Path: ...!news.misty.com!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: olcott Newsgroups: comp.theory Subject: Re: DDD specifies recursive emulation to HHH and halting to HHH1 Date: Mon, 31 Mar 2025 13:06:35 -0500 Organization: A noiseless patient Spider Lines: 77 Message-ID: References: <3ade9e84224ba9b99c7363e0e9b69181804b7daa@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Mon, 31 Mar 2025 20:06:34 +0200 (CEST) Injection-Info: dont-email.me; posting-host="68fa68df0c7e701292a0536bcb59f4c8"; logging-data="967856"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/54kFHDkYAkJPqnyqXXLoK" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:+M0cXgi4Yy3k8MedMWRMa17Bb8M= In-Reply-To: X-Antivirus-Status: Clean X-Antivirus: Norton (VPS 250331-6, 3/31/2025), Outbound message Content-Language: en-US Bytes: 5154 On 3/31/2025 3:47 AM, Mikko wrote: > On 2025-03-30 20:32:07 +0000, olcott said: > >> On 3/30/2025 1:52 PM, Richard Damon wrote: >>> On 3/30/25 2:27 PM, olcott wrote: >>>> On 3/30/2025 3:12 AM, joes wrote: >>>>> Am Sat, 29 Mar 2025 16:46:26 -0500 schrieb olcott: >>>>>> On 3/29/2025 3:14 PM, dbush wrote: >>>>>>> On 3/29/2025 4:01 PM, olcott wrote: >>>>> >>>>>>>> We can know that when this adapted UTM simulates a finite number of >>>>>>>> steps of its input that this finite number of steps were simulated >>>>>>>> correctly. >>>>>>> And therefore does not do a correct UTM simulation that matches the >>>>>>> behavior of the direct execution as it is incomplete. >>>>>> It is dishonest to expect non-terminating inputs to complete. >>>>> A complete simulation of a nonterminating input doesn't halt. >>>>> >>>>>>>>> 2) changing the input is not allowed >>>>>>>> The input is unchanged. There never was any indication that the >>>>>>>> input >>>>>>>> was in any way changed. >>>>>>> False, if the starting function calls UTM and UTM changes, you're >>>>>>> changing the input. >>>>>> When UTM1 is a UTM that has been adapted to only simulate a finite >>>>>> number of steps >>>>> So not an UTM. >>>>> >>>>>> and input D calls UTM1 then the behavior of D simulated >>>>>> by UTM1 never reaches its final halt state. >>>>>> When D is simulated by ordinary UTM2 that D does not call Then D >>>>>> reaches >>>>>> its final halt state. >>>>> Doesn't matter if it calls it, but if the UTM halts. >>>>> >>>>>>> Changing the input is not allowed. >>>>>> I never changed the input. D always calls UTM1. >>>>>> thus is the same input to UTM1 as it is to UTM2. >>>>> You changed UTM1, which is part of the input D. >>>>> >>>> >>>> UTM1 simulates D that calls UTM1 >>>> simulated D NEVER reaches final halt state >>>> >>>> UTM2 simulates D that calls UTM1 >>>> simulated D ALWAYS reaches final halt state >>>> >>> >>> Only because UTM1 isn't actually a UTM, but a LIE since it only does >>> a partial simulation, not a complete as REQURIED by the definition of >>> a UTM. >>> >> >> _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 EMULATED BY HHH DOES SPECIFY THAT IT >> CANNOT POSSIBLY REACH ITS OWN FINAL HALT STATE. > > No, it does not. HHH misintepretes, contrary to the semantics of x86, > the specification to mean that. > It is a truism that a correct x86 emulator would emulate itself emulating DDD whenever DDD calls this emulator with itself. -- Copyright 2025 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer