On Sat, 2008-02-23 at 15:40 +0000, Andrew Haley wrote: > The DWARF question I can answer: it's required by the processor- > specific ABI. > > Andrew. > Thank you. I should explain my application. I'm working on an introductory machine organization textbook. It's based on x86-64 running a GNU/Linux system. My approach is to start with C, look at gcc's assembly language, then show how a programmer might write the assembly language. Since it's introductory, I'm less concerned about industrial quality error handling. I use gdb to single-step through code and look at registers and memory. I don't need to explain all the details in my book, but I would like to be able to say something beyond "the stork brought it." My take at this point is that the DWARF is used for 64 bit because parameters are passed in registers, making it more difficult to unwind the stack. Since 32 bit passes parameters only in the stack frame, it is easier to unwind the stack. (Pointing out my misconceptions is much appreciated.) Bob