From:	Vic <tudor AT cam DOT org>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: DJGPP division optimisations
Date:	Mon, 13 Jul 1998 20:32:05 -0400
Organization:	Communications Accessibles Montreal, Quebec Canada
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Message-ID:	<35AAA705.1BDE@cam.org>
References:	<35AA8994 DOT 3FC1 AT virgin DOT net> <6oe4in$1m7$1 AT rosenews DOT rose DOT hp DOT com>
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To:	djgpp AT delorie DOT com
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Andrew Crabtree wrote:
> 
> >on long integers. In the source code I used x /= 2; y /=2; for clarity,
> >on the assumption that the compiler would replace these operations with
> >shifts.However, it seems this isn't a valid assumption. Replacing the code
> with
> >x >>= 1; y >>= 1; made a large speed up.
> 
> Just a guess, but maybe GCC only does that optimization on unisignd
> integers, not signed integers.

it's true, I checked this. I put "unsigned" in front of the variables
and the 2 loops performed the same (2.74 seconds)

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