Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!zaphod.mps.ohio-state.edu!rpi!leah!bingvaxu!vu0310 From: vu0310@bingvaxu.cc.binghamton.edu (R. Kym Horsell) Newsgroups: comp.lang.prolog Subject: Re: Fun With Floats in Quintus Message-ID: <3830@bingvaxu.cc.binghamton.edu> Date: 14 Aug 90 08:24:28 GMT References: <3829@bingvaxu.cc.binghamton.edu> <1990Aug14.034632.5561@twinsun.com> Reply-To: vu0310@bingvaxu.cc.binghamton.edu.cc.binghamton.edu (R. Kym Horsell) Organization: SUNY Binghamton, NY Lines: 19 In article <1990Aug14.034632.5561@twinsun.com> eggert@twinsun.com (Paul Eggert) writes: [stuff deleted] >Perhaps Quintus's problem is that they've stolen some low order bits of the >fraction for Prolog tag bits, but their I/O routines are the same as C's and >are thus programmed as if the low order bits were significant. Yep, representation thy has a few wrinkles. Thanks for the references; I'll follow them up. I don't think Quintus uses tag bits in its representation of floats (at the expense of mantissa). From the C routines I use (under Ultix) it seems the low order 4 or 5 bits would have to be used to account for the discrepancy observed by Iverson -- too much surely (there aren't that many primitive types in QP for one thing). R O'K may be able to correct me if I've applied S Holmes incorrectly here. -Kym Horsell