Path: csiph.com!weretis.net!feeder6.news.weretis.net!news.misty.com!news.iecc.com!.POSTED.news.iecc.com!nerds-end From: Hans-Peter Diettrich Newsgroups: comp.compilers Subject: Re: C arithmetic, was Software proofs, was Are there different Date: Fri, 10 Feb 2023 19:11:31 +0100 Organization: Compilers Central Sender: johnl@iecc.com Approved: comp.compilers@iecc.com Message-ID: <23-02-037@comp.compilers> References: <23-01-092@comp.compilers> <23-02-003@comp.compilers> <23-02-019@comp.compilers> <23-02-025@comp.compilers> <23-02-026@comp.compilers> <23-02-029@comp.compilers> <23-02-033@comp.compilers> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Info: gal.iecc.com; posting-host="news.iecc.com:2001:470:1f07:1126:0:676f:7373:6970"; logging-data="44892"; mail-complaints-to="abuse@iecc.com" Keywords: arithmetic, comment Posted-Date: 10 Feb 2023 13:18:46 EST X-submission-address: compilers@iecc.com X-moderator-address: compilers-request@iecc.com X-FAQ-and-archives: http://compilers.iecc.com In-Reply-To: <23-02-033@comp.compilers> Xref: csiph.com comp.compilers:3378 On 2/8/23 11:19 AM, Anton Ertl wrote: > With a ones-complement or two's-complement mantissa the hidden bit > would just have the same sign as the sign bit, so this trick is not > tied to sign-magnitude representation. Please explain the provenience or purpose of that hidden bit with integral numbers. How can integral values be *normalized* so that a previously required bit can be hidden? Sign extension to a higher number of bits does not increase the value or accuracy of an integral number. DoDi [He said "mantissa", so it's floating point. I've certainly seen scaled integer arithmetic, but normalized integers other than +/- zero in systems with signed zeros seems unlikely. -John]