Many thanks to everyone who has helped me on this issue. I ended up abandoning the crosstool approach. It supports mips32 well, but not mips64. Linux from scratch has a very good step by step procedure for building a tool chain for mips64. I was able to build with very little headaches. Unfortunately, I have not yet been able to execute any programs compiled with the tool chain. I'm not sure where I went wrong. PMC sierra is working on an update for their tool chain. They have supplied me with a "beta" version tool chain that has solved my problems. Now, I am able to compile with -mabi=64 and -lpthread. The executable no longer Segfaults. Since I'm past this problem, I will probably not spend much more time trying to build a working tool chain. Bryan