From: zaphod AT sci DOT fi (Aatu Koskensilta)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Fixed Point (Optimization)
Date: 20 Jan 1997 17:33:37 GMT
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References: <32cd6b2c DOT 4726585 AT nntp DOT southeast DOT net> <01b9bb84$bc3275a0$e2c5b7c7 AT platko DOT ix DOT netcom DOT com> <32cedb2d DOT 17212822 AT ursa DOT smsu DOT edu>
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Tony O'Bryan (aho450s AT nic DOT smsu DOT edu) wrote:
: On 4 Jan 1997 03:39:34 GMT, "Bob Platko" <platko AT ix DOT netcom DOT com> wrote:

: >Fixed Point math is still very essential for dramatic speed increasement
: >even with today's FPU's.  I never bench marked Fixed Point compared to
: >floating point, so I don't know how much faster it will be; it depends on
: >how often you use it.  A lookup table will most likely increase your speed.

: I did a quick check on floating point vs. integers not too long ago.
: I wrote a small loop that only added an integer to an integer counter,
: then rewrote it using floating point variables.  On my Pentium 120,
: integers were THOUSANDS of times faster.  I don't remember the exact
: numbers, but 50,000 loops required a few seconds with the floating
: point.  The integers were so fast that the timer (calculated to
: several digits [7 or 8, I think]) couldn't register the elapsed time.

You must notice that while floating point ADDITION is very much slower
than integer addition, this doesn't prove that for ie. multipliction would
be equally more faster. In fact, floating point multipliction is at least
as fast (if not faster) than integer one.

Just some of my humble thoughts...

Aatu Koskensilta aka Sqrt(-1)
www.sci.fi/~zaphod