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Subject: Re: attacks_from[] and attacks_to[] info

Author: Gerd Isenberg

Date: 00:44:25 10/24/02

Go up one level in this thread


On October 23, 2002 at 16:48:00, Peter Fendrich wrote:

>On October 23, 2002 at 10:29:27, Gerd Isenberg wrote:
>
>>On October 23, 2002 at 03:36:58, Peter Fendrich wrote:
>>
>>>On October 22, 2002 at 19:16:42, Gerd Isenberg wrote:
>>>
>>>>On October 22, 2002 at 19:01:43, Peter Fendrich wrote:
>>>>
>>>>>On October 22, 2002 at 18:27:11, Gerd Isenberg wrote:
>>>>>
>>>>>Hi Gerd,
>>>>>I'm not sure I understand this:
>>>>>
>>>>>- snip -
>>>>>>Due to the
>>>>>>simultanious feature this algorithms seem a favorably alternative to rotated
>>>>>>bitboards, even without assembler.
>>>>>- snip -
>>>>>
>>>>>Do you really mean that the c-code in the previous post in this thread is faster
>>>>>than rotated bitboards?
>>>>>
>>>>>Peter
>>>>
>>>>Hi Peter,
>>>>
>>>>I believe yes on 64-bit processors in conjunktion with using this routines with
>>>>sets of multiple pieces.
>>>>
>>>>I use it currently with mmx-registers in Leiden.
>>>>
>>>>http://www.talkchess.com/forums/1/message.html?259095
>>>>
>>>>See also the reply of Steffan using move target set for each direction!
>>>>
>>>>Regards,
>>>>Gerd
>>>
>>>Yes, I saw your mmx code but didn't think that c-code could match that. Maybe
>>>64-bits processors would make a difference.
>>
>>Yes, with hammers sixteen general purpuse registers even c-code may be faster
>>then.
>>
>>>BTW your link is outdated!
>>>Peter
>>
>>oups, only valid for one week. If you like, i may send it by mail
>
>Yes, please!
>
>>- or hopefully it goes to the archives soon,
>
>It will take some time IIRC.
>
>
>>specially the replies of Steffan.
>>His point was that i lose information, if i combine the directions to early into
>>the final attack set register. His Idea is to hold eight disjoint direction sets
>>for all sliding pieces, to gain really from generating attack sets for multiple
>>pieces. These sets anded with ~ownPieces may be usefull as a kind of movelist
>>entry with implicite bookholding.
>>
>>I stated that i use the mmx-stuff now in IsiChess instead of rotated bitboards,
>>without changing function interfaces (so far).
>>Due to valid move generation the winner is currently a mmx-routine, that gets
>>all attacks by all pieces of one (opposite) side. So i get all tabu squares for
>>the king to move. Instead of calling multiple getAttackedBy for possible king
>>move (castle) target squares, i call getAllAttacks once.
>>I made also dedicated mmx-routines for determing pinned pieces and covered
>>checkers (remove checker?).
>>
>>Gerd
>
>You, Steffen et al have posted some interesting ideas about this!
>I'm using rotated bitboards as described by Bob Hyatt (but a somewhat different
>implementation). I have to be very convinced before I rewrite all that stuff!
>
>Peter

That's OK, Peter. But if some redisign with hammer in mind is required...
Gerd



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