MMIXware is copyright 1999 Donald E. Knuth

The MMIXware files may be freely copied and distributed, provided that
no changes whatsoever are made. All users are asked to help keep the
MMIXware files consistent and "uncorrupted", identical everywhere in
the world. Changes are permissible only if the modified file is given
a new name, different from the names of existing files in the MMIXware
package, and only if the modified file is clearly identified as not
being part of that package.
