IEEE 754-2008 governs binary floating-point arithmetic. It specifies number formats, basic operations, conversions, and exceptional conditions. The 2008 edition supersedes both the 754-1985 standard and the related IEEE 854-1987 which generalized 754-1985 to cover decimal arithmetic as well as binary.

Note that materials provided on this page and sub-pages are not approved as IEEE standards. The current, approved standard is 754-2008. The materials provided through this page are purely informative. The standard itself is the official document.

There is a mailing list at stds-754@ieee.org that supports the standard. Nothing on that list is an official interpretation, but the list can be an excellent way to reach people involved in 754. To join the list, send the message text "subscribe stds-754" to listserv@listserv.ieee.org.

Related Groups

Consider assisting the interval standardization effort. Instructions for getting involved are available through Interval Computations web site. Their mailing list archive is hosted by the IEEE.

Revision

The standard recently underwent revision. Participants enganged in mortal combat during meetings in the San Francisco Bay area. The revision page summarizes some of the effort. The mailing list tracks discussions from that time.

Reading Material

Some answers to frequently asked questions are available. A large amount of material, online and dead-tree, has accumulated over the years. The earlier publications provide rationale for the previous standard, IEEE 754-1985.

Good, on-line works include the following:

• David Goldberg's article, What Every Computer Scientist Should Know about Floating-Point Arithmetic, covers important aspects of floating-point arithmetic from the perspective of IEEE 754. Doug Priest's supplement describes many 754 implementations.
• Lecture Notes on the Status of IEEE Standard 754 for Binary Floating-Point Arithmetic by Prof. W. Kahan provides a tour of some under-appreciated features of IEEE 754 and includes many examples where they clarify numerical algorithms.
• Lefèvre and Muller's work on the table-maker's dilemma outlines the difficulties in specifying elementary functions.
• David Bindel has collected an annotated bibliography that lists many relevant works.