X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.cpp;h=57b24e2ef61b88ce5a4785b368df05739ffbbd44;hp=474e321c09fff8184330be1f27c79dae7c904d6f;hb=6482ce2bb2cb2c2450008afb58c7ef2e04d56841;hpb=9c428afb6dd0dcba2aa4e2a367a6b35c6f335be0 diff --git a/src/bitboard.cpp b/src/bitboard.cpp index 474e321c..57b24e2e 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) 2008-2009 Marco Costalba + Copyright (C) 2008-2012 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 @@ -17,527 +17,350 @@ along with this program. If not, see . */ - -//// -//// Includes -//// - -#ifdef _MSC_VER - #include - #ifdef _WIN64 - #pragma intrinsic(_BitScanForward64) - #else - #pragma intrinsic(_BitScanForward) - #endif - #define USING_INTRINSICS -#endif - +#include +#include #include #include "bitboard.h" -#include "direction.h" - - -#if defined(USE_COMPACT_ROOK_ATTACKS) - -Bitboard RankAttacks[8][64], FileAttacks[8][64]; - -#elif defined(USE_32BIT_ATTACKS) - -const uint64_t RMult[64] = { - 0xd7445cdec88002c0ULL, 0xd0a505c1f2001722ULL, 0xe065d1c896002182ULL, - 0x9a8c41e75a000892ULL, 0x8900b10c89002aa8ULL, 0x9b28d1c1d60005a2ULL, - 0x15d6c88de002d9aULL, 0xb1dbfc802e8016a9ULL, 0x149a1042d9d60029ULL, - 0xb9c08050599e002fULL, 0x132208c3af300403ULL, 0xc1000ce2e9c50070ULL, - 0x9d9aa13c99020012ULL, 0xb6b078daf71e0046ULL, 0x9d880182fb6e002eULL, - 0x52889f467e850037ULL, 0xda6dc008d19a8480ULL, 0x468286034f902420ULL, - 0x7140ac09dc54c020ULL, 0xd76ffffa39548808ULL, 0xea901c4141500808ULL, - 0xc91004093f953a02ULL, 0x2882afa8f6bb402ULL, 0xaebe335692442c01ULL, - 0xe904a22079fb91eULL, 0x13a514851055f606ULL, 0x76c782018c8fe632ULL, - 0x1dc012a9d116da06ULL, 0x3c9e0037264fffa6ULL, 0x2036002853c6e4a2ULL, - 0xe3fe08500afb47d4ULL, 0xf38af25c86b025c2ULL, 0xc0800e2182cf9a40ULL, - 0x72002480d1f60673ULL, 0x2500200bae6e9b53ULL, 0xc60018c1eefca252ULL, - 0x600590473e3608aULL, 0x46002c4ab3fe51b2ULL, 0xa200011486bcc8d2ULL, - 0xb680078095784c63ULL, 0x2742002639bf11aeULL, 0xc7d60021a5bdb142ULL, - 0xc8c04016bb83d820ULL, 0xbd520028123b4842ULL, 0x9d1600344ac2a832ULL, - 0x6a808005631c8a05ULL, 0x604600a148d5389aULL, 0xe2e40103d40dea65ULL, - 0x945b5a0087c62a81ULL, 0x12dc200cd82d28eULL, 0x2431c600b5f9ef76ULL, - 0xfb142a006a9b314aULL, 0x6870e00a1c97d62ULL, 0x2a9db2004a2689a2ULL, - 0xd3594600caf5d1a2ULL, 0xee0e4900439344a7ULL, 0x89c4d266ca25007aULL, - 0x3e0013a2743f97e3ULL, 0x180e31a0431378aULL, 0x3a9e465a4d42a512ULL, - 0x98d0a11a0c0d9cc2ULL, 0x8e711c1aba19b01eULL, 0x8dcdc836dd201142ULL, - 0x5ac08a4735370479ULL, -}; - -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 -}; - -#else // if defined(USE_32BIT_ATTACKS) - -const uint64_t RMult[64] = { - 0xa8002c000108020ULL, 0x4440200140003000ULL, 0x8080200010011880ULL, - 0x380180080141000ULL, 0x1a00060008211044ULL, 0x410001000a0c0008ULL, - 0x9500060004008100ULL, 0x100024284a20700ULL, 0x802140008000ULL, - 0x80c01002a00840ULL, 0x402004282011020ULL, 0x9862000820420050ULL, - 