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From: dewar@cs.nyu.edu (Robert Dewar)
Subject: Re: Truncation of FLOAT values
Date: 1996/04/21
Message-ID: <dewar.830122309@schonberg>#1/1
X-Deja-AN: 150716022
references: <4l5nmq$fhv@inrou.erno.de> <4l6bjn$b96@cliffy.lfwc.lockheed.com>
 <dewar.829887687@schonberg> <4lal5h$4qb@cliffy.lfwc.lockheed.com>
organization: Courant Institute of Mathematical Sciences
newsgroups: comp.lang.ada
Date: 1996-04-21T00:00:00+00:00
List-Id: <comp.lang.ada>

Michael said:

"Unless you are telling me that single implementation of an Ada compiler
_may_, in practice, round 2.5 to 3 and round 3.5 to 3, you can write
an implementation specific solution. However, in the case where a
compiler does round x.5 to x (and not x+1), the solution is less
simple."

  That seems unlikely, but rounding 2.5 to 2 and 3.5 to 4 is not only
  allowed, but likely to be encountered in practice (e.g. the Alsys
  compiler for the 386 did this). This style of rounding is called
  unbiased rounding, and corresponds to IEEE round-to-nearest-even.
  Ada 95 forbids this kind of rounding (unless you use the specific
  attribute), but Ada 83 certainly allows it.

Also, note my discussion of problems with non-model numbers.