701 lines
16 KiB
C
701 lines
16 KiB
C
#include "mm.h"
|
||
|
||
|
||
/*块不太小 */
|
||
#define heapMINIMUM_BLOCK_SIZE ( ( size_t ) ( xHeapStructSize << 1 ) )
|
||
/* Assumes 8bit bytes!假设为8位 */
|
||
#define heapBITS_PER_BYTE ( ( size_t ) 8 )
|
||
|
||
/* Max value that fits in a size_t type. size_t最大值 */
|
||
#define heapSIZE_MAX ( ~( ( size_t ) 0 ) )
|
||
/* Check if multiplying a and b will result in overflow. 检查a 和B 相乘是否会溢出*/
|
||
#define heapMULTIPLY_WILL_OVERFLOW( a, b ) ( ( ( a ) > 0 ) && ( ( b ) > ( heapSIZE_MAX / ( a ) ) ) )
|
||
/* Check if adding a and b will result in overflow. 检查a 和b相加是否会溢出*/
|
||
#define heapADD_WILL_OVERFLOW( a, b ) ( ( a ) > ( heapSIZE_MAX - ( b ) ) )
|
||
|
||
/* BlockLink_t结构中的xBlockSize成员的最高有效位（MSB）用于追踪块的分配状态。
|
||
当设置了BlockLink_t结构中的xBlockSize成员的MSB时，该块被归属于应用程序。
|
||
而当该位为空闲时，该块仍然是空闲堆空间的一部分。 */
|
||
#define heapBLOCK_ALLOCATED_BITMASK ( ( ( size_t ) 1 ) << ( ( sizeof( size_t ) * heapBITS_PER_BYTE ) - 1 ) ) //内存对齐使用
|
||
#define heapBLOCK_SIZE_IS_VALID( xBlockSize ) ( ( ( xBlockSize ) & heapBLOCK_ALLOCATED_BITMASK ) == 0 )
|
||
#define heapBLOCK_IS_ALLOCATED( pxBlock ) ( ( ( pxBlock->xBlockSize ) & heapBLOCK_ALLOCATED_BITMASK ) != 0 )
|
||
#define heapALLOCATE_BLOCK( pxBlock ) ( ( pxBlock->xBlockSize ) |= heapBLOCK_ALLOCATED_BITMASK )
|
||
#define heapFREE_BLOCK( pxBlock ) ( ( pxBlock->xBlockSize ) &= ~heapBLOCK_ALLOCATED_BITMASK )
|
||
|
||
|
||
|
||
static uint8_t ucHeap[ configTOTAL_HEAP_SIZE ];//堆内存大小分配
|
||
|
||
typedef struct A_BLOCK_LINK
|
||
{
|
||
struct A_BLOCK_LINK * pxNextFreeBlock; /*<< The next free block in the list. 下一个空闲块*/
|
||
size_t xBlockSize; /*<< The size of the free block.空闲块的大小 */
|
||
} BlockLink_t;
|
||
|
||
/* 将正在释放的内存块插入到空闲内存块列表中的正确位置。
|
||
如果内存块彼此相邻，被释放的块将与它前面的块和/或它后面的块合并。 */
|
||
|
||
|
||
|
||
|
||
|
||
static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert );
|
||
static void prvHeapInit( void );
|
||
/* 位于每个分配的内存块开头的结构的大小必须按正确的字节对齐。 */
|
||
|
||
|
||
static const size_t xHeapStructSize = ( sizeof( BlockLink_t ) + ( ( size_t ) ( portBYTE_ALIGNMENT - 1 ) ) ) & ~( ( size_t ) portBYTE_ALIGNMENT_MASK );
|
||
/* 创建两个列表链接来标记列表的开始和结束。*/
|
||
|
||
static BlockLink_t xStart;
|
||
static BlockLink_t * pxEnd = NULL;//如果不是NULL就是已经初始化话内存了,这个很重要
|
||
|
||
|
||
/* 跟踪分配和释放内存的调用数量以及剩余空闲字节数，但没有说明碎片。* / */
|
||
|
||
static size_t xFreeBytesRemaining = 0U;
|
||
static size_t xMinimumEverFreeBytesRemaining = 0U;
|
||
static size_t xNumberOfSuccessfulAllocations = 0;
|
||
|
||
static size_t xNumberOfSuccessfulFrees = 0;
|
||
|
||
|
||
/*-----------------------------------------------------------*/
|
||
|
||
void * pvPortMalloc( size_t xWantedSize )
|
||
{
|
||
BlockLink_t * pxBlock;
|
||
BlockLink_t * pxPreviousBlock;
|
||
BlockLink_t * pxNewBlockLink;
|
||
void * pvReturn = NULL;
|
||
size_t xAdditionalRequiredSize;
