X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.cpp;h=9598aa706552f5f38da88c50bc7b734dd6b35919;hp=bc05bfa070c7d9d4afd7dba717443eaa957208e6;hb=49e110c52b19f5c99954d4797b8e991b0b60007c;hpb=d85cf6d9c3fb31865d9b671d2475a6a81e84e070 diff --git a/src/bitboard.cpp b/src/bitboard.cpp index bc05bfa0..9598aa70 100644 --- a/src/bitboard.cpp +++ b/src/bitboard.cpp @@ -1,7 +1,7 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -17,486 +17,323 @@ along with this program. If not, see . */ +#include +#include #include #include "bitboard.h" #include "bitcount.h" +#include "misc.h" +#include "rkiss.h" + +CACHE_LINE_ALIGNMENT + +Bitboard RMasks[SQUARE_NB]; +Bitboard RMagics[SQUARE_NB]; +Bitboard* RAttacks[SQUARE_NB]; +unsigned RShifts[SQUARE_NB]; + +Bitboard BMasks[SQUARE_NB]; +Bitboard BMagics[SQUARE_NB]; +Bitboard* BAttacks[SQUARE_NB]; +unsigned BShifts[SQUARE_NB]; + +Bitboard SquareBB[SQUARE_NB]; +Bitboard FileBB[FILE_NB]; +Bitboard RankBB[RANK_NB]; +Bitboard AdjacentFilesBB[FILE_NB]; +Bitboard InFrontBB[COLOR_NB][RANK_NB]; +Bitboard StepAttacksBB[PIECE_NB][SQUARE_NB]; +Bitboard BetweenBB[SQUARE_NB][SQUARE_NB]; +Bitboard DistanceRingsBB[SQUARE_NB][8]; +Bitboard ForwardBB[COLOR_NB][SQUARE_NB]; +Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB]; +Bitboard PawnAttackSpan[COLOR_NB][SQUARE_NB]; +Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB]; + +int SquareDistance[SQUARE_NB][SQUARE_NB]; -#if defined(IS_64BIT) - -const uint64_t BMult[64] = { - 0x0440049104032280ULL, 0x1021023C82008040ULL, 0x0404040082000048ULL, - 0x48C4440084048090ULL, 0x2801104026490000ULL, 0x4100880442040800ULL, - 0x0181011002E06040ULL, 0x9101004104200E00ULL, 0x1240848848310401ULL, - 0x2000142828050024ULL, 0x00001004024D5000ULL, 0x0102044400800200ULL, - 0x8108108820112000ULL, 0xA880818210C00046ULL, 0x4008008801082000ULL, - 0x0060882404049400ULL, 0x0104402004240810ULL, 0x000A002084250200ULL, - 0x00100B0880801100ULL, 0x0004080201220101ULL, 0x0044008080A00000ULL, - 0x0000202200842000ULL, 0x5006004882D00808ULL, 0x0000200045080802ULL, - 0x0086100020200601ULL, 0xA802080A20112C02ULL, 0x0080411218080900ULL, - 0x000200A0880080A0ULL, 0x9A01010000104000ULL, 0x0028008003100080ULL, - 0x0211021004480417ULL, 0x0401004188220806ULL, 0x00825051400C2006ULL, - 0x00140C0210943000ULL, 0x0000242800300080ULL, 0x00C2208120080200ULL, - 0x2430008200002200ULL, 0x1010100112008040ULL, 0x8141050100020842ULL, - 0x0000822081014405ULL, 0x800C049E40400804ULL, 0x4A0404028A000820ULL, - 0x0022060201041200ULL, 0x0360904200840801ULL, 0x0881A08208800400ULL, - 0x0060202C00400420ULL, 0x1204440086061400ULL, 0x0008184042804040ULL, - 0x0064040315300400ULL, 0x0C01008801090A00ULL, 0x0808010401140C00ULL, - 0x04004830C2020040ULL, 0x0080005002020054ULL, 0x40000C14481A0490ULL, - 0x0010500101042048ULL, 0x1010100200424000ULL, 0x0000640901901040ULL, - 0x00000A0201014840ULL, 0x00840082AA011002ULL, 0x010010840084240AULL, - 0x0420400810420608ULL, 0x8D40230408102100ULL, 0x4A00200612222409ULL, - 0x0A08520292120600ULL -}; - -const uint64_t RMult[64] = { - 0x0A8002C000108020ULL, 0x4440200140003000ULL, 0x8080200010011880ULL, - 0x0380180080141000ULL, 0x1A00060008211044ULL, 0x410001000A0C0008ULL, - 0x9500060004008100ULL, 0x0100024284A20700ULL, 0x0000802140008000ULL, - 0x0080C01002A00840ULL, 0x0402004282011020ULL, 0x9862000820420050ULL, - 0x0001001448011100ULL, 0x6432800200800400ULL, 0x040100010002000CULL, - 0x0002800D0010C080ULL, 0x90C0008000803042ULL, 0x4010004000200041ULL, - 0x0003010010200040ULL, 0x0A40828028001000ULL, 0x0123010008000430ULL, - 0x0024008004020080ULL, 0x0060040001104802ULL, 0x00582200028400D1ULL, - 0x4000802080044000ULL, 0x0408208200420308ULL, 0x0610038080102000ULL, - 0x3601000900100020ULL, 0x0000080080040180ULL, 0x00C2020080040080ULL, - 0x0080084400100102ULL, 0x4022408200014401ULL, 0x0040052040800082ULL, - 0x0B08200280804000ULL, 0x008A80A008801000ULL, 0x4000480080801000ULL, - 0x0911808800801401ULL, 0x822A003002001894ULL, 0x401068091400108AULL, - 0x000004A10A00004CULL, 0x2000800640008024ULL, 0x1486408102020020ULL, - 0x000100A000D50041ULL, 0x00810050020B0020ULL, 0x0204000800808004ULL, - 0x00020048100A000CULL, 0x0112000831020004ULL, 0x0009000040810002ULL, - 0x0440490200208200ULL, 0x8910401000200040ULL, 0x6404200050008480ULL, - 0x4B824A2010010100ULL, 0x04080801810C0080ULL, 0x00000400802A0080ULL, - 0x8224080110026400ULL, 0x40002C4104088200ULL, 0x01002100104A0282ULL, - 0x1208400811048021ULL, 0x3201014A40D02001ULL, 0x0005100019200501ULL, - 0x0101000208001005ULL, 0x0002008450080702ULL, 0x001002080301D00CULL, - 0x410201CE5C030092ULL -}; - -const int BShift[64] = { - 58, 59, 59, 59, 59, 59, 59, 58, 59, 59, 59, 59, 59, 59, 59, 59, - 59, 59, 57, 57, 57, 57, 59, 59, 59, 59, 57, 55, 55, 57, 59, 59, - 59, 59, 57, 55, 55, 57, 59, 59, 59, 59, 57, 57, 57, 57, 59, 59, - 59, 59, 59, 59, 59, 59, 59, 59, 58, 59, 59, 59, 59, 59, 59, 58 -}; - -const int RShift[64] = { - 52, 53, 53, 53, 53, 53, 53, 52, 53, 54, 54, 54, 54, 54, 54, 53, - 53, 54, 54, 54, 54, 54, 54, 53, 53, 54, 54, 54, 54, 54, 54, 53, - 53, 54, 54, 54, 54, 54, 54, 53, 53, 54, 54, 54, 54, 54, 54, 53, - 53, 54, 54, 54, 54, 54, 54, 53, 52, 53, 53, 53, 53, 53, 53, 52 -}; - -#else // if !defined(IS_64BIT) - -const uint64_t BMult[64] = { - 0x54142844C6A22981ULL, 0x710358A6EA25C19EULL, 0x704F746D63A4A8DCULL, - 0xBFED1A0B80F838C5ULL, 0x90561D5631E62110ULL, 0x2804260376E60944ULL, - 0x84A656409AA76871ULL, 0xF0267F64C28B6197ULL, 0x70764EBB762F0585ULL, - 0x92AA09E0CFE161DEULL, 0x41EE1F6BB266F60EULL, 0xDDCBF04F6039C444ULL, - 0x5A3FAB7BAC0D988AULL, 0xD3727877FA4EAA03ULL, 0xD988402D868DDAAEULL, - 0x812B291AFA075C7CULL, 0x94FAF987B685A932ULL, 0x3ED867D8470D08DBULL, - 0x92517660B8901DE8ULL, 0x2D97E43E058814B4ULL, 0x880A10C220B25582ULL, - 0xC7C6520D1F1A0477ULL, 0xDBFC7FBCD7656AA6ULL, 0x78B1B9BFB1A2B84FULL, - 0x2F20037F112A0BC1ULL, 0x657171EA2269A916ULL, 0xC08302B07142210EULL, - 0x0880A4403064080BULL, 0x3602420842208C00ULL, 0x852800DC7E0B6602ULL, - 0x595A3FBBAA0F03B2ULL, 0x9F01411558159D5EULL, 0x2B4A4A5F88B394F2ULL, - 0x4AFCBFFC292DD03AULL, 0x4A4094A3B3F10522ULL, 0xB06F00B491F30048ULL, - 0xD5B3820280D77004ULL, 0x8B2E01E7C8E57A75ULL, 0x2D342794E886C2E6ULL, - 0xC302C410CDE21461ULL, 0x111F426F1379C274ULL, 0xE0569220ABB31588ULL, - 0x5026D3064D453324ULL, 0xE2076040C343CD8AULL, 0x93EFD1E1738021EEULL, - 0xB680804BED143132ULL, 0x44E361B21986944CULL, 0x44C60170EF5C598CULL, - 0xF4DA475C195C9C94ULL, 0xA3AFBB5F72060B1DULL, 0xBC75F410E41C4FFCULL, - 