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From: dewar@gnat.com (Robert Dewar)
Newsgroups: comp.lang.ada
Subject: Re: Math Update for Ada 2005
Date: 23 Dec 2001 07:13:52 -0800
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"Steven Deller" <deller@smsail.com> wrote in message news:<mailman.1009040342.32000.comp.lang.ada@ada.eu.org>...
> All the email about Math libraries reminded me of one of Ada 95's
> shortcomings.
> 
> The IEEE math definitions have included NaN and Inf semantics for quite
> some time. Many (if not all) native platforms and many embedded
> platforms can support this.  I have run into C++ and C code that uses
> these.  Ada 95 does NOT support these.

Ada 95 was carefully designed so that support can be
added for infinities and Nan's without in anyway violating
the RM semantics, and in fact GNAT does support the use of
Inf and Nan semantics in full generality, though it does
not provide all the IEEE facilities for manipulating such
values.

These facilities can be added with external packages. For
an *extensive* discussion of this entire issue see Sam
Figueroa's thesis (NYU, Robert Dewar thesis advisor). This
thesis addresses the entire issue of floating-point evaluation schemes
in high level languages from an IEEE
point of view, and specifically proposes a package and
other facilities (pragmas attributes etc) for full support
of the IEEE model in Ada 95 in an upwards compatible manner.

At least start from Sam's work, don't reinvent the wheel :-)