Wednesday, December 2, 2020

Digest for comp.lang.c++@googlegroups.com - 7 updates in 3 topics

olcott <NoOne@NoWhere.com>: Dec 01 09:25PM -0600

On 11/30/2020 7:40 PM, Ben Bacarisse wrote:
> forever unless its simulation were halted. Its simulation would not
> need to be halted. It halts of its own accord as soon a Halts returns
> false.
 
Here is the actual execution trace proving that you are factually
incorrect.
 
void Confound_Halts(u32 P)
{
if (DebugTrace(P, P))
while (1);
}
 
 
int main()
{
DebugTrace((u32)Confound_Halts, (u32)Confound_Halts);
HALT;
}
 
 
_Confound_Halts()
[0000053c](01) 55 push ebp
[0000053d](02) 8bec mov ebp,esp
[0000053f](03) 8b4508 mov eax,[ebp+08]
[00000542](01) 50 push eax
[00000543](03) 8b4d08 mov ecx,[ebp+08]
[00000546](01) 51 push ecx
[00000547](05) e8f0fdffff call 0000033c
[0000054c](03) 83c408 add esp,+08
[0000054f](02) 85c0 test eax,eax
[00000551](02) 740b jz 0000055e
[00000553](05) ba01000000 mov edx,00000001
[00000558](02) 85d2 test edx,edx
[0000055a](02) 7402 jz 0000055e
[0000055c](02) ebf5 jmp 00000553
[0000055e](01) 5d pop ebp
[0000055f](01) c3 ret
 
_main()
[0000056c](01) 55 push ebp
[0000056d](02) 8bec mov ebp,esp
[0000056f](05) 683c050000 push 0000053c
[00000574](05) 683c050000 push 0000053c
[00000579](05) e8befdffff call 0000033c
[0000057e](03) 83c408 add esp,+08
[00000581](01) f4 hlt
[00000582](01) 5d pop ebp
[00000583](01) c3 ret
 
Output_Debug_Trace() [00010b24] size(72) capacity(65536)
[0000056c](01) 55 push ebp
[0000056d](02) 8bec mov ebp,esp
[0000056f](05) 683c050000 push 0000053c
[00000574](05) 683c050000 push 0000053c
[00000579](05) e8befdffff call 0000033c ----CALL [0000033c]
[0000053c](01) 55 push ebp
[0000053d](02) 8bec mov ebp,esp
[0000053f](03) 8b4508 mov eax,[ebp+08]
[00000542](01) 50 push eax
[00000543](03) 8b4d08 mov ecx,[ebp+08]
[00000546](01) 51 push ecx
[00000547](05) e8f0fdffff call 0000033c ----CALL [0000033c]
[0000053c](01) 55 push ebp
[0000053d](02) 8bec mov ebp,esp
[0000053f](03) 8b4508 mov eax,[ebp+08]
[00000542](01) 50 push eax
[00000543](03) 8b4d08 mov ecx,[ebp+08]
[00000546](01) 51 push ecx
[00000547](05) e8f0fdffff call 0000033c ----CALL [0000033c]
The PRIOR Instruction Specifies Infinite Recursion: Simulation Stopped:
 
 
 
 
--
Copyright 2020 Pete Olcott
 
"Great spirits have always encountered violent opposition from mediocre
minds." Einstein
olcott <NoOne@NoWhere.com>: Dec 02 11:11AM -0600

On 12/1/2020 9:40 PM, Chris M. Thomasson wrote:
> }
> ______________________________
 
> Will this halt or not?
 
 
That does not matter.
 
>>> void Confound_Halts(u32 P) { if (Halts(P, P)) while (1); }
 
What matters is that the above code is computationally equivalent to the
Peter Linz:
 
Ĥ.q0 wM ⊢* Ĥ.qx wM wM ⊢* Ĥ.qy ∞
Ĥ.q0 wM ⊢* Ĥ.qx wM wM ⊢* Ĥ.qn
 
http://www.liarparadox.org/Peter_Linz_HP(Pages_315-320).pdf
 
When I show that the computational equivalent of the Linz Ĥ is
decidable, then then Linz proof is refuted.
 
 
--
Copyright 2020 Pete Olcott
 
"Great spirits have always encountered violent opposition from mediocre
minds." Einstein
olcott <NoOne@NoWhere.com>: Dec 02 11:38AM -0600

On 12/2/2020 11:17 AM, Malcolm McLean wrote:
 
> H_Hat is decideable. It either halts or it doesn't. However it's not decideable
> by H. That is the challenge, to get consistent results from running H(H_Hat, H_Hat)
> and running H_Hat(H_Hat) on its own.
 
http://www.liarparadox.org/Peter_Linz_HP(Pages_315-320).pdf
 
Linz, Peter 1990. An Introduction to Formal Languages and Automata.
Lexington/Toronto: D. C. Heath and Company.
 
x86 language ≡ von Neumann architecture ≡ UTM ≡ RASP Machine
 
Here is H_Hat (computational equivalent to the Linz Ĥ) being correctly
decided by DebugTrace() (computational equivalent to the Linz H).
 
