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From: Phil Carmody <pc+usenet@asdf.org>
Newsgroups: sci.crypt
Subject: Re: Efficient dword bitwise rotate / circular shift using Bash shell ?
Date: Sat, 11 May 2024 18:37:40 +0300
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SugarBug <3883@sugar.bug> writes:
> Example:
>
> rol() { num="$@" ; pre=$((num<<13)) ; suf=$((num>>19)) ;
>         num=$((pre^suf)) ; num=$((num&0xffffffff)) ; echo "$num" ; }
>
> What tricks will make this more efficient in Bash?

If you can be sure the input will never be 0xffffffff, then this should
work:

rol () { echo "$(($1*8192%0xffffffff))" ; }

Phil
-- 
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