>>302
http://www.freebsd.org/releases/5.2R/todo.html
より引用。

Tier-1 Support for AMD64 Hammer

Productionable support for the AMD64 platform. Currently, AMD64 runs
fully in 32-bit emulation mode, and boots to single-user in 64-bit
mode. We expect full production support for the AMD64 architecture in
5.2-RELEASE.