If you are an Emacs user and write your MIXAL programs using this
editor, you will find the elisp program mixvm.el quite
useful1. mixvm.el allows running
the MIX virtual machine
mixvm (see mixvm) inside an Emacs
GUD buffer, while visiting the MIXAL source file in another
After installing mixvm.el (see Emacs support), you can initiate an mdk/GUD session inside Emacs with the command
and you will have a
mixvm prompt inside a newly created
GUD buffer. GUD will reflect the current line in the
corresponding source file buffer.
 mixvm.el has been kindly contributed by Philip E. King. mixvm.el is based on a study of gdb, perldb, and pdb as found in gud.el, and rubydb3x.el distributed with the source code to the Ruby language.