Path: ...!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: Every sufficiently competent C programmer knows --- posthumous reviewers Date: Fri, 14 Mar 2025 08:32:33 +0100 Organization: A noiseless patient Spider Lines: 48 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Fri, 14 Mar 2025 08:32:35 +0100 (CET) Injection-Info: dont-email.me; posting-host="2309bdc4e851ad7a0f935340aeac3006"; logging-data="891976"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/zNE8ooq/AplQ58TPd5crv" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:oJ9bamb+zmRTjvsLc4Pggpz3H90= In-Reply-To: Content-Language: nl, en-GB Bytes: 3287 Op 13.mrt.2025 om 21:56 schreef olcott: > On 3/13/2025 4:22 AM, Mikko wrote: >> On 2025-03-13 00:36:04 +0000, olcott said: >> >>> >>> void DDD() >>> { >>>    HHH(DDD); >>>    return; >>> } >>> >>> int DD() >>> { >>>    int Halt_Status = HHH(DD); >>>    if (Halt_Status) >>>      HERE: goto HERE; >>>    return Halt_Status; >>> } >>> >>> When HHH correctly emulates N steps of the >>> above functions none of them can possibly reach >>> their own "return" instruction and terminate normally. >> >> Nevertheless, assuming HHH is a decider, Infinite_Loop and >> Infinite_Recursion >> specify a non-terminating behaviour, DDD specifies a terminating >> behaviour > > _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] > > What is the sequence of machine language > instructions of DDD emulated by HHH such that DDD > reaches its machine address 00002183? I built an aeroplane. After flying three times around the globe, I found out that my aeroplane cannot possibly reach the moon, so I aborted the flight. My conclusion is that any flight to the moon does not terminate. The moon is unreachable. It is irrelevant that other vehicles reached the moon, because they have no pathological relation with the moon. Anyone claiming that the moon is reachable should show the next kilometers of my aeroplane up to when it reaches the moon.