surfing the web, searching some tool for statically analize the stack usage I found a pdf from 5 years ago, from the 2005 GCC Developers’ Summit: http://www.gccsummit.org/2005/2005-GCC-Summit-Proceedings.pdf
In that document is described a GCC command line options: -fstack-usage (par 2.2.1, pag 96). There is also an example with a slice of C code and the .su output so wonderful, so usefull... I use avr-gcc and arm-elf-gcc, both version 4.4.3. I tryed to invoke gcc with -fstack-usage: cc1: error: unrecognized command line option "-fstack-usage" why? where is that option? bye