Lines 175, 180, 185 have some extremely weird structs, that do not make sense in today's C language. Back in 6th Edition C, all struct fields were in the same namespace, so you could use '->lobyte' or '->hibyte' on any pointer you cared to. Good stuff, I'm sure it made for very interesting bugs.

Which also explains why very old APIs like struct timeval and struct stat have namespaced field names.