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Subject: Re: How do you represent chess boards in your chess programms

Author: Christophe Theron

Date: 00:11:21 09/26/99

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On September 25, 1999 at 23:20:02, Robert Hyatt wrote:

>>There are hundreds of millions of 16 and 32 bits PCs in the world today. How
>>many 64 bits PCs? NONE, ZERO, NIL, NADA.
>>
>
>
>this is wrong.  Ask bruce as he owns a PC with a 533 mhz alpha in it, made
>by Polywell.  There are several such machines.  PC magazine has even covered
>them in detail.


OK, sorry. You are right, let's be accurate. From a mathematical point of view
the 64 bits PCs represent a percentage strictly greater than 0. Say 0.1%, OK?



>>It will take several years (maybe 10) before the number of 64 bits PCs becomes
>>larger than the number of 16 and 32 bits ones.
>>
>
>folks were saying that about the 386 not replacing the 286 for most businesses
>too.  Care to guess how many 286's are left?  :)

I'm not saying they will not replace older computers. I'm just saying it will
take time.

And that non bitboard program will also benefit from more powerful computers.



>>You live in a country where only a fraction of your monthly salary is enough to
>>buy a new powerful personal computer.
>>
>>Of course you know it's not the case everywhere in the world.
>>
>>So maybe you can easily erase 16 and 32 bits computers from your memory as soon
>>as Intel produces a 64 bits processor, but there are many people in the world
>>who will stick to 16 and 32 bits for 10 years or more.
>
>
>
>that is crazy.  How many people do you know with 286 computers?  they are
>10 years old. How many do you know with 486 computers? They are 5 years old.
>How many do you know with p5 pentium machines?  they are 4 years old.  How
>about pentium pros?  3 years.  Pentium II?  1.5, pentium III?  < 1 year.

A friend of mine stopped using his 286 2 years ago. Another one had upgraded
from 286 to 486 the year before.

Here the majority of computers are 486.



>People replace technology _all_ the time.  I don't know of _anybody_ that
>doesn't have at least a pentium CPU.    Which means _no_ machines I know of are
>over 3 years old.  These are home computers.  Office computers.  Business
>computers.  Game computers. Etc.


Looks like we are not living in the same world...



>Sticking to 16 bits won't be possible if the new software releases don't support
>it.  Care to boot up windows 2000 on a 286?  That's only a 10 year old processor
>so it ought to work right?


My 386sx20 (1990) notebook boots Windows 95.

I know next versions of Windows won't run anymore on it (I did not even try
W98).

Guess why?

The industry needs a strong reason to push people to buy new computers.



>>Funny you mention this. I was recently thinking that I could produce a 16 bits
>>version of Chess Tiger.
>>
>>In 1997 I rewrote everything to port from 16 to 32 bits. In fact, the rewrite
>>was essentially optmizing my algorithms for efficiency. I have used my older 16
>>bits version as a laboratory. I was very flexible, so I could try many different
>>things, but because of this was not optimized.
>>
>>So I rewrote everything with the algorithm I was targetting for in mind.
>>Additionnaly, I thought I would take advantage of 32 bits processing where it
>>would make sense.
>>
>>Recently I realized that I needed 32 bits integer very unfrequently. In fact I
>>could use 16 bits integer in 99% of my program. The 32 bits integer processing
>>is needed only for hash keys calculations and hash table access, and a 16 bits
>>processor can emulate them with only a very small speed penalty.
>>
>
>
>From a performance perspective, you are thinking wrongly.  You don't want
>to think "How can I reduce my data sizes so that 16 bits works?"  You do
>want to ask "How can I increase my data sizes to 64 bits so that I can use
>the increased data density in a 64 bit cpu?"


I understand, and I suppose bitboards fit very well this goal. It's just that I
don't think this power is needed. What we need is mainly more speed, and better
parallelism. I guess you are going to say that processing the 64 squares in one
operation is a kind of parallelism... :)



>As a challenge, I'll get you time on a Cray.  Let's see how well you run on
>that machine compared to a program that is optimized for it.  My eyes were
>opened years ago to this problem...


I take the offer. How can I compile my program for the Cray?



    Christophe



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