Gather all magic relevant data into a struct.
This changes memory layout putting everything necessary for processing a single square
in the same memory location thus speeding up access.
Original patch by @snicolet
No functional change.
Closes #1127
Closes #1128
uint8_t PopCnt16[1 << 16];
int SquareDistance[SQUARE_NB][SQUARE_NB];
uint8_t PopCnt16[1 << 16];
int SquareDistance[SQUARE_NB][SQUARE_NB];
-Bitboard RookMasks [SQUARE_NB];
-Bitboard RookMagics [SQUARE_NB];
-Bitboard* RookAttacks[SQUARE_NB];
-unsigned RookShifts [SQUARE_NB];
-
-Bitboard BishopMasks [SQUARE_NB];
-Bitboard BishopMagics [SQUARE_NB];
-Bitboard* BishopAttacks[SQUARE_NB];
-unsigned BishopShifts [SQUARE_NB];
+Magic RookMagics[SQUARE_NB];
+Magic BishopMagics[SQUARE_NB];
Bitboard SquareBB[SQUARE_NB];
Bitboard FileBB[FILE_NB];
Bitboard SquareBB[SQUARE_NB];
Bitboard FileBB[FILE_NB];
typedef unsigned (Fn)(Square, Bitboard);
typedef unsigned (Fn)(Square, Bitboard);
- void init_magics(Bitboard table[], Bitboard* attacks[], Bitboard magics[],
- Bitboard masks[], unsigned shifts[], Square deltas[], Fn index);
+ void init_magics(Bitboard table[], Magic magics[], Square deltas[], Fn index);
// bsf_index() returns the index into BSFTable[] to look up the bitscan. Uses
// Matt Taylor's folding for 32 bit case, extended to 64 bit by Kim Walisch.
// bsf_index() returns the index into BSFTable[] to look up the bitscan. Uses
// Matt Taylor's folding for 32 bit case, extended to 64 bit by Kim Walisch.
Square RookDeltas[] = { NORTH, EAST, SOUTH, WEST };
Square BishopDeltas[] = { NORTH_EAST, SOUTH_EAST, SOUTH_WEST, NORTH_WEST };
Square RookDeltas[] = { NORTH, EAST, SOUTH, WEST };
Square BishopDeltas[] = { NORTH_EAST, SOUTH_EAST, SOUTH_WEST, NORTH_WEST };
- init_magics(RookTable, RookAttacks, RookMagics, RookMasks, RookShifts, RookDeltas, magic_index<ROOK>);
- init_magics(BishopTable, BishopAttacks, BishopMagics, BishopMasks, BishopShifts, BishopDeltas, magic_index<BISHOP>);
+ init_magics(RookTable, RookMagics, RookDeltas, magic_index<ROOK>);
+ init_magics(BishopTable, BishopMagics, BishopDeltas, magic_index<BISHOP>);
for (Square s1 = SQ_A1; s1 <= SQ_H8; ++s1)
{
for (Square s1 = SQ_A1; s1 <= SQ_H8; ++s1)
{
// chessprogramming.wikispaces.com/Magic+Bitboards. In particular, here we
// use the so called "fancy" approach.
// chessprogramming.wikispaces.com/Magic+Bitboards. In particular, here we
// use the so called "fancy" approach.
- void init_magics(Bitboard table[], Bitboard* attacks[], Bitboard magics[],
- Bitboard masks[], unsigned shifts[], Square deltas[], Fn index) {
+ void init_magics(Bitboard table[], Magic magics[], Square deltas[], Fn index) {
int seeds[][RANK_NB] = { { 8977, 44560, 54343, 38998, 5731, 95205, 104912, 17020 },
{ 728, 10316, 55013, 32803, 12281, 15100, 16645, 255 } };
int seeds[][RANK_NB] = { { 8977, 44560, 54343, 38998, 5731, 95205, 104912, 17020 },
{ 728, 10316, 55013, 32803, 12281, 15100, 16645, 255 } };
int age[4096] = {0}, current = 0, i, size;
// attacks[s] is a pointer to the beginning of the attacks table for square 's'
int age[4096] = {0}, current = 0, i, size;
// attacks[s] is a pointer to the beginning of the attacks table for square 's'
- attacks[SQ_A1] = table;
+ magics[SQ_A1].attacks = table;
for (Square s = SQ_A1; s <= SQ_H8; ++s)
{
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.
// 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]);
+ magics[s].mask = sliding_attack(deltas, s, 0) & ~edges;
+ magics[s].shift = (Is64Bit ? 64 : 32) - popcount(magics[s].mask);
// Use Carry-Rippler trick to enumerate all subsets of masks[s] and
// store the corresponding sliding attack bitboard in reference[].
// Use Carry-Rippler trick to enumerate all subsets of masks[s] and
// store the corresponding sliding attack bitboard in reference[].
reference[size] = sliding_attack(deltas, s, b);
if (HasPext)
reference[size] = sliding_attack(deltas, s, b);
if (HasPext)
- attacks[s][pext(b, masks[s])] = reference[size];
+ magics[s].attacks[pext(b, magics[s].mask)] = reference[size];
- b = (b - masks[s]) & masks[s];
+ b = (b - magics[s].mask) & magics[s].mask;
} 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)
} 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;
+ magics[s + 1].attacks = magics[s].attacks + size;
// until we find the one that passes the verification test.
do {
do
// until we find the one that passes the verification test.
do {
do
- magics[s] = rng.sparse_rand<Bitboard>();
- while (popcount((magics[s] * masks[s]) >> 56) < 6);
+ magics[s].magic = rng.sparse_rand<Bitboard>();
+ while (popcount((magics[s].magic * magics[s].mask) >> 56) < 6);
// A good magic must map every possible occupancy to an index that
// looks up the correct sliding attack in the attacks[s] database.
// A good magic must map every possible occupancy to an index that
// looks up the correct sliding attack in the attacks[s] database.
if (age[idx] < current)
{
age[idx] = current;
if (age[idx] < current)
{
age[idx] = current;
- attacks[s][idx] = reference[i];
+ magics[s].attacks[idx] = reference[i];
- else if (attacks[s][idx] != reference[i])
+ else if (magics[s].attacks[idx] != reference[i])
break;
}
} while (i < size);
break;
}
} while (i < size);
template<> inline int distance<Rank>(Square x, Square y) { return distance(rank_of(x), rank_of(y)); }
template<> inline int distance<Rank>(Square x, Square y) { return distance(rank_of(x), rank_of(y)); }
+/// Magic holds all magic relevant data for a single square
+struct Magic {
+
+ Bitboard mask;
+ Bitboard magic;
+ Bitboard* attacks;
+ unsigned shift;
+};
+
/// attacks_bb() returns a bitboard representing all the squares attacked by a
/// piece of type Pt (bishop or rook) placed on 's'. The helper magic_index()
/// looks up the index using the 'magic bitboards' approach.
template<PieceType Pt>
inline unsigned magic_index(Square s, Bitboard occupied) {
/// attacks_bb() returns a bitboard representing all the squares attacked by a
/// piece of type Pt (bishop or rook) placed on 's'. The helper magic_index()
/// looks up the index using the 'magic bitboards' approach.
template<PieceType Pt>
inline unsigned magic_index(Square s, Bitboard occupied) {
- extern Bitboard RookMasks[SQUARE_NB];
- extern Bitboard RookMagics[SQUARE_NB];
- extern unsigned RookShifts[SQUARE_NB];
- extern Bitboard BishopMasks[SQUARE_NB];
- extern Bitboard BishopMagics[SQUARE_NB];
- extern unsigned BishopShifts[SQUARE_NB];
+ extern Magic RookMagics[SQUARE_NB];
+ extern Magic BishopMagics[SQUARE_NB];
- Bitboard* const Masks = Pt == ROOK ? RookMasks : BishopMasks;
- Bitboard* const Magics = Pt == ROOK ? RookMagics : BishopMagics;
- unsigned* const Shifts = Pt == ROOK ? RookShifts : BishopShifts;
+ const Magic* Magics = Pt == ROOK ? RookMagics : BishopMagics;
+ Bitboard mask = Magics[s].mask;
+ Bitboard magic = Magics[s].magic;
+ unsigned shift = Magics[s].shift;
- return unsigned(pext(occupied, Masks[s]));
+ return unsigned(pext(occupied, mask));
- return unsigned(((occupied & Masks[s]) * Magics[s]) >> Shifts[s]);
+ return unsigned(((occupied & mask) * magic) >> shift);
- unsigned lo = unsigned(occupied) & unsigned(Masks[s]);
- unsigned hi = unsigned(occupied >> 32) & unsigned(Masks[s] >> 32);
- return (lo * unsigned(Magics[s]) ^ hi * unsigned(Magics[s] >> 32)) >> Shifts[s];
+ unsigned lo = unsigned(occupied) & unsigned(mask);
+ unsigned hi = unsigned(occupied >> 32) & unsigned(mask >> 32);
+ return (lo * unsigned(magic) ^ hi * unsigned(magic >> 32)) >> shift;
}
template<PieceType Pt>
inline Bitboard attacks_bb(Square s, Bitboard occupied) {
}
template<PieceType Pt>
inline Bitboard attacks_bb(Square s, Bitboard occupied) {
- extern Bitboard* RookAttacks[SQUARE_NB];
- extern Bitboard* BishopAttacks[SQUARE_NB];
+ extern Magic RookMagics[SQUARE_NB];
+ extern Magic BishopMagics[SQUARE_NB];
-
return (Pt == ROOK ? RookAttacks : BishopAttacks)[s][magic_index<Pt>(s, occupied)];
+
return (Pt == ROOK ? RookMagics : BishopMagics)[s].attacks[magic_index<Pt>(s, occupied)];
}
inline Bitboard attacks_bb(PieceType pt, Square s, Bitboard occupied) {
}
inline Bitboard attacks_bb(PieceType pt, Square s, Bitboard occupied) {
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