Path: csiph.com!weretis.net!feeder6.news.weretis.net!news.misty.com!news.iecc.com!.POSTED.news.iecc.com!nerds-end From: anton@mips.complang.tuwien.ac.at (Anton Ertl) Newsgroups: comp.compilers Subject: Re: C arithmetic, was Software proofs, was Are there different Date: Sat, 11 Feb 2023 22:34:25 GMT Organization: Institut fuer Computersprachen, Technische Universitaet Wien Sender: johnl@iecc.com Approved: comp.compilers@iecc.com Message-ID: <23-02-040@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> <23-02-037@comp.compilers> <23-02-038@comp.compilers> Injection-Info: gal.iecc.com; posting-host="news.iecc.com:2001:470:1f07:1126:0:676f:7373:6970"; logging-data="72081"; mail-complaints-to="abuse@iecc.com" Keywords: arithmetic, history, comment Posted-Date: 11 Feb 2023 20:28:32 EST X-submission-address: compilers@iecc.com X-moderator-address: compilers-request@iecc.com X-FAQ-and-archives: http://compilers.iecc.com Xref: csiph.com comp.compilers:3381 gah4 writes: >[I am not aware of any hidden bit formats before IEEE The VAX FP formats have a hidden bit , and AFAIK VAX F and G are pretty close to IEEE binary32 and binary64. According to already Zuse used a hidden bit in FP numbers on his machines (1940s and 1950s). -- M. Anton Ertl anton@mips.complang.tuwien.ac.at http://www.complang.tuwien.ac.at/anton/ [Oh, right, I forgot about Zuse. He invented a lot of stuff that other people reinvented later. Squinting at my VAX architecture handbook, the formats have the same layout as IEEE but the exponents are excess 128 and 1024 rather than 127 and 1023 and there's no infinities or denormals. -John]