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From: haynes@ucscc.UCSC.EDU.ucsc.edu (99700000)
Newsgroups: comp.arch
Subject: Re: What should be in hardware but isn't
Message-ID: <867@saturn.ucsc.edu>
Date: Mon, 21-Sep-87 23:01:23 EDT
Article-I.D.: saturn.867
Posted: Mon Sep 21 23:01:23 1987
Date-Received: Thu, 24-Sep-87 01:03:46 EDT
References: <581@l.cc.purdue.edu>
Sender: usenet@saturn.ucsc.edu
Reply-To: haynes@ucscc.UCSC.EDU (Jim Haynes)
Organization: California State Home for the Weird
Lines: 15

In article <581@l.cc.purdue.edu> cik@l.cc.purdue.edu (Herman Rubin) writes:
>...
>With the advent of floating point, fixed point operations seem to be 
>vanishing.  On the early floating point machines, frequently numerical
>functions would be done in fixed point for speed and accuracy.  The need
>for this has not changed, but the availability has.  Also, it should be
>possible to convert between fixed and floating point without the overhead
>of a multiply; this was possible on the UNIVAC 1108 and 1110.
Burroughs (pre-Unisys) handles this by making all numbers floating point.
Integers simply have a zero exponent.  The normalizing algorithm tries to
keep the exponent zero rather than invariably normalizing.  So fixed-to-float
takes no time; float-to-fixed may take time.
haynes@ucscc.ucsc.edu
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