/*
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
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see .
*/
#include
#include "bitboard.h"
#include "bitcount.h"
// Global bitboards definitions with static storage duration are
// automatically set to zero before enter main().
Bitboard RAttacks[0x19000];
Bitboard BAttacks[0x1480];
Magics RMagics[64];
Magics BMagics[64];
Bitboard SetMaskBB[65];
Bitboard ClearMaskBB[65];
Bitboard SquaresByColorBB[2];
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];
uint8_t BitCount8Bit[256];
namespace {
#if defined(IS_64BIT)
const uint64_t DeBruijnMagic = 0x218A392CD3D5DBFULL;
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 uint32_t DeBruijnMagic = 0x783A9B23;
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)
CACHE_LINE_ALIGNMENT int BSFTable[64];
void init_sliding_attacks(Bitboard attacks[], Magics m[], const int shift[],
const Bitboard mult[], Square deltas[]);
}
/// print_bitboard() prints a bitboard in an easily readable format to the
/// standard output. This is sometimes useful for debugging.
void print_bitboard(Bitboard 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' : ' ') << ' ';
std::cout << "|\n";
}
std::cout << "+---+---+---+---+---+---+---+---+" << std::endl;
}
/// 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)
Square first_1(Bitboard b) {
return Square(BSFTable[((b & -b) * DeBruijnMagic) >> 58]);
}
Square pop_1st_bit(Bitboard* b) {
Bitboard bb = *b;
*b &= (*b - 1);
return Square(BSFTable[((bb & -bb) * DeBruijnMagic) >> 58]);
}
#elif !defined(USE_BSFQ)
Square first_1(Bitboard b) {
b ^= (b - 1);
uint32_t fold = unsigned(b) ^ unsigned(b >> 32);
return Square(BSFTable[(fold * DeBruijnMagic) >> 26]);
}
// 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(BSFTable[((u.dw.l ^ (u.dw.l - 1)) * DeBruijnMagic) >> 26]);
u.dw.l &= (u.dw.l - 1);
*bb = u.b;
return ret;
}
ret = Square(BSFTable[((~(u.dw.h ^ (u.dw.h - 1))) * DeBruijnMagic) >> 26]);
u.dw.h &= (u.dw.h - 1);
*bb = u.b;
return ret;
}
#endif // !defined(USE_BSFQ)
/// init_bitboards() initializes various bitboard arrays. It is called during
/// program initialization.
void init_bitboards() {
SquaresByColorBB[DARK] = 0xAA55AA55AA55AA55ULL;
SquaresByColorBB[LIGHT] = ~SquaresByColorBB[DARK];
for (Square s = SQ_A1; s <= SQ_H8; s++)
{
SetMaskBB[s] = (1ULL << s);
ClearMaskBB[s] = ~SetMaskBB[s];
}
ClearMaskBB[SQ_NONE] = ~EmptyBoardBB;
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 (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];
}
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 (Bitboard b = 0; b < 256; b++)
BitCount8Bit[b] = (uint8_t)count_1s(b);
for (int i = 1; i < 64; i++)
if (!CpuIs64Bit) // Matt Taylor's folding trick for 32 bit systems
{
Bitboard b = 1ULL << i;
b ^= b - 1;
b ^= b >> 32;
BSFTable[uint32_t(b * DeBruijnMagic) >> 26] = i;
}
else
BSFTable[((1ULL << i) * DeBruijnMagic) >> 58] = i;
int steps[][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}
};
for (Color c = WHITE; c <= BLACK; c++)
for (Square s = SQ_A1; s <= SQ_H8; s++)
for (PieceType pt = PAWN; pt <= KING; pt++)
for (int k = 0; steps[pt][k]; k++)
{
Square to = s + Square(c == WHITE ? steps[pt][k] : -steps[pt][k]);
if (square_is_ok(to) && square_distance(s, to) < 3)
set_bit(&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_sliding_attacks(RAttacks, RMagics, RShift, RMult, RDeltas);
init_sliding_attacks(BAttacks, BMagics, BShift, BMult, BDeltas);
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);
}
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))
{
int f = file_distance(s1, s2);
int r = rank_distance(s1, s2);
Square d = (s2 - s1) / Max(f, r);
for (Square s3 = s1 + d; s3 != s2; s3 += d)
set_bit(&BetweenBB[s1][s2], s3);
}
}
namespace {
Bitboard submask(Bitboard mask, int key) {
Bitboard subMask = 0;
int bitNum = -1;
// Extract an unique submask out of a mask according to the given key
for (Square s = SQ_A1; s <= SQ_H8; s++)
if (bit_is_set(mask, s) && bit_is_set(key, Square(++bitNum)))
set_bit(&subMask, s);
return subMask;
}
Bitboard sliding_attacks(Square sq, Bitboard occupied, Square deltas[], bool skipLast) {
Bitboard attacks = 0;
for (int i = 0; i < 4; i++)
{
Square s = sq + deltas[i];
while ( square_is_ok(s)
&& square_distance(s, s - deltas[i]) == 1
&& (!skipLast || !file_distance(s, sq) || (square_file(s) != FILE_A && square_file(s) != FILE_H))
&& (!skipLast || !rank_distance(s, sq) || (square_rank(s) != RANK_1 && square_rank(s) != RANK_8)))
{
attacks |= 1ULL << s;
if (occupied & (1ULL << s))
break;
s += deltas[i];
}
}
return attacks;
}
void init_sliding_attacks(Bitboard attacks[], Magics m[], const int shift[],
const Bitboard mult[], Square deltas[]) {
Bitboard occupancy, index;
int maxKey, offset = 0;
for (Square s = SQ_A1; s <= SQ_H8; s++)
{
m[s].offset = offset;
m[s].mult = mult[s];
m[s].shift = shift[s];
m[s].mask = sliding_attacks(s, EmptyBoardBB, deltas, true);
maxKey = 1 << (CpuIs64Bit ? 64 - shift[s] : 32 - shift[s]);
for (int key = 0; key < maxKey; key++)
{
occupancy = submask(m[s].mask, key);
index = CpuIs64Bit ? occupancy * mult[s]
: unsigned(occupancy * mult[s] ^ (occupancy >> 32) * (mult[s] >> 32));
attacks[offset + (index >> shift[s])] = sliding_attacks(s, occupancy, deltas, false);
}
offset += maxKey;
}
}
}