MMIX

This article is about the instruction set architecture. For the year, see 2009. For the song, see Mylo Xyloto.
MMIX
DesignerDonald Knuth
Bits64-bit
Introduced1999
DesignRISC
EncodingFixed
BranchingCondition Code
EndiannessBig
OpenYes, and royalty free
Registers
32 special-purpose registers
General-purpose256

MMIX (pronounced em-mix) is a 64-bit reduced instruction set computing (RISC) architecture designed by Donald Knuth, with significant contributions by John L. Hennessy (who contributed to the design of the MIPS architecture) and Richard L. Sites (who was an architect of the Alpha architecture). Knuth has said that,

MMIX is a computer intended to illustrate machine-level aspects of programming. In my books The Art of Computer Programming, it replaces MIX, the 1960s-style machine that formerly played such a role… I strove to design MMIX so that its machine language would be simple, elegant, and easy to learn. At the same time I was careful to include all of the complexities needed to achieve high performance in practice, so that MMIX could in principle be built and even perhaps be competitive with some of the fastest general-purpose computers in the marketplace."[1]

Knuth started the design of MMIX in 1999, and released the stable version of the design in 2011.[2] The processor is numbered as "2009" with Knuth explaining that this is the arithmetic mean from the numbers of other computer architectures; as well as being "MMIX" in Roman numerals.[3]

  1. ^ Knuth, Donald E. (October 1999), MMIXware: A RISC Computer for the Third Millennium, Lecture Notes in Computer Science Tutorial, vol. 1750, Heidelberg: Springer-Verlag, ISBN 3-540-66938-8 (Errata)
  2. ^ "MMIX Home: A Message From Don Knuth". mmix.cs.hm.edu. Retrieved 2021-05-23.
  3. ^ Knuth, Donald (1999-02-09). MMIX: A RISC Computer for the New Millennium (offset 7:36). Stanford Lecture. Archived from the original on 2021-12-11. (Cray-1 + IBM 801 + RISC II + Clipper C300 + AMD 29k + Motorola 88k + IBM 601 + Intel i960 + Alpha 21164 + POWER2 + MIPS R4000 + Hitachi Super H4 + StrongARM 110 + SPARC64) / 14 = 28126 / 14 = 2009