Comment by IshKebab
2 days ago
I don't think we had out of order designs with speculative execution 40 years ago? That seems like a pretty huge change.
2 days ago
I don't think we had out of order designs with speculative execution 40 years ago? That seems like a pretty huge change.
These are mostly internal implementation details, instructions still appear to resolve in order from the outside (with some subtle exceptions for memory read/writes depending on the CPU architecture). It may become important to know such details for performance profiling though.
What has drastically changed is that you cannot do trivial 'cycle counting' anymore.
Not to step on your toes, but it shall be said that instructions in a CPU "retire" in order.
They don't even always do that anymore.
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