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From: "Jeffrey R. Carter" <spam.not.jrcarter@acm.not.spam.org>
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Newsgroups: comp.lang.ada
Subject: Re: How do you bitwise operations in Ada '83 and '95
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jimmaureenrogers@worldnet.att.net wrote:
> 
> Here you will note that the algorithm is the same as the
> Ada version. The bit-wise operations in the nsieve function
> are expressed in the manner you described. According to
> your analysis, if the algorithm is the same and the results
> are the same, the programs are the same. Logic tells me,
> therefore, that accessing individual bits of
> contiguous storage through an array of boolean in Ada is
> a bit-wise operation just as the combination of AND, OR and
> shift operations used in the C program.

The algorithm is the same. The levels of abstraction differ. The Ada 
abstraction of a packed array of Boolean is higher level than accessing 
individual bits in an unsigned integer but lower level than a set 
abstraction. To me, using a set abstraction (that is implemented using 
bitwise operations) is not using bitwise operations; perhaps you would 
would disagree. Similarly, a compiler probably implements indexing a 
packed array of Boolean with shift and mask operations, but using such 
an indexing operation is not a bitwise operation.

-- 
Jeff Carter
"People called Romanes, they go the house?"
Monty Python's Life of Brian
79