Add page_address()

src/hulk/pagetable.d

@@ -183,3 +183,11 @@ struct PageTable
     }
 }
 static assert(PageTable.sizeof == 4096u);
+
+/**
+ * Get the base address of the page containing the given address.
+ */
+T page_address(T)(T address)
+{
+    return cast(T)(cast(ulong)address & ~(PAGE_SIZE - 1u));
+}