0xB51C099390520922ULL, 0x902C011F8F8EC368ULL, 0x950B56B3D6F5490AULL, - 0x3909E0635BF202D0ULL, 0x5744F90206EC10CCULL, 0xDC59FD76317ABBC1ULL, - 0x881C7C67FCBFC4F6ULL, 0x47CA41E7E440D423ULL, 0xEB0C88112048D004ULL, - 0x51C60E04359AEF1AULL, 0x1AA1FE0E957A5554ULL, 0xDD9448DB4F5E3104ULL, - 0xDC01F6DCA4BEBBDCULL, -}; - -const uint64_t RMult[64] = { - 0xD7445CDEC88002C0ULL, 0xD0A505C1F2001722ULL, 0xE065D1C896002182ULL, - 0x9A8C41E75A000892ULL, 0x8900B10C89002AA8ULL, 0x9B28D1C1D60005A2ULL, - 0x015D6C88DE002D9AULL, 0xB1DBFC802E8016A9ULL, 0x149A1042D9D60029ULL, - 0xB9C08050599E002FULL, 0x132208C3AF300403ULL, 0xC1000CE2E9C50070ULL, - 0x9D9AA13C99020012ULL, 0xB6B078DAF71E0046ULL, 0x9D880182FB6E002EULL, - 0x52889F467E850037ULL, 0xDA6DC008D19A8480ULL, 0x468286034F902420ULL, - 0x7140AC09DC54C020ULL, 0xD76FFFFA39548808ULL, 0xEA901C4141500808ULL, - 0xC91004093F953A02ULL, 0x02882AFA8F6BB402ULL, 0xAEBE335692442C01ULL, - 0x0E904A22079FB91EULL, 0x13A514851055F606ULL, 0x76C782018C8FE632ULL, - 0x1DC012A9D116DA06ULL, 0x3C9E0037264FFFA6ULL, 0x2036002853C6E4A2ULL, - 0xE3FE08500AFB47D4ULL, 0xF38AF25C86B025C2ULL, 0xC0800E2182CF9A40ULL, - 0x72002480D1F60673ULL, 0x2500200BAE6E9B53ULL, 0xC60018C1EEFCA252ULL, - 0x0600590473E3608AULL, 0x46002C4AB3FE51B2ULL, 0xA200011486BCC8D2ULL, - 0xB680078095784C63ULL, 0x2742002639BF11AEULL, 0xC7D60021A5BDB142ULL, - 0xC8C04016BB83D820ULL, 0xBD520028123B4842ULL, 0x9D1600344AC2A832ULL, - 0x6A808005631C8A05ULL, 0x604600A148D5389AULL, 0xE2E40103D40DEA65ULL, - 0x945B5A0087C62A81ULL, 0x012DC200CD82D28EULL, 0x2431C600B5F9EF76ULL, - 0xFB142A006A9B314AULL, 0x06870E00A1C97D62ULL, 0x2A9DB2004A2689A2ULL, - 0xD3594600CAF5D1A2ULL, 0xEE0E4900439344A7ULL, 0x89C4D266CA25007AULL, - 0x3E0013A2743F97E3ULL, 0x0180E31A0431378AULL, 0x3A9E465A4D42A512ULL, - 0x98D0A11A0C0D9CC2ULL, 0x8E711C1ABA19B01EULL, 0x8DCDC836DD201142ULL, - 0x5AC08A4735370479ULL, -}; - -const int BShift[64] = { - 26, 27, 27, 27, 27, 27, 27, 26, 27, 27, 27, 27, 27, 27, 27, 27, - 27, 27, 25, 25, 25, 25, 27, 27, 27, 27, 25, 23, 23, 25, 27, 27, - 27, 27, 25, 23, 23, 25, 27, 27, 27, 27, 25, 25, 25, 25, 27, 27, - 27, 27, 27, 27, 27, 27, 27, 27, 26, 27, 27, 27, 27, 27, 27, 26 -}; - -const int RShift[64] = { - 20, 21, 21, 21, 21, 21, 21, 20, 21, 22, 22, 22, 22, 22, 22, 21, - 21, 22, 22, 22, 22, 22, 22, 21, 21, 22, 22, 22, 22, 22, 22, 21, - 21, 22, 22, 22, 22, 22, 22, 21, 21, 22, 22, 22, 22, 22, 22, 21, - 21, 22, 22, 22, 22, 22, 22, 21, 20, 21, 21, 21, 21, 21, 21, 20 -}; - -#endif // defined(IS_64BIT) - -static const Bitboard DarkSquaresBB = 0xAA55AA55AA55AA55ULL; - -const Bitboard SquaresByColorBB[2] = { DarkSquaresBB, ~DarkSquaresBB }; - -const Bitboard FileBB[8] = { - FileABB, FileBBB, FileCBB, FileDBB, FileEBB, FileFBB, FileGBB, FileHBB -}; - -const Bitboard NeighboringFilesBB[8] = { - FileBBB, FileABB|FileCBB, FileBBB|FileDBB, FileCBB|FileEBB, - FileDBB|FileFBB, FileEBB|FileGBB, FileFBB|FileHBB, FileGBB -}; - -const Bitboard ThisAndNeighboringFilesBB[8] = { - FileABB|FileBBB, FileABB|FileBBB|FileCBB, - FileBBB|FileCBB|FileDBB, FileCBB|FileDBB|FileEBB, - FileDBB|FileEBB|FileFBB, FileEBB|FileFBB|FileGBB, - FileFBB|FileGBB|FileHBB, FileGBB|FileHBB -}; - -const Bitboard