ascherer/mmix

MMIX 2009 – a RISC computer for the third millennium

MMIX 2009

A RISC Computer for the Third Millennium

“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.)

Prerequisites

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.

Getting Started

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

Why have yet another project here?

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 2023 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.

Major features added

• Fix compiler warnings (gcc -W -Wall -O) with a set of changefiles
• 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

Postscript

Recently it has come to my attention that the local modifications are used in the Cygwin port of MMIXware.

mmix's Issues

Vectorize MMIX titular

http://mmix.cs.hm.edu/index.html

Analyze `wow` situation

The word wow occurs exactly once in the whole source distribution of MMIX.

Typos

• mmix/mmix-config.w

  Line 212 in b32eba1

  \bull ports (default 1), number of processes that can simultaneous

  should be simultaneously.

• mmix/mmix-sim.w

  Line 250 in b32eba1

  on that file. It returns 0 if the file was opened successfully; otherwise

  should add an it.

• The triple operator ?: is formatted inconsistently for Fopen and Fseek in section 4 of mmix-sim.w, i.e., there are several spaces (\ ) missing.

• Also in section 4 of mmix-sim.w, purge two commas in displayed lines.

• The tricky sequence in section 6 of mmix-sim.w should purge two extra spaces.

• Section 59 of mmix-sim.w: list of lists and built into.

• #define rQ 16 in section 12 of mmmix.w repeats the same line form mmix-pipe.h.

Update to C99

In mmixal.w, replace typedef bool with <stdbool.h>.

Emacs mode

Great to see all the activity in this repo!

Last year I made an emacs mode, mmix-mode. Might be useful in combination with your compiler.

Fix another bug

Apply SVN@150 to mmix-pipe.w.

[C99] Use compound literals.

See https://en.cppreference.com/w/c/language/compound_literal for details.

Reseach problems

At various places in the MMIX sources, Don Knuth asks the interested reader to make significant changes for advanced system features:

• Unicode support using wchar for Char (MMOTYPE§27, MMIXAL§§{7,30})
• octa as single 64-bit integer, e.g., using uint64_t instead of the current struct with two tetras (ILP64 interface) (MMIX-ARITH§1)
• Graphical interface (MMIX-SIM§1)
• …

Time permitting, I'll try to look up the relevant sections in the codes.

extern floatit.

Rewrite panic with vfprintf

mmix-config.w and mmix-pipe.w.

Purge ARGS macro.

CLang 15 started to issue warnings for the mixture of C99 prototype declarations and K&R definitions. GCC 14 likely will follow suite.

Look up C2x (especially C23) for details, or https://news.ycombinator.com/item?id=30396083

§51 of mmix-pipe.w typeset badly

Indentation of §51 is completely wrong. Compare §50 right above.

Affected sections are §48, §51, §83, §107.

Fix: Replace forced break @/ with soft break @|.

code differences to mmix home.

master differs from svn co svn://mmix.cs.hm.edu/mmixware/trunk.

Update README.md

Major features in local

• C99 types
• Shared library libmmix.so

Run simple system tests

Add %check section to specfile.

shift_right: parameter 'u' is boolean, not integer.

Also floatit(.,..,u,p).

Roll back the 'shared library' idea.

The copy test case produces a floating point exception 8 on MacOS. Analysis shows that there are several external relationships from mmix-io.w to both mmix-sim.w and mmix-pipe.w (mmgetchars, mmputchars, stdin_chr, ...) and back (mmix_fopen, mmix_fwrite, mmix_fputs, etc.). The former is the main module for mmix, the latter for mmmix.

ATTOW, it seems impossible to create a working mmix.so shared object containing mmix-pipe.o (in order to resolve external dependencies from mmix-io.o et al.) and simultaneously link this to mmix-sim.o (in order to create mmix).

Miraculously, the shared object approach seems to work on Linux. However, the code base does not support this.