Re: [avr-gcc-list] jump_to_null question

[Rolf Magnus]

On Donnerstag, 24. Mai 2007, Dr. Jan Menzel wrote:
> Hi all!
>       I'm currently working on a bootloader for Mega8 and 88 and found a
> problem I do not yet understand. At the end of the bootloader the code
> has to jump to the main reset vector at address 0x0000. If I do the
> usual way
>       void (*jump_to_null)(void) = 0x0000;
> gcc 3.4.6 complies:
>       LDI     R30, 0x0102
>       LDI     R31, 0x0103
>       ICALL
> and everything works fine, as expected.
>       But if I try to be more specific and define
>       void (* const jump_to_main)(void) = 0x0000;
> gcc 3.4.6 complies
>       RCALL   PC-0x0009
> which unfortunately does not what I intended.
>       Could anyone please point me to my error in reasoning or lack of
> understanding? Many thanks!

If you want to jump to address 0, you can also do:

goto *0x0000;