Date: Tue, 14 Jun 2011 08:18:56 +0200 From: Oliver Pinter <oliver.pntr@gmail.com> To: Robert Lorentz <robert.lorentz@gmail.com> Cc: freebsd-bugs@freebsd.org Subject: Re: bin/157177: primes(1) prints non-prime for numbers > 2^32 Message-ID: <BANLkTi=abw_3p_59mtPafC2N4cUr2MLvLg@mail.gmail.com> In-Reply-To: <201106140400.p5E40OML033995@freefall.freebsd.org> References: <201106140400.p5E40OML033995@freefall.freebsd.org>
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On 6/14/11, Robert Lorentz <robert.lorentz@gmail.com> wrote: > The following reply was made to PR bin/157177; it has been noted by GNATS. > > From: Robert Lorentz <robert.lorentz@gmail.com> > To: bug-followup@FreeBSD.org, > kcwu@kcwu.csie.org > Cc: > Subject: Re: bin/157177: primes(1) prints non-prime for numbers > 2^32 > Date: Mon, 13 Jun 2011 23:29:33 -0400 > > I regression tested this on FreeBSD 8.2-RELEASE against FreeBSD = > 9.0-CURRENT r221981, using primegen-0.97 on amd64 platform and came up = > with some interesting results. > > First off, from primes(1) man page, syntax is: > > primes [ low [high] ] > > So your bc line effectively says: > > primes 4294967296=20 > > Where low =3D 4294967296 and high is not explicitly stated. According = > to the man page high defaults to 1000000000 where the last prime = > possible is 999999937. Since 1,000,000,000 < 4,294,967,296, the correct = > output of "primes 4294967296" should be nothing. > > In FreeBSD 8.2-RELEASE, primes correctly does output nothing. > > However on FreeBSD 9.0-CURRENT, primes incorrectly prints primes = > starting at 4,294,967,296 and seems to go forever (not sure where it = > will stop). This is contrary to what the manual page says and is a = > problem. > > Your original problem I did regression test and confirm to be working in = > 8.2-RELEASE and broken in 9.0-CURRENT. I isolated one of your examples = > using: > > primes 4295360520 4295360522 | xargs -n 1 factor > > On FreeBSD 9.0-CURRENT: 4295360521: 65539 65539 > On FreeBSD 8.2-RELEASE: No output=20 op@pandora-d ~> uname -m -r -p && primes 4295360520 4295360522 | xargs -n 1 factor 7.4-STABLE amd64 amd64 4295360521: 65539 65539 > > > On FreeBSD 9.0-CURRENT I debugged the source in = > /usr/ports/math/primegen/work/primegen-0.97 a bit and realized that if I = > ran the compiled version in = > /usr/ports/math/primegen/work/primegen-0.97/primes I got the correct = > expected results. However, if I run the installed version in = > /usr/games/primes, I get the incorrect results. The binaries in those = > two places aren't the same (verified using md5). =20 > > This appears to be an issue with the port building, probably building in = > 32 bit. If the inputs to primes are interpreted as 32bit then a "low" = > of (2^32 + 1) is interpreted as 1, therefore being less than 1000000000, = > therefore the code would continue to generate primes, and if this is the = > case then I wouldn't be surprised that the prime generation code also = > would misbehave. > > _______________________________________________ > freebsd-bugs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-bugs > To unsubscribe, send any mail to "freebsd-bugs-unsubscribe@freebsd.org" >
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