Weird CPU architectures, the MOV only CPU (2020)
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Weird CPU architectures, the MOV only CPU (2020)
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Re: Weird CPU architectures, the MOV only CPU (2020)
#2The Intel architecture is already Turing complete when you just use MOV instructions: https://github.com/xoreaxeaxeax/movfuscator. Of course, you don't even need instructions at all: https://news.ycombinator.com/item?id=5261598
Re: Weird CPU architectures, the MOV only CPU (2020)
#3Looks like an interesting read, thank you @v9v.
Just when my night was going through a meditative sleep about basing ontological models using change as fundamental block. Identity is such a brittle choice as foundation, even if it's a great tool in many situations otherwise.
Re: Weird CPU architectures, the MOV only CPU (2020)
#4The Intel architecture is already Turing complete when you just use MOV instructions: https://github.com/xoreaxeaxeax/movfuscator . Of course, you don't even need instructions at all: https://news.ycombinator.com/item?id=5261598
While this is true, I suspect a spec compliant implementation of the x86 mov instruction would many use more transistors than OP’s entire CPU.
Re: Weird CPU architectures, the MOV only CPU (2020)
#5The Intel architecture is already Turing complete when you just use MOV instructions: https://github.com/xoreaxeaxeax/movfuscator . Of course, you don't even need instructions at all: https://news.ycombinator.com/item?id=5261598
While this is true, I suspect a spec compliant implementation of the x86 mov instruction would many use more transistors than OP’s entire CPU.
Of course, but you don't have the toy CPU under your desk or in your laptop running at several GHz nor are you likely to find it in a target that really needs a cute hack to obscure your exploit.
Re: Weird CPU architectures, the MOV only CPU (2020)
#6The Intel architecture is already Turing complete when you just use MOV instructions: https://github.com/xoreaxeaxeax/movfuscator . Of course, you don't even need instructions at all: https://news.ycombinator.com/item?id=5261598
I came back to reply with just this.
Christopher Domas's conference talk on the movfuscator is legendary:
Re: Weird CPU architectures, the MOV only CPU (2020)
#7If you were interested in co-designing a CPU with software the TTA is an attractive way to do it, particularly in that it is easy to design it so you can do more than one MOV at the same time and thus have explicit parallelism.
The tough part though is that memory is usually slow and you have to wait an undetermined number of cycles for data to get back from DRAM and while one operation is blocked all the other operations are blocked.
I guess you could have something like this with a fancy memory controller that could be programming explicitly to start fetching ahead of time so data is available when it is needed, at least most of the time.
Re: Weird CPU architectures, the MOV only CPU (2020)
#8Looks like an interesting read, thank you @v9v. Just when my night was going through a meditative sleep about basing ontological models using change as fundamental block. Identity is such a brittle choice as foundation, even if it's a great tool in many situations otherwise.
Many ancient cultures use behavior as identity. It certainly has a charm.
Re: Weird CPU architectures, the MOV only CPU (2020)
#9Looks like an interesting read, thank you @v9v. Just when my night was going through a meditative sleep about basing ontological models using change as fundamental block. Identity is such a brittle choice as foundation, even if it's a great tool in many situations otherwise.
Many ancient cultures use behavior as identity. It certainly has a charm.
Was it the Navajos whose language doesn't have nouns, only verbs? A noun is a kind of illusion of eternal identity. A chair is only chair-ing for the moment as a configuration of matter that was doing something else before, and will fall apart and transform into doing something else in the future.
Re: Weird CPU architectures, the MOV only CPU (2020)
#10Earlier quoted context omitted.
Many ancient cultures use behavior as identity. It certainly has a charm.
Was it the Navajos whose language doesn't have nouns, only verbs? A noun is a kind of illusion of eternal identity. A chair is only chair-ing for the moment as a configuration of matter that was doing something else before, and will fall apart and transform into doing something else in the future.
IIRC Navajo has a pretty robust noun-verb distinction. However there definitely are other languages where nouns and verbs behave very similarly, e.g. most famously Salishan languages. That said, there don’t seem to be any natural languages in which nouns and verbs are completely indistinguishable — there’s always some minor difference in how they behave.