/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 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
#include "bitcount.h"
#include "misc.h"
-Bitboard RookMasks[SQUARE_NB];
-Bitboard RookMagics[SQUARE_NB];
+int SquareDistance[SQUARE_NB][SQUARE_NB];
+
+Bitboard RookMasks [SQUARE_NB];
+Bitboard RookMagics [SQUARE_NB];
Bitboard* RookAttacks[SQUARE_NB];
-unsigned RookShifts[SQUARE_NB];
+unsigned RookShifts [SQUARE_NB];
-Bitboard BishopMasks[SQUARE_NB];
-Bitboard BishopMagics[SQUARE_NB];
+Bitboard BishopMasks [SQUARE_NB];
+Bitboard BishopMagics [SQUARE_NB];
Bitboard* BishopAttacks[SQUARE_NB];
-unsigned BishopShifts[SQUARE_NB];
+unsigned BishopShifts [SQUARE_NB];
Bitboard SquareBB[SQUARE_NB];
Bitboard FileBB[FILE_NB];
Bitboard StepAttacksBB[PIECE_NB][SQUARE_NB];
Bitboard BetweenBB[SQUARE_NB][SQUARE_NB];
Bitboard LineBB[SQUARE_NB][SQUARE_NB];
-Bitboard DistanceRingsBB[SQUARE_NB][8];
+Bitboard DistanceRingBB[SQUARE_NB][8];
Bitboard ForwardBB[COLOR_NB][SQUARE_NB];
Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB];
Bitboard PawnAttackSpan[COLOR_NB][SQUARE_NB];
Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB];
-int SquareDistance[SQUARE_NB][SQUARE_NB];
-
namespace {
// De Bruijn sequences. See chessprogramming.wikispaces.com/BitScan
- const uint64_t DeBruijn_64 = 0x3F79D71B4CB0A89ULL;
- const uint32_t DeBruijn_32 = 0x783A9B23;
+ const uint64_t DeBruijn64 = 0x3F79D71B4CB0A89ULL;
+ const uint32_t DeBruijn32 = 0x783A9B23;
- int MS1BTable[256];
- Square BSFTable[SQUARE_NB];
- Bitboard RookTable[0x19000]; // Storage space for rook attacks
- Bitboard BishopTable[0x1480]; // Storage space for bishop attacks
+ int MS1BTable[256]; // To implement software msb()
+ Square BSFTable[SQUARE_NB]; // To implement software bitscan
+ Bitboard RookTable[0x19000]; // To store rook attacks
+ Bitboard BishopTable[0x1480]; // To store bishop attacks
typedef unsigned (Fn)(Square, Bitboard);
void init_magics(Bitboard table[], Bitboard* attacks[], Bitboard magics[],
Bitboard masks[], unsigned shifts[], Square deltas[], Fn index);
- FORCE_INLINE unsigned bsf_index(Bitboard b) {
+ // 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.
- // Matt Taylor's folding for 32 bit systems, extended to 64 bits by Kim Walisch
- b ^= (b - 1);
- return Is64Bit ? (b * DeBruijn_64) >> 58
- : ((unsigned(b) ^ unsigned(b >> 32)) * DeBruijn_32) >> 26;
+ unsigned bsf_index(Bitboard b) {
+ b ^= b - 1;
+ return Is64Bit ? (b * DeBruijn64) >> 58
+ : ((unsigned(b) ^ unsigned(b >> 32)) * DeBruijn32) >> 26;
}
}
-/// lsb()/msb() finds the least/most significant bit in a non-zero bitboard.
-/// pop_lsb() finds and clears the least significant bit in a non-zero bitboard.
