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From: Sam Halliday <sam.halliday@gmail.com>
To: help-gnu-emacs@gnu.org
Subject: Re: calc-eval and lsh/logand of large numbers
Date: Tue, 28 Oct 2014 02:34:12 -0700 (PDT)	[thread overview]
Message-ID: <3dfc548c-5076-47e8-841c-1b394129a83a@googlegroups.com> (raw)
In-Reply-To: <bcee5025-f781-4fb6-9ede-9c47c6ae76e4@googlegroups.com>

On Monday, 27 October 2014 22:58:39 UTC, Sam Halliday  wrote:
>   (require 'calc)
>   (defmath bitIndex (i)
>     (lsh 1 i))
> 
>   (calc-eval "bitIndex(64)") ; "0"
> 
> I would have expected this to return "18446744073709551616".

I got it. The default word length is 32 bits and needs to be specified explicitly for left-shift.

http://www.gnu.org/software/emacs/manual/html_node/calc/Binary-Functions.html

  (defmath bitIndex (i) 
    (lsh 1 i (+ 1 i)))




      reply	other threads:[~2014-10-28  9:34 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-27 22:58 calc-eval and lsh/logand of large numbers Sam Halliday
2014-10-28  9:34 ` Sam Halliday [this message]

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