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From: root@cca.ucsf.edu (Computer Center)
Newsgroups: comp.arch
Subject: Re: IBM Stretch rounding modes
Summary: Here is the stretch "noisy mode"
Message-ID: <1311@ucsfcca.ucsf.edu>
Date: 26 Jul 88 07:47:48 GMT
References: <14659@apple.Apple.COM>
Organization: Computer Center, UCSF
Lines: 22

In article <14659@apple.Apple.COM>, baum@Apple.COM (Allen J. Baum) writes:
> 
> I don't think that the "noisy" floating point mode rounded randomly. I think
> it rounded in the opposite direction that the normal rounding did.
> 

The "Noisy Mode" of floating point on the Stretch is described on p. 84
of the Reference Manual, 7030 Data Processing System, A22-6530-1, August
1960.

Essentially it involves using 1-bit fill instead of the 0-bit fill
usually occuring during normalization.

In addition certain operand extensions when using single precision
(48 bit mantissa) use 1-bits in extending to the intermediate (96 bit)
operand format.

Thos Sumner       (thos@cca.ucsf.edu)   BITNET:  thos@ucsfcca
(The I.G.)        (...ucbvax!ucsfcgl!cca.ucsf!thos)

OS|2 -- an Operating System for puppets.

#include <disclaimer.std>