Re: Hypothetical possibilities --- Correct emulation has been proven for three years

On 7/31/2024 3:01 PM, Fred. Zwarts wrote:

Op 31.jul.2024 om 17:14 schreef olcott:

On 7/31/2024 3:44 AM, Fred. Zwarts wrote:

Op 31.jul.2024 om 06:09 schreef olcott:

We don't show any of HHH and show the execution trace of of just DDD
assuming that HHH is an x86 emulator.

This assumption is incorrect if it means that HHH is an unconditional
simulator that does not abort.

This algorithm is used by all the simulating termination analyzers:

So, Sipser only agreed to a correct simulation, not with an incorrect
simulation that violates the semantics of the x86 language by skipping
the last few instructions of a halting program.
 

int DD()
{
   int Halt_Status = HHH(DD);
   if (Halt_Status)
     HERE: goto HERE;
   return Halt_Status;
}
int main()
{
   HHH(DD);
}
DD correctly emulated by HHH cannot possibly reach its own second line.