I've just commited support for x86_64 (athlon64, athlon fx, opteron) for both the stable (rel_0_8_14) and unstable (HEAD) cvs branches. The x86_64 support is still experimental (it compiles, it starts, but I haven't run any extensive tests).

Special thanks go to Michael Shuler for providing access to an Athlon64 machine.

Andrei