The goal of this assembler is to eventually not be simply an M68K assembler, but to be relatively easily retargetable. Also, this assembler should be callable from other CL applications, as well as executable as a stand-alone program. The code's not so clean right now, maybe, but I've been using it for various Atari ST projects for a little while now to great personal satisfaction. The a.out object format supported here and by st-linker is not really quite exactly a.out. It's close, though. To build this from scratch, you'll need to do something like: (in the m68k-asm directory)

CL-USER> (asdf:oos 'asdf:load-op :lalr-parser-generator)
CL-USER> (load "m68k-grammar")
CL-USER> (with-open-file (stream "parser.lisp" :direction :output)
            (lalr:make-parser m68k-asm::*m68k-asm-grammar*
                              :package (find-package "M68K-ASSEMBLER")
                              :stream stream))

I'm going to make that a bit cleaner at some point.