Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site spar.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!decwrl!spar!baba From: baba@spar.UUCP Newsgroups: net.micro Subject: Re: 8086 et al status bits question. Message-ID: <12@spar.UUCP> Date: Wed, 19-Dec-84 03:06:01 EST Article-I.D.: spar.12 Posted: Wed Dec 19 03:06:01 1984 Date-Received: Fri, 21-Dec-84 00:45:55 EST References: <435@gitpyr.UUCP> Distribution: net Organization: Schlumberger Palo Alto Research, CA Lines: 10 > > Is it really useful to be able to do a comparison followed by an INC > (or DEC), and then be able to do a JC or JNC on the comparison? > -- It makes the equivalent of the C "while(*pointer++ > VALUE)" construct more efficient. In preserving only the carry flag it would appear that intel learned from their mistake on the 8080, where 16-bit increments and decrements don't even affect the zero flag, forcing two additional instructions into every 16-bit down-counter.