Bitboard FileBB[8];
Bitboard RankBB[8];
-Bitboard NeighboringFilesBB[8];
-Bitboard ThisAndNeighboringFilesBB[8];
+Bitboard AdjacentFilesBB[8];
+Bitboard ThisAndAdjacentFilesBB[8];
Bitboard InFrontBB[2][8];
Bitboard StepAttacksBB[16][64];
Bitboard BetweenBB[64][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];
CACHE_LINE_ALIGNMENT
int BSFTable[64];
- Bitboard RookTable[0x19000]; // Storage space for rook attacks
- Bitboard BishopTable[0x1480]; // Storage space for bishop attacks
+ Bitboard RTable[0x19000]; // Storage space for rook attacks
+ Bitboard BTable[0x1480]; // Storage space for bishop attacks
- void init_magic_bitboards(PieceType pt, Bitboard* attacks[], Bitboard magics[],
- Bitboard masks[], int shifts[]);
+ typedef unsigned (Fn)(Square, Bitboard);
+
+ void init_magics(Bitboard table[], Bitboard* attacks[], Bitboard magics[],
+ Bitboard masks[], int shifts[], Square deltas[], Fn get_index);
}
void bitboards_init() {
for (Bitboard b = 0; b < 256; b++)
- BitCount8Bit[b] = (uint8_t)count_1s<CNT32_MAX15>(b);
+ BitCount8Bit[b] = (uint8_t)popcount<Max15>(b);
for (Square s = SQ_A1; s <= SQ_H8; s++)
{
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];
+ AdjacentFilesBB[f] = (f > FILE_A ? FileBB[f - 1] : 0) | (f < FILE_H ? FileBB[f + 1] : 0);
+ ThisAndAdjacentFilesBB[f] = FileBB[f] | AdjacentFilesBB[f];
}
for (int rw = RANK_7, rb = RANK_2; rw >= RANK_1; rw--, rb++)
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));
+ PassedPawnMask[c][s] = in_front_bb(c, s) & this_and_adjacent_files_bb(file_of(s));
+ AttackSpanMask[c][s] = in_front_bb(c, s) & adjacent_files_bb(file_of(s));
}
for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++)
Bitboard b = 1ULL << i;
b ^= b - 1;
b ^= b >> 32;
- BSFTable[uint32_t(b * 0x783A9B23) >> 26] = i;
+ BSFTable[(uint32_t)(b * 0x783A9B23) >> 26] = i;
}
else
BSFTable[((1ULL << i) * 0x218A392CD3D5DBFULL) >> 58] = i;
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);
+ 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, r_index);
+ init_magics(BTable, BAttacks, BMagics, BMasks, BShifts, BDeltas, b_index);
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);
+ PseudoAttacks[BISHOP][s] = bishop_attacks_bb(s, 0);
+ PseudoAttacks[ROOK][s] = rook_attacks_bb(s, 0);
+ PseudoAttacks[QUEEN][s] = PseudoAttacks[BISHOP][s] | PseudoAttacks[ROOK][s];
}
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))
+ if (bit_is_set(PseudoAttacks[QUEEN][s1], s2))
{
Square delta = (s2 - s1) / square_distance(s1, s2);
namespace {
- Bitboard sliding_attacks(PieceType pt, Square sq, Bitboard occupied) {
+ Bitboard sliding_attack(Square deltas[], 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]);
+ Bitboard attack = 0;
for (int i = 0; i < 4; i++)
- {
- Square s = sq + delta[i];
-
- while (square_is_ok(s) && square_distance(s, s - delta[i]) == 1)
+ for (Square s = sq + deltas[i];
+ square_is_ok(s) && square_distance(s, s - deltas[i]) == 1;
+ s += deltas[i])
{
- set_bit(&attacks, s);
+ set_bit(&attack, s);
if (bit_is_set(occupied, s))
break;
-
- s += delta[i];
}
- }
- return attacks;
+
+ return attack;
}
}
- // 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
+ // 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.
- void init_magic_bitboards(PieceType pt, Bitboard* attacks[], Bitboard magics[],
- Bitboard masks[], int shifts[]) {
+ void init_magics(Bitboard table[], Bitboard* attacks[], Bitboard magics[],
+ Bitboard masks[], int shifts[], Square deltas[], Fn get_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, index, booster;
+ int i, size, booster;
// attacks[s] is a pointer to the beginning of the attacks table for square 's'
- attacks[SQ_A1] = (pt == ROOK ? RookTable : BishopTable);
+ attacks[SQ_A1] = table;
for (Square s = SQ_A1; s <= SQ_H8; s++)
{
// 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) - count_1s<CNT32_MAX15>(masks[s]);
+ masks[s] = sliding_attack(deltas, s, 0) & ~edges;
+ shifts[s] = (Is64Bit ? 64 : 32) - popcount<Max15>(masks[s]);
// Use Carry-Rippler trick to enumerate all subsets of masks[s] and
- // store the corresponding sliding attacks bitboard in reference[].
+ // store the corresponding sliding attack bitboard in reference[].
b = size = 0;
do {
occupancy[size] = b;
- reference[size++] = sliding_attacks(pt, s, b);
+ reference[size++] = sliding_attack(deltas, s, b);
b = (b - masks[s]) & masks[s];
} while (b);
// effect of verifying the magic.
for (i = 0; i < size; i++)
{
- index = (pt == ROOK ? rook_index(s, occupancy[i])
- : bishop_index(s, occupancy[i]));
+ Bitboard& attack = attacks[s][get_index(s, occupancy[i])];
- if (!attacks[s][index])
- attacks[s][index] = reference[i];
-
- else if (attacks[s][index] != reference[i])
+ if (attack && attack != reference[i])
break;
+
+ attack = reference[i];
}
} while (i != size);
}
projects / stockfish / blobdiff