• Re: Every sufficiently competent C programmer knows --- Freaking Nitwit

    From Richard Damon@21:1/5 to olcott on Wed Mar 12 23:56:11 2025
    On 3/12/25 8:41 PM, olcott wrote:
    On 3/12/2025 5:47 PM, Richard Damon wrote:
    On 3/12/25 9:37 AM, olcott wrote:
    On 3/11/2025 12:42 PM, Mike Terry wrote:
    On 11/03/2025 13:46, Richard Heathfield wrote:
    On 11/03/2025 13:31, olcott wrote:
    On 3/11/2025 5:28 AM, Mikko wrote:
    On 2025-03-10 23:41:13 +0000, olcott said:

    typedef void (*ptr)();
    int HHH(ptr P);

    void Infinite_Loop()
    {
       HERE: goto HERE;
       return;
    }

    void Infinite_Recursion()
    {
       Infinite_Recursion();
       return;
    }

    void DDD()
    {
       HHH(DDD);
       return;
    }

    int DD()
    {
       int Halt_Status = HHH(DD);
       if (Halt_Status)
         HERE: goto HERE;
       return Halt_Status;
    }

    That when HHH correctly emulates N steps of the
    above functions that none of these functions can
    possibly reach their own "return" instruction
    and terminate normally.

    Every competent programmer knows that the information given is
    insufficient to determine whether HHH emulates at all, and whether >>>>>>> it emulates correctly if it does.

    Since HHH does see that same pattern that competent
    C programmers see it correctly aborts its emulation
    and rejects these inputs as non terminating.

    Whether HHH does see those patterns cannot be inferred from the
    information
    given. Only about DDD one can see that it halts if HHH returns.
    In addition,
    the given information does not tell whether HHH can see patterns >>>>>>> that are
    not there.

    How many competent programmers you have asked?


    Two C programmers with masters degrees in computer science
    agree that DDD correctly emulated by HHH cannot possibly
    reach its own "return" instruction and terminate normally.

    Bring 'em on. Perhaps /they/ have the source to HHH, because
    without it you don't have anything. (And btw whatever it is you
    claim to have is far from clear, because all I've seen so far is an
    attempt to express the Halting Problem in C and pseuodocode, where
    the pseudocode reads: HHH(){ magic happens }

    It takes newcommers a while to understand the context behind what PO
    is saying, and he never bothers to properly explain it himself, and
    is incapable of doing so in any rigorous fashion.

    So I'll explain for you my interpretation.

    His HHH is a C function called by DDD, which will "simulate" DDD().
    The simulation consists of simulating the individual x86
    instructions of DDD [and functions it calls] sequentially, and may
    only be a / partial/ simulation, because HHH also contains logic to
    analyse the progress of the simulation, and it may decide at some
    point to simply stop simulating.  (This being referred to as HHH
    "aborting" its simulation.)

    Of course, we expect that the (partial) simulation of DDD will
    exactly track the direct execution of DDD, up to the point where HHH
    aborts the simulation.  [This is NOT what PO's actual HHH code does,
    due to bugs/ design errors/misunderstandings etc., but for the
    purpose of PO's current point, you might consider this to be what
    happens.]

    So if we imagine HHH never aborts, then HHH simulates DDD(), which
    calls HHH, and (simulated) HHH will again simulate DDD() - a nested
    simulation.  (PO calls this recursive simulation.)  This continues,
    and such an HHH will obviously never terminate - in particular THE
    SIMULATION by outer HHH will never proceed as far as DDD's final ret
    instruction.  (This is genuine "infinitely recursive simulation")

    OTOH if HHH logic aborts the simulation at some point, regardless of
    how many nested levels of simulation have built up, it will be the /
    outer/ HHH that aborts, because the outer HHH is ahead of all the
    simulated HHH's in its progress and will reach its abort criterion
    first.  At the point where it aborts, the DDD it is simulating will
    clearly not have reached its final ret instruction, as then its
    simulation would have ended "normally" rather than aborting.

    So whatever HHH's exact logic and abort criteria, it will not be the
    case that its *simulation of DDD* progresses as far as DDD's final
    ret instruction:  either HHH never aborts so never terminates, or if
    it does abort, the (outer) HHH simulating it will abort DDD before
    it gets to the final ret instruction.

