Debug gcc? :( The last time I built a kernel without -O2 it didn't even get as far as kmain(). You can try it, but I doubt it'll work any better for you than for me. You could also try -O1, which is likely to make gdb happier. I don't know if that will work or not - based on what I've heard about the mips gcc, I expect probably not. A reasonable question would be "why are we using MIPS, then, if the compiler's broken?" The answer is, more or less: cs161 has always used MIPS in the past without much trouble. By the time we realized there was a problem, it was too late to switch - we might have been able to switch if there were another simple architecture we had in-house experience with, but there wasn't. -- - David A. Holland | VINO project home page: dholland(a)eecs.harvard.edu | http://www.eecs.harvard.edu/vino