/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008 Marco Costalba
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, 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 <http://www.gnu.org/licenses/>.
*/
-
-////
-//// Includes
-////
-
+#include <algorithm>
#include <cassert>
+#include "bitboard.h"
#include "pawns.h"
+#include "position.h"
+#include "thread.h"
+namespace {
-////
-//// Local definitions
-////
+ #define V Value
+ #define S(mg, eg) make_score(mg, eg)
-namespace {
+ // Isolated pawn penalty
+ const Score Isolated = S(13, 18);
- /// Constants and variables
+ // Backward pawn penalty
+ const Score Backward = S(24, 12);
- // Doubled pawn penalty by file, middle game.
- const Value DoubledPawnMidgamePenalty[8] = {
- Value(20), Value(30), Value(34), Value(34),
- Value(34), Value(34), Value(30), Value(20)
- };
+ // Connected pawn bonus by opposed, phalanx, #support and rank
+ Score Connected[2][2][3][RANK_NB];
- // Doubled pawn penalty by file, endgame.
- const Value DoubledPawnEndgamePenalty[8] = {
- Value(35), Value(40), Value(40), Value(40),
- Value(40), Value(40), Value(40), Value(35)
- };
+ // Doubled pawn penalty
+ const Score Doubled = S(18, 38);
- // Isolated pawn penalty by file, middle game.
- const Value IsolatedPawnMidgamePenalty[8] = {
- Value(20), Value(30), Value(34), Value(34),
- Value(34), Value(34), Value(30), Value(20)
+ // Weakness of our pawn shelter in front of the king by [isKingFile][distance from edge][rank].
+ // RANK_1 = 0 is used for files where we have no pawns or our pawn is behind our king.
+ const Value ShelterWeakness[][int(FILE_NB) / 2][RANK_NB] = {
+ { { V( 98), V(20), V(11), V(42), V( 83), V( 84), V(101) }, // Not On King file
+ { V(103), V( 8), V(33), V(86), V( 87), V(105), V(113) },
+ { V(100), V( 2), V(65), V(95), V( 59), V( 89), V(115) },
+ { V( 72), V( 6), V(52), V(74), V( 83), V( 84), V(112) } },
+ { { V(105), V(19), V( 3), V(27), V( 85), V( 93), V( 84) }, // On King file
+ { V(121), V( 7), V(33), V(95), V(112), V( 86), V( 72) },
+ { V(121), V(26), V(65), V(90), V( 65), V( 76), V(117) },
+ { V( 79), V( 0), V(45), V(65), V( 94), V( 92), V(105) } }
};
- // Isolated pawn penalty by file, endgame.
- const Value IsolatedPawnEndgamePenalty[8] = {
- Value(35), Value(40), Value(40), Value(40),
- Value(40), Value(40), Value(40), Value(35)
+ // Danger of enemy pawns moving toward our king by [type][distance from edge][rank].
+ // For the unopposed and unblocked cases, RANK_1 = 0 is used when opponent has
+ // no pawn on the given file, or their pawn is behind our king.
+ const Value StormDanger[][4][RANK_NB] = {
+ { { V( 0), V(-290), V(-274), V(57), V(41) }, // BlockedByKing
+ { V( 0), V( 60), V( 144), V(39), V(13) },
+ { V( 0), V( 65), V( 141), V(41), V(34) },
+ { V( 0), V( 53), V( 127), V(56), V(14) } },
+ { { V( 4), V( 73), V( 132), V(46), V(31) }, // Unopposed
+ { V( 1), V( 64), V( 143), V(26), V(13) },
+ { V( 1), V( 47), V( 110), V(44), V(24) },
+ { V( 0), V( 72), V( 127), V(50), V(31) } },
+ { { V( 0), V( 0), V( 79), V(23), V( 1) }, // BlockedByPawn
+ { V( 0), V( 0), V( 148), V(27), V( 2) },
+ { V( 0), V( 0), V( 161), V(16), V( 1) },
+ { V( 0), V( 0), V( 171), V(22), V(15) } },
+ { { V(22), V( 45), V( 104), V(62), V( 6) }, // Unblocked
+ { V(31), V( 30), V( 99), V(39), V(19) },
+ { V(23), V( 29), V( 96), V(41), V(15) },
+ { V(21), V( 23), V( 116), V(41), V(15) } }
};
- // Backward pawn penalty by file, middle game.
- const Value BackwardPawnMidgamePenalty[8] = {
- Value(16), Value(24), Value(27), Value(27),
- Value(27), Value(27), Value(24), Value(16)
- };
+ // Max bonus for king safety. Corresponds to start position with all the pawns
+ // in front of the king and no enemy pawn on the horizon.