0x1001448011100ULL, 0x6432800200800400ULL, 0x40100010002000cULL, - 0x2800d0010c080ULL, 0x90c0008000803042ULL, 0x4010004000200041ULL, - 0x3010010200040ULL, 0xa40828028001000ULL, 0x123010008000430ULL, - 0x24008004020080ULL, 0x60040001104802ULL, 0x582200028400d1ULL, - 0x4000802080044000ULL, 0x408208200420308ULL, 0x610038080102000ULL, - 0x3601000900100020ULL, 0x80080040180ULL, 0xc2020080040080ULL, - 0x80084400100102ULL, 0x4022408200014401ULL, 0x40052040800082ULL, - 0xb08200280804000ULL, 0x8a80a008801000ULL, 0x4000480080801000ULL, - 0x911808800801401ULL, 0x822a003002001894ULL, 0x401068091400108aULL, - 0x4a10a00004cULL, 0x2000800640008024ULL, 0x1486408102020020ULL, - 0x100a000d50041ULL, 0x810050020b0020ULL, 0x204000800808004ULL, - 0x20048100a000cULL, 0x112000831020004ULL, 0x9000040810002ULL, - 0x440490200208200ULL, 0x8910401000200040ULL, 0x6404200050008480ULL, - 0x4b824a2010010100ULL, 0x4080801810c0080ULL, 0x400802a0080ULL, - 0x8224080110026400ULL, 0x40002c4104088200ULL, 0x1002100104a0282ULL, - 0x1208400811048021ULL, 0x3201014a40d02001ULL, 0x5100019200501ULL, - 0x101000208001005ULL, 0x2008450080702ULL, 0x1002080301d00cULL, - 0x410201ce5c030092ULL -}; - -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 -}; - -#endif // defined(USE_32BIT_ATTACKS) +#include "bitcount.h" +#include "rkiss.h" -#if !defined(USE_COMPACT_ROOK_ATTACKS) -Bitboard RMask[64]; -int RAttackIndex[64]; -Bitboard RAttacks[0x19000]; -#endif - -#if defined(USE_32BIT_ATTACKS) - -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, - 0x880a4403064080bULL, 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, -}; +Bitboard RMasks[64]; +Bitboard RMagics[64]; +Bitboard* RAttacks[64]; +int RShifts[64]; -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 -}; - -#else // if defined(USE_32BIT_ATTACKS) - -const uint64_t BMult[64] = { - 0x440049104032280ULL, 0x1021023c82008040ULL, 0x404040082000048ULL, - 0x48c4440084048090ULL, 0x2801104026490000ULL, 0x4100880442040800ULL, - 0x181011002e06040ULL, 0x9101004104200e00ULL, 0x1240848848310401ULL, - 0x2000142828050024ULL, 0x1004024d5000ULL, 0x102044400800200ULL, - 0x8108108820112000ULL, 0xa880818210c00046ULL, 0x4008008801082000ULL, - 0x60882404049400ULL, 0x104402004240810ULL, 0xa002084250200ULL, - 0x100b0880801100ULL, 0x4080201220101ULL, 0x44008080a00000ULL, - 0x202200842000ULL, 0x5006004882d00808ULL, 0x200045080802ULL, - 0x86100020200601ULL, 0xa802080a20112c02ULL, 0x80411218080900ULL, - 0x200a0880080a0ULL, 0x9a01010000104000ULL, 0x28008003100080ULL, - 0x211021004480417ULL, 0x401004188220806ULL, 0x825051400c2006ULL, - 0x140c0210943000ULL, 0x242800300080ULL, 0xc2208120080200ULL, - 0x2430008200002200ULL, 0x1010100112008040ULL, 0x8141050100020842ULL, - 0x822081014405ULL, 0x800c049e40400804ULL, 0x4a0404028a000820ULL, - 0x22060201041200ULL, 0x360904200840801ULL, 0x881a08208800400ULL, - 0x60202c00400420ULL, 0x1204440086061400ULL, 0x8184042804040ULL, - 