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Re: LYNX-DEV floating-point (was: using a dos xt)
From: |
Bela Lubkin |
Subject: |
Re: LYNX-DEV floating-point (was: using a dos xt) |
Date: |
Sun, 3 Aug 1997 23:02:36 +0000 |
I wrote:
> David Woolley wrote:
>
> > > > (Lynx makes heavy, unnecessary use of floating point).
> > HTStyle.h:70:typedef float HTCoord;
> I looked at every use of this and it seemed that replacing it with "int"
> would be safe. So I tried it, and it compiled cleanly and did not
> change Lynx's output for any page that I tested it with (about 30 of the
> largest pages of SCO's HTML online documentation). The resulting Lynx
> binary was also an average of 4% faster, over the same set. My machine
> has hardware floating point. I didn't go to the hassle of rebooting to
> test under emulation, but if it makes 4% difference with an integrated
> P5 FPU, it probably makes a *huge* difference with software FP.
I decided to try it after all. Rebooted my machine with the floating
point hardware disabled, so that it would use software floating point.
I then tested
time lynx -dump /usr/lib/scohelp/...whatever.html > /dev/null
for 35 of the largest HTML documents in SCO's online help. I averaged
and normalized the results.
The four results:
1. Lynx compiled with "typedef float HTCoord", run with hardware FPU:
1.00 (average; time units normalized to this run)
2. Lynx compiled with "typedef float HTCoord", run with software FPU:
5.52
3. Lynx compiled with "typedef int HTCoord", run with hardware FPU:
0.97
4. Lynx compiled with "typedef int HTCoord", run with software FPU:
1.04
We can see that the major FP slowdown is due to HTCoord being a float.
Without attempting to change the other uses of floating point, this one
change made the software FPU performance 5.31 (5.52 / 1.04) times
faster. It also made Lynx 3% faster even *with* hardware floating
point.
CPU: Intel Pentium MMX 166
Compiler: SCO OpenServer Release 5.0.4 USL cc -O
>Bela<
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- Re: LYNX-DEV floating-point (was: using a dos xt),
Bela Lubkin <=