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From: olcott <polcott333@gmail.com>
Newsgroups: comp.theory
Subject: Re: DDD correctly emulated by HHH --- Correct Emulation Defined
Date: Thu, 20 Mar 2025 09:15:25 -0500
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On 3/20/2025 6:00 AM, Richard Damon wrote:
> On 3/19/25 10:32 PM, olcott wrote:
>>

_DDD()
[00002177] 55               push ebp      ; 1st line
[00002178] 8bec             mov ebp,esp   ; 2nd line
[0000217a] 6877210000       push 00002177 ; push DDD
[0000217f] e853f4ffff       call 000015d7 ; call HHH
[00002184] 83c404           add esp,+04
[00002187] 5d               pop ebp
[00002188] c3               ret
Size in bytes:(0018) [00002188]

>>
>> When N steps of DDD are emulated by HHH according
>> to the semantics of the x86 language then these
>> N steps are emulated correctly.
>>
> 
> Right, The N Steps of DDD were emulated correctly, but not the WHOLE of 
> DDD, that wasn't correctly emulated.
> 

After the first four instructions of DDD has been correctly
emulated by HHH and HHH emulates itself correctly emulating
the first four instructions DDD again then

DDD has met the infinite recursion behavior pattern of HHH.
HHH has no idea that DDD is calling itself
See _Infinite_Recursion() BELOW

// executed HHH emulates 1st instance of DDD
New slave_stack at:10388d
Begin Local Halt Decider Simulation   Execution Trace Stored at:113895
[00002177][00113885][00113889] 55         push ebp      ; 1st line
[00002178][00113885][00113889] 8bec       mov ebp,esp   ; 2nd line
[0000217a][00113881][00002177] 6877210000 push 00002177 ; push DDD
[0000217f][0011387d][00002184] e853f4ffff call 000015d7 ; call HHH

// emulated HHH emulates 2nd instance of DDD
New slave_stack at:14e2b5
[00002177][0015e2ad][0015e2b1] 55         push ebp      ; 1st line
[00002178][0015e2ad][0015e2b1] 8bec       mov ebp,esp   ; 2nd line
[0000217a][0015e2a9][00002177] 6877210000 push 00002177 ; push DDD
[0000217f][0015e2a5][00002184] e853f4ffff call 000015d7 ; call HHH
Local Halt Decider: Infinite Recursion Detected Simulation Stopped

_Infinite_Recursion()
[00002082] 55             push ebp
[00002083] 8bec           mov ebp,esp
[00002085] e8f8ffffff     call 00002082
[0000208a] 90             nop
[0000208b] 5d             pop ebp
[0000208c] c3             ret
Size in bytes:(0011) [0000208c]

HHH only sees that DDD calls the same function twice in
sequence with no conditional branch instructions between
00002082 and 00002085 that could possibly allow
_Infinite_Recursion() to ever reach its own "ret"
instruction.



-- 
Copyright 2025 Olcott "Talent hits a target no one else can hit; Genius
hits a target no one else can see." Arthur Schopenhauer