The choice here is an expanded bitboard and non obvious. WPawn(wp), WKnight(wn), WBishop(wb), WRook(wr), WQueen(wq), WKing(wk), Map wp, map wn, map wb, map wr, map wq, map wk) :īPawn(bp), BKnight(bn), BBishop(bb), BRook(br), BQueen(bq), BKing(bk), Map bp, map bn, map bb, map br, map bq, map bk, It takes one instruction to remove forbidden moves no matter how many there are.Ĭonst map BPawn const map BKnight const map BBishop const map BRook Ĭonst map WPawn const map WKnight map WBishop const map WRook That is the beauty of the bitboard approach. Moving the king up and left on the board is literally only King <<= 9. But Bitboards also means that moving can be done very efficiently by just shifting the king around. It is clear that the space efficiency for the king is not very good since it's only a single bit out of 64. We define a canonical Chess Bitboard: map = uint64_t This is one core piece of any chess engine.
#CHINESE CHECKERS MOVES CODE#
A very fast piece of code to expand any position into all possible answers. Asking the possible move count question for depth 7 - will take 2100ms. Where if building an engine aggressive pruning methods need to happen to see good and appropriate moves 20 plys deep. (I will count a move as a node)Ĭhess is an exponential expanding tree with a branching factor of ~25. That is 119 Million in 85ms or just about 1400 Million nodes per second. How many moves are in this position after 3 moves by each player?Ī movegenerator can answer these questions very fast. The cost is there but it is hidden most of the time. Compilers and Cpus do a good job of hiding branch latency - yet by replacing an if else chain by branchless bitwise arithmetic - an order of magnitude, faster code can be achieved.
Every State that exists in only a handful of positions out of Billions should not even need an if statement.
It can be captured in a special way by another pawn. inserting domain knowledge into the codeįor example, after pushing a pawn from the first Rank - an Enpassant Pawn is created.replacing branches by branchless programming.moving as much work as possible into compiletime.Writing fast code in any programming language means: Template metaprogramming and constexpr evaluation in C++ give us these tools. The fastest possible piece of code you can ever write is non existing code.
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