Macro register

macro_rules! register {
    (
        name: $name:tt,
        ty: $ty:ty,
        offset: $offset:expr,
        reset_value: $rv:expr,
        guest_writeable_mask: $mask:expr,
        guest_write_1_to_clear_mask: $w1tcm:expr,
    ) => { ... };
    (name: $name:tt, ty: $ty:ty,offset: $offset:expr,reset_value: $rv:expr,) => { ... };
}