To: J3                                                     J3/19-191
From: Robert Corbett
Subject: IEEE 754 Liaison Report
Date: 2019-July-31

The 2019 edition of the IEEE floating-point standard has been
approved and published.  The new edition is designated
IEEE 754-2019.  The publication date was 2019 July 22.

Work on the new edition began in 2015.  The previous edition
was due to expire in 2018.  The new edition was originally
intended to incorporate corrections and clarifications, but no
new features.  Eventually, new features to support augmented
arithmetic were added.  The working group considered augmented
arithmetic to be easy to implement in hardware.

The IEEE 754 working group met by teleconference on a biweekly
schedule.  Now that work on the new edition is complete, the
working group is going into maintenance mode.  The last
regularly scheduled meeting was held on 2019 July 26.  Meetings
will be held as needed until further notice.

David Hough was the convenor and the secretary for the working
group.  Mike Cowlishaw was the editor.  Both David and Mike are
stepping down.  Rich Painter volunteered to be the new editor.
The positions of convenor and secretary remain open.

Jason Riedy volunteered to maintain the bug list for
IEEE 754-2019 and feature requests for the next edition of the
standard.  He gives the URL

https://gitlab.com/ejr/ieee754

as the place to file bug reports and feature requests.

With work on IEEE 754-2019 complete, the drafts repository has
been made inaccessible.  It will be deleted, as is required by
the IEEE.

The IEEE 754 working group maintains an archive of background
papers that explain why certain choices were made.  The URL for
the background papers is

http://grouper.ieee.org/groups/msc/754

For those who are interested, there is a paper on augmented
arithmetic.

IEEE 754-2019 can be purchased from the IEEE or from Techstreet.
IEEE members receive a discount if they purchased the standard
from www.ieee.org.  Techstreet cannot verify membership and so
does not offer the discount.  The official version of the
standard includes a page added by the IEEE.  The extra page
throws off the left and right orientation of the pages.  David
Hough recommended deleting the extra page before printing.
Techstreet sells printed copies of the standard.  My guess is
that they are print-on-demand copies.  I doubt that they do
anything about the extra page, but I am prepared to be
surprised.

I asked David Hough when IEC 60559 will be updated.  He said
he has no information about that.  I also asked which of the
new features in IEEE 754-2019 should be supported in the next
edition of the Fortran standard.  He thought that the new
max/min operations and the augmented arithmetic operations
should be supported.  I told him I had recommended against
supporting augmented arithmetic in the Fortran standard,
because I thought it would be hard to support in software and
I did not think hardware support would be available soon, if
ever.  He said that he expects hardware implementations to be
available soon.