3 ms·
Yes, this already happens. Address bus width is usually different from register width due to cost. I found this, old CPU's address bus only getting to 44 bits
by mixmastamyk 2y ago
Yes, this already happens. Address bus width is usually different from register width due to cost. I found this, old CPU's address bus only getting to 44 bits wide on Itanium.
https://www.tech-faq.com/address-bus.html https://www.tech-faq.com/address-bus.html
My newish AMD laptop: `grep 'address sizes' /proc/cpuinfo`
address sizes : 48 bits physical, 48 bits virtual
Looks like 36 bits wide is already plenty for anything typical, up to 68 GB:
>>> f'{2**32:>30_}'
' 4_294_967_296'
>>> f'{2**36:>30_}'
' 68_719_476_736'
>>> f'{2**40:>30_}'
' 1_099_511_627_776'
>>> f'{2**48:>30_}'
' 281_474_976_710_656'
>>> f'{2**64:>30_}'
' 18_446_744_073_709_551_616'
- ChocolateGod 2y agoI guess no point wasting hardware supporting things that will never be possible for the lifetime of the processor.
- p_l 2y agoAMD64 mandates 48bit virtual addressing minimum, with the rest sign-extended unless certain optional features are enabled.