My X11 pointer was stuck to left side of screen. This led me to NetBSD PR 
30418 (fixed by NetBSD's pkgsrc/xorg-libs/patches/patch-bl). This NetBSD 
PR led me to xorg bug #3113
https://bugs.freedesktop.org/show_bug.cgi?id=3113

So I downloaded and compiled OpenBSD's fpsig.c regression test.
http://www.openbsd.org/cgi-bin/cvsweb.cgi/src/regress/sys/kern/signal/fpsig/

It had inconsistent results. So I bumped up the loop as suggested to me.

As I was told via the xorg bug report, this fpsig "test program computes 
the same floating point value, using variables on the stack both in the 
main code path and in a signal handler." Also, the xorg bug report says if 
the signal handlers do not correctly save/restore the FPU registers, the 
results are unpredictable and will probably not be the same (and are 
printed). When no corruption of the FPU, the two results are the same and 
nothing is printed (and the exit status is 0).

Here is my output three times:

rainier:~/tmp$ ./fpsig
fpsig: 5700.000000 580.000000
rainier:~/tmp$ ./fpsig
fpsig: 5700.000000 5365.000000
rainier:~/tmp$ ./fpsig
fpsig: 5700.000000 5263.000000

I am running NetBSD/i386 2.0.2 kernel and I have not tried this with newer 
kernel. I looked at some source, but I am really unfamiliar with this so I 
don't know if any changes are in netbsd-2 related to this.

I was told since the the FPU context save/restore has been fixed on 
OpenBSD/i386 no one reported this X11 pointer bug again for OpenBSD.

Please see the following for some ideas:

http://archives.neohapsis.com/archives/openbsd/cvs/2005-07/0599.html
http://www.openbsd.org/cgi-bin/cvsweb/src/sys/arch/i386/i386/genassym.cf
http://www.openbsd.org/cgi-bin/cvsweb/src/sys/arch/i386/i386/locore.s
http://www.openbsd.org/cgi-bin/cvsweb/src/sys/arch/i386/i386/machdep.c
http://www.openbsd.org/cgi-bin/cvsweb/src/sys/arch/i386/include/frame.h

Any comments about this?

Thanks,

Jeremy C. Reed

p.s. Please carbon-copy me on replies. I read this problem may be on other 
platforms also, but I chose this i386 list as my references above are for 
i386.