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Posting-Version: version B 2.10.1 6/24/83; site burl.UUCP
Path: utzoo!watmath!clyde!burl!geoff
From: geoff@burl.UUCP (geoff)
Newsgroups: net.math,net.wanted,att.wanted
Subject: need fast algorithm for reciprocal
Message-ID: <480@burl.UUCP>
Date: Tue, 12-Jun-84 10:28:58 EDT
Article-I.D.: burl.480
Posted: Tue Jun 12 10:28:58 1984
Date-Received: Wed, 13-Jun-84 00:24:10 EDT
Organization: AT&T Technologies; Burlington, NC
Lines: 19

I am working on a very primitive machine which lacks a division
operation.  What I really need is a reciprocal, so either type
algorithm would be fine.  I have shift, +,-, and *, as well as
logical operators, available.  I recall that IBM had an algorithm
many years ago which used multiplication to divide (sort of a binary
search -- multiply guess * number, compare to 1, adjust guess), but
I don't remember it well enough (my attempt at such an algorithm
required an avg of 20 iterations for reciprocals of numbers between 2
and 8000).

Any help from the net would be sincerely appreciated.

	thanks,
		geoff sherwood
		burl!geoff

	<"take care of the luxuries
		and the necessities take care
			of themselves">