Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site sdcc6.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!ittvax!dcdwest!sdcsvax!sdcc6!ix269 From: ix269@sdcc6.UUCP Newsgroups: net.lang.c Subject: Re: Re: reversing a mask Message-ID: <1838@sdcc6.UUCP> Date: Wed, 19-Dec-84 04:29:34 EST Article-I.D.: sdcc6.1838 Posted: Wed Dec 19 04:29:34 1984 Date-Received: Fri, 21-Dec-84 00:36:27 EST References: <691@gloria.UUCP> <9000034@uiucdcsb.UUCP> Reply-To: ix269@sdcc6.UUCP (Jim) Organization: U.C. San Diego, Academic Computer Center Lines: 12 Keywords: But_WHY? Summary: fig() It is quite simple, to reverse a bit mask, merely get a ones compliment (sp?). that is ~mask mask = 011101 /* binary notation, leading zero */ 010 = ~mask this is convenient for purists who *know* that 0 is always FALSE and that !0 is the value of TRUE, ~0 is most definitely the opposite of 0, but I may be asking for it. fourier transforms? Must be a nice machine for that overhead :-).