Re: Every D(D) simulated by H presents non-halting behavior to H ###

On 5/25/2024 4:40 AM, Mikko wrote:

On 2024-05-24 13:03:47 +0000, olcott said:
 

On 5/24/2024 5:08 AM, Mikko wrote:

On 2024-05-23 13:09:01 +0000, olcott said:
>

On 5/23/2024 3:23 AM, Mikko wrote:

On 2024-05-22 14:59:24 +0000, olcott said:
>

On 5/22/2024 3:50 AM, David Brown wrote:

On 21/05/2024 22:13, Keith Thompson wrote:

David Brown <david.brown@hesbynett.no> writes:
[...]

However, my point was that the common excuse of "I hate this crime so
much I lashed out" is not a valid excuse.

[...]
>
And you could have made that point without accompanying it by a long
article about various kinds of child abuse in a newsgroup that's
supposed to be about C.
>
You didn't have to let yourself be trolled.
>

>
I don't consider James' post to be trolling.  But of course that in itself does not mean it is appropriate to reply here.  However, I replied to that post in the group (rather than email) because it seemed to me that a point I had made previously needed clarification.
>
As has been pointed out by others, topicality in this thread was doomed from the first post.  I'd be happier if Olcott had never cross-posted here, but we can't change that.
>

>
*Someone could simply answer the question instead of*
*spending countless messages on dodging the question*
>
For every H/D pair matching the following template where
H is a pure function:
>
Does any D correctly simulated by H reach its own line 06 and
halt or does the fact that D remains stuck in recursive simulation
prevent that?
>
typedef int (*ptr)();  // ptr is pointer to int function in C
00       int H(ptr p, ptr i);
01       int D(ptr p)
02       {
03         int Halt_Status = H(p, p);
04         if (Halt_Status)
05           HERE: goto HERE;
06         return Halt_Status;
07       }
08
09       int main()
10       {
11         H(D,D);
12         return 0;
13       }
>
It is trivial to see that for every H/D pair of the infinite
set of H/D pairs that match the above template that
>
D correctly simulated by H cannot possibly reach its own final
state at line 06 and halt because D correctly simulated by
H remains stuck in recursive simulation.
>
This provides the basis for simulating termination analyzer H to
correctly determine that the halting problem's counter-example
input D cannot possibly halt.

>
Someone already pointed out that the question is ill-posed (undefined
and insonsistently used symbols). No reason to expect any other answer.
>

>
That assessment can only come from not carefully looking at what I said.
It is dead obvious that D correctly simulated by H remains stuck in
recursive simulation thus cannot possibly reach its own line 06 and
halt.

>
That is possible. What you said is scattered over so many messages
that nobody can be expedted to carefully look at all of them.
>

>
typedef int (*ptr)();  // ptr is pointer to int function in C
00       int H(ptr p, ptr i);
01       int D(ptr p)
02       {
03         int Halt_Status = H(p, p);
04         if (Halt_Status)
05           HERE: goto HERE;
06         return Halt_Status;
07       }
08
09       int main()
10       {
11         H(D,D);
12         return 0;
13       }
>
The above template refers to an infinite set of H/D pairs where D is correctly simulated by pure function H. This was done because many reviewers used the shell game ploy to endlessly switch which H/D pair was being referred to.
>
*Correct Simulation Defined*
    This is provided because many reviewers had a different notion of
    correct simulation that diverges from this notion.
>
    A simulator is an x86 emulator that correctly emulates at least one
    of the x86 instructions of D in the order specified by the x86
    instructions of D.
>
    This may include correctly emulating the x86 instructions of H in the
    order specified by the x86 instructions of H thus calling H(D,D) in
    recursive simulation.
>
*Execution Trace*
Line 11: main() invokes H(D,D); H(D,D) simulates lines 01, 02, and 03 of D. This invokes H(D,D) again to repeat the process in endless recursive simulation.

 I think all C questions are already answered.
 

The only C question has always been can any D of every H/D
pair matching the template reach its own line 06 and halt
when D is correctly simulated by pure function H? Most
people on  this forum "answered" that question with ad
hominem personal attacks.
Keith Thompson was gracious enough to determine that it is
valid C, would compile and seems to conform to c17 standards.
Keith only examined one like of code for c17 standards. The
rest of the lines are quite conventional.
--
Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius
hits a target no one else can see." Arthur Schopenhauer