Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!brl-adm!adm!rgenter@j.bbn.com From: rgenter@j.bbn.com (Rick Genter) Newsgroups: comp.lang.c Subject: Re: (unsigned) -1 yields all 1s Message-ID: <1555@brl-adm.ARPA> Date: Tue, 16-Dec-86 10:16:17 EST Article-I.D.: brl-adm.1555 Posted: Tue Dec 16 10:16:17 1986 Date-Received: Wed, 17-Dec-86 07:29:17 EST Sender: news@brl-adm.ARPA Lines: 16 > Actually, I think (unsigned) -1 does have to give you a bit pattern of > all 1's. I can not find an explicit reason, but I can deduce this from the > following: > [...] > 3. The value in the range 0 to 2^n-1 (inclusive) congruent mod 2^n > to -1 is 2^n-1. In straight binary notation this value is repre- > sented as all 1's. This assumes your machine is in straight binary notation. If your machine uses one's complement notation (CDC Cyber?), -0 is represented as all ones. - Rick -------- Rick Genter BBN Laboratories Inc. (617) 497-3848 10 Moulton St. 6/512 rgenter@bbn.COM (Internet new) Cambridge, MA 02238 rgenter@bbnj.ARPA (Internet old) seismo!bbn.com!rgenter (UUCP)