basic parrot questions

[Terrence Brannon <address@hidden>]

Why would a software machine closely emulating CISC architecture 
be expected to execute as efficiently on RISC and CISC machines?

Does it make any sense to create a low-level machine modeled on 
one-architecture instead of a high-level architecture which can 
flexibly optimize to either architecture?

Also, I thought Parrot was not "stack-based" If that is the case 
then why does Overview.pod say this:

"Registers will be stored in register frames, which can be pushed and
popped onto the register stack. For instance, a subroutine or a block
might need its own register frame."