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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: Sun, 2 Mar 2025 09:15:59 +0100
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Op 02.mrt.2025 om 00:58 schreef olcott:
> On 3/1/2025 3:58 PM, Richard Damon wrote:
>> On 3/1/25 2:01 PM, olcott wrote:
>>> On 3/1/2025 10:05 AM, Richard Damon wrote:
>>>> On 3/1/25 9:41 AM, olcott wrote:
>>>>> 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 non-termination whether aborted or not.
>>>>>
>>>>> Cannot possibly reach its own "ret" instruction and terminate normally
>>>>> proves non-termination whether aborted or not.
>>>>>
>>>>> Cannot possibly reach its own "ret" instruction and terminate normally
>>>>> proves non-termination whether aborted or not.
>>>>>
>>>>>
>>>>
>>>> But it DOES terminate 
>>>
>>> DD emulated by HHH never terminates no matter how many
>>> times you try to get away with the straw-man deception
>>> of referring to anything at all besides
>>>
>>> DD EMULATED BY HHH
>>> DD EMULATED BY HHH
>>> DD EMULATED BY HHH
>>> DD EMULATED BY HHH
>>> DD EMULATED BY HHH
>>> DD EMULATED BY HHH
>>>
>>>
>>
>> Which since HHH doesn't correctly emulate DD is just a fantasy.
>>
> 
> If it was actually incorrect then someone could show
> how the above code is correctly emulated by HHH.
Invalid logic. If there a correct way does not exist, Oloctt is 
incorrect and nobody else can show a correct way.