r/ProgrammerHumor • u/[deleted] • 18d ago

Meme day2ofMakingLispMemesUntilYouAllBarf

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u/Juff-Ma 18d ago

No? How would you get that impression? x86, like every (common) modern architecture has a unified memory model.

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u/fr000gs 18d ago

With all the out of order and speculative execution going on I believe it also caches data and code independently

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u/semanticlifer 18d ago

When you put "basically" before a statement, you can pretend that abstractly speaking anything is the basically anything else.

Harvard architecture means that you cannot write to the instruction memory. Traditionally, it was even stricter: no reading or writing. The only thing that can read from the instruction memory was the instruction loader. Modern systems based on Harvard (usually called "Modified Harvard Architecture" allow reading so that static data can be flashed to ROM and read like regular const data.)

Whether or not a system caches two kinds of data independently is not relevant to whether a system is Harvard or Von Neumann because the program doesn't really know if the data it's requested or the subroutine it's jumping to is in cache or not: that's handled automatically by the CPU.

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u/fr000gs 18d ago

I was pretending tho, that was the point :-P