From: MenTaLguY <mental@...>
Date: 2008-01-26T07:15:54+09:00
Subject: Re: Circular shift

On Sat, 26 Jan 2008 07:03:12 +0900, "Judson Lester" <nyarly@gmail.com> wrote:
> On Jan 25, 2008 1:47 PM, Mental Guy <mental@rydia.net> wrote:
>> Since you showed interest, though, I'll continue with what I would
>> have eventually gotten to:  if the register width is a power of two,
>> you can do some additional tricks.
> 
> Let's just say I share your love for binary arithmetic.  But, hey, I'm
> more than happy to play straight man for a good punchline.

Yeah, your reply struck me as fairly bit-savvy; I'm mostly just writing
for the benefit of any bit-curious folks out there on the list.
 
>> [1] Be careful when porting code to other languages; they may differ
>> in their treatment of negative numbers with the modulo operator, and
>> in C its behavior is platform-dependent.  Ruby's way is the best way
>> for modular arithmetic though.
> 
> Yeah, no kidding.  C (and many related languages) also fix the width
> of numeric types and have built-in (<<<) circular shifts.

Then there's also the whole shift-with-sign-extension (or not) thing...

-mental