Roman Mashak wrote:
> Hello,
>
> I define a constant in the linker script and want access it from C-code:
>
> SECTIONS
> {
> ...
>  _bootsize = 0x00004000;
> ...
> }
>
> Here is code snippet:
>
> extern unsigned long _bootsize;
> char message[10];
> ...
> siprintf(message, "Bootsize: 0x%x\n\r", _bootsize);
> AT91F_DBGU_Frame(message);
>
> But it always prints out "Bootsize: 0x2004d4" Why so?
> As far as I understand, it's quite possible to do what I want.

Looking at the documentation here:
http://sourceware.org/binutils/docs-2.18/ld/Source-Code-Reference.html#Source-Code-Reference

If I understood it right _bootsize is the address of your constant, the
constant is allocated there as a word.

Roman Mashak wrote:
> Hello,
>
> I define a constant in the linker script and want access it from C-code:
>
> SECTIONS
> {
> ...
>  _bootsize = 0x00004000;
> ...
> }
>
> Here is code snippet:
>
> extern unsigned long _bootsize;
> char message[10];
> ...
> siprintf(message, "Bootsize: 0x%x\n\r", _bootsize);
> AT91F_DBGU_Frame(message);
>
> But it always prints out "Bootsize: 0x2004d4" Why so?
> As far as I understand, it's quite possible to do what I want.

Look at a sample here with the file syscall.c, you will have a sample on
how to access a constant address from C source.

Jonathan

Giovanni Di Sirio wrote:
> Looking at the documentation here:
> 
http://sourceware.org/binutils/docs-2.18/ld/Source-Code-Reference.html#Source-Code-Reference
>
> If I understood it right _bootsize is the address of your constant, the
> constant is allocated there as a word.
Hm.. After reading documentation at the link, I come to the conclusion
that there is no way to assign a value to a linker script defined
symbol. Such symbol will always hold only address.

Am I right, there is no way to get what I want?

Jonathan Dumaresq wrote:
> Look at a sample here with the file syscall.c, you will have a sample on
> how to access a constant address from C source.
Before posting I studied that code and did as in there. It seems I can't
achieve what I need: to define a constant value in a linker script and
use it from the C code.

Giovanni Di Sirio wrote:
> Looking at the documentation here:
> 
http://sourceware.org/binutils/docs-2.18/ld/Source-Code-Reference.html#Source-Code-Reference

I must have read the link thoughtlessly the first time and missed the
point. Now I got it right - accessing the symbol defined in linker
script as "&_bootsize" works fine for me.

Thanks again.