0x64040315300400ULL, 0xc01008801090a00ULL, 0x808010401140c00ULL, - 0x4004830c2020040ULL, 0x80005002020054ULL, 0x40000c14481a0490ULL, - 0x10500101042048ULL, 0x1010100200424000ULL, 0x640901901040ULL, - 0xa0201014840ULL, 0x840082aa011002ULL, 0x10010840084240aULL, - 0x420400810420608ULL, 0x8d40230408102100ULL, 0x4a00200612222409ULL, - 0xa08520292120600ULL -}; - -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 -}; - -#endif // defined(USE_32BIT_ATTACKS) - -Bitboard BMask[64]; -int BAttackIndex[64]; -Bitboard BAttacks[0x1480]; +Bitboard BMasks[64]; +Bitboard BMagics[64]; +Bitboard* BAttacks[64]; +int BShifts[64]; Bitboard SetMaskBB[65]; Bitboard ClearMaskBB[65]; -Bitboard StepAttackBB[16][64]; -Bitboard RayBB[64][8]; +Bitboard FileBB[8]; +Bitboard RankBB[8]; +Bitboard NeighboringFilesBB[8]; +Bitboard ThisAndNeighboringFilesBB[8]; +Bitboard InFrontBB[2][8]; +Bitboard StepAttacksBB[16][64]; Bitboard BetweenBB[64][64]; - +Bitboard SquaresInFrontMask[2][64]; Bitboard PassedPawnMask[2][64]; -Bitboard OutpostMask[2][64]; +Bitboard AttackSpanMask[2][64]; Bitboard BishopPseudoAttacks[64]; Bitboard RookPseudoAttacks[64]; Bitboard QueenPseudoAttacks[64]; - -//// -//// Local definitions -//// +uint8_t BitCount8Bit[256]; +int SquareDistance[64][64]; namespace { - void init_masks(); - void init_ray_bitboards(); - void init_attacks(); - void init_between_bitboards(); - Bitboard sliding_attacks(int sq, Bitboard block, int dirs, int deltas[][2], - int fmin, int fmax, int rmin, int rmax); - Bitboard index_to_bitboard(int index, Bitboard mask); - void init_sliding_attacks(Bitboard attacks[], - int attackIndex[], Bitboard mask[], - const int shift[2], const Bitboard mult[], - int deltas[][2]); - void init_pseudo_attacks(); -#if defined(USE_COMPACT_ROOK_ATTACKS) - void init_file_and_rank_attacks(); -#endif -} + CACHE_LINE_ALIGNMENT + int BSFTable[64]; + Bitboard RookTable[0x19000]; // Storage space for rook attacks + Bitboard BishopTable[0x1480]; // Storage space for bishop attacks + + void init_magic_bitboards(PieceType pt, Bitboard* attacks[], Bitboard magics[], + Bitboard masks[], int shifts[]); +} -//// -//// Functions -//// /// print_bitboard() prints a bitboard in an easily readable format to the -/// standard output. This is sometimes useful for debugging. +/// standard output. This is sometimes useful for debugging. void print_bitboard(Bitboard b) { - for(Rank r = RANK_8; r >= RANK_1; r--) { - std::cout << "+---+---+---+---+---+---+---+---+" << std::endl; - for(File f = FILE_A; f <= FILE_H; f++) - std::cout << "| " << (bit_is_set(b, make_square(f, r))? 