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Failed to connect to MySQL: (1203) User howardkn already has more than 'max_user_connections' active connectionsPath: ...!weretis.net!feeder9.news.weretis.net!news.quux.org!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: "Fred. Zwarts" Newsgroups: comp.theory Subject: Re: DD emulated by HHH cannot possibly terminate normally --- x86 code Date: Sun, 2 Mar 2025 09:15:59 +0100 Organization: A noiseless patient Spider Lines: 72 Message-ID: References: <5c444106eafa1235cc4953d9be6faddf8825bcf3@i2pn2.org> <1fa130b5ec11e0472fad3aca4cfef9bcb9741652@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Sun, 02 Mar 2025 09:16:01 +0100 (CET) Injection-Info: dont-email.me; posting-host="2c4e3ccf99657293cc6a8efcc8948d8f"; logging-data="736149"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+1etM4eiAQiCz9ET4XViOA" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:y/qMFryqUVngFcWNr6xOH+ijC3o= In-Reply-To: Content-Language: nl, en-GB Bytes: 4268 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.