3 ms·

I find that a little surprising, because one of the side effects of 64-bit address spaces is a lot of redundancy in pointer representations stored in RAM. 64-bi

I find that a little surprising, because one of the side effects of 64-bit address spaces is a lot of redundancy in pointer representations stored in RAM. 64-bit pointer-based data structures have more redundant zeros. Much of the energy in a computer goes on communication between chips, so increased memory use means increased energy use. As well as more going on inside the CPU transferring all those redundant pointer bits around And phones are notably sensitive to energy use.

zozbot234 7y ago
You don't have to use full 64-bit pointers for your "pointer-based data structures". You can store indexes into an arena allocation. This is common in languages such as C++ and Rust, and will become increasingly so as 32-bit is less and less used.
rsynnott 7y ago
I believe ObjC and Swift on 64bit machines use the upper section of the pointers to store reference counts. I'd guess that Android Java uses pointer compression like normal Java does, though I don't know for certain. The 64bit transition on ARM also allowed an arch overhaul, with extra registers etc. ARMv8 cores were usually a good bit faster than their immediate predecessors, but it wasn't much to do with 64bitness. This also happened with x86, of course.