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Message-ID: <CAAepdCYN6f02bWxCE3wxv5D+79a3H4AxyvU4TGNGjDxxthoyEw@mail.gmail.com>
Date: Fri, 23 Aug 2013 00:23:55 +0100
From: Rafael Waldo Delgado Doblas <lord.rafa@...il.com>
To: john-dev@...ts.openwall.com
Subject: Re: Parallella: Litecoin mining
Hello,
2013/8/22 Solar Designer <solar@...nwall.com>
> It appears that you forgot (or failed?) to do this, and it never got
> onto your "Priorities" lists (it should).
>
> Looking at "e-objdump -d epiphany-scrypt.elf", you actually have
> ___udivsi3 and ___umodsi3 in there. These consume local memory space
> and are pretty slow.
>
> (Actually, I am surprised gcc did not optimize the division by 6 into
> multiplication by a constant needed to achieve division by 3, followed
> by a right shift by 1.)
>
Sorry I forgot about it, but currently I don't understand.
(x/6) = x * (1/6) = (x * (n/6)) / n, well I choose I nice power of 2 n the
down division can be replaced by a m shift and the upper (n/6) can be
computer and round it. for example if I say n = 16.
(x/6) = (x * (16/6)) >> 4 ~ (x * 3) >> 4.
I need to do a right shift by 1 how do you find the constant for right
shift by 1
Regards,
Rafael.
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