heap_1.c

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*/


/*
 * The simplest possible implementation of pvPortMalloc().  Note that this
 * implementation does NOT allow allocated memory to be freed again.
 *
 * See heap_2.c, heap_3.c and heap_4.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

/* A few bytes might be lost to byte aligning the heap start address. */
#define configADJUSTED_HEAP_SIZE    ( configTOTAL_HEAP_SIZE - portBYTE_ALIGNMENT )

/* Allocate the memory for the heap. */
static unsigned char ucHeap[ configTOTAL_HEAP_SIZE ];
static size_t xNextFreeByte = ( size_t ) 0;

/*-----------------------------------------------------------*/

void *pvPortMalloc( size_t xWantedSize )
{
void *pvReturn = NULL;
static unsigned char *pucAlignedHeap = NULL;

    /* Ensure that blocks are always aligned to the required number of bytes. */
    #if portBYTE_ALIGNMENT != 1
        if( xWantedSize & portBYTE_ALIGNMENT_MASK )
        {
            /* Byte alignment required. */
            xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) );
        }
    #endif

    vTaskSuspendAll();
    {
        if( pucAlignedHeap == NULL )
        {
            /* Ensure the heap starts on a correctly aligned boundary. */
            pucAlignedHeap = ( unsigned char * ) ( ( ( portPOINTER_SIZE_TYPE ) &ucHeap[ portBYTE_ALIGNMENT ] ) & ( ( portPOINTER_SIZE_TYPE ) ~portBYTE_ALIGNMENT_MASK ) );
        }

        /* Check there is enough room left for the allocation. */
        if( ( ( xNextFreeByte + xWantedSize ) < configADJUSTED_HEAP_SIZE ) &&
            ( ( xNextFreeByte + xWantedSize ) > xNextFreeByte ) )/* Check for overflow. */
        {
            /* Return the next free byte then increment the index past this
            block. */
            pvReturn = pucAlignedHeap + xNextFreeByte;
            xNextFreeByte += xWantedSize;
        }

        traceMALLOC( pvReturn, xWantedSize );
    }   
    xTaskResumeAll();

    #if( configUSE_MALLOC_FAILED_HOOK == 1 )
    {
        if( pvReturn == NULL )
        {
            extern void vApplicationMallocFailedHook( void );
            vApplicationMallocFailedHook();
        }
    }
    #endif

    return pvReturn;
}
/*-----------------------------------------------------------*/

void vPortFree( void *pv )
{
    /* Memory cannot be freed using this scheme.  See heap_2.c, heap_3.c and
    heap_4.c for alternative implementations, and the memory management pages of
    http://www.FreeRTOS.org for more information. */
    ( void ) pv;

    /* Force an assert as it is invalid to call this function. */
    configASSERT( pv == NULL );
}
/*-----------------------------------------------------------*/

void vPortInitialiseBlocks( void )
{
    /* Only required when static memory is not cleared. */
    xNextFreeByte = ( size_t ) 0;
}
/*-----------------------------------------------------------*/

size_t xPortGetFreeHeapSize( void )
{
    return ( configADJUSTED_HEAP_SIZE - xNextFreeByte );
}