|
||
|
||
|
||
{
|
||
/* If this is the first call to malloc then the heap will require
|
||
* initialisation to setup the list of free blocks. */
|
||
if( pxEnd == NULL )
|
||
{
|
||
prvHeapInit();
|
||
}
|
||
else
|
||
{
|
||
mtCOVERAGE_TEST_MARKER();
|
||
}
|
||
|
||
if( xWantedSize > 0 )
|
||
{
|
||
/* The wanted size must be increased so it can contain a BlockLink_t
|
||
* structure in addition to the requested amount of bytes. Some
|
||
* additional increment may also be needed for alignment. */
|
||
xAdditionalRequiredSize = xHeapStructSize + portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK );
|
||
|
||
if( heapADD_WILL_OVERFLOW( xWantedSize, xAdditionalRequiredSize ) == 0 )
|
||
{
|
||
xWantedSize += xAdditionalRequiredSize;
|
||
}
|
||
else
|
||
{
|
||
xWantedSize = 0;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
mtCOVERAGE_TEST_MARKER();
|
||
}
|
||
|
||
/* Check the block size we are trying to allocate is not so large that the
|
||
* top bit is set. The top bit of the block size member of the BlockLink_t
|
||
* structure is used to determine who owns the block - the application or
|
||
* the kernel, so it must be free. */
|
||
if( heapBLOCK_SIZE_IS_VALID( xWantedSize ) != 0 )
|
||
{
|
||
if( ( xWantedSize > 0 ) && ( xWantedSize <= xFreeBytesRemaining ) )
|
||
{
|
||
/* Traverse the list from the start (lowest address) block until
|
||
* one of adequate size is found. */
|
||
pxPreviousBlock = &xStart;
|
||
pxBlock = xStart.pxNextFreeBlock;
|
||
|
||
while( ( pxBlock->xBlockSize < xWantedSize ) && ( pxBlock->pxNextFreeBlock != NULL ) )
|
||
{
|
||
pxPreviousBlock = pxBlock;
|
||
pxBlock = pxBlock->pxNextFreeBlock;
|
||
}
|
||
|
||
/* If the end marker was reached then a block of adequate size
|
||
* was not found. */
|
||
if( pxBlock != pxEnd )
|
||
{
|
||
/* Return the memory space pointed to - jumping over the
|
||
* BlockLink_t structure at its start. */
|
||
pvReturn = ( void * ) ( ( ( uint8_t * ) pxPreviousBlock->pxNextFreeBlock ) + xHeapStructSize );
|
||
|
||
/* This block is being returned for use so must be taken out
|
||
* 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 * ) ( ( ( uint8_t * ) pxBlock ) + xWantedSize );
|
||
configASSERT( ( ( ( size_t ) pxNewBlockLink ) & portBYTE_ALIGNMENT_MASK ) == 0 );
|
||
|
||
/* 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 );
|
||
}
|
||
else
|
||
{
|
||
mtCOVERAGE_TEST_MARKER();
|
||
}
|
||
|
||
xFreeBytesRemaining -= pxBlock->xBlockSize;
|
||
|
||
if( xFreeBytesRemaining < xMinimumEverFreeBytesRemaining )
|
||
{
|
||
xMinimumEverFreeBytesRemaining = xFreeBytesRemaining;
|
||
}
|
||
else
|
||
{
|
||
mtCOVERAGE_TEST_MARKER();
|
||
}
|
||
|
||
/* The block is being returned - it is allocated and owned
|
||
* by the application and has no "next" block. */
|