'X' : ' ') << ' '; - std::cout << "|" << std::endl; + + 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 " : " "); + + std::cout << "|\n"; } std::cout << "+---+---+---+---+---+---+---+---+" << std::endl; } -/// init_bitboards() initializes various bitboard arrays. It is called during -/// program initialization. - -void init_bitboards() { - 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_ray_bitboards(); - init_attacks(); - init_between_bitboards(); -#if defined(USE_COMPACT_ROOK_ATTACKS) - init_file_and_rank_attacks(); -#else - init_sliding_attacks(RAttacks, RAttackIndex, RMask, RShift, - RMult, rookDeltas); -#endif - init_sliding_attacks(BAttacks, BAttackIndex, BMask, BShift, - BMult, bishopDeltas); - init_pseudo_attacks(); -} - +/// 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. -#if defined(USE_FOLDED_BITSCAN) +#if defined(IS_64BIT) && !defined(USE_BSFQ) -static 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 -}; +Square first_1(Bitboard b) { + return Square(BSFTable[((b & -b) * 0x218A392CD3D5DBFULL) >> 58]); +} +Square pop_1st_bit(Bitboard* b) { + Bitboard bb = *b; + *b &= (*b - 1); + return Square(BSFTable[((bb & -bb) * 0x218A392CD3D5DBFULL) >> 58]); +} -/// first_1() finds the least significant nonzero bit in a nonzero bitboard. +#elif !defined(USE_BSFQ) Square first_1(Bitboard b) { b ^= (b - 1); - uint32_t fold = int(b) ^ int(b >> 32); - return Square(BitTable[(fold * 0x783a9b23) >> 26]); + uint32_t fold = unsigned(b) ^ unsigned(b >> 32); + return Square(BSFTable[(fold * 0x783A9B23) >> 26]); } - -/// pop_1st_bit() finds and clears the least significant nonzero bit in a -/// nonzero bitboard. - -#if defined(USE_32BIT_ATTACKS) - // 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; }; -// WARNING: Needs -fno-strict-aliasing compiler option -Square pop_1st_bit(Bitboard *bb) { +Square pop_1st_bit(Bitboard* bb) { - b_union u; - uint32_t b; + b_union u; + Square ret; - u.b = *bb; + u.b = *bb; - if (u.dw.l) - { - b = u.dw.l; - *((uint32_t*)bb) = b & (b - 1); - b ^= (b - 1); - } - else - { - b = u.dw.h; - *((uint32_t*)bb+1) = b & (b - 1); // Little endian only? - b = ~(b ^ (b - 1)); - } - return Square(BitTable[(b * 0x783a9b23) >> 26]); + if (u.dw.l) + { + ret = Square(BSFTable[((u.dw.l ^ (u.dw.l - 1)) * 0x783A9B23) >> 26]); + u.dw.l &= (u.dw.l - 1); + *bb = u.b; + return ret; + } + ret = Square(BSFTable[((~(u.dw.h ^ (u.dw.h - 1))) * 0x783A9B23) >> 26]); + u.dw.h &= (u.dw.h - 1); + *bb = u.b; + return ret; } -#else +#endif // !defined(USE_BSFQ) -Square pop_1st_bit(Bitboard *b) { - Bitboard bb = *b ^ (*b - 1); - uint32_t fold = int(bb) ^ int(bb >> 32); - *b &= (*b - 1); - return Square(BitTable[(fold * 0x783a9b23) >> 26]); -} -#endif +/// bitboards_init() initializes various bitboard arrays. It is called during +/// program initialization. -#else +void bitboards_init() { -static 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 -}; + for (Bitboard b = 0; b < 256; b++) + BitCount8Bit[b] = (uint8_t)popcount(b); + for (Square s = SQ_A1; s <= SQ_H8; s++) + { + SetMaskBB[s] = 1ULL << s; + ClearMaskBB[s] = ~SetMaskBB[s]; + } -/// first_1() finds the least significant nonzero bit in a nonzero bitboard. + ClearMaskBB[SQ_NONE] = ~0ULL; -Square