Python CPU

[Steven D'Aprano]

On Sun, 03 Apr 2011 12:10:35 +1200, Gregory Ewing wrote:

> Brad wrote:
> 
>> I've heard of Java CPUs. Has anyone implemented a Python CPU in VHDL or
>> Verilog?
> 
> Not that I know of.
> 
> I've had thoughts about designing one, just for the exercise.
> 
> It's doubtful whether such a thing would ever be of practical use.
> Without as much money as Intel has to throw at CPU development, it's
> likely that a Python chip would always be slower and more expensive than
> an off-the-shelf CPU running a tightly-coded interpreter.

I recall back in the late 80s or early 90s, Apple and Texas Instruments 
collaborated to build a dual-CPU Lisp machine. I don't remember all the 
details, but it was an Apple Macintosh II with a second CPU running (I 
think) a TI Explorer (possibly on a Nubus card?), with an integration 
layer that let the two hardware machines talk to each other. It was dual-
branded Apple and TI.

It was a major flop. It was released around the time that general purpose 
CPUs started to get fast enough to run Lisp code faster than a custom-
made Lisp CPU could. I don't remember the actual pricing, so I'm going to 
make it up... you got better performance from a standard Mac II with 
software Lisp for (say) $12,000 than you got with a dedicated Lisp 
machine for (say) $20,000.

(These are vaguely recalled 1980s prices. I'm assuming $10K for a Mac II 
and $2K for the Lisp compiler. Of course these days a $400 entry level PC 
is far more powerful than a Mac II.)

There were also Forth chips, which let you run Forth in hardware. I 
believe they were much faster than Forth in software, but were killed by 
the falling popularity of Forth.


-- 
Steven