Re: What is byte-code ?

>>Rather than the array of f() * , if you use gcc,
>
>
> I didn't want to commit to gcc (especially since one of my targets
> was the ARM).
>
>
>>and because you won't have to jump back to the initial jump to begin the
>>next instruction. If you were to do this, I would suggest that you make
>>an automated process of building the C source file that has the
>>implementation of the instructions in it from one or more files that
>>contain the per-instruction implementations and make it so that the
>>method of jump table can be changed for different compilers.
>
>
> Indeed. My friend Steve Leach has done some VM investigation where the
> same code fragments for the instructions) are stitched together in
> different ways for comparison purposes: switch cases, functions, and
> GCC label targets. If I remember rightly, label targets were fastest
> on x86 machines, but functions were fastest on Power PC. Were I to
> be doing another round of VM exercises, I'd play the same kind of
> trick.


One other thing that you could do if you were to create a tool to take
your implementations of the instructions and make them into the
different types of jump tables (*F(), label[], switch/case) would be
to use that same instruction implementation code to make a simple jit
compiler, with a little fiddling w/ the variables used, so that the
system's C compiler could be fed the output from the jit/vm and then
load the code from it (possibly after running the system's linker over
it). This should be really simple.


Nathan

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