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Message-ID: <CANJ2NMPa0VkQuD8nNSTTE1uuSkyz9buk4CQbVMOnCqPQgx+CuA@mail.gmail.com>
Date: Wed, 16 May 2012 16:21:22 +0800
From: myrice <qqlddg@...il.com>
To: john-dev@...ts.openwall.com
Subject: Re: Myrice: Weekly Report #5
On Wed, May 16, 2012 at 3:28 PM, magnum <john.magnum@...hmail.com> wrote:
>
> Are you having problems with swap64 only, or other things too?
Now I think it is only the SWAP64. Maybe I have to change it into
other forms. But from my experiment, if followings are true, I think
the problem is complex and all 64bit operation will be influenced.
I find problems with bit operation like: &, | and <<.
I think compiler optimization does something strange. If I use two of
bit operations in a sentence like: n = (a & 0xff) << 32, the result
will be 0 when the operation on high 32bit of a 64bit variable.
I have tried using violate variables to avoid this. Such as: violate
ulong a; a &= 0xff; n = a << 32; This would be correct. If I use a for
next sentence, the a will be 0 also.
I suspect the AMD OpenCL compiler has some bugs with 64bit bit operation.
Thanks
myrice
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