X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.cpp;h=5c6b6e026f25c2ddd4b68f0e4e6f85475a88a407;hp=0c38e182ba3633f5c6040f3f810d34de74657a6f;hb=b05fbb3733df535a3fdf99e8d832001e57929699;hpb=14f059072af34bc21b71ae7fc550f03b4a075b3b
diff --git a/src/bitboard.cpp b/src/bitboard.cpp
index 0c38e182..5c6b6e02 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) 2008-2012 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
@@ -17,326 +17,95 @@
along with this program. If not, see .
*/
-
-////
-//// Includes
-////
-
+#include
+#include
#include
#include "bitboard.h"
#include "bitcount.h"
-#include "direction.h"
-
-
-#if defined(IS_64BIT)
-
-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 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 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,
- 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,
-};
-
-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 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)
-
-const Bitboard LightSquaresBB = 0x55AA55AA55AA55AAULL;
-const Bitboard DarkSquaresBB = 0xAA55AA55AA55AA55ULL;
-
-const Bitboard SquaresByColorBB[2] = { DarkSquaresBB, LightSquaresBB };
-
-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
-};
+#include "rkiss.h"
-const Bitboard RankBB[8] = {
- Rank1BB, Rank2BB, Rank3BB, Rank4BB, Rank5BB, Rank6BB, Rank7BB, Rank8BB
-};
-
-const Bitboard RelativeRankBB[2][8] = {
- { Rank1BB, Rank2BB, Rank3BB, Rank4BB, Rank5BB, Rank6BB, Rank7BB, Rank8BB },
- { Rank8BB, Rank7BB, Rank6BB, Rank5BB, Rank4BB, Rank3BB, Rank2BB, Rank1BB }
-};
-
-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
- }
-};
-
-Bitboard RMask[64];
-int RAttackIndex[64];
-Bitboard RAttacks[0x19000];
+Bitboard RMasks[64];
+Bitboard RMagics[64];
+Bitboard* RAttacks[64];
+int RShifts[64];
-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 AttackSpanMask[2][64];
-Bitboard BishopPseudoAttacks[64];
-Bitboard RookPseudoAttacks[64];
-Bitboard QueenPseudoAttacks[64];
+Bitboard PseudoAttacks[6][64];
uint8_t BitCount8Bit[256];
+int SquareDistance[64][64];
+namespace {
-////
-//// Local definitions
-////
+ CACHE_LINE_ALIGNMENT
-namespace {
+ int BSFTable[64];
+ Bitboard RookTable[0x19000]; // Storage space for rook attacks
+ Bitboard BishopTable[0x1480]; // Storage space for bishop attacks
- void init_masks();
- void init_ray_bitboards();
- void init_attacks();
- void init_between_bitboards();
- void init_pseudo_attacks();
- Bitboard index_to_bitboard(int index, Bitboard mask);
- Bitboard sliding_attacks(int sq, Bitboard block, int dirs, 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]);
+ 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;
+ 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 << "| " << (bit_is_set(b, make_square(f, r)) ? "X " : " ");
- std::cout << "|" << std::endl;
+ 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();
- init_sliding_attacks(RAttacks, RAttackIndex, RMask, RShift, RMult, rookDeltas);
- 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(IS_64BIT) && !defined(USE_BSFQ)
-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
-};
-
Square first_1(Bitboard b) {
- return Square(BitTable[((b & -b) * 0x218a392cd3d5dbfULL) >> 58]);
+ return Square(BSFTable[((b & -b) * 0x218A392CD3D5DBFULL) >> 58]);
}
Square pop_1st_bit(Bitboard* b) {
Bitboard bb = *b;
*b &= (*b - 1);
- return Square(BitTable[((bb & -bb) * 0x218a392cd3d5dbfULL) >> 58]);
+ return Square(BSFTable[((bb & -bb) * 0x218A392CD3D5DBFULL) >> 58]);
}
#elif !defined(USE_BSFQ)
-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
-};
-
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]);
}
// Use type-punning
@@ -363,185 +132,233 @@ Square pop_1st_bit(Bitboard* bb) {
if (u.dw.l)
{
- ret = Square(BitTable[((u.dw.l ^ (u.dw.l - 1)) * 0x783a9b23) >> 26]);
+ 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(BitTable[((~(u.dw.h ^ (u.dw.h - 1))) * 0x783a9b23) >> 26]);
+ ret = Square(BSFTable[((~(u.dw.h ^ (u.dw.h - 1))) * 0x783A9B23) >> 26]);
u.dw.h &= (u.dw.h - 1);
*bb = u.b;
return ret;
}
-#endif
+#endif // !defined(USE_BSFQ)
-namespace {
+/// bitboards_init() initializes various bitboard arrays. It is called during
+/// program initialization.
