Jasmin Emacs Mode is an Emacs major mode for editing Jasmin Java bytecode assembler files. It provides automatic formatting, customizable fontifying, and quick-reference syntax help. Font-lock specifications are derived from an encoded grammar, for detailed syntax coloring.

It was written by NeilVanDyke in 1996, and used extensively by as many as a billion people throughout the known universe.

See old screenshot at: http://www.neilvandyke.org/jasmin-emacs/