Re: [avr-gcc-list] code for 90s4433 is using SPH

[Joerg Wunsch]

As Marek Michalkiewicz wrote:

> > Strange.  Than i'd say that -mtiny-stack doesn't work as announced.
> 
> That's because -mtiny-stack can be used on devices with SPH, too.
> SPH is initialized at startup, and never changed later.  This is
> fine if we know the stack fits within a 256-byte aligned page.

Hmm, after all, it seems it would make sense for us to invent a new
architecture for it, say "avr2small".  The devices in questions are
the AT90S{2313,2323,2333,2343,4433}, ATtiny{22,26}.  For all these,
SPH is not defined and doesn't need to be handled.  Since this will
also save a few bytes of flash, it would make sense to also ship a
different library for them.

> Perhaps a new attribute would be useful - "this function can
> return, but it's OK to clobber all registers, no need to save
> anything".  It's called "OS_Task" in the h8300 port, but not
> documented anywhere - should we use the same name?  Is this
> the same thing as "__C_task void main(void)" in IAR C code?

No idea about AVR, but it sounds useful to me.  We could even include
a prototype for main() in a central header file.

-- 
J"org Wunsch                                           Unix support engineer
address@hidden        http://www.interface-systems.de/~j/