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1994-11-23 - Re: Pentium bug and CRYPTO

Header Data

From: m5@vail.tivoli.com (Mike McNally)
To: Dave Horsfall <dave@esi.COM.AU>
Message Hash: 0d3f9921430909fd80d3e039ce004fbf7cffec1987fe8329bfa8957c60dc2a6a
Message ID: <9411231326.AA11476@vail.tivoli.com>
Reply To: <199411220139.RAA05434@netcom19.netcom.com>
UTC Datetime: 1994-11-23 13:27:43 UTC
Raw Date: Wed, 23 Nov 94 05:27:43 PST

Raw message

From: m5@vail.tivoli.com (Mike McNally)
Date: Wed, 23 Nov 94 05:27:43 PST
To: Dave Horsfall <dave@esi.COM.AU>
Subject: Re: Pentium bug and CRYPTO
In-Reply-To: <199411220139.RAA05434@netcom19.netcom.com>
Message-ID: <9411231326.AA11476@vail.tivoli.com>
MIME-Version: 1.0
Content-Type: text/plain



Dave Horsfall writes:
 > I'd be horrified if a crypto implementation used floating point, with
 > the implied imprecision...

The imprecision in floating point is a factor only if you choose to
pay attention to it.  It is possible to use floating point all day
long to do what are essentially integer calculations.  indeed, there
have been CPUs (the CDC 6000 series come to mind) that have no integer
multiply or divide instruction.  Instead, one used the floating point
instructions and then extracted the result (carefully) from the
mantissa.

Floating point isn't magic, it's just microcode.  (Well, not in the
CDC 6000 I guess...)

| GOOD TIME FOR MOVIE - GOING ||| Mike McNally <m5@tivoli.com>       |
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