From owner-freebsd-i386@freebsd.org Thu Jan 14 09:09:38 2016 Return-Path: Delivered-To: freebsd-i386@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 054A4A81E9B for ; Thu, 14 Jan 2016 09:09:38 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id EAC961E1C for ; Thu, 14 Jan 2016 09:09:37 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from bugs.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id u0E99bM4038746 for ; Thu, 14 Jan 2016 09:09:37 GMT (envelope-from bugzilla-noreply@freebsd.org) From: bugzilla-noreply@freebsd.org To: freebsd-i386@FreeBSD.org Subject: [Bug 206230] dc(1) bugs Date: Thu, 14 Jan 2016 09:09:37 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: bin X-Bugzilla-Version: 9.3-RELEASE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: nibbana@gmx.us X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: freebsd-bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter cc Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-i386@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: I386-specific issues for FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 14 Jan 2016 09:09:38 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D206230 Bug ID: 206230 Summary: dc(1) bugs Product: Base System Version: 9.3-RELEASE Hardware: i386 OS: Any Status: New Severity: Affects Some People Priority: --- Component: bin Assignee: freebsd-bugs@FreeBSD.org Reporter: nibbana@gmx.us CC: freebsd-i386@FreeBSD.org CC: freebsd-i386@FreeBSD.org FreeBSD-9.3 dc(1) ##### FIRST ##### $ dc -xe '50k16o16i.1vp' 0 $ dc -xe '50k10o16i.1vp' 0 $ dc -xe '50k10o10i.1vp' [0].31622776601683793319988935444327185337195551393252 This should be telling dc(1): a) scale is 50 (in decimal) digits. b) output in base16, base10, and base10 respectively. c) input will be in base16, base16, and base10 respectively. d) take the square root, and print it to the display. Of course, the 3rd example above is correct, but the first 2? Why 0? ###### SECOND ###### $ dc -xe '50k16o16i.4 2^p' [0].0A $ dc -xe '50k16o16i.0Avp' [0].2C572B0D5A1443EC508B9E24D8DF392750959EE138 This should be telling dc(1): a) scale is 50 (in decimal) digits. b) output in base16, input is now base16. c) square "0.4", and print it to the display (result=3D0.0A). d) take the square-root of "0.0A", and print it to the display. Of course, the square-root of a squared number should result in the orginal number. But, this is not happening. ##### THIRD ##### $ dc -xe '50k16o16i.4 2^p' [0].0A $ dc -xe '50k16o16i.40 2^p' [0].1000 $ dc -xe '50k16o16i.400 2^p' [0].10000 $ dc -xe '50k16o16i.4000 2^p' [0].1000000 dc(1) is supposed to be precise in the digits it calculates, but here? Something is not right about these results, or so it appears to me. ###### FOURTH ###### $ dc -xe '50k16o16i.1vp' 0 $ dc -xe '50k16o16i.10vp' [0].3EB4F9D9B6D094C33D38373D38777A7D9233A1B0FB $ dc -xe '50k16o16i.100vp' [0].3FBE55183CA5ADC8B39B27C6258E4C7E64338B909F $ dc -xe '50k16o16i.1000vp' [0].400000000000000000000000000000000000000000 Checking the result of the THIRD example, dc(1) is not outputting to the scale specified, and despite having all a scale of 50, they are all giving different results with inputs having a scale of only 1/2/3/4; Something seems broken to me. -- GNU's dc(1) is broken too (reported to GNU bc maintainer also): Thanks! I really needed a calculator to do squares and square-roots of hexadecimal fractions, and I use FreeBSD, but their dc(1) is broken too ... http://lists.freebsd.org/pipermail/freebsd-questions/2016-January/269999.ht= ml http://lists.freebsd.org/pipermail/freebsd-bugs/2016-January/065825.html I would assert scale is the number of fractional digits displayed regardless of any base. Why should anyone care about base10 or whatever other base the dc(1) author decided to assign as an across-the-board base for the scale value? That makes no sense at all for a user of dc(1). Scale is the number of fractional digits the dc(1) user wants, not what the author of dc(1) decided secretly for everybody. I don't think it was ever intended to be the "base10" fractional digits only, or whatever other scale was used "behind t= he scenes". Scale is a "user demand" for the result, IMHO. A modern computer should have a working calculator - at least, I think so.= =20 Thank you so much for your reply, I have some encryption-related software t= hat depends on it. > On Tuesday 12 January 2016 23:05:41: > > > dc (GNU bc 1.06.95) 1.3.95 > > > > $ dc -e '50k16o16i.4vp' > > [0].727C9716FFB764D594A519C0252BE9AE6D00DC9192 > > > > This is not a 50-digit scale. > > It is a 50 digit scale base 10 which is of course shorter base 16. > > > $ dc -e '50k16o16i.727C9716FFB764D594A519C0252BE9AE6D00DC9192 2^p' > > [0].333333333333333333333333333333333325CC2DCA > > > > This is not even close to being the original number: 0.4. > > This appears to be true. I'll investigate why the algorithm is wrong. --=20 You are receiving this mail because: You are on the CC list for the bug.=