Hello Uz, * On Wed, Nov 04, 2009 at 02:42:37PM +0100 Ullrich von Bassewitz wrote: > I'm looking for a signed 16x16 => 32 multiplication routine. Currently I'm > using the 16x16 => 32 unsigned routine with the absolute values of the > operands, and adjust the sign of the result if necessary. But this quite some > overhead. Have you had a look at the Booth Algorithm? http://en.wikipedia.org/wiki/Booth_algorithm http://de.wikipedia.org/wiki/Booth-Algorithmus or at my former working group: http://ivs.cs.uni-magdeburg.de/EuK/lehre/lehrveranstaltungen/ws0809/tgi.shtml, here: Slides for "Computerarithmetik (Part 4)", Slides 34ff I do not know of a 6502 implementation of it, though, and I do not know if it would be faster than what is currently available. Looking for example at http://www.freepatentsonline.com/y2007/0198625.html, Booth algorithm still seems to be widely used. AFAIK, it is often used for hardware implementations of Multiplications. HTH, Spiro. -- Spiro R. Trikaliotis http://opencbm.sf.net/ http://www.trikaliotis.net/ http://www.viceteam.org/ Message was sent through the cbm-hackers mailing listReceived on 2009-11-07 12:00:04
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