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From: Alinabi <alexander.the.average@gmail.com>
Newsgroups: comp.lang.ada
Subject: Re: sub-optimal code for packed boolean arrays -- bug or inherent
 limitation
Date: Tue, 03 Jul 2007 18:17:42 -0000
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Date: 2007-07-03T18:17:42+00:00
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One more thing: some inline assembly is unavoidable. There are two
other bitboard operations that are required: First_One(Bitboard_T)
returns Natural and Last_One(Bitboard_T) returns Natural; They return
the position of the least significant and most significant set bit
respectively. On x86 processors you can do this with one instruction
BSF (bit scan forward) and BSR (bit scan reverse), and you cannot
expect a compiler to generate them.