    The key point here is that we are not talking about whether DDD()
    halts!  We are only talking about whether HHH's /simulation/ of DDD
    proceeds as far as simulating the final DDD ret instruction.  So at
    this point we are not talking about the Halting Problem, as that is
    concerned with whether DDD() halts, not whether some partial
    simulation of DDD() simulates as far as the ret instruction.

    Given that HHH is free to stop simulating DDD *whenever it wants*,
    you might consider it rather banal to be arguing for several months
    over whether it actually simulates as far as DDD's return. After
    all, it could simulate one instruction and then give up, so it
    didn't get as far as DDD returning - but SO WHAT!?  Why is PO even
    considering such a question?

    [PO would say something like "/however far/ HHH simulates this
    remains the case", misunderstanding the fact that here he is talking
    about multiple different HHHs, each with their own distinct DDDs.
    (Yes, none of those different HHHs simulate their corresponding DDD
    to completion, but all of those DDD halt [if run directly], assuming
    their HHH aborts the simulation at some point.  We can see this just
    from the given code of DDD: if HHH returns, DDD returns...)]

    But if you think PO properly understands this you would be vastly
    overestimating his reasoning powers and his capacity for abstract
    thought.  Even if you "agree" that HHH (however coded) will not
    simulate DDD to completion, you would not really be "agreeing" with
    PO as such, because that would imply you understand PO's
    understanding of all that's been said, and that there is a shared
    agreement on the meaning of what's been said and its consequences
    etc., and we can guarantee that will NOT be the case!  We could say
    PO "fractally" misunderstands every technical concept needed to
    properly discuss the halting problem (or any other technical topic).

    PO's "understanding" will entail some idea that the situation means
    that DDD "actually" doesn't halt, or that HHH is "correct" to say
    that DDD doesn't halt.


    This is Mike's very stupid mistake:
    I always thought that Mike was much smarter than this (he usually is)
    (Even though it demonstrably DOES halt if not aborted and simulated
    further.

    void DDD()
    {
       HHH(DDD);
       return;
    }

    Every competent C programmer knows when any N steps of DDD
    are correctly emulated by x86 emulator HHH (that can emulate
    itself emulating DDD) that DDD never reaches its own "return"
    instruction in any finite (or infinite) number of steps.

    As a matter of actual verified fact HHH emulates the
    first four instructions of the x86 machine code of DDD
    which call itself to repeat this process.

    And any even half competent programmer knows you define the behavior
    of a program by what it does when run or fully emulate it,


    _DDD()
    [00002172] 55         push ebp      ; housekeeping
    [00002173] 8bec       mov  ebp,esp  ; housekeeping
    [00002175] 6872210000 push 00002172 ; push DDD
    [0000217a] e853f4ffff call 000015d2 ; call HHH(DDD)
    [0000217f] 83c404     add  esp,+04
    [00002182] 5d         pop  ebp
    [00002183] c3         ret
    Size in bytes:(0018) [00002183]

    NOT WHEN IT IS STIPULATED THAT THE BEHAVIOR BEING
    MEASURED IS DDD CORRECTLY EMULATED BY HHH ACCORDING
    TO THE SEMANTICS OF THE X86 LANGUAGE
    YOU FREAKING NITWIT !!!

    Then you are stiputing that you are lying about talking about Halting
    and/or termination analysis.

    Also, you are effectivly stipulating that you are an idiot, as your HHH
    doesn't do what you claim, so you are stipulating that you are just lying.


    I would have not added that last part if you had
    not dishonestly make this same "mistake" hundreds
    of times.


    No, the problem is your stipulation is just your admission of everything
    you have done is a lie and a fraud.

    You are just so stupid you beleive in your own lies and can't see that
    you have sunk your own reputation and ideas by lying.

    If the behavior is stipulated to be based on the correct emulation by
    HHH, then HHH must do a correct emuation and isn't allowed to abort, no
    matter how stupid that sounds, that is what you stipulation means, so
    you are stipulating that you are forcing yourself to be stupid.

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