3 ms·
Value tagging may (and often does) use the lower bits to distinguish pointers from other values (integer, boolean, character, etc.) as objects are memory aligne
by guenthert 6y ago
Value tagging may (and often does) use the lower bits to distinguish pointers from other values (integer, boolean, character, etc.) as objects are memory aligned. In those schemes the growth of the address space doesn't matter.
- monocasa 6y agoYou can use the upper bits too. It's fairly common to use the top bit to discriminate between a pointer or an integer, since you can just test if the value is negative, which can be free on some architectures.