AW: [avr-gcc-list] Bootloader interrupt callbacks

[Sven Schlender]

Hi Eric,

thanks for quick reply.

> Do you really have problems or where you only preoccupied about
> this case ?

No really problems yet, only thinking about this.



> In fact, you are wondering how the compiler should threat function calls
> from an ISR.
> I do not see any difference between callback or direct call.
> Every procedure should preserve/restore any register, except r18-r31 and
> take care of r1, r0.

Yes: Pushing and popping all the registers would solve the problem. But: We
have some quick ISRs, which are written in assembler. Pushing and popping
all registers would be true overkill if you only need a few. Thats why I
thought about a way, where callback functions store and resolve the used
registers by its own.


Regards,

Sven