+ const Value MaxSafetyBonus = V(258);
+
+ #undef S
+ #undef V
+
+ template<Color Us>
+ Score evaluate(const Position& pos, Pawns::Entry* e) {
+
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Direction Up = (Us == WHITE ? NORTH : SOUTH);
+
+ Bitboard b, neighbours, stoppers, doubled, supported, phalanx;
+ Bitboard lever, leverPush;
+ Square s;
+ bool opposed, backward;
+ Score score = SCORE_ZERO;
+ const Square* pl = pos.squares<PAWN>(Us);
+
+ Bitboard ourPawns = pos.pieces( Us, PAWN);
+ Bitboard theirPawns = pos.pieces(Them, PAWN);
+
+ e->passedPawns[Us] = e->pawnAttacksSpan[Us] = e->weakUnopposed[Us] = 0;
+ e->semiopenFiles[Us] = 0xFF;
+ e->kingSquares[Us] = SQ_NONE;
+ e->pawnAttacks[Us] = pawn_attacks_bb<Us>(ourPawns);
+ e->pawnsOnSquares[Us][BLACK] = popcount(ourPawns & DarkSquares);
+ e->pawnsOnSquares[Us][WHITE] = pos.count<PAWN>(Us) - e->pawnsOnSquares[Us][BLACK];
+
+ // Loop through all pawns of the current color and score each pawn
+ while ((s = *pl++) != SQ_NONE)
+ {
+ assert(pos.piece_on(s) == make_piece(Us, PAWN));
+
+ File f = file_of(s);
+
+ e->semiopenFiles[Us] &= ~(1 << f);
+ e->pawnAttacksSpan[Us] |= pawn_attack_span(Us, s);
+
+ // Flag the pawn
+ opposed = theirPawns & forward_file_bb(Us, s);
+ stoppers = theirPawns & passed_pawn_mask(Us, s);
+ lever = theirPawns & PawnAttacks[Us][s];
+ leverPush = theirPawns & PawnAttacks[Us][s + Up];
+ doubled = ourPawns & (s - Up);
+ neighbours = ourPawns & adjacent_files_bb(f);
+ phalanx = neighbours & rank_bb(s);
+ supported = neighbours & rank_bb(s - Up);
+
+ // A pawn is backward when it is behind all pawns of the same color on the
+ // adjacent files and cannot be safely advanced.
+ if (!neighbours || lever || relative_rank(Us, s) >= RANK_5)
+ backward = false;
+ else
+ {
+ // Find the backmost rank with neighbours or stoppers
+ b = rank_bb(backmost_sq(Us, neighbours | stoppers));
+
+ // The pawn is backward when it cannot safely progress to that rank:
+ // either there is a stopper in the way on this rank, or there is a
+ // stopper on adjacent file which controls the way to that rank.
+ backward = (b | shift<Up>(b & adjacent_files_bb(f))) & stoppers;
+
+ assert(!(backward && (forward_ranks_bb(Them, s + Up) & neighbours)));
+ }
- // Backward pawn penalty by file, endgame.
- const Value BackwardPawnEndgamePenalty[8] = {
- Value(28), Value(32), Value(32), Value(32),
- Value(32), Value(32), Value(32), Value(28)
- };
+ // Passed pawns will be properly scored in evaluation because we need
+ // full attack info to evaluate them. Include also not passed pawns
+ // which could become passed after one or two pawn pushes when are
+ // not attacked more times than defended.
+ if ( !(stoppers ^ lever ^ leverPush)
+ && !(ourPawns & forward_file_bb(Us, s))
+ && popcount(supported) >= popcount(lever)
+ && popcount(phalanx) >= popcount(leverPush))
+ e->passedPawns[Us] |= s;
+
+ else if ( stoppers == SquareBB[s + Up]
+ && relative_rank(Us, s) >= RANK_5)
+ {
+ b = shift<Up>(supported) & ~theirPawns;
+ while (b)
+ if (!more_than_one(theirPawns & PawnAttacks[Us][pop_lsb(&b)]))
+ e->passedPawns[Us] |= s;
+ }
- // Pawn chain membership bonus by file, middle game.
- const Value ChainMidgameBonus[8] = {
- Value(14), Value(16), Value(17), Value(18),
- Value(18), Value(17), Value(16), Value(14)
- };
+ // Score this pawn
+ if (supported | phalanx)
+ score += Connected[opposed][bool(phalanx)][popcount(supported)][relative_rank(Us, s)];
- // Pawn chain membership bonus by file, endgame.
- const Value ChainEndgameBonus[8] = {
- Value(16), Value(16), Value(16), Value(16),
- Value(16), Value(16), Value(16), Value(16)
- };
+ else if (!neighbours)
+ score -= Isolated, e->weakUnopposed[Us] += !opposed;
- // Candidate passed pawn bonus by rank, middle game.
- const Value CandidateMidgameBonus[8] = {
- Value(0), Value(12), Value(12), Value(20),
- Value(40), Value(90), Value(0), Value(0)
- };
+ else if (backward)
+ score -= Backward, e->weakUnopposed[Us] += !opposed;
- // Candidate passed pawn bonus by rank, endgame.
- const Value CandidateEndgameBonus[8] = {
- Value(0), Value(24), Value(24), Value(40),
- Value(80), Value(180), Value(0), Value(0)
- };
+ if (doubled && !supported)
+ score -= Doubled;
+ }
- // Evaluate pawn storms?
- const bool EvaluatePawnStorms = true;
-
- // Pawn storm tables for positions with opposite castling:
- const int QStormTable[64] = {
- 0, 0, 0, 0, 0, 0, 0, 0,
- -22, -22, -22, -13, -4, 0, 0, 0,
- -4, -9, -9, -9, -4, 0, 0, 0,
- 9, 18, 22, 18, 9, 0, 0, 0,
- 22, 31, 31, 22, 0, 0, 0, 0,
- 31, 40, 40, 31, 0, 0, 0, 0,
- 31, 40, 40, 31, 0, 0, 0, 0,
- 0, 0, 0, 0, 0, 0, 0, 0
- };
-
- const int KStormTable[64] = {
- 0, 0, 0, 0, 0, 0, 0, 0,
- 0, 0, 0, -4, -13, -22, -27, -27,
- 0, 0, 0, -4, -9, -13, -18, -18,
- 0, 0, 0, 0, 9, 9, 9, 9,
- 0, 0, 0, 0, 9, 18, 27, 27,
- 0, 0, 0, 0, 9, 27, 40, 36,
- 0, 0, 0, 0, 0, 31, 40, 31,
- 0, 0, 0, 0, 0, 0, 0, 0
- };
+ return score;
+ }
- // Pawn storm open file bonuses by file:
- const int KStormOpenFileBonus