I would think the simplest is to let Perl do the
work for you. Since 0x428C0000 is an allowed number
format in Perl, just evaluate the string using eval()
and let Perl translate it into a number for you.
in reply to Converting Hex to Float (and vise versa)
This trick will also work
for the other allowed number formats, such as 0777
(leading 0 implies octal).
I put together a CGI script to do this sort of
conversion (and a few other IP network translations)
which you might find instructive; see
this link and
the source code. Feel free to adopt as you see fit.
print " $_ is " . eval($_) . "\n" for qw( 0x428C000 0777 );