 
void H_Hat(u32 P)
{
u32 Aborted = DebugTrace(P, P);
if (Aborted)
HALT
else
HERE: goto HERE;
}
 
 
int main()
{
DebugTrace((u32)H_Hat, (u32)H_Hat);
HALT;
}
 
 
_H_Hat()
[00000584](01) 55 push ebp
[00000585](02) 8bec mov ebp,esp
[00000587](01) 51 push ecx
[00000588](03) 8b4508 mov eax,[ebp+08]
[0000058b](01) 50 push eax
[0000058c](03) 8b4d08 mov ecx,[ebp+08]
[0000058f](01) 51 push ecx
[00000590](05) e8bffdffff call 00000354
[00000595](03) 83c408 add esp,+08
[00000598](03) 8945fc mov [ebp-04],eax
[0000059b](04) 837dfc00 cmp dword [ebp-04],+00
[0000059f](02) 7403 jz 000005a4
[000005a1](01) f4 hlt
[000005a2](02) eb02 jmp 000005a6
[000005a4](02) ebfe jmp 000005a4
[000005a6](02) 8be5 mov esp,ebp
[000005a8](01) 5d pop ebp
[000005a9](01) c3 ret
 
_main()
[000005b4](01) 55 push ebp
[000005b5](02) 8bec mov ebp,esp
[000005b7](05) 6884050000 push 00000584
[000005bc](05) 6884050000 push 00000584
[000005c1](05) e88efdffff call 00000354
[000005c6](03) 83c408 add esp,+08
[000005c9](01) f4 hlt
[000005ca](01) 5d pop ebp
[000005cb](01) c3 ret
 
 
Output_Debug_Trace() [00010bd3] size(80) capacity(65536)
[000005b4](01) 55 push ebp
[000005b5](02) 8bec mov ebp,esp
[000005b7](05) 6884050000 push 00000584
[000005bc](05) 6884050000 push 00000584
[000005c1](05) e88efdffff call 00000354 ----CALL [00000354]
[00000584](01) 55 push ebp
[00000585](02) 8bec mov ebp,esp
[00000587](01) 51 push ecx
[00000588](03) 8b4508 mov eax,[ebp+08]
[0000058b](01) 50 push eax
[0000058c](03) 8b4d08 mov ecx,[ebp+08]
[0000058f](01) 51 push ecx
[00000590](05) e8bffdffff call 00000354 ----CALL [00000354]
[00000584](01) 55 push ebp
[00000585](02) 8bec mov ebp,esp
[00000587](01) 51 push ecx
[00000588](03) 8b4508 mov eax,[ebp+08]
[0000058b](01) 50 push eax
[0000058c](03) 8b4d08 mov ecx,[ebp+08]
[0000058f](01) 51 push ecx
[00000590](05) e8bffdffff call 00000354 ----CALL [00000354]
The PRIOR Instruction Specifies Infinite Recursion: Simulation Stopped:
 
 
 
--
Copyright 2020 Pete Olcott
 
"Great spirits have always encountered violent opposition from mediocre
minds." Einstein
olcott <NoOne@NoWhere.com>: Dec 02 04:19PM -0600

On 12/2/2020 3:45 PM, Kaz Kylheku wrote:
 
> the runaway recursion is still there, but now there are many
> instructions in the code path, including conditional ones.
> The trivial recursion detector will not work.
 
This is no longer a proof that the halting problem us undecidable. It is
merely evidence that solving the halting problem may be difficult.
 
 
> The technique you are using is only good for showing that the strawman
> cases used in the proof sketches have some flaws, and those examples
> cannot be taken literally as the basis for the halting theorem.
 
It directly refutes the computational equivalent of the Linz proof based
on the Linz Ĥ. The Ĥ template <is> decidable. I could write it up on
that basis.
 
> But that is already obvious; you've put a lot of effort into
> not discovering anything new.
 
Please cite sources for this claim.
 
You are the very first one that did not simply claim that I am incorrect
on the basis of either a flat out lie or woeful ignorance.
 
Your claim is that I am correct, yet this is not of great significance.
 
I will not accept that my work is of inconsequential significance until
I see a specific citation that can be validated.
 
 
--
Copyright 2020 Pete Olcott
 
"Great spirits have always encountered violent opposition from mediocre
minds." Einstein
Vir Campestris <vir.campestris@invalid.invalid>: Dec 02 05:57PM

On 01/12/2020 14:24, Bo Persson wrote:
> So if you write a member operator<< with two other parameter types, the
> compiler will treat it as having 3 parameters.
 
... and then refuse to compile it because it is only allowed to have two
parameters, not three :(
 
You can't even make it a static member.
 
Andy
Bonita Montero <Bonita.Montero@gmail.com>: Dec 02 07:14PM +0100

There are two things you must be aware if you define member-operators:
1. The operator only applies to objects of the defined class and its
descendants and not convertible classes.
2. With external operators you can attach semantics to a class like
if you would have defined a member-operator.
Brian Wood <woodbrian77@gmail.com>: Dec 02 06:53AM -0800

On Sunday, November 29, 2020 at 8:59:59 PM UTC-6, Brian Wood wrote:
> This is what I've come up with to address the UB:
> https://github.com/Ebenezer-group/onwards/commit/ed35386a1732a193638ba49648300cfce106edfe
 
> Does it look like an improvement? Tia.
 
Can I get a witness?
 
Brian
Ebenezer Enterprises
https://webEbenezer.net
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