From: tmoran@bix.com (Tom Moran)
Subject: Re: fixed point vs floating point
Date: 1997/11/23
Date: 1997-11-23T00:00:00+00:00 [thread overview]
Message-ID: <3478ac76.237781@SantaClara01.news.InterNex.Net> (raw)
In-Reply-To: 65846t$4vq$1@gonzo.sun3.iaf.nl
>Converting a fixed point value to fpt, issue the sinus instruction
>and convert it back is much faster than even thinking about doing it in
>fixed point. ;-)
But "type degrees is delta 1.0/16 range 0.0 .. 360.0;" has only 5760
possible values, and a table lookup with a table of 5760 entries is
often quite reasonable, and surely faster than converting to fp,
calculating a sin, and converting back. Not to mention if the
function is not just sin, but, say the 6th power of the cos (in a
Phong illumination calculation, say).
I can't seem to find my Cody&Waite, but I think they give fixed
point algorithms, and I also think I've seen mention of Ada code for
it in the PAL or some such public place.
next prev parent reply other threads:[~1997-11-23 0:00 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
1997-11-22 0:00 fixed point vs floating point Matthew Heaney
1997-11-22 0:00 ` Tucker Taft
1997-11-22 0:00 ` Robert Dewar
1997-11-22 0:00 ` Matthew Heaney
1997-11-23 0:00 ` Geert Bosch
1997-11-23 0:00 ` Tom Moran [this message]
1997-11-25 0:00 ` John A. Limpert
1997-11-25 0:00 ` Robert Dewar
1997-11-25 0:00 ` Robert Dewar
1997-11-23 0:00 ` Matthew Heaney
1997-11-23 0:00 ` Robert Dewar
1997-11-24 0:00 ` Herman Rubin
1997-11-24 0:00 ` Robert Dewar
1997-11-25 0:00 ` Joe Gwinn
1997-11-25 0:00 ` Robert Dewar
1997-11-25 0:00 ` Joe Gwinn
1997-11-25 0:00 ` Robert Dewar
1997-11-26 0:00 ` Joe Gwinn
1997-11-26 0:00 ` Robert Dewar
1997-12-01 0:00 ` Joe Gwinn
1997-12-01 0:00 ` Robert Dewar
1997-12-01 0:00 ` Joe Gwinn
1997-12-03 0:00 ` robin
1997-11-25 0:00 ` Matthew Heaney
1997-11-26 0:00 ` William A Whitaker
1997-11-24 0:00 ` Geert Bosch
1997-11-24 0:00 ` Vince Del Vecchio
1997-11-24 0:00 ` Vince Del Vecchio
1997-12-03 0:00 ` robin
-- strict thread matches above, loose matches on Subject: below --
2011-09-29 10:25 RasikaSrinivasan@gmail.com
2011-09-29 10:49 ` AdaMagica
2011-09-29 13:38 ` Martin
2011-09-30 10:17 ` Stephen Leake
2011-09-30 16:25 ` tmoran
2011-09-30 16:52 ` Dmitry A. Kazakov
2011-10-01 11:09 ` Stephen Leake
2011-09-30 19:26 ` tmoran
2011-09-30 22:31 ` tmoran
2011-10-01 13:37 ` RasikaSrinivasan@gmail.com
2011-10-02 14:19 ` Stephen Leake
1997-12-02 0:00 Robert Dewar
1997-12-02 0:00 ` Joe Gwinn
1997-12-02 0:00 ` Ken Garlington
1997-12-03 0:00 ` Joe Gwinn
1997-12-04 0:00 ` Robert Dewar
1997-12-04 0:00 ` Shmuel (Seymour J.) Metz
1997-12-02 0:00 ` Robert Dewar
1997-12-02 0:00 ` Matthew Heaney
1997-12-03 0:00 ` Robert Dewar
1997-12-03 0:00 ` Shmuel (Seymour J.) Metz
1997-12-03 0:00 ` Matthew Heaney
1997-12-04 0:00 ` Shmuel (Seymour J.) Metz
1997-12-04 0:00 ` Robert Dewar
1997-12-03 0:00 ` Robert Dewar
1997-12-03 0:00 ` Robert Dewar
1997-12-03 0:00 ` robin
1997-12-03 0:00 ` Robert Dewar
1997-12-03 0:00 ` robin
1997-11-28 0:00 tmoran
1997-11-28 0:00 ` Robert Dewar
1997-11-27 0:00 tmoran
1997-11-27 0:00 ` Robert Dewar
1997-11-29 0:00 ` Tarjei T. Jensen
[not found] <9711221603.AA03295@nile.gnat.com>
1997-11-22 0:00 ` Ken Garlington
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