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Subject: Re: Question for Gerd: reduce rbb lookup tables

Author: Sune Fischer

Date: 17:35:01 07/14/03

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On July 14, 2003 at 19:48:05, Russell Reagan wrote:

Thanks Russell, it's hereby been bookmarked :)

Though, as you can understand I've run my own experiments ;)
Theory doesn't always replace hands on experience, IMO.

I don't remember the exact times, but typedef'ing a move as unsigned int instead
of signed, yielded a measurable speed increase. Also I tried some of the piece
square and scoring tables as signed ints rather than chars, that ran also faster
in some cases. Definitely modern processors like ints.

I could run the tests again, was it not because I'm in the midst of tracking a
horrible bug, the program is sadly gutted at the moment.

-S.

>On July 14, 2003 at 19:38:40, Sune Fischer wrote:
>
>>I once heard that working with byte size variables is slower than native
>>integers (32 bit) sizes, so I'm not fully convinced 8 bit casting it that much
>>faster(?).
>
>Hi Sune,
>
>You might find this site interesting, "C++ Optimization Strategies and
>Techniques". Some 8-bit ops are the same speed as 32-bit ops, but some are
>slower.
>
>http://www.tantalon.com/pete/cppopt/main.htm
>
>There is one section that covers "Relative Costs of Common Programming
>Operations". It tells you approximate how long different operations take on
>different types (8-bit, 32-bit, signed, unsigned, etc.). Below that table there
>is also one regarding converting from one type to another. For instance, it says
>converting from an 8-bit value to 32-bit value is 70% of the speed of 32-bit to
>32-bit.
>
>http://www.tantalon.com/pete/cppopt/appendix.htm#AppendixB_RelativeCosts



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