Greetings. :)

Jeff Kesselman jeffk at
Wed Apr 9 23:15:43 New Zealand Standard Time 1997

At 11:48 AM 4/9/97 -1000, you wrote:
>On Mon, 7 Apr 1997, Chris Gray wrote:
>:Ok, terminology differences. I think of bytecodes as interpreted. Perhaps
>:'simulated' is a better word. 'Emulated'?
>:Perhaps we can come up with a gradient (I'm sure this has been done
>:and we can all point to where we are on it:
>:1.  native machine code
>:2.  threaded code
>:3.  bytecode
>:4.  parse tree traversal
>:5.  pre-tokenized interpretation
>:6.  straight text interpretation

Hmm, theres a wide range in 3.

Ild devide it as follows...

3a) Byte code on a true VM (generally a stack based system with a small number
    of highly efficiently parsed opcodes).  My Kelvin VM is this, a
    stack based  OO machine with about 15 opcodes total.

3b) Tokenized form.  Thsi is where every statement (if, while, etc) has a
    corrosponding byte code.  Coldmud/ColdX does this.,


>:You're at 3? I'm at 4 in AmigaMUD, 6 in ToyMud. However, differences
>:like the need for run-time symbol lookup, or type conversions, can easily
>:move something up a notch in execution overhead. LP is at 3 now isn't
>:it? Are MOO and ColdX at 3 as well? Let's see, REXX is 5? Tcl is 6.
>:Shell scripts are 6+, Perl is 5? This is just *so* relevant to MUDs! :-/
>Erm. I'm a rather strange hybrid of 1, 2, and 4. But... well, I'm not sure
>what you mean by parse tree transversal... what I've got is referenced
>blocks of native code getting tacked together by dereferenced function
>pointers, dynamicly when needed, staticly when possible. In theory, the
>whole chunk should be about 3/2 machine, but I'm coming from a PPC asm
>bias, and that neglects any compiler optimizations rendered impossible by
>this scheme. Its also about 3/1 machine for memory, so far... The flaw is
>that it renders bootup a much longer process, as most of the work gets
>done then, and is impossible to save in a reusable form, as some addresses
>are locally dependent at startup time, thanks to the dynaload provisions,
>in part. Any suggestions or criticisms by the more experienced?
>   __    _   __  _   _   ,  ,  , ,  
>  /_  / / ) /_  /_) / ) /| /| / /\            First Light of a Nova Dawn
> /   / / \ /_  /_) / \ /-|/ |/ /_/            Final Night of a World Gone
>Nathan F. Yospe - University of Hawaii Dept of Physics - yospe at

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