Path: ...!2.eu.feeder.erje.net!feeder.erje.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: "Fred. Zwarts" Newsgroups: comp.theory Subject: Re: People are still trying to get away with disagreeing with the semantics of the x86 language Date: Wed, 3 Jul 2024 20:25:18 +0200 Organization: A noiseless patient Spider Lines: 44 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Wed, 03 Jul 2024 20:25:20 +0200 (CEST) Injection-Info: dont-email.me; posting-host="6cedb142f34e03a5852de86ea322d5ac"; logging-data="2418000"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19/gZz5akWJPJuFK1I6i50I" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:qNBeVGAijy4TcEvf3hSSfiQY51U= Content-Language: en-GB In-Reply-To: Bytes: 3240 Op 03.jul.2024 om 19:58 schreef olcott: > On 7/3/2024 12:51 PM, Fred. Zwarts wrote: >> Op 03.jul.2024 om 18:03 schreef olcott: >>> > > _DDD() > [00002172] 55               push ebp      ; housekeeping > [00002173] 8bec             mov ebp,esp   ; housekeeping > [00002175] 6872210000       push 00002172 ; push DDD > [0000217a] e853f4ffff       call 000015d2 ; call HHH(DDD) > [0000217f] 83c404           add esp,+04 > [00002182] 5d               pop ebp > [00002183] c3               ret > Size in bytes:(0018) [00002183] > >>> DDD is correctly emulated by HHH which calls an emulated HHH(DDD) >>> to repeat this process an endless number of times until aborted >>> or out-of-memory error. >> Anyone knowing the x86 language knows that a program cannot be >> programmed to do two different things >> It cannot do both run out of memory *and* abort. > > DDD correctly emulated by any element of the infinite > set of every pure function HHH cannot possibly reach > its own ret instruction and halt. Exactly! Well done! This proves that HHH cannot possibly correctly simulate itself. If it aborts, it does so one cycle too soon. > That HHH aborts its > emulation at some point or never aborts its emulation > cannot possibly change this. Indeed, an abort does not make the simulation correct and an infinite simulation is not correct either. > >> So make up your mind. What does it do? >> And what does "endless number of times until aborted" mean? Does it >> abort after an infinite number of steps? >> Make clear what you mean. After how many cycles is the simulation >> aborted? >