Speaking as somebody who actually ported it (or at least the second-generation "intent/elate") to new platforms, it took more than three days (though you could

Speaking as somebody who actually ported it (or at least the second-generation "intent/elate") to new platforms, it took more than three days (though you could probably get to "hello world" in three days or so if you were in a hurry and you only needed to handle new hardware or a new host OS, not a whole new CPU architecture).