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> internally, the x86 memory bus is word addressable The 'memory bus' is not architectural. Different microarchitectures implement things differently, but mos
by moonchild 4y ago
> internally, the x86 memory bus is word addressable
The 'memory bus' is not architectural. Different microarchitectures implement things differently, but most high-performance microarchitectures these days have relatively efficient misaligned accesses.
- csense 4y ago> The 'memory bus' is not architectural Whether we classify the issue as "architectural" (whatever that means) is beside the point. Alignment has real effects on performance, and being aware of those effects is practically useful for working programmers. I do agree with you about one thing: The unaligned access penalty is probably less on the x86 CPU's of the 2020's than it was, say, on a 486 from the mid-1990's.