causing function not to clobber

[Dima Sorkin <dmitri.sorkin@xxxxxxxxx>]

Hi.
  Consider a function
void f();

Is there a way to specify that this function should not clobber any register (i.e. save every register it uses on the stack), even if ABI permits to clobber certain registers ?

If a way exists, is it in standard C (for example C99), or GCC extension ?

Thanks, regards,
  Dima.
 
P.S.
  Please CC me, I am not in the list.