RankBB[8] = { - Rank1BB, Rank2BB, Rank3BB, Rank4BB, Rank5BB, Rank6BB, Rank7BB, Rank8BB -}; - -const Bitboard InFrontBB[2][8] = { - { Rank2BB | Rank3BB | Rank4BB | Rank5BB | Rank6BB | Rank7BB | Rank8BB, - Rank3BB | Rank4BB | Rank5BB | Rank6BB | Rank7BB | Rank8BB, - Rank4BB | Rank5BB | Rank6BB | Rank7BB | Rank8BB, - Rank5BB | Rank6BB | Rank7BB | Rank8BB, - Rank6BB | Rank7BB | Rank8BB, - Rank7BB | Rank8BB, - Rank8BB, - EmptyBoardBB - }, - { EmptyBoardBB, - Rank1BB, - Rank2BB | Rank1BB, - Rank3BB | Rank2BB | Rank1BB, - Rank4BB | Rank3BB | Rank2BB | Rank1BB, - Rank5BB | Rank4BB | Rank3BB | Rank2BB | Rank1BB, - Rank6BB | Rank5BB | Rank4BB | Rank3BB | Rank2BB | Rank1BB, - Rank7BB | Rank6BB | Rank5BB | Rank4BB | Rank3BB | Rank2BB | Rank1BB - } -}; - -// Global bitboards definitions with static storage duration are -// automatically set to zero before enter main(). -Bitboard RMask[64]; -int RAttackIndex[64]; -Bitboard RAttacks[0x19000]; - -Bitboard BMask[64]; -int BAttackIndex[64]; -Bitboard BAttacks[0x1480]; +namespace { -Bitboard SetMaskBB[65]; -Bitboard ClearMaskBB[65]; + // De Bruijn sequences. See chessprogramming.wikispaces.com/BitScan + const uint64_t DeBruijn_64 = 0x3F79D71B4CB0A89ULL; + const uint32_t DeBruijn_32 = 0x783A9B23; -Bitboard NonSlidingAttacksBB[16][64]; -Bitboard BetweenBB[64][64]; + CACHE_LINE_ALIGNMENT -Bitboard SquaresInFrontMask[2][64]; -Bitboard PassedPawnMask[2][64]; -Bitboard AttackSpanMask[2][64]; + int MS1BTable[256]; + Square BSFTable[SQUARE_NB]; + Bitboard RTable[0x19000]; // Storage space for rook attacks + Bitboard BTable[0x1480]; // Storage space for bishop attacks -Bitboard BishopPseudoAttacks[64]; -Bitboard RookPseudoAttacks[64]; -Bitboard QueenPseudoAttacks[64]; + typedef unsigned (Fn)(Square, Bitboard); -uint8_t BitCount8Bit[256]; + void init_magics(Bitboard table[], Bitboard* attacks[], Bitboard magics[], + Bitboard masks[], unsigned shifts[], Square deltas[], Fn index); + FORCE_INLINE unsigned bsf_index(Bitboard b) { -namespace { - - void init_masks(); - void init_non_sliding_attacks(); - void init_pseudo_attacks(); - void init_between_bitboards(); - Bitboard index_to_bitboard(int index, Bitboard mask); - Bitboard sliding_attacks(int sq, Bitboard occupied, int deltas[][2], - int fmin, int fmax, int rmin, int rmax); - void init_sliding_attacks(Bitboard attacks[], int attackIndex[], Bitboard mask[], - const int shift[], const Bitboard mult[], int deltas[][2]); + // Matt Taylor's folding for 32 bit systems, extended to 64 bits by Kim Walisch + b ^= (b - 1); + return Is64Bit ? (b * DeBruijn_64) >> 58 + : ((unsigned(b) ^ unsigned(b >> 32)) * DeBruijn_32) >> 26; + } } +/// lsb()/msb() finds the least/most significant bit in a nonzero bitboard. +/// pop_lsb() finds and clears the least significant bit in a nonzero bitboard. -/// print_bitboard() prints a bitboard in an easily readable format to the -/// standard output. This is sometimes useful for debugging. +#ifndef USE_BSFQ -void print_bitboard(Bitboard b) { +Square lsb(Bitboard b) { return BSFTable[bsf_index(b)]; } - for (Rank r = RANK_8; r >= RANK_1; r--) - { - std::cout << "+---+---+---+---+---+---+---+---+" << '\n'; - for (File f = FILE_A; f <= FILE_H; f++) - std::cout << "| " << (bit_is_set(b, make_square(f, r)) ? 'X' : ' ') << ' '; +Square pop_lsb(Bitboard* b) { - std::cout << "|\n"; - } - std::cout << "+---+---+---+---+---+---+---+---+" << std::endl; + Bitboard bb = *b; + *b = bb & (bb - 1); + return BSFTable[bsf_index(bb)]; } +Square msb(Bitboard b) { -/// first_1() finds the least significant nonzero bit in a nonzero bitboard. -/// pop_1st_bit() finds and clears the least significant nonzero bit in a -/// nonzero bitboard. + unsigned b32; + int result = 0; -#if defined(IS_64BIT) && !defined(USE_BSFQ) + if (b > 0xFFFFFFFF) + { + b >>= 32; + result = 32; + } -static CACHE_LINE_ALIGNMENT -const int BitTable[64] = { - 0, 1, 2, 7, 3, 13, 8, 19, 4, 25, 14, 28, 9, 34, 20, 40, 5, 17, 26, - 38, 15, 46, 29, 48, 10, 31, 35, 54, 21, 50, 41, 57, 63, 6, 12, 18, 24, 27, - 33, 39, 16, 37, 45, 47, 30, 53, 49, 56, 62, 11, 23, 32, 36, 44, 52, 55, 61, - 22, 43, 51, 60, 42, 59, 58 -}; + b32 = unsigned(b); -Square first_1(Bitboard b) { - return Square(BitTable[((b & -b) * 0x218a392cd3d5dbfULL) >> 58]); -} + if (b32 > 0xFFFF) + { + b32 >>= 16; + result += 16; + } -Square pop_1st_bit(Bitboard* b) { - Bitboard bb = *b; - *b &= (*b - 1); - return Square(BitTable[((bb & -bb) * 0x218a392cd3d5dbfULL) >> 58]); -} + if (b32 > 0xFF) + { + b32 >>= 8; + result += 8; + } -#elif !defined(USE_BSFQ) + return (Square)(result + MS1BTable[b32]); +} -static CACHE_LINE_ALIGNMENT -const int BitTable[64] = { - 63, 30, 3, 32, 25, 41, 22, 33, 15, 50, 42, 13, 11, 53, 19, 34, 61, 29, 2, - 51, 21, 43, 45, 10, 18, 47, 1, 54, 9, 57, 0, 35, 62, 31, 40, 4, 49, 5, - 52, 26, 60, 6, 23, 44, 46, 27, 56, 16, 7, 39, 48, 24, 59, 14, 12, 55, 38, - 28, 58, 20, 37, 17, 36, 8 -}; +#endif // ifndef USE_BSFQ -Square first_1(Bitboard b) { - b ^= (b - 1); - uint32_t fold = int(b) ^ int(b >> 32); - return Square(BitTable[(fold * 0x783a9b23) >> 26]); -} +/// Bitboards::print() prints a bitboard in an easily readable format to the +/// standard output. This is sometimes useful for debugging. -// Use type-punning -union b_union { - - Bitboard b; - struct { -#if defined (BIGENDIAN) - uint32_t h; - uint32_t l; -#else - uint32_t l; - uint32_t h; -#endif - } dw; -}; - -Square pop_1st_bit(Bitboard* bb) { - - b_union u; - Square ret; - - u.b = *bb; - - if (u.dw.l) - { - ret = Square(BitTable[((u.dw.l ^ (u.dw.l - 1)) * 0x783a9b23) >> 26]); - u.dw.l &= (u.dw.l - 1); - *bb = u.b; - return ret; - } - ret = Square(BitTable[((~(u.dw.h ^ (u.dw.h - 1))) * 0x783a9b23) >> 26]); - u.dw.h &= (u.dw.h - 1); - *bb = u.b; - return ret; -} +void Bitboards::print(Bitboard b) { -#endif // !defined(USE_BSFQ) + sync_cout; + for (Rank rank = RANK_8; rank >= RANK_1; rank--) + { + std::cout << "+---+---+---+---+---+---+---+---+" << '\n'; -/// init_bitboards() initializes various bitboard arrays. It is called during -/// program initialization. + for (File file = FILE_A; file <= FILE_H; file++) + std::cout << "| " << (b & (file | rank) ? "X " : " "); -void init_bitboards() { + std::cout << "|\n"; + } + std::cout << "+---+---+---+---+---+---+---+---+" << sync_endl; +} - int rookDeltas[4][2] = {{0,1},{0,-1},{1,0},{-1,0}}; - int bishopDeltas[4][2] = {{1,1},{-1,1},{1,-1},{-1,-1}}; - init_masks(); - init_non_sliding_attacks(); - init_sliding_attacks(RAttacks, RAttackIndex, RMask, RShift, RMult, rookDeltas); - init_sliding_attacks(BAttacks, BAttackIndex, BMask, BShift, BMult, bishopDeltas); - init_pseudo_attacks(); - init_between_bitboards(); -} +/// Bitboards::init() initializes various bitboard arrays. It is called during +/// program initialization. -namespace { +void Bitboards::init() { - // All functions below are used to precompute various bitboards during - // program initialization. Some of the functions may be difficult to - // understand, but they all seem to work correctly, and it should never - // be necessary to touch any of them. + for (int k = 0, i = 0; i < 8; i++) + while (k < (2 << i)) + MS1BTable[k++] = i; - void init_masks() { + for (int i = 0; i < 64; i++) + BSFTable[bsf_index(1ULL << i)] = Square(i); - SetMaskBB[SQ_NONE] = EmptyBoardBB; - ClearMaskBB[SQ_NONE] = ~SetMaskBB[SQ_NONE]; + for (Square s = SQ_A1; s <= SQ_H8; s++) + SquareBB[s] = 1ULL << s; - for (Square s = SQ_A1; s <= SQ_H8; s++) - { - SetMaskBB[s] = (1ULL << s); - ClearMaskBB[s] = ~SetMaskBB[s]; - } + FileBB[FILE_A] = FileABB; + RankBB[RANK_1] = Rank1BB; - for (Color c = WHITE; c <= BLACK; c++) - for (Square s = SQ_A1; s <= SQ_H8; s++) - { - SquaresInFrontMask[c][s] = in_front_bb(c, s) & file_bb(s); - PassedPawnMask[c][s] = in_front_bb(c, s) & this_and_neighboring_files_bb(s); - AttackSpanMask[c][s] = in_front_bb(c, s) & neighboring_files_bb(s); - } + for (int i = 1; i < 8; i++) + { + FileBB[i] = FileBB[i - 1] << 1; + RankBB[i] = RankBB[i - 1] << 8; + } - for (Bitboard b = 0; b < 256; b++) - BitCount8Bit[b] = (uint8_t)count_1s(b); + for (File f = FILE_A; f <= FILE_H; f++) + AdjacentFilesBB[f] = (f > FILE_A ? FileBB[f - 1] : 0) | (f < FILE_H ? FileBB[f + 1] : 0); + + for (Rank r = RANK_1; r < RANK_8; r++) + InFrontBB[WHITE][r] = ~(InFrontBB[BLACK][r + 1] = InFrontBB[BLACK][r] | RankBB[r]); + + for (Color c = WHITE; c <= BLACK; c++) + for (Square s = SQ_A1; s <= SQ_H8; s++) + { + ForwardBB[c][s] = InFrontBB[c][rank_of(s)] & FileBB[file_of(s)]; + PawnAttackSpan[c][s] = InFrontBB[c][rank_of(s)] & AdjacentFilesBB[file_of(s)]; + PassedPawnMask[c][s] = ForwardBB[c][s] | PawnAttackSpan[c][s]; + } + + for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++) + for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++) + { + SquareDistance[s1][s2] = std::max(file_distance(s1, s2), rank_distance(s1, s2)); + if (s1 != s2) + DistanceRingsBB[s1][SquareDistance[s1][s2] - 1] |= s2; + } + + int steps[][9] = { {}, { 7, 9 }, { 17, 15, 10, 6, -6, -10, -15, -17 }, + {}, {}, {}, { 9, 7, -7, -9, 8, 1, -1, -8 } }; + + for (Color c = WHITE; c <= BLACK; c++) + for (PieceType pt = PAWN; pt <= KING; pt++) + for (Square s = SQ_A1; s <= SQ_H8; s++) + for (int k = 0; steps[pt][k]; k++) + { + Square to = s + Square(c == WHITE ? steps[pt][k] : -steps[pt][k]); + + if (is_ok(to) && square_distance(s, to) < 3) + StepAttacksBB[make_piece(c, pt)][s] |= to; + } + + Square RDeltas[] = { DELTA_N, DELTA_E, DELTA_S, DELTA_W }; + Square BDeltas[] = { DELTA_NE, DELTA_SE, DELTA_SW, DELTA_NW }; + + init_magics(RTable, RAttacks, RMagics, RMasks, RShifts, RDeltas, magic_index); + init_magics(BTable, BAttacks, BMagics, BMasks, BShifts, BDeltas, magic_index); + + for (Square s = SQ_A1; s <= SQ_H8; s++) + { + PseudoAttacks[QUEEN][s] = PseudoAttacks[BISHOP][s] = attacks_bb(s, 0); + PseudoAttacks[QUEEN][s] |= PseudoAttacks[ ROOK][s] = attacks_bb< ROOK>(s, 0); } - void init_non_sliding_attacks() { + for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++) + for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++) + if (PseudoAttacks[QUEEN][s1] & s2) + { + Square delta = (s2 - s1) / square_distance(s1, s2); + + for (Square s = s1 + delta; s != s2; s += delta) + BetweenBB[s1][s2] |= s; + } +} - const int step[][9] = { - {0}, - {7,9,0}, {17,15,10,6,-6,-10,-15,-17,0}, {0}, {0}, {0}, - {9,7,-7,-9,8,1,-1,-8,0}, {0}, {0}, - {-7,-9,0}, {17,15,10,6,-6,-10,-15,-17,0}, {0}, {0}, {0}, - {9,7,-7,-9,8,1,-1,-8,0} - }; - for (Square s = SQ_A1; s <= SQ_H8; s++) - for (Piece pc = WP; pc <= BK; pc++) - for (int k = 0; step[pc][k] != 0; k++) - { - Square to = s + Square(step[pc][k]); +namespace { - if (square_is_ok(to) && square_distance(s, to) < 3) - set_bit(&NonSlidingAttacksBB[pc][s], to); - } - } + Bitboard sliding_attack(Square deltas[], Square sq, Bitboard occupied) { - Bitboard sliding_attacks(int sq, Bitboard occupied, int deltas[][2], - int fmin, int fmax, int rmin, int rmax) { - int dx, dy, f, r; - int rk = sq / 8; - int fl = sq % 8; - Bitboard attacks = EmptyBoardBB; + Bitboard attack = 0; for (int i = 0; i < 4; i++) - { - dx = deltas[i][0]; - dy = deltas[i][1]; - f = fl + dx; - r = rk + dy; - - while ( (dx == 0 || (f >= fmin && f <= fmax)) - && (dy == 0 || (r >= rmin && r <= rmax))) + for (Square s = sq + deltas[i]; + is_ok(s) && square_distance(s, s - deltas[i]) == 1; + s += deltas[i]) { - attacks |= (1ULL << (f + r * 8)); + attack |= s; - if (occupied & (1ULL << (f + r * 8))) + if (occupied & s) break; - - f += dx; - r += dy; } - } - return attacks; + + return attack; } - Bitboard index_to_bitboard(int index, Bitboard mask) { - Bitboard result = EmptyBoardBB; - int sq, cnt = 0; + Bitboard pick_random(RKISS& rk, int booster) { - while (mask) - { - sq = pop_1st_bit(&mask); + // Values s1 and s2 are used to rotate the candidate magic of a + // quantity known to be the optimal to quickly find the magics. + int s1 = booster & 63, s2 = (booster >> 6) & 63; - if (index & (1 << cnt++)) - result |= (1ULL << sq); - } - return result; + Bitboard m = rk.rand(); + m = (m >> s1) | (m << (64 - s1)); + m &= rk.rand(); + m = (m >> s2) | (m << (64 - s2)); + return m & rk.rand(); } - void init_sliding_attacks(Bitboard attacks[], int attackIndex[], Bitboard mask[], - const int shift[], const Bitboard mult[], int deltas[][2]) { - Bitboard b, v; - int i, j, index; - for (i = index = 0; i < 64; i++) - { - attackIndex[i] = index; - mask[i] = sliding_attacks(i, 0, deltas, 1, 6, 1, 6); - j = 1 << ((CpuIs64Bit ? 64 : 32) - shift[i]); + // init_magics() computes all rook and bishop attacks at startup. Magic + // bitboards are used to look up attacks of sliding pieces. As a reference see + // chessprogramming.wikispaces.com/Magic+Bitboards. In particular, here we + // use the so called "fancy" approach. - for (int k = 0; k < j; k++) - { - b = index_to_bitboard(k, mask[i]); - v = CpuIs64Bit ? b * mult[i] : unsigned(b * mult[i] ^ (b >> 32) * (mult[i] >> 32)); - attacks[index + (v >> shift[i])] = sliding_attacks(i, b, deltas, 0, 7, 0, 7); - } - index += j; - } - } + void init_magics(Bitboard table[], Bitboard* attacks[], Bitboard magics[], + Bitboard masks[], unsigned shifts[], Square deltas[], Fn index) { + + int MagicBoosters[][8] = { { 3191, 2184, 1310, 3618, 2091, 1308, 2452, 3996 }, + { 1059, 3608, 605, 3234, 3326, 38, 2029, 3043 } }; + RKISS rk; + Bitboard occupancy[4096], reference[4096], edges, b; + int i, size, booster; - void init_pseudo_attacks() { + // attacks[s] is a pointer to the beginning of the attacks table for square 's' + attacks[SQ_A1] = table; for (Square s = SQ_A1; s <= SQ_H8; s++) { - BishopPseudoAttacks[s] = bishop_attacks_bb(s, EmptyBoardBB); - RookPseudoAttacks[s] = rook_attacks_bb(s, EmptyBoardBB); - QueenPseudoAttacks[s] = queen_attacks_bb(s, EmptyBoardBB); - } - } - - void init_between_bitboards() { - - Square s1, s2, s3, d; - int f, r; - - for (s1 = SQ_A1; s1 <= SQ_H8; s1++) - for (s2 = SQ_A1; s2 <= SQ_H8; s2++) - if (bit_is_set(QueenPseudoAttacks[s1], s2)) + // Board edges are not considered in the relevant occupancies + edges = ((Rank1BB | Rank8BB) & ~rank_bb(s)) | ((FileABB | FileHBB) & ~file_bb(s)); + + // Given a square 's', the mask is the bitboard of sliding attacks from + // 's' computed on an empty board. The index must be big enough to contain + // all the attacks for each possible subset of the mask and so is 2 power + // the number of 1s of the mask. Hence we deduce the size of the shift to + // apply to the 64 or 32 bits word to get the index. + masks[s] = sliding_attack(deltas, s, 0) & ~edges; + shifts[s] = (Is64Bit ? 64 : 32) - popcount(masks[s]); + + // Use Carry-Rippler trick to enumerate all subsets of masks[s] and + // store the corresponding sliding attack bitboard in reference[]. + b = size = 0; + do { + occupancy[size] = b; + reference[size++] = sliding_attack(deltas, s, b); + b = (b - masks[s]) & masks[s]; + } while (b); + + // Set the offset for the table of the next square. We have individual + // table sizes for each square with "Fancy Magic Bitboards". + if (s < SQ_H8) + attacks[s + 1] = attacks[s] + size; + + booster = MagicBoosters[Is64Bit][rank_of(s)]; + + // Find a magic for square 's' picking up an (almost) random number + // until we find the one that passes the verification test. + do { + do magics[s] = pick_random(rk, booster); + while (popcount((magics[s] * masks[s]) >> 56) < 6); + + std::memset(attacks[s], 0, size * sizeof(Bitboard)); + + // A good magic must map every possible occupancy to an index that + // looks up the correct sliding attack in the attacks[s] database. + // Note that we build up the database for square 's' as a side + // effect of verifying the magic. + for (i = 0; i < size; i++) { - f = file_distance(s1, s2); - r = rank_distance(s1, s2); + Bitboard& attack = attacks[s][index(s, occupancy[i])]; + + if (attack && attack != reference[i]) + break; - d = (s2 - s1) / Max(f, r); + assert(reference[i] != 0); - for (s3 = s1 + d; s3 != s2; s3 += d) - set_bit(&(BetweenBB[s1][s2]), s3); + attack = reference[i]; } + } while (i != size); + } } - }