Yes, I forgot about that :( . But now I tried and it makes a little different results with negatives:

$/ = " ";
$y = 2;
while($x = <DATA>){
    chop $x;
    print $num = ($x - $x % $y) / $y xor
    print " " xor
    print $num = int $x / $y xor
    print "\n"
}
__DATA__
-3 -2 -1 0 1 2 3
[download]

Output:
-2 -1
-1 -1
-1 0
0 0
0 0
1 1
1 1
[download]

Yes. I like that Perl has sqrt.

UPDATE: seems that my approach was not int_div, but floor.