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From: reiter@endor.harvard.edu (Ehud Reiter)
Newsgroups: comp.arch
Subject: Packed Decimal on VAX
Message-ID: <1982@husc6.UUCP>
Date: Thu, 14-May-87 17:03:15 EDT
Article-I.D.: husc6.1982
Posted: Thu May 14 17:03:15 1987
Date-Received: Sat, 16-May-87 11:18:13 EDT
Sender: news@husc6.UUCP
Reply-To: reiter@endor.UUCP (Ehud Reiter)
Organization: Aiken Computation Lab Harvard, Cambridge, MA
Lines: 14

I've just been reading the article on 360/370 architecture in the April
issue of Communications of the ACM.  In this article, it says that the
only reason the 360/370 series had a packed decimal data type was because
one of the original machines (360/30?) had an 8-bit data path.  The article
also said the 360/370 EDIT instruction is regarded as a mistake now.

Now, the VAX has a packed decimal data type.  If I remember correctly, it
also has a form of EDIT instruction.  My question is, does anyone know why
DEC put these features into the VAX?  Did they have a reason, or were they
just trying to make the VAX instruction set a "superset" of the 360's?

					Ehud Reiter
					reiter@harvard	(ARPA,BITNET,UUCP)
					reiter@harvard.harvard.EDU  (new ARPA i