topic Initialization of BSS section to zero in the Linker command file in ColdFire/68K Microcontrollers and Processors

Initialization of BSS section to zero in the Linker command file

chr — Mon, 13 Aug 2007 12:47:41 GMT

Hi,

I am working with MCF5282 Controller.

The problem is :

I need to initialize the total bss section to zero(default data)in the Linker command file

I used the FILL attribute for output section but it is giving error.

Section

{

data :

{

*(.bss)

*(COMMON)

}> Data_Memory = 0x0000

}

How to use that?

can anybody give the correct syntax?

Re: Initialization of BSS section to zero in the Linker command file

sjmelnikoff — Mon, 13 Aug 2007 15:23:30 GMT

The FILL attribute is used primarily to fill unused areas of flash and EEPROM when the device is programmed; it won't work for RAM.

If you want to zero the RAM at startup, you need to write some code to do it. To avoid messing up the stack, it may be best to do it right at the start of initialisation, and in assembler so you can ensure that any variables you use are stored in registers, not RAM.

In any case, the default startup code already does this, so you might want to have a look at that.

Steve.

Re: Initialization of BSS section to zero in the Linker command file

Kremer — Mon, 13 Aug 2007 20:03:36 GMT

You need something like:

if (__BSS_START != __BSS_END)
{
  sp = (uint8 *)__BSS_START;
  n = (uint32)(__BSS_END - __BSS_START);
  while (n--)
   *sp++ = 0;
}

Courtesy code by freescale.

Regards