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Re: calc-eval and lsh/logand of large numbers
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From: |
Sam Halliday |
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Subject: |
Re: calc-eval and lsh/logand of large numbers |
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Date: |
Tue, 28 Oct 2014 02:34:12 -0700 (PDT) |
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User-agent: |
G2/1.0 |
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)))