Re: [avr-gcc-list] GCC Startupcode

[Joerg Wunsch]

Andreas Strodl <address@hidden> wrote:

> Could anyone please tell me were I can find that startupcode in the
> AVRlibc and if there is somthing special to care about.

avr-libc/crt1/gcrt1.S

Just read it, then you'll know what to care about.

If you don't know where to look for the source code, start at the
project's web page:

http://savannah.nongnu.org/projects/avr-libc/

Either download the source archive from the download area, or pick
just the gcrt1.S file up from CVS (this can even be done through the
Web interface).

My guess is that you're primarily interested to get a fast startup in
some situations only (like, after a watchdog reset), so you'd probably
best try identifying this situation, handle it accordingly, and
otherwise resort to the standard sequence.  Remember that some of the
behaviour dictated by the C standard (clearing .bss and copying over
..data's initial values) is performed by the startup code, so if you
modify that, your application can no longer rely on this.  (Other
things, like the initialization of the IO subsystem is performed upon
each reset by hardware.)

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