Path: ...!weretis.net!feeder8.news.weretis.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Mikko Newsgroups: comp.theory Subject: Re: DDD correctly emulated by HHH is correctly rejected as non-halting. Date: Sat, 13 Jul 2024 11:00:37 +0300 Organization: - Lines: 57 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Sat, 13 Jul 2024 10:00:38 +0200 (CEST) Injection-Info: dont-email.me; posting-host="80608967e749872573752d941ad4d527"; logging-data="3688883"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+B63yZ/+wj5+eyNWic0fUP" User-Agent: Unison/2.2 Cancel-Lock: sha1:6572VFAngnJdAg+X+UwQhcnBSbM= Bytes: 2784 On 2024-07-12 13:20:53 +0000, olcott said: > On 7/12/2024 3:03 AM, Mikko wrote: >> On 2024-07-11 14:10:24 +0000, olcott said: >> >>> On 7/11/2024 1:25 AM, Mikko wrote: >>>> On 2024-07-10 17:53:38 +0000, olcott said: >>>> >>>>> On 7/10/2024 12:45 PM, Fred. Zwarts wrote: >>>>>> Op 10.jul.2024 om 17:03 schreef olcott: >>>>>>> typedef void (*ptr)(); >>>>>>> int HHH(ptr P); >>>>>>> >>>>>>> void DDD() >>>>>>> { >>>>>>>    HHH(DDD); >>>>>>> } >>>>>>> >>>>>>> int main() >>>>>>> { >>>>>>>    HHH(DDD); >>>>>>> } >>>>>> >>>>>> Unneeded complexity. It is equivalent to: >>>>>> >>>>>>        int main() >>>>>>        { >>>>>>          return HHH(main); >>>>>>        } >>>>>> >>>>> >>>>> >>>>> Every time any HHH correctly emulates DDD it calls the >>>>> x86utm operating system to create a separate process >>>>> context with its own memory virtual registers and stack, >>>>> thus each recursively emulated DDD is a different instance. >>>> >>>> However, each of those instances has the same sequence of instructions >>>> that the x86 language specifies the same operational meaning. >>>> >>> >>> *That is counter-factual* >>> When DDD is correctly emulated by HHH according to the >>> semantics of the x86 programming language HHH must abort >>> its emulation of DDD or both HHH and DDD never halt. >> >> There is not "must" anywhere in the semantics of the programming language. >> > > The semantics of the language specifies the behavior of > the machine code thus deriving the must. How can one derive "must" from the semantics of the machine code? -- Mikko