||
heapALLOCATE_BLOCK( pxBlock );
|
||
pxBlock->pxNextFreeBlock = NULL;
|
||
xNumberOfSuccessfulAllocations++;
|
||
}
|
||
else
|
||
{
|
||
mtCOVERAGE_TEST_MARKER();
|
||
}
|
||
}
|
||
else
|
||
{
|
||
mtCOVERAGE_TEST_MARKER();
|
||
}
|
||
}
|
||
else
|
||
{
|
||
mtCOVERAGE_TEST_MARKER();
|
||
}
|
||
|
||
traceMALLOC( pvReturn, xWantedSize );
|
||
}
|
||
|
||
|
||
|
||
|
||
configASSERT( ( ( ( size_t ) pvReturn ) & ( size_t ) portBYTE_ALIGNMENT_MASK ) == 0 );
|
||
return pvReturn;
|
||
}
|
||
/*-----------------------------------------------------------*/
|
||
|
||
void vPortFree( void * pv )
|
||
{
|
||
uint8_t * puc = ( uint8_t * ) pv;
|
||
BlockLink_t * pxLink;
|
||
|
||
if( pv != NULL )
|
||
{
|
||
/* The memory being freed will have an BlockLink_t structure immediately
|
||
* before it. */
|
||
puc -= xHeapStructSize;
|
||
|
||
/* This casting is to keep the compiler from issuing warnings. */
|
||
pxLink = ( void * ) puc;
|
||
|
||
configASSERT( heapBLOCK_IS_ALLOCATED( pxLink ) != 0 );
|
||
configASSERT( pxLink->pxNextFreeBlock == NULL );
|
||
|
||
if( heapBLOCK_IS_ALLOCATED( pxLink ) != 0 )
|
||
{
|
||
if( pxLink->pxNextFreeBlock == NULL )
|
||
{
|
||
/* The block is being returned to the heap - it is no longer
|
||
* allocated. */
|
||
heapFREE_BLOCK( pxLink );
|
||
#if ( configHEAP_CLEAR_MEMORY_ON_FREE == 1 )
|
||
{
|
||
( void ) memset( puc + xHeapStructSize, 0, pxLink->xBlockSize - xHeapStructSize );
|
||
}
|
||
#endif
|
||
|
||
|
||
{
|
||
/* Add this block to the list of free blocks. */
|
||
xFreeBytesRemaining += pxLink->xBlockSize;
|
||
traceFREE( pv, pxLink->xBlockSize );
|
||
prvInsertBlockIntoFreeList( ( ( BlockLink_t * ) pxLink ) );
|
||
xNumberOfSuccessfulFrees++;
|
||
}
|
||
|
||
}
|
||
else
|
||
{
|
||
mtCOVERAGE_TEST_MARKER();
|
||
}
|
||
}
|
||
else
|
||
{
|
||
mtCOVERAGE_TEST_MARKER();
|
||
}
|
||
}
|
||
}
|
||
/*-----------------------------------------------------------*/
|
||
|
||
size_t xPortGetFreeHeapSize( void )
|
||
{
|
||
return xFreeBytesRemaining;
|
||
}
|
||
/*-----------------------------------------------------------*/
|
||
|
||
size_t xPortGetMinimumEverFreeHeapSize( void )
|
||
{
|
||
return xMinimumEverFreeBytesRemaining;
|
||
}
|
||
/*-----------------------------------------------------------*/
|
||
|
||
void vPortInitialiseBlocks( void )
|
||
{
|
||
/* This just exists to keep the linker quiet. */
|
||
}
|
||
/*-----------------------------------------------------------*/
|
||
|
||
void * pvPortCalloc( size_t xNum,
|
||
size_t xSize )
|
||
{
|
||
void * pv = NULL;
|
||
|
||
if( heapMULTIPLY_WILL_OVERFLOW( xNum, xSize ) == 0 )
|
||
{
|
||
pv = pvPortMalloc( xNum * xSize );
|
||
|
||
if( pv != NULL )
|
||
{
|
||
( void ) memset( pv, 0, xNum * xSize );
|
||
}
|
||
}
|
||
|
||
return pv;
|
||
}
|
||