- // 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.
+void bitboards_init() {
- void init_masks() {
+ for (Bitboard b = 0; b < 256; b++)
+ BitCount8Bit[b] = (uint8_t)popcount(b);
- 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 (Square s = SQ_A1; s <= SQ_H8; s++)
- {
- SetMaskBB[s] = (1ULL << s);
- ClearMaskBB[s] = ~SetMaskBB[s];
- }
+ ClearMaskBB[SQ_NONE] = ~0ULL;
- 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);
- }
+ 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;
+ }
+
+ 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];
+ }
- for (Bitboard b = 0ULL; b < 256ULL; b++)
- BitCount8Bit[b] = (uint8_t)count_1s(b);
+ 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];
}
- int remove_bit_8(int i) { return ((i & ~15) >> 1) | (i & 7); }
+ 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));
+ }
- void init_ray_bitboards() {
+ 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;
- int d[8] = {1, -1, 16, -16, 17, -17, 15, -15};
+ int steps[][9] = { {}, { 7, 9 }, { 17, 15, 10, 6, -6, -10, -15, -17 },
+ {}, {}, {}, { 9, 7, -7, -9, 8, 1, -1, -8 } };
- for (int i = 0; i < 128; i = (i + 9) & ~8)
- for (int j = 0; j < 8; j++)
- {
- RayBB[remove_bit_8(i)][j] = EmptyBoardBB;
- for (int k = i + d[j]; (k & 0x88) == 0; k += d[j])
- set_bit(&(RayBB[remove_bit_8(i)][j]), Square(remove_bit_8(k)));
- }
- }
+ 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_attacks() {
+ if (square_is_ok(to) && square_distance(s, to) < 3)
+ set_bit(&StepAttacksBB[make_piece(c, pt)][s], to);
+ }
- const 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}
- };
+ init_magic_bitboards(ROOK, RAttacks, RMagics, RMasks, RShifts);
+ init_magic_bitboards(BISHOP, BAttacks, BMagics, BMasks, BShifts);
- for (int i = 0; i < 64; i++)
- for (int j = 0; j <= int(BK); j++)
- {
- StepAttackBB[j][i] = EmptyBoardBB;
- for (int k = 0; k < 8 && step[j][k] != 0; k++)
- {
- int l = i + step[j][k];
- if (l >= 0 && l < 64 && abs((i & 7) - (l & 7)) < 3)
- StepAttackBB[j][i] |= (1ULL << l);
- }
- }
+ for (Square s = SQ_A1; s <= SQ_H8; s++)
+ {
+ PseudoAttacks[BISHOP][s] = bishop_attacks_bb(s, 0);
+ PseudoAttacks[ROOK][s] = rook_attacks_bb(s, 0);
+ PseudoAttacks[QUEEN][s] = queen_attacks_bb(s, 0);
}
- 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;
- int fl = sq % 8;
+ for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++)
+ for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++)
+ if (bit_is_set(PseudoAttacks[QUEEN][s1], s2))
+ {
+ Square delta = (s2 - s1) / square_distance(s1, s2);
+
+ for (Square s = s1 + delta; s != s2; s += delta)
+ set_bit(&BetweenBB[s1][s2], s);
+ }
+}
+
- for (int i = 0; i < dirs; i++)
+namespace {
+
+ Bitboard sliding_attacks(PieceType pt, Square sq, Bitboard occupied) {
+
+ 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++)
{
- int dx = deltas[i][0];
- int dy = deltas[i][1];
- int f = fl + dx;
- int r = rk + dy;
+ Square s = sq + delta[i];
- while ( (dx == 0 || (f >= fmin && f <= fmax))
- && (dy == 0 || (r >= rmin && r <= rmax)))
+ while (square_is_ok(s) && square_distance(s, s - delta[i]) == 1)
{
- result |= (1ULL << (f + r*8));
- if (block & (1ULL << (f + r*8)))
+ set_bit(&attacks, s);
+
+ if (bit_is_set(occupied, s))
break;
- f += dx;
- r += dy;
+ s += delta[i];
}
}
- return result;
+ return attacks;
}
- void init_between_bitboards() {
- const SquareDelta step[8] = { DELTA_E, DELTA_W, DELTA_N, DELTA_S,
- DELTA_NE, DELTA_SW, DELTA_NW, DELTA_SE };
+ Bitboard pick_random(Bitboard mask, RKISS& rk, int booster) {
- for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++)
- for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++)
- {
- BetweenBB[s1][s2] = EmptyBoardBB;
- SignedDirection d = signed_direction_between_squares(s1, s2);
+ Bitboard magic;
- if (d != SIGNED_DIR_NONE)
- {
- for (Square s3 = s1 + step[d]; s3 != s2; s3 += step[d])
- set_bit(&(BetweenBB[s1][s2]), s3);
- }
- }
- }
+ // 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;
- Bitboard index_to_bitboard(int index, Bitboard mask) {
-
- Bitboard result = 0ULL;
- int bits = count_1s(mask);
-
- for (int i = 0; i < bits; i++)
+ while (true)
{
- int j = pop_1st_bit(&mask);
- if (index & (1 << i))
- result |= (1ULL << j);
+ magic = rk.rand();
+ magic = (magic >> s1) | (magic << (64 - s1));
+ magic &= rk.rand();
+ magic = (magic >> s2) | (magic << (64 - s2));
+ magic &= rk.rand();
+
+ if (BitCount8Bit[(mask * magic) >> 56] >= 6)
+ return magic;
}
- return result;
}
- void init_sliding_attacks(Bitboard attacks[], int attackIndex[], Bitboard mask[],
- const int shift[], const Bitboard mult[], int deltas[][2]) {
- for (int i = 0, index = 0; i < 64; i++)
- {
- attackIndex[i] = index;
- mask[i] = sliding_attacks(i, 0ULL, 4, deltas, 1, 6, 1, 6);
+ // 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.
-#if defined(IS_64BIT)
- int j = (1 << (64 - shift[i]));
-#else
- int j = (1 << (32 - shift[i]));
-#endif
+ void init_magic_bitboards(PieceType pt, Bitboard* attacks[], Bitboard magics[],
+ Bitboard masks[], int shifts[]) {
- for (int k = 0; k < j; k++)
- {
-#if defined(IS_64BIT)
- Bitboard b = index_to_bitboard(k, mask[i]);
- attacks[index + ((b * mult[i]) >> shift[i])] = sliding_attacks(i, b, 4, deltas);
-#else
- Bitboard b = index_to_bitboard(k, mask[i]);
- unsigned v = int(b) * int(mult[i]) ^ int(b >> 32) * int(mult[i] >> 32);
- attacks[index + (v >> shift[i])] = sliding_attacks(i, b, 4, deltas);
-#endif
- }
- index += j;
- }
- }
+ 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;
- void init_pseudo_attacks() {
+ // 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++)
{
- BishopPseudoAttacks[s] = bishop_attacks_bb(s, EmptyBoardBB);
- RookPseudoAttacks[s] = rook_attacks_bb(s, EmptyBoardBB);
- QueenPseudoAttacks[s] = queen_attacks_bb(s, EmptyBoardBB);
+ // 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;
+ }
+ } while (i != size);
}
}
-
}