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Subject: Re: Faster Board Representations/Move Generators

Author: Christopher Conkie

Date: 12:02:25 02/23/06

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On February 23, 2006 at 14:49:01, Dann Corbit wrote:

>On February 23, 2006 at 14:47:23, Christopher Conkie wrote:
>
>>Is there a way to keep board representations entirely in hexadecimal format
>>until output of moves are required. How would one accomplish rotation for
>>diagonals without conversion. For example, is it needed to convert pieces to a
>>number if you started with something like.....
>>
>>typedef unsigned long long bitboard;
>>
>>bitboard B_Occ = 0xffff000000000000ULL;
>>bitboard W_Occ = 0x000000000000ffffULL;
>>
>>bitboard All_P = 0x00ff00000000ff00ULL;
>>bitboard All_N = 0x4200000000000042ULL;
>>bitboard All_B = 0x2400000000000024ULL;
>>bitboard All_R = 0x8100000000000081ULL;
>>bitboard All_Q = 0x1000000000000010ULL;
>>bitboard All_K = 0x0800000000000008ULL;
>>
>>I have been toying with this idea but am not quite sure of the validity of it's
>>basis. I was thinking that if less conversion took place it would improve speed
>>significantly.
>>
>>Any thoughts would be nice.
>
>Internally, all the numbers are binary.  If you assign them a decimal number, it
>gets converted to binary internal format.  It happens at compile time and so the
>speed difference is 0.00000%
>
>Or maybe you are joking and left out the smiley.

Yes and no. ;-)

Seriously I am looking at ways to improve speed without having to use arrays to
rotate for diagonals.

There is a max of 7 squares in any one specific horizontal, vertical or diagonal
direction for a piece to move to. If we know that, why not have a table that
looks at each of the 8 directions and subsequent squares in turn until a
friendly or opposing piece is found and deal with that accordingly. This would
require a table that is stepped through consisting of the 56 values that shift
up, down or across.

Did I explain that well enough. It is a bit bitty I know.....

It just seems to me simpler to me to comprehend. Question is would it be
significantly slower or maybe even faster?

:-)

Christopher



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