“Thirty years have passed since the MIX computer was designed [in 1969], and computer architecture has been converging during those years towards a rather different style of machine. Therefore it is time to replace MIX with a new computer that contains even less saturated fat than its predecessor.” — The successor MMIX was developed and published by Donald E. Knuth in 1999. The fully documented source code is available from the MMIX home and in the book MMIXware: A RISC Computer for the Third Millennium published by Springer-Verlag in 1999. (This book contains several chapters with additional information not available in the electronic distribution.)

The source code of MMIX is written in accordance with the rules of the Literate Programming philosophy, so you need to make sure that your computer supports the CWEB system. The CWEB sources are available for anonymous ftp from Stanford University. Bootstrapping CWEB on Unix systems is elementary and documented in the CWEB distribution; pre-compiled binary executables of the CWEB tools for Win32 systems are available from www.literateprogramming.com.

Details of this software can be found in the README file.

DEK has passed the baton of development to the group behind “MMIX home”. Besides several “official” releases from DEK in the form of gzipped tarballs, they provide their working sources through a Web-accessible repository.

The present project on Github is a separate effort and holds all releases by DEK from 1999 to 2025 in the master branch. Much more interesting is the local branch; it provides further improvements to the MMIX sources plus a “specfile” mmix.spec for building installable packages for rpm and deb based Linux distributions with the help of the rpmbuild and debbuild utilities respectively.

• Advanced build script mmix.spec for rpm and deb packaging
• Modified Makefile for target optimization
• Use C99/C++ types bool, uint8_t and uint32_t
• New in 2023: Completely updated module structure with new header files
• New in 2023: Purge ARGS macro in preparation for C2x
• New in 2024: Build “shared object” libmmix.so (again)
• New in 2025: Secondary set of change files for CTWILL formatting
• New in 2025: Code compiles with C23 standard compilers