RAM 6.0 BUX II Series Guia do Utilizador descarregar pdf (Página 42)

VxWorks

BSP Developer’s Guide, 6.0

sysMemTop( )

The sysMemTop( ) routine returns the address of the top of VxWorks memory.

During early BSP development, the sysMemTop( ) routine in sysLib.c simply

returns a constant value based on

LOCAL_MEM_LOCAL_ADRS,

LOCAL_MEM_SIZE, PM_RESERVED_MEM (VxWorks 6.0 only), and

USER_RESERVED_MEM.

In most implementations, sysMemTop( ) calls sysPhysMemTop( ) to obtain the

address at the top of physical memory (for more information, see

sysPhysMemTop( ), p.35). Later, during BSP cleanup, the sysPhysMemTop( )

routine can be enhanced to allow automatic memory sizing.

The following is a macro-controlled version of sysMemTop( ) that can be used by

any BSP to support fixed memory size:

/***************************************************************************

* sysMemTop - get the address of the top of VxWorks memory

* This routine returns a pointer to the first byte of memory not

* controlled or used by VxWorks.

* The user can reserve memory space by defining the macro USER_RESERVED_MEM

* in config.h. This routine returns the address of the reserved memory

* area. The value of USER_RESERVED_MEM is in bytes.

* RETURNS: The address of the top of VxWorks memory.

char *sysMemTop

(

void

)

{

static char * memTop = NULL;

if ( memTop == NULL )

{

memTop = sysPhysMemTop () - USER_RESERVED_MEM;

#ifdef INCLUDE_EDR_PM

/* account for ED&R persistent memory */

memTop = memTop - PM_RESERVED_MEM;

#endif

}

return memTop ;

}

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RAM 6.0 BUX II Series Guia do Utilizador Página 42