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I could imagine we might see an architecture with 128 bit word sizes, but I doubt we'd see 128 bit pointers (aka a 128 bit address space) any time soon. Itd jus
by xxpor 6y ago
I could imagine we might see an architecture with 128 bit word sizes, but I doubt we'd see 128 bit pointers (aka a 128 bit address space) any time soon. Itd just be more annoying than anything. I personally have even written software where we do pointer path to get 32 bit indexes rather than storing full 64 bit pointers simply because of space constraints (like trying to fit a hot struct into a single cache line)
Having a native uint128_t would make dealing with IPv6 addresses a lot nicer though :)
- ip26 6y agoCurrent chips don't even actually support 64 bits of hardware address yet, seeing as few users can afford 2 exbibytes of DRAM and shuffling around a full 64 bits of hardware address is a noticeable tax on the chip.
- saagarjha 6y agoLarge address spaces are useful for virtual memory reasons, not because you literally have petabytes of RAM physically attached to your machine.
- DaiPlusPlus 6y ago> but I doubt we'd see 128 bit pointers (aka a 128 bit address space) any time soon. I can see 128-bit pointers being a thing: not because of 128-bits of address space, but for the ability to embed type information directly in the pointer - which could improve performance for dynamic-dispatch scenarios or runtime type-safety built-in to the hardware itself. > Having a native uint128_t would make dealing with IPv6 addresses a lot nicer though :) [We're already there](https://stackoverflow.com/questions/34234407/is-there-hardware-support-for-128bit-integers-in-modern-processors https://stackoverflow.com/questions/34234407/is-there-hardwa...)
- saagarjha 6y agoNot type information, but CHERI capabilities: https://www.cl.cam.ac.uk/research/security/ctsrd/cheri/cheri-morello.html https://www.cl.cam.ac.uk/research/security/ctsrd/cheri/cheri...