Re: Sequence of sequence, selection and iteration matters

On 2024-07-09 14:19:59 +0000, olcott said:

On 7/9/2024 1:22 AM, Mikko wrote:

On 2024-07-08 13:04:13 +0000, olcott said:

<MIT Professor Sipser agreed to ONLY these verbatim words 10/13/2022>
     If simulating halt decider H correctly simulates its input D
     until H correctly determines that its simulated D would never
     stop running unless aborted then
      H can abort its simulation of D and correctly report that D
     specifies a non-halting sequence of configurations.
</MIT Professor Sipser agreed to ONLY these verbatim words 10/13/2022>
 

Whether a partial simulation of DDD simulates the return depends
on the simulator.

 That is false proving that you have insufficient knowledge.

 It is true. There are partial simulators that do simulate D(I) to its termination (if it terminates) and there are simulators that don't.
That you cannot imagine something does not mean it can't exist.
 

 No pure function x86 emulator HHH can possibly emulate DDD
to its termination.
 _DDD()
[00002163] 55         push ebp      ; housekeeping
[00002164] 8bec       mov ebp,esp   ; housekeeping
[00002166] 6863210000 push 00002163 ; push DDD
[0000216b] e853f4ffff call 000015c3 ; call HHH(DDD)
[00002170] 83c404     add esp,+04
[00002173] 5d         pop ebp
[00002174] c3         ret
Size in bytes:(0018) [00002174]

An emulator can take a shortcut when it has to emulate a call to a
fuction it knows. In case it detects a call to itself it may simply
assume (correctly or incorrectly) that the function returns and
emulate the instructions after the call.
--
Mikko