first_1(Bitboard b) { - return Square(BitTable[((b & -b) * 0x218a392cd3d5dbfULL) >> 58]); -} + FileBB[FILE_A] = FileABB; + RankBB[RANK_1] = Rank1BB; + for (int f = FILE_B; f <= FILE_H; f++) + { + FileBB[f] = FileBB[f - 1] << 1; + RankBB[f] = RankBB[f - 1] << 8; + } -/// pop_1st_bit() finds and clears the least significant nonzero bit in a -/// nonzero bitboard. + for (int f = FILE_A; f <= FILE_H; f++) + { + NeighboringFilesBB[f] = (f > FILE_A ? FileBB[f - 1] : 0) | (f < FILE_H ? FileBB[f + 1] : 0); + ThisAndNeighboringFilesBB[f] = FileBB[f] | NeighboringFilesBB[f]; + } -Square pop_1st_bit(Bitboard *b) { - Bitboard bb = *b; - *b &= (*b - 1); - return Square(BitTable[((bb & -bb) * 0x218a392cd3d5dbfULL) >> 58]); -} + for (int rw = RANK_7, rb = RANK_2; rw >= RANK_1; rw--, rb++) + { + InFrontBB[WHITE][rw] = InFrontBB[WHITE][rw + 1] | RankBB[rw + 1]; + InFrontBB[BLACK][rb] = InFrontBB[BLACK][rb - 1] | RankBB[rb - 1]; + } -#endif // defined(USE_FOLDED_BITSCAN) + 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(file_of(s)); + AttackSpanMask[c][s] = in_front_bb(c, s) & neighboring_files_bb(file_of(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)); + + for (int i = 0; i < 64; i++) + if (!Is64Bit) // Matt Taylor's folding trick for 32 bit systems + { + Bitboard b = 1ULL << i; + b ^= b - 1; + b ^= b >> 32; + BSFTable[(uint32_t)(b * 0x783A9B23) >> 26] = i; + } + else + BSFTable[((1ULL << i) * 0x218A392CD3D5DBFULL) >> 58] = i; -namespace { + int steps[][9] = { {}, { 7, 9 }, { 17, 15, 10, 6, -6, -10, -15, -17 }, + {}, {}, {}, { 9, 7, -7, -9, 8, 1, -1, -8 } }; - // 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 (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]); - void init_masks() { - SetMaskBB[SQ_NONE] = 0ULL; - ClearMaskBB[SQ_NONE] = ~SetMaskBB[SQ_NONE]; - for(Square s = SQ_A1; s <= SQ_H8; s++) { - SetMaskBB[s] = (1ULL << s); - ClearMaskBB[s] = ~SetMaskBB[s]; - } - for(Color c = WHITE; c <= BLACK; c++) - for(Square s = SQ_A1; s <= SQ_H8; s++) { - PassedPawnMask[c][s] = - in_front_bb(c, s) & this_and_neighboring_files_bb(s); - OutpostMask[c][s] = in_front_bb(c, s) & neighboring_files_bb(s); - } - } + if (square_is_ok(to) && square_distance(s, to) < 3) + set_bit(&StepAttacksBB[make_piece(c, pt)][s], to); + } + init_magic_bitboards(ROOK, RAttacks, RMagics, RMasks, RShifts); + init_magic_bitboards(BISHOP, BAttacks, BMagics, BMasks, BShifts); - void init_ray_bitboards() { - int d[8] = {1, -1, 16, -16, 17, -17, 15, -15}; - for(int i = 0; i < 128; i = (i + 9) & ~8) { - for(int j = 0; j < 8; j++) { - RayBB[(i&7)|((i>>4)<<3)][j] = EmptyBoardBB; - for(int k = i + d[j]; (k & 0x88) == 0; k += d[j]) - set_bit(&(RayBB[(i&7)|((i>>4)<<3)][j]), Square((k&7)|((k>>4)<<3))); - } - } + for (Square s = SQ_A1; s <= SQ_H8; s++) + { + BishopPseudoAttacks[s] = bishop_attacks_bb(s, 0); + RookPseudoAttacks[s] = rook_attacks_bb(s, 