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From: "Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org>
Newsgroups: comp.lang.ada
Subject: Re: Efficient Bit Vector Manipulation.
Date: Fri, 15 May 2015 09:58:11 -0700
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Date: 2015-05-15T09:58:11-07:00
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On 05/15/2015 05:07 AM, Vincent wrote:
> 
> I need to extract in a very efficient way, information from the bit sequence
> that represents a 32 bits Positive number, named I > 0.

Given your need to extract sequences of bits as integers, I'd say using an
Unsigned_* type from Interfaces would probably be best. This also has the
advantage of being endian independent.

Finding the most-significant 1 bit can be done with a binary search. Shifting
and masking out the B and E values is then fairly simple.

-- 
Jeff Carter
"C++ is like jamming a helicopter inside a Miata
and expecting some sort of improvement."
Drew Olbrich
51