/*-----------------------------------------------------------*/
|
||
|
||
static void prvHeapInit( void ) /* PRIVILEGED_FUNCTION */
|
||
{
|
||
BlockLink_t * pxFirstFreeBlock;
|
||
uint8_t * pucAlignedHeap;
|
||
portPOINTER_SIZE_TYPE uxAddress;
|
||
size_t xTotalHeapSize = configTOTAL_HEAP_SIZE;
|
||
|
||
/* Ensure the heap starts on a correctly aligned boundary. */
|
||
uxAddress = ( portPOINTER_SIZE_TYPE ) ucHeap;
|
||
|
||
if( ( uxAddress & portBYTE_ALIGNMENT_MASK ) != 0 )
|
||
{
|
||
uxAddress += ( portBYTE_ALIGNMENT - 1 );
|
||
uxAddress &= ~( ( portPOINTER_SIZE_TYPE ) portBYTE_ALIGNMENT_MASK );
|
||
xTotalHeapSize -= uxAddress - ( portPOINTER_SIZE_TYPE ) ucHeap;
|
||
}
|
||
|
||
pucAlignedHeap = ( uint8_t * ) uxAddress;
|
||
|
||
/* 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 * ) pucAlignedHeap;
|
||
xStart.xBlockSize = ( size_t ) 0;
|
||
|
||
/* pxEnd is used to mark the end of the list of free blocks and is inserted
|
||
* at the end of the heap space. */
|
||
uxAddress = ( ( portPOINTER_SIZE_TYPE ) pucAlignedHeap ) + xTotalHeapSize;
|
||
uxAddress -= xHeapStructSize;
|
||
uxAddress &= ~( ( portPOINTER_SIZE_TYPE ) portBYTE_ALIGNMENT_MASK );
|
||
pxEnd = ( BlockLink_t * ) uxAddress;
|
||
pxEnd->xBlockSize = 0;
|
||
pxEnd->pxNextFreeBlock = NULL;
|
||
|
||
/* To start with there is a single free block that is sized to take up the
|
||
* entire heap space, minus the space taken by pxEnd. */
|
||
pxFirstFreeBlock = ( BlockLink_t * ) pucAlignedHeap;
|
||
pxFirstFreeBlock->xBlockSize = ( size_t ) ( uxAddress - ( portPOINTER_SIZE_TYPE ) pxFirstFreeBlock );
|
||
pxFirstFreeBlock->pxNextFreeBlock = pxEnd;
|
||
|
||
/* Only one block exists - and it covers the entire usable heap space. */
|
||
xMinimumEverFreeBytesRemaining = pxFirstFreeBlock->xBlockSize;
|
||
xFreeBytesRemaining = pxFirstFreeBlock->xBlockSize;
|
||
}
|
||
/*-----------------------------------------------------------*/
|
||
|
||
static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert ) /* PRIVILEGED_FUNCTION */
|
||
{
|
||
BlockLink_t * pxIterator;
|
||
uint8_t * puc;
|
||
|
||
/* Iterate through the list until a block is found that has a higher address
|
||
* than the block being inserted. */
|
||
for( pxIterator = &xStart; pxIterator->pxNextFreeBlock < pxBlockToInsert; pxIterator = pxIterator->pxNextFreeBlock )
|
||
{
|
||
/* Nothing to do here, just iterate to the right position. */
|
||
}
|
||
|
||
/* Do the block being inserted, and the block it is being inserted after
|
||
* make a contiguous block of memory? */
|
||
puc = ( uint8_t * ) pxIterator;
|
||
|
||
if( ( puc + pxIterator->xBlockSize ) == ( uint8_t * ) pxBlockToInsert )
|
||
{
|
||
pxIterator->xBlockSize += pxBlockToInsert->xBlockSize;
|
||
pxBlockToInsert = pxIterator;
|
||
}
|
||
else
|
||
{
|
||
mtCOVERAGE_TEST_MARKER();
|
||
