Defining symbols in a linker script
Iain Buclaw via D.gnu
d.gnu at puremagic.com
Fri Apr 18 18:50:28 PDT 2014
On 19 Apr 2014 01:35, "Mike via D.gnu" <d.gnu at puremagic.com> wrote:
>
> Hello,
>
> It is common practice in ARM Cortex-M bare metal C/C++ programs to define
symbols in the linker so one can initialize the .data and .bss segments and
know the boundaries of one's stack and heap. It looks something like this.
>
> **** linkerscript ****
> __text_end__ = .;
>
> .data : AT(__text_end__)
> {
> __data_start__ = .;
> *(.data)
> *(.data.*)
> __data_end__ = .;
> } > SRAM
>
> **** C++ file ****
> extern "C" uint32_t __text_end__;
> extern "C" uint32_t __data_start__;
> extern "C" uint32_t __data_end__;
>
> void startup()
> {
> // copy mutable state out of ROM into RAM
> memcpy(&__data_start__, &__text_end__, (&__data_end__ -
&__data_start__) * 4);
> }
>
> I tried to do something similar in D with...
>
> extern(C) __gshared uint __text_end__;
> extern(C) __gshared uint __data_start__;
> extern(C) __gshared uint __data_end__;
>
> ... but unfortunately this puts new variables in the .bss segment. I
want the un-mangled name, so I can refer to it easily, but I also want it
to be truly "extern" (defined elsewhere). Is that possible at this moment
in D?
>
> Thanks for the help,
> Mike
I think you mean to 'extern (C) extern'
Iain
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.puremagic.com/pipermail/d.gnu/attachments/20140419/cbac4c51/attachment.html>
More information about the D.gnu
mailing list