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by tsimionescu
1162 days ago
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Actually, x86 assembly also embodies plenty of abstractions. Not sure on ARM or RISC-V, but x86 assembly instructions are not executed the way you'd think by any modern processor. Essentially the processor reads a while bunch of instructions at once, splits each in the raw microinstructions, arranges them in a graph of dependencies, and then solves an optimization problem to find the best way to schedule nodes from that graph onto its internal execution pipelines. In real-world execution, you can't even tell what assembly instruction(s ) are the ones being executed at a partocular time - disparate parts of various instructions. Some instructions, like "mov ax, 0", don't even execute: they just serve to mark which the tens of real registers is now free to use for another symbolic register like bx. |
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No matter what the cpu does internally to arrive at producing the requested output from the supplied instructions, it DOES produce exactly the reqested and expected output from the given instructions.
What it does not do is for example maybe a + operator doesn't mean the same thing after some unknowable prior step changed the definition of +, or flatly not provide a means to manipulate some data in a way that a language author thought was crazy and no one could ever have a valid reason to do $thing like idk execute a string or something. Sure there are now optional settings and features you could consciously use, for example to enforce that data/exec seperation, but it doesn't just do it by it's own magic according to someone else's rules instead of your own code.