m68k-coff: Unused memory region included in output file?

[Bill Gatliff]

Toralf:

What does the stuff that ends up in "reseved" look like?  It could be 
that the newer tools have some new sections that you aren't putting 
anywhere else (they do have more sections than 2.95.x), and the linker 
is just doing a "pick a section, any section"...

b.g.

Toralf Lund wrote:

> I've been using the following memory region setup for applications 
> running on our custom M68K board:
>
> MEMORY
> {
>  reserved (rwx) : ORIGIN = 0x000000, LENGTH = 4K
>  ram (rwx) : ORIGIN = 0x001000, LENGTH = 1M-4K
>  rom (rx) : ORIGIN = 0xF00000, LENGTH = 128K
>  user (rx) : ORIGIN = 0xF20000, LENGTH = 768K
>  registers (rx): ORIGIN = 0xFE0000, LENGTH = 16K
>  sio (rx): ORIGIN = 0xFE4000, LENGTH = 16K
>  ivhc (rx): ORIGIN = 0xFE8000, LENGTH = 16K
>  vme (rx): ORIGIN = 0xFF0000, LENGTH = 64K
> }
>
> Of these I actually only use "ram", i.e. all sections have "> ram"; 
> the rest are included mainly as a reminder of what the memory looks 
> like. When building with gcc-2.95.3, it looks like only data from ram 
> is included in the output file, but with 3.3.3 it's different - the 
> "reserved" region seems to be written, too, even though no output data 
> is directed to it. Or at least, the .text segment, which is written to 
> the start of "ram" appears at offset 0x1000 of the actual program data 
> within the file, while it used to start at the very beginning.
>
> If I change "reserved (rwx)" to "reserved (rx)" this no longer 
> happens. Actually that's the way it should have been set up from the 
> beginning, and it may not even be such a great idea to include unused 
> regions in the first place, but the point is that *something* has 
> changed between gcc 2 and 3, and I'd like to know what.
>
> Can anyone enlighten me?
>
> - Toralf
>
>
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-- 
Bill Gatliff
Embedded GNU, Linux, and other board support packages.
bgat@billgatliff.com


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