0); + QueenPseudoAttacks[s] = queen_attacks_bb(s, 0); } + for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++) + for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++) + if (bit_is_set(QueenPseudoAttacks[s1], s2)) + { + Square delta = (s2 - s1) / square_distance(s1, s2); - void init_attacks() { - int i, j, k, l; - int step[16][8] = { - {0}, - {7,9,0}, {17,15,10,6,-6,-10,-15,-17}, {9,7,-7,-9,0}, {8,1,-1,-8,0}, - {9,7,-7,-9,8,1,-1,-8}, {9,7,-7,-9,8,1,-1,-8}, {0}, {0}, - {-7,-9,0}, {17,15,10,6,-6,-10,-15,-17}, {9,7,-7,-9,0}, {8,1,-1,-8,0}, - {9,7,-7,-9,8,1,-1,-8}, {9,7,-7,-9,8,1,-1,-8} - }; - - for(i = 0; i < 64; i++) { - for(j = 0; j <= int(BK); j++) { - StepAttackBB[j][i] = EmptyBoardBB; - for(k = 0; k < 8 && step[j][k] != 0; k++) { - l = i + step[j][k]; - if(l >= 0 && l < 64 && abs((i&7) - (l&7)) < 3) - StepAttackBB[j][i] |= (1ULL << l); - } - } - } - } + for (Square s = s1 + delta; s != s2; s += delta) + set_bit(&BetweenBB[s1][s2], s); + } +} - Bitboard sliding_attacks(int sq, Bitboard block, int dirs, int deltas[][2], - int fmin=0, int fmax=7, int rmin=0, int rmax=7) { - Bitboard result = 0ULL; - int rk = sq / 8, fl = sq % 8, r, f, i; - for(i = 0; i < dirs; i++) { - int dx = deltas[i][0], dy = deltas[i][1]; - for(f = fl+dx, r = rk+dy; - (dx==0 || (f>=fmin && f<=fmax)) && (dy==0 || (r>=rmin && r<=rmax)); - f += dx, r += dy) { - result |= (1ULL << (f + r*8)); - if(block & (1ULL << (f + r*8))) break; - } - } - return result; - } +namespace { + Bitboard sliding_attacks(PieceType pt, Square sq, Bitboard occupied) { - void init_between_bitboards() { - SquareDelta step[8] = { - DELTA_E, DELTA_W, DELTA_N, DELTA_S, DELTA_NE, DELTA_SW, DELTA_NW, DELTA_SE - }; - SignedDirection d; - for(Square s1 = SQ_A1; s1 <= SQ_H8; s1++) - for(Square s2 = SQ_A1; s2 <= SQ_H8; s2++) { - BetweenBB[s1][s2] = EmptyBoardBB; - d = signed_direction_between_squares(s1, s2); - if(d != SIGNED_DIR_NONE) - for(Square s3 = s1 + step[d]; s3 != s2; s3 += step[d]) - set_bit(&(BetweenBB[s1][s2]), s3); - } - } + Square deltas[][4] = { { DELTA_N, DELTA_E, DELTA_S, DELTA_W }, + { DELTA_NE, DELTA_SE, DELTA_SW, DELTA_NW } }; + Bitboard attacks = 0; + Square* delta = (pt == ROOK ? deltas[0] : deltas[1]); + + for (int i = 0; i < 4; i++) + { + Square s = sq + delta[i]; + + while (square_is_ok(s) && square_distance(s, s - delta[i]) == 1) + { + set_bit(&attacks, s); + if (bit_is_set(occupied, s)) + break; - Bitboard index_to_bitboard(int index, Bitboard mask) { - int i, j, bits = count_1s(mask); - Bitboard result = 0ULL; - for(i = 0; i < bits; i++) { - j = pop_1st_bit(&mask); - if(index & (1 << i)) result |= (1ULL << j); + s += delta[i]; + } } - return result; + return attacks; } - void init_sliding_attacks(Bitboard attacks[], - int attackIndex[], Bitboard mask[], - const int shift[2], const Bitboard mult[], - int deltas[][2]) { - int i, j, k, index = 0; - Bitboard b; - for(i = 0; i < 