3 ms·
Can I just use the first 48 bits of a 64 bit pointer forever for the address and then the rest for whatever else? Or is there a forward-compatibility risk?
by avgcorrection 4y ago
Can I just use the first 48 bits of a 64 bit pointer forever for the address and then the rest for whatever else? Or is there a forward-compatibility risk?
- aw1621107 4y agoAccording to Wikipedia, Intel's Ice Lake microarchitecture, released in 2019 Sept, supports 5-level paging, which uses bits 0-56 for virtual addresses [0]. A quick search hasn't yielded any info on when AMD support for this may be coming, but I'd assume it (or something similar) is in the works. [0]: https://en.wikipedia.org/wiki/Intel_5-level_paging https://en.wikipedia.org/wiki/Intel_5-level_paging
- Findecanor 4y agoOn ARM, there are a couple of security extensions that use the upper bits for memory tagging and/or a short pointer authentication code. The latter is already in use on iOS. I would expect Intel or AMD to follow (if they haven't already).