Hier ein Thread auf TalkChess über einen sehr schnellen Bitboard-Zuggenerator:http://talkchess.com/forum3/viewtopic.php?f=7&t=78352#p908018
I would like to release the sourcecode to the fastest Chess movegenerator I was able to write during the last 2½ years.
It is able to generate 2 Billion Moves per Thread per Second. No Hashing is used - and it still is single threaded.
What makes it so fast is summarized below - but in short: Make/Unmake and a Movelist is not needed and 2x slower than a visitor pattern - which is even more powerful and faster and implemented in this movegen. Also expanding the enumeration template for color to include enpassant and all castling squares helps a lot!
Explanation Article: https://www.codeproject.com/Articles/53
Linux/Windows Binary: https://www.codeproject.com/KB/Articles
It is a Bitboard movegenerator. As it turns out incremental bitboards are slower for this type of generator. Remembering previous from | to square is more expensive than recalculating many of the moves. It is possible to add that to the sourcecode easily and maybe I will merge the exploration branches in the future.
It uses heavy template instantiation with a template inlined "callback" function. What makes this so fast is that you dont need a movelist anymore for this approach. When a legal move is encountered it instantly is decided what to do with it. Expand more - Store - Or sort into a list of good moves. All possible with this approach.
The pin and checkmask is what makes bitboards so good. With a handful of & operations all moves are pruned to only cointain legal moves. An I mean all moves. Even the most ugliest of pinned - prevention of promotion - or check double check pin combos are almost free and certainly branchless!
Also what I think no one implemented before me: Enpassant and Castling are moved to a Boardstate Template. You can input any fen - the appropriate template is called with a single switch and off you go enumerating. The cost of a single switch at the very start of enumerating saves billions of noop instructions for castling / enpassant. The Boardstate contains: Moving Color, HasEnpassant, 4 Castling Squares. Which makes the C++ compiler emit 64 functions for all 6 independent flags.
The beauty of this is that the current color implemented as a template removes all lookups like pawn move direction etc. Code checks for Castling are only in the assembly if it is possible to castle. Once a Rook / King moves - Not a single instruction is used for castling. Not even a single if. It gets if constexpr pruned away.
The reciever for all possible moves are 8 Methods that are named after each piece and movetype - and the from - to squares are there for you in bitboard form. So its almost free to count all castling moves etc. It wont even add a single if instruction. This approach needs no movelist at all - but you can still store the move inside the callback.
What I would like for you the reader to do: Try to find any mistakes or slow stuff in my code. Tear it apart - think about it - ideally comment below with ideas how to make it faster - or better send a pull request into the github repo!https://github.com/Gigantua/Gigantua
Compile with Visual studio or Linux - Clang -march=native -std=c++20 -lstdc++ -O3 Gigantua.cpp -flto -o giga_clang
Greetings! - Daniel Inführ