bin/157177: primes(1) prints non-prime for numbers > 2^32

[Oliver Pinter]

On 6/14/11, Robert Lorentz <robert.lorentz at gmail.com> wrote:
> The following reply was made to PR bin/157177; it has been noted by GNATS.
>
> From: Robert Lorentz <robert.lorentz at gmail.com>
> To: bug-followup at FreeBSD.org,
>  kcwu at kcwu.csie.org
> Cc:
> Subject: Re: bin/157177: primes(1) prints non-prime for numbers &gt; 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 at 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.
>
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