Re: [avr-gcc-list] May avr-gcc emit EIJMP/EICALL?

[Erik Christiansen]

On 23.10.11 14:01, Georg-Johann Lay wrote:

{ Beautifully documented investigation results snipped }

>    and the application be linked with -Wl,-defsym=func_4=0x4
> 
> ==
> 
> Text like above should be added to GCC's documentation.
> 
> If there is something missing, incorrect or bad style, please suggest.
> 
> In my understanding, caveats are no problem.  But problems will arise
> if caveats are not documented and one is not aware of them.

Many thanks for illuminating the murk for us all. Now we have no excuse
for being unaware. A little bit of linker script tweaking if we need to
be adventurous with EIND, is no obstacle at all.

There's benefit in defining absolute addresses, such as the func_4 example,
in the linker script, I think [1]. If jump tables or other such addressing
constructs needed to be customised prior to linking (e.g. by a script
handling multiple builds) then it's often convenient to do that in a
separate file, and INCLUDE it in the main linker script, at the
appropriate place.

Thanks again for making it so clear.

Erik

[1] So that the linker script documents the product's memory map, and
    fixed addresses need not be hunted in makefiles and source code.

-- 
manual, n.:
A unit of documentation. There are always three or more on a given item.
One is on the shelf; someone has the others.
The information you need is in the others.               - Ray Simard