Right, any language could do this -- `malloc` and friends return pointers aligned to 16 bytes How does the having the bottom 4 bits free in a pointer help if y

Right, any language could do this -- `malloc` and friends return pointers aligned to 16 bytes How does the having the bottom 4 bits free in a pointer help if you can't use them to tell the difference between a pointer and an integer 1 or 2? He is asking for a reserved set of bits on every data type so that he can store minimal type information like pointer, not pointer.