[m-rev.] time additions (was Re: for review: Add random.init/3)

Mark Brown mark at mercurylang.org
Sat Jun 4 20:44:34 AEST 2016


On Sun, May 29, 2016 at 7:55 PM, Julien Fischer <jfischer at opturion.com> wrote:
> On Sun, 29 May 2016, Mark Brown wrote:
>> As an aside, note that the tausworthe3 generator mentioned (which I
>> think is the one from extras/gator) fails almost all of the dieharder
>> tests on 64-bit platforms, which is a slight bug. Looking at the code,
>> it seems that 64-bit platforms would need to truncate values to 32
>> bits after some of the left-shift operations, since this is what would
>> happen on on a 32-bit platform.
>
>
> That's not surprising -- the original author of that implementation
> wasn't working on a 64-bit machine when he wrote it.

It also performs an arithmetic shift instead of a logical one, which
would affect the behaviour on 32-bit machines.

Mark


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