Newbie on PHP looking for some operators ^=, >>, <<

I found this in a script.

[fischermx]

Hi,

I'm starting to learn PHP trying to decipher a script a I found. My only help today is a couple of tutorials I found on line.
I have these 3 operators :
^=
>>
<<

The current tutorials I have don't say a word about this.
Could anybody give me some hints?

[Timotheos]

These are bitwise operators
[php.net...]

The first one is a little trickier. The ^ is an XOR. So $a = $a ^ $b can be shortened to $a ^= $b.

The other two are left and right shifts.