From:	EDWARD CASHIN <cashin AT pollux DOT cs DOT uga DOT edu>
Message-Id:	<199807271629.MAA14391@woodstock.cs.uga.edu>
Subject:	implementation of modulo operator in djgpp
To:	djgpp AT delorie DOT com
Date:	Mon, 27 Jul 1998 12:29:10 -0400 (EDT)
MIME-Version:	1.0

Hello.  I was just considering the case of a circular
buffer.  Indexing the subscripts could be done with
something like this:

/* subscripts: "front" is subscript of first stored value
	       "back" is subscript of last stored value
	       "last" is subscript of the last available 
			array spot */

front = (front + 1 > last) ? 0 : front + 1;
back = (back + 1 > last) ? 0 : back + 1;

...or you could say:

front = (++front) % last;
back = (++back) % last;

...which begs the question, "How fast is the modulo?"
and more specifically, how is it implemented?

Thanks,
--Ed

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