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Subject: Re: HW based Crafty (Boule's thesis)

Author: Robert Hyatt

Date: 06:46:39 04/01/02

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On April 01, 2002 at 04:20:57, Tom Kerrigan wrote:

>On March 31, 2002 at 16:29:10, Keith Evans wrote:
>
>>generator for his program MBChess. His thesis is almost complete.  Marc got his
>>program from about 2M nps to 10M nps using an FPGA for move ordering and movegen
>>only."
>>
>>Does he really say this? It sounds too good to be true. Let's take a look at
>>this from the perspective of the PCI bus. To be able to generate 10M moves per
>>second on a 33 MHz PCI bus, Marc seems to be implying that he can complete a PCI
>>read in 3.3 cycles and that the master will completely saturate the PCI bus with
>
>Right, and presumably much more data needs to be transferred than just reading
>moves. (I'd like to read the paper but I'm on dial-up right now.) Also, this
>assumes the logic can generate moves that fast. Seems like the critical paths
>for move generation would be pretty darn long on an FPGA; I'd be surprised if it
>could run at ~33MHz. (Not that it would necessarily have to, but I do think
>clock speed is a likely bottleneck.) Of course, my biggest problem with the 2M
>-> 10M NPS jump is that MBChess must be spending more than 80% of its CPU time
>generating and ordering moves, which is way beyond realistic, IMO.
>


It depends on what he is going to do.  IE if he tries to do a full
Belle-implementation, then the PCI bus speed is irrelevant.  Because all
the move generation, and search stuff is done _inside_ the FPGA hardware,
and all that needs to run over the PCI bus is the _result_ of the search.

That was how both Belle and Deep Thought/Deep Blue worked...  DT/DB used the
VME bus...  Belle used a very slow connection from a PDP 11 to the special-
purpose chess hardware...

A high bandwidth is not necessarily needed, depending on what is implemented.




>Interesting conversation, too bad I found out about it late.
>
>-Tom



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