This is a port of IsForth to PPC Linux. The port is almost complete — with the exception of sockets, I believe all the extensions work. I'm still doing some clean-up and consolidating changes with the original author before doing a full release. However, there is currently a pre-release tarball available, which you can play with if you like.
IsForth is a nice direct-threaded forth, written in assembly language, which runs directly on top of the Linux kernel — no libraries required. It is not intended to be minimal, and includes a bunch of nice features, including terminfo support (curses-like capabilities), a dynamic memory allocator, the ability to turnkey (save out binaries), and more.
I did include a pre-built binary in the tarball. However, if you want to built it yourself, you'll need a fairly recent version of the GNU binutils package. I used the assembler's macro facility, and I know I've upgraded a few times to get bugfixes to this. I have binutils 2.15.90.0.3 — earlier versions may work, but have not been tested. It will be immediately obvious if it doesn't work: the build will fail with an error message from the assembler.