}
|
||
|
||
/* Do the block being inserted, and the block it is being inserted before
|
||
* make a contiguous block of memory? */
|
||
puc = ( uint8_t * ) pxBlockToInsert;
|
||
|
||
if( ( puc + pxBlockToInsert->xBlockSize ) == ( uint8_t * ) pxIterator->pxNextFreeBlock )
|
||
{
|
||
if( pxIterator->pxNextFreeBlock != pxEnd )
|
||
{
|
||
/* Form one big block from the two blocks. */
|
||
pxBlockToInsert->xBlockSize += pxIterator->pxNextFreeBlock->xBlockSize;
|
||
pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock->pxNextFreeBlock;
|
||
}
|
||
else
|
||
{
|
||
pxBlockToInsert->pxNextFreeBlock = pxEnd;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock;
|
||
}
|
||
|
||
/* If the block being inserted plugged a gab, so was merged with the block
|
||
* before and the block after, then it's pxNextFreeBlock pointer will have
|
||
* already been set, and should not be set here as that would make it point
|
||
* to itself. */
|
||
if( pxIterator != pxBlockToInsert )
|
||
{
|
||
pxIterator->pxNextFreeBlock = pxBlockToInsert;
|
||
}
|
||
else
|
||
{
|
||
mtCOVERAGE_TEST_MARKER();
|
||
}
|
||
}
|
||
/*-----------------------------------------------------------*/
|
||
|
||
void vPortGetHeapStats( HeapStats_t * pxHeapStats )
|
||
{
|
||
BlockLink_t * pxBlock;
|
||
size_t xBlocks = 0, xMaxSize = 0, xMinSize = portMAX_DELAY; /* portMAX_DELAY used as a portable way of getting the maximum value. */
|
||
|
||
|
||
{
|
||
pxBlock = xStart.pxNextFreeBlock;
|
||
|
||
/* pxBlock will be NULL if the heap has not been initialised. The heap
|
||
* is initialised automatically when the first allocation is made. */
|
||
if( pxBlock != NULL )
|
||
{
|
||
while( pxBlock != pxEnd )
|
||
{
|
||
/* Increment the number of blocks and record the largest block seen
|
||
* so far. */
|
||
xBlocks++;
|
||
|
||
if( pxBlock->xBlockSize > xMaxSize )
|
||
{
|
||
xMaxSize = pxBlock->xBlockSize;
|
||
}
|
||
|
||
if( pxBlock->xBlockSize < xMinSize )
|
||
{
|
||
xMinSize = pxBlock->xBlockSize;
|
||
}
|
||
|
||
/* Move to the next block in the chain until the last block is
|
||
* reached. */
|
||
pxBlock = pxBlock->pxNextFreeBlock;
|
||
}
|
||
}
|
||
}
|
||
|
||
|
||
pxHeapStats->xSizeOfLargestFreeBlockInBytes = xMaxSize;
|
||
pxHeapStats->xSizeOfSmallestFreeBlockInBytes = xMinSize;
|
||
pxHeapStats->xNumberOfFreeBlocks = xBlocks;
|
||
|
||
|
||
{
|
||
pxHeapStats->xAvailableHeapSpaceInBytes = xFreeBytesRemaining;
|
||
pxHeapStats->xNumberOfSuccessfulAllocations = xNumberOfSuccessfulAllocations;
|
||
pxHeapStats->xNumberOfSuccessfulFrees = xNumberOfSuccessfulFrees;
|
||
pxHeapStats->xMinimumEverFreeBytesRemaining = xMinimumEverFreeBytesRemaining;
|
||
}
|
||
|
||
}
|
||
/*-----------------------------------------------------------*/
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|
||
|