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From: "Fred. Zwarts" <F.Zwarts@HetNet.nl>
Newsgroups: comp.theory
Subject: Re: DD emulated by HHH cannot possibly terminate normally --- x86
 code
Date: Sat, 1 Mar 2025 23:39:07 +0100
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Op 01.mrt.2025 om 22:11 schreef olcott:
> On 3/1/2025 2:16 PM, Fred. Zwarts wrote:
>> Op 01.mrt.2025 om 17:33 schreef olcott:
>>> On 3/1/2025 9:39 AM, Fred. Zwarts wrote:
>>>> Op 01.mrt.2025 om 15:41 schreef olcott:
>>>>> On 3/1/2025 6:49 AM, Richard Damon wrote:
>>>>>> On 2/28/25 7:47 PM, olcott wrote:
>>>>>>> _DD()
>>>>>>> [00002133] 55         push ebp      ; housekeeping
>>>>>>> [00002134] 8bec       mov ebp,esp   ; housekeeping
>>>>>>> [00002136] 51         push ecx      ; make space for local
>>>>>>> [00002137] 6833210000 push 00002133 ; push DD
>>>>>>> [0000213c] e882f4ffff call 000015c3 ; call HHH(DD)
>>>>>>> [00002141] 83c404     add esp,+04
>>>>>>> [00002144] 8945fc     mov [ebp-04],eax
>>>>>>> [00002147] 837dfc00   cmp dword [ebp-04],+00
>>>>>>> [0000214b] 7402       jz 0000214f
>>>>>>> [0000214d] ebfe       jmp 0000214d
>>>>>>> [0000214f] 8b45fc     mov eax,[ebp-04]
>>>>>>> [00002152] 8be5       mov esp,ebp
>>>>>>> [00002154] 5d         pop ebp
>>>>>>> [00002155] c3         ret
>>>>>>> Size in bytes:(0035) [00002155]
>>>>>>>
>>>>>>> When we hypothesize that the code at machine address
>>>>>>> 0000213c is an x86 emulator then we know that DD
>>>>>>> remains stuck in recursive emulation and cannot possibly
>>>>>>> reach its own "ret" instruction and terminate normally.
>>>>>>>
>>>>>>> When we add the additional complexity that HHH also
>>>>>>> aborts this sequence at some point then every level
>>>>>>> of recursive emulation immediately stops. This does
>>>>>>> not enable any DD to ever reach its "ret" instruction.
>>>>>>>
>>>>>>
>>>>>> But then you just negated your first assumption, as a partial 
>>>>>> emulator that aborts its emulation, then DD no longer gets stuck.
>>>>>>
>>>>>
>>>>> Cannot possibly reach its own "ret" instruction and terminate normally
>>>> proves failure of HHH to reach the end of a proven terminating program.
>>>
>>> DD emulated by HHH according to the above x86 machine code of DD
>>> cannot possibly reach its own "ret" instruction and terminate normally
>>
>>
>> In other words, 
> 
> The DD input to HHH unequivocally specifies a
> non terminating computation.
> 
> 

What is the meaning of 'non terminating computation'? Olcott explicitly 
tells us that it has nothing to do with the direct execution of the same 
finite string that is the input for HHH. The only meaning left is, that 
HHH cannot normally terminate the simulation.
Conclusion: Olcott is able to write a simulator that reports that it 
cannot normally terminate the simulation of a program for which the 
direct execution halts. Is that the work of a genius? Will the world be 
happy with such a simulator?