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From: Jens Gustedt <jens.gustedt@inria.fr>
To: musl@lists.openwall.com
Subject: Re: Re: drand48() gives wrong sequence?
Date: Sun, 21 Sep 2014 15:45:59 +0200	[thread overview]
Message-ID: <1411307159.4884.183.camel@eris.loria.fr> (raw)
In-Reply-To: <CAK4o1WxR7gBi-54sp2cOS0DmRDt=H5CcYuvovxneJjyxD-4B2A@mail.gmail.com>

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Am Sonntag, den 21.09.2014, 14:27 +0100 schrieb Justin Cormack:
> Hmm, just checked on a non-OSv Musl system and get the same result as
> you. I also checked on NetBSD and FreeBSD and they give the same
> result as glibc, so I think there must be a Musl bug.

In __rand48_step there is this line

	x = xi[0] | xi[1]<<16 | xi[2]+0ULL<<32;

on arch with 16bit int this would be UB, no? Do we have such archs,
still?

In any case, doing something like

	x = xi[0]+0ULL | xi[1]+0ULL<<16 | xi[2]+0ULL<<32;

shouldn't cost anything and should ensure the correct conversion in
all cases.

Jens

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  reply	other threads:[~2014-09-21 13:45 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-21 11:45 Nadav Har'El
2014-09-21 12:02 ` Jens Gustedt
     [not found] ` <CANEVyjv9wwEBibFjqV7XTLzBU2BLvpVPzvxig7ArGceOfpzY7w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-09-21 13:27   ` Justin Cormack
2014-09-21 13:45     ` Jens Gustedt [this message]
2014-09-21 13:57       ` Jens Gustedt
2014-09-21 14:23         ` Jens Gustedt
2014-09-21 12:20 Nadav Har'El
2014-09-21 12:40 ` Jens Gustedt

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