-@code{argv}. The order ensure that @code{argv[0]} is at the lowest
-virtual address. Word-aligned accesses are faster than unaligned
-accesses, so for best performance round the stack pointer down to a
-multiple of 4 before the first push.
+@code{argv}. The null pointer sentinel ensures that @code{argv[argc]}
+is a null pointer, as required by the C standard. The order ensures
+that @code{argv[0]} is at the lowest virtual address. Word-aligned
+accesses are faster than unaligned accesses, so for best performance
+round the stack pointer down to a multiple of 4 before the first push.