Values of os:type() on 32/64-bit Windows

[Winston Smith]

I don't have access to any Windows machines running Erlang, let alone
any 64-bit versions.  Does anyone know what the values of os:type()
are on Windows platforms?  The documentation states that it'll return
{win32, nt|windows} (with windows being Windows 95).  Is this still
the case for 64-bit platforms?  Are there any other ways to detect the
bitness of the platform? x86-64 vs Itanium?  I actually don't care
about the Windows version, just the CPU architecture.

More specifically, I have a linked in driver and I load it by looking
at the platform via os:type() (and on unix, uname -m) to generate a
platform-architecture specific directory name, e.g. linux-x86_64 or
darwin-i386.  I'm really trying to differentiate between Windows i386,
Windows x86_64 and Windows Itanium from within Erlang.

Many thanks!