Am 15.08.2010 09:02, schrieb Joerg Wunsch: > Johannes Bauer <jb....@gmx.de> wrote: > >> I've got another question regarding the AVR ISR prologues: Let's say >> I compile with -fno-omit-frame-pointer. > > As a side note, I don't think this option has received extended > testing in AVR-GCC. People are usually interested in getting the > smallest code size possible, so creating a stack frame when it's not > really needed (many functions don't need it) is a waste of time and > code.
When sporadic deadlocks occur in a system, a stacktrace can really help find bugs. In an application, this is currently the case for me. If I could produce an effective stacktrace, this would help immensely. However, a frame pointer with arbitrary displacement from the return address is quite useless. I tried patching the avr-gcc and managed to move the FP to the beginning of the prologue, but all references to the Y-Ptr still are the same (and I didn't find out how to change that). Changing the initial_elimination_offset return value to reflect the new values did not change the output at all, playing around with avr_hard_regno_mode_ok and legitimate_address_p did affect the way the code is generated (i.e. copying the value from Y to X, doing arithmetic, dereferencing X), but ultimately the actual offset which was used remained the same. Could you please point me to where I should look/poke around in order to get this resolved? I think stack unwinding in-system could be useful for other people as well. Kind regards, Johannes _______________________________________________ AVR-GCC-list mailing list AVR-GCC-list@nongnu.org http://lists.nongnu.org/mailman/listinfo/avr-gcc-list
