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From: Mikko <mikko.levanto@iki.fi>
Newsgroups: comp.theory
Subject: Re: DD correctly emulated by HHH --- Kicking the straw-man deception out on its ass
Date: Mon, 3 Mar 2025 16:44:45 +0200
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On 2025-03-02 21:21:04 +0000, olcott said:

> int DD()
> {
>    int Halt_Status = HHH(DD);
>    if (Halt_Status)
>      HERE: goto HERE;
>    return Halt_Status;
> }
> 
> _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]
> 
> DD emulated by HHH according to the behavior that DD
> specifies cannot possibly reach its own "ret" instruction
> and terminate normally.

DD does not fully specify a behaviour. The behaviour depends on HHH,
which is not a part of DD. If HHH returns 0 then DD specifies a non-
terminatingg behaviour but that is a big if.

-- 
Mikko