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Re: AW: AW: AW: [avr-gcc-list] Using current avr-gcc for target ATmega25
Re: AW: AW: AW: [avr-gcc-list] Using current avr-gcc for target ATmega2561
Tue, 04 Oct 2005 12:29:39 +0200
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Haase Bjoern (PT-BEU/EMT) * wrote:
I think that pointers to functions must not happen often in bootloaders
so that would be fine. I did not encounter yet problems with table jumps
in bootloaders so I can't say if it is because the compiler never
built/used a table jump for switch/case in one of my bootloaders
(probably the case) or if table jumps already works (it should since I'm
using only atmega128 at the moment).
After reading your message I conclude that you will probably not be having any
problem unless that you are planing to use pointers to functions in your
bootloader code. The jump stubs will be used *only* in case that you are using
a function pointer because this way, we could stick to 2-byte function pointers.
The second restriction for your boot-loader code would probably be that you
must disable table jump instructions by the appropriate compiler switch because
these address tables usually do not end up in the bootloader section. This,
however, probably is a restriction that applies already now.
Now where will it be possible to document these requirements? It could
be tricky for someone to discover such problems. What about having some
kind of 'application notes' provided with avr-libc documentation?