Newsgroups: comp.arch
Path: utzoo!henry
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: ieee floating standard
Message-ID: <1991May22.162955.21149@zoo.toronto.edu>
Date: Wed, 22 May 1991 16:29:55 GMT
References: <9105220041.AA14355@ucbvax.Berkeley.EDU>
Organization: U of Toronto Zoology

In article <9105220041.AA14355@ucbvax.Berkeley.EDU> jbs@WATSON.IBM.COM writes:
>         Let me explain what I meant.  When I stated that the IEEE
>standard has become so entrenched that manufacturers are effective-
>ly forced to use it, I was referring primarily to the representa-
>tion of 32 and 64 bit floating point numbers and secondarily to the
>way floating arithmetic (in round to nearest mode) is defined to
>work.  I do not believe the entire standard is so entrenched.

By and large it is.  But you have to understand that the standard does
allow some flexibility.  In particular, you can be completely conforming
with 32-bit numbers plus some kind of extended format for them, so many
penny-pinching manufacturers say that 64-bit numbers are the extended
32-bit format rather than a second "fully supported" format.  This is
within the letter of the law.  Unfortunately.

(Well, maybe I am too harsh.  Having IEEE behavior for 32 and 64 is a
lot better than having, say, 370 floating point.  But having an extended
format for 64 too is even better.)
-- 
And the bean-counter replied,           | Henry Spencer @ U of Toronto Zoology
"beans are more important".             |  henry@zoo.toronto.edu  utzoo!henry