNextFreeBlock = NULL;
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456 /* To start with there is a single free block in this region that is
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457 sized to take up the entire heap region minus the space taken by the
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458 free block structure. */
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459 pxFirstFreeBlockInRegion = ( BlockLink_t * ) xAlignedHeap;
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460 pxFirstFreeBlockInRegion->xBlockSize = xAddress - ( size_t ) pxFirstFreeBlockInRegion;
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461 pxFirstFreeBlockInRegion->pxNextFreeBlock = pxEnd;
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463 /* If this is not the first region that makes up the entire heap space
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464 then link the previous region to this region. */
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465 if( pxPreviousFreeBlock != NULL )
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467 pxPreviousFreeBlock->pxNextFreeBlock = pxFirstFreeBlockInRegion;
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470 xTotalHeapSize += pxFirstFreeBlockInRegion->xBlockSize;
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472 /* Move onto the next HeapRegion_t structure. */
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474 pxHeapRegion = &( pxHeapRegions[ xDefinedRegions ] );
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477 xMinimumEverFreeBytesRemaining = xTotalHeapSize;
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478 xFreeBytesRemaining = xTotalHeapSize;
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480 /* Check something was actually defined before it is accessed. */
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481 configASSERT( xTotalHeapSize );
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483 /* Work out the position of the top bit in a size_t variable. */
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484 xBlockAllocatedBit = ( ( size_t ) 1 ) << ( ( sizeof( size_t ) * heapBITS_PER_BYTE ) - 1 );
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