[U-Boot-Users] Why are some global vars part of the image, and some not?

Wolfgang Denk wd at denx.de
Sat Nov 4 01:33:59 CET 2006

In message <454BDA40.5090806 at freescale.com> you wrote:
> > I don't see any problem that needed fixing.
> The problem is that without specifying the section attribute, when I ran my 
> code, i2c_bus_num was equal to 0xFFFFFFFF.

Yes, this to be expected. And explained in the README:

        ... and BSS is not initialized as zero.

> > What exactly is the "problem" you are experiencing? Did you read  the
> > documentation, especially section "Initial Stack, Global Data" in the
> > README? Please let me know if there is anything in this text which is
> > not clear enough.
> That section doesn't address issues with global (static or otherwise) 
> variables that need to be read prior to relocation.

Yes, it does:

	This means that we don't have writable Data or BSS segments,
	and BSS is not initialized as zero.

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
An expert is a person who avoids the small errors while  sweeping  on
to the grand fallacy.

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