[Info-vax] OpenVMS.Org quick pool

[Bob Koehler]

 JF Mezei wrote:
> 
> Would an Alpha emulator incorporate much of the alpha smarts in it ?
> (such as predictive branching and pre-translating both possible outcomes
> of a branch ?)
> 
> Or do they end up being more akin to compilers, translating a big chunk
> of foreign machine code into native code and branching to it, allowing
> the X86 CPU to do any optimisations it can while running native code ?

   By example, VEST does some of both.  On first pass it "compiles" what
   it can, using the original instructions as "source".  What it can't
   "compile" it will interpret at run time.  The resulting code may not
   be optimal, so it has a feedback mechanism to improve performance over 
   first guess.