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From: Douglas Lewan <d.lewan2000@gmail.com>
To: help-gnu-emacs@gnu.org
Subject: Re: Bit shift oddity?
Date: Mon, 19 Oct 2020 03:48:01 -0400	[thread overview]
Message-ID: <3b4def4b-28c5-d549-0645-0056f0709549@gmail.com> (raw)
In-Reply-To: <20201019070610.GB9024@tuxteam.de>

Thanks. I see the same behavior with (ash).

On 10/19/20 3:06 AM, tomas@tuxteam.de wrote:
> On Sun, Oct 18, 2020 at 08:19:24PM -0400, Douglas Lewan wrote:
>> I see the following:
>>
>>     ELISP> (= (lsh -1 (lognot 0)) (lsh -2 (lognot 0)))
>>
>>     t
>>
>>     ELISP> (= (lsh -1 (lognot 0)) (lsh -3 (lognot 0)))
>>
>>     nil
>>
>> The first seems odd to me. Is it really what's expected?
> The manual for lsh talks about "quirky behaviour" of lsh when
> both arguments are negative, in the name of backward-compatibility
> and suggests resorting to ash. Cf. the Emacs lisp manual "3.8
> Bitwise Operations on Integers"
>
> Cheers
>   - t

-- 
,Doug
d.lewan2000@gmail.com
(908) 720 7908

You know, it's amazing how much closer to 0 that 8 067 332 is than 15 is. (2020 Oct 18)



  reply	other threads:[~2020-10-19  7:48 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-19  0:19 Bit shift oddity? Douglas Lewan
2020-10-19  7:06 ` tomas
2020-10-19  7:48   ` Douglas Lewan [this message]
2020-10-19  9:01     ` tomas
2020-10-19 15:14       ` Stefan Monnier
2020-10-19 15:30         ` tomas
2020-10-19  9:23 ` Gregory Heytings via Users list for the GNU Emacs text editor
2020-10-19 15:19   ` Douglas Lewan

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