64; i++) { - attackIndex[i] = index; - mask[i] = sliding_attacks(i, 0ULL, 4, deltas, 1, 6, 1, 6); + Bitboard pick_random(Bitboard mask, RKISS& rk, int booster) { -#if defined(USE_32BIT_ATTACKS) - j = (1 << (32 - shift[i])); -#else - j = (1 << (64 - shift[i])); -#endif + Bitboard magic; - for(k = 0; k < j; k++) { - -#if defined(USE_32BIT_ATTACKS) - b = index_to_bitboard(k, mask[i]); - attacks[index + - (unsigned(int(b) * int(mult[i]) ^ - int(b >> 32) * int(mult[i] >> 32)) - >> shift[i])] = - sliding_attacks(i, b, 4, deltas); -#else - b = index_to_bitboard(k, mask[i]); - attacks[index + ((b * mult[i]) >> shift[i])] = - sliding_attacks(i, b, 4, deltas); -#endif - } - index += j; - } - } + // 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; + while (true) + { + magic = rk.rand(); + magic = (magic >> s1) | (magic << (64 - s1)); + magic &= rk.rand(); + magic = (magic >> s2) | (magic << (64 - s2)); + magic &= rk.rand(); - void init_pseudo_attacks() { - Square s; - for(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); + if (BitCount8Bit[(mask * magic) >> 56] >= 6) + return magic; } } -#if defined(USE_COMPACT_ROOK_ATTACKS) - void init_file_and_rank_attacks() { - int i, j, k, l, m, s; - Bitboard b1, b2; - for(i = 0; i < 64; i++) { - - for(m = 0; m <= 1; m++) { - b1 = 0ULL; - for(j = 0; j < 6; j++) if(i & (1<= 0 && l <= 7; l += s) { - b2 |= (m? RankBB[l] : FileBB[l]); - if(b1 & (1ULL << (l*(1+m*7)))) break; + + // init_magic_bitboards() computes all rook and bishop magics at startup. + // Magic bitboards are used to look up attacks of sliding pieces. As reference + // see chessprogramming.wikispaces.com/Magic+Bitboards. In particular, here we + // use the so called "fancy" approach. + + void init_magic_bitboards(PieceType pt, Bitboard* attacks[], Bitboard magics[], + Bitboard masks[], int shifts[]) { + + 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, index, booster; + + // attacks[s] is a pointer to the beginning of the attacks table for square 's' + attacks[SQ_A1] = (pt == ROOK ? RookTable : BishopTable); + + for (Square s = SQ_A1; s <= SQ_H8; s++) + { + // 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_attacks(pt, 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 attacks bitboard in reference[]. + b = size = 0; + do { + occupancy[size] = b; + reference[size++] = sliding_attacks(pt, 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 { + magics[s] = pick_random(masks[s], rk, booster); + 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++) + { + index = (pt == ROOK ? rook_index(s, occupancy[i]) + : bishop_index(s, occupancy[i])); + + if (!attacks[s][index]) + attacks[s][index] = reference[i]; + + else if (attacks[s][index] != reference[i]) + break; } - } - if(m) FileAttacks[j][(b1*0xd6e8802041d0c441ULL) >> 58] = b2; - else RankAttacks[j][i] = b2; - } - } + } while (i != size); } } -#endif // defined(USE_COMPACT_ROOK_ATTACKS) - }