I am needing to obtain the algorithm used in this little bit of Perl code, but I know nothing about Perl. Usually that's not a problem since I will research the language, but this regular expression stuff is way over my head!

Could anybody pseudo-code this? I just need to know what's going on so I can implement it in something else, preferably PHP or even C++, but I'll worry about that part. I just need to somehow decipher what this is doing:

```
$a = $ARGV[0];
$a =~ s/[^A-F0-9]+//simg;
@b = reverse split /(\S{2})/,$a;
$c = join "", @b;
$c .= "0000";
$d = hex($c) % 999999929;
print "$d\n";

```