using the ^ operator on my system causes httpd to die with sig 8. here's the line from the error_log:

[Mon Aug 21 12:36:10 2000] [notice] child pid 42640 exit signal Floating point exception (8)

here's the code:

http://miki.instinct.org/~pgl/xor.phps

found out because someone was complaining in alt.php that xor didn't return the correct value.