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From: sjl@amdahl.UUCP (Steve Langdon)
Newsgroups: comp.arch
Subject: Success of IEEE Floating Point Standard (IEEE 754)
Message-ID: <5307@amdahl.UUCP>
Date: Fri, 23-Jan-87 02:38:56 EST
Article-I.D.: amdahl.5307
Posted: Fri Jan 23 02:38:56 1987
Date-Received: Fri, 23-Jan-87 22:19:48 EST
References: <760@orcisi.UUCP> <112@lmi-angel.UUCP> <172@ames.UUCP> <203@ames.UUCP> <11939@sun.uucp>
Reply-To: sjl@amdahl.UUCP (Steve Langdon)
Organization: Amdahl Corp, Advanced Systems Planning
Lines: 22
Keywords: IEEE754 supercomputer standards
Summary: It is difficult to use IEEE 754 on a supercomputer

In article <11939@sun.uucp> guy%gorodish@Sun.COM (Guy Harris) provides (as
usual) sensible comments on this topic.  However, he did not cover all of
the reasons for opposition to the IEEE Floating Point Standard.  As an
active participant in ANSI and ISO I clearly believe that standards are
valuable.  However, those opposed to IEEE 754 had some legitimate arguments.

My only source of information comes from conversations with other members
of the system architecture group I worked for at Control Data.  My responsibility
at Control Data, and now at Amdahl, is network architecture.  However, others
in the group had to worry about *very* fast floating point.  While they saw
the appeal of many features of the IEEE standard, it is very difficult to
support in a high end machine.  I am not qualified to provide a detailed
explanation, but the major problems appear to be in the various rounding modes,
and gradual underflow.

IEEE floating point has certainly captured the low end, it will be interesting
to see what happens at the high end.

-- 
Steve Langdon  ...!{decwrl,sun,hplabs,ihnp4,cbosgd}!amdahl!sjl  +1 408 746 6970

[I speak for myself not others.]