-
#ifndef USE_BSFQ
-Square lsb(Bitboard b) { return BSFTable[bsf_index(b)]; }
+/// Software fall-back of lsb() and msb() for CPU lacking hardware support
-Square pop_lsb(Bitboard* b) {
-
- Bitboard bb = *b;
- *b = bb & (bb - 1);
- return BSFTable[bsf_index(bb)];
+Square lsb(Bitboard b) {
+ return BSFTable[bsf_index(b)];
}
Square msb(Bitboard b) {
#endif // ifndef USE_BSFQ
-/// Bitboards::pretty() returns an ASCII representation of a bitboard to be
-/// printed to standard output. This is sometimes useful for debugging.
+/// Bitboards::pretty() returns an ASCII representation of a bitboard suitable
+/// to be printed to standard output. Useful for debugging.
const std::string Bitboards::pretty(Bitboard b) {
if (s1 != s2)
{
SquareDistance[s1][s2] = std::max(distance<File>(s1, s2), distance<Rank>(s1, s2));
- DistanceRingsBB[s1][SquareDistance[s1][s2] - 1] |= s2;
+ DistanceRingBB[s1][SquareDistance[s1][s2] - 1] |= s2;
}
int steps[][9] = { {}, { 7, 9 }, { 17, 15, 10, 6, -6, -10, -15, -17 },
PseudoAttacks[QUEEN][s1] = PseudoAttacks[BISHOP][s1] = attacks_bb<BISHOP>(s1, 0);
PseudoAttacks[QUEEN][s1] |= PseudoAttacks[ ROOK][s1] = attacks_bb< ROOK>(s1, 0);
- for (Square s2 = SQ_A1; s2 <= SQ_H8; ++s2)
- {
- Piece pc = (PseudoAttacks[BISHOP][s1] & s2) ? W_BISHOP :
- (PseudoAttacks[ROOK][s1] & s2) ? W_ROOK : NO_PIECE;
-
- if (pc == NO_PIECE)
- continue;
+ for (Piece pc = W_BISHOP; pc <= W_ROOK; ++pc)
+ for (Square s2 = SQ_A1; s2 <= SQ_H8; ++s2)
+ {
+ if (!(PseudoAttacks[pc][s1] & s2))
+ continue;
- LineBB[s1][s2] = (attacks_bb(pc, s1, 0) & attacks_bb(pc, s2, 0)) | s1 | s2;
- BetweenBB[s1][s2] = attacks_bb(pc, s1, SquareBB[s2]) & attacks_bb(pc, s2, SquareBB[s1]);
- }
+ LineBB[s1][s2] = (attacks_bb(pc, s1, 0) & attacks_bb(pc, s2, 0)) | s1 | s2;
+ BetweenBB[s1][s2] = attacks_bb(pc, s1, SquareBB[s2]) & attacks_bb(pc, s2, SquareBB[s1]);
+ }
}
}
{ 728, 10316, 55013, 32803, 12281, 15100, 16645, 255 } };
Bitboard occupancy[4096], reference[4096], edges, b;
- int i, size;
+ int age[4096], current = 0, i, size;
+
+ std::memset(age, 0, sizeof(age));
// attacks[s] is a pointer to the beginning of the attacks table for square 's'
attacks[SQ_A1] = table;
reference[size] = sliding_attack(deltas, s, b);
if (HasPext)
- attacks[s][_pext_u64(b, masks[s])] = reference[size];
+ attacks[s][pext(b, masks[s])] = reference[size];
size++;
b = (b - masks[s]) & masks[s];
magics[s] = rng.sparse_rand<Bitboard>();
while (popcount<Max15>((magics[s] * masks[s]) >> 56) < 6);
- std::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)
+ for (++current, i = 0; i < size; ++i)
{
- Bitboard& attack = attacks[s][index(s, occupancy[i])];
-
- if (attack && attack != reference[i])
+ unsigned idx = index(s, occupancy[i]);
+
+ if (age[idx] < current)
+ {
+ age[idx] = current;
+ attacks[s][idx] = reference[i];
+ }
+ else if (attacks[s][idx] != reference[i])
break;
-
- assert(reference[i]);
-
- attack = reference[i];
}
} while (i < size);
}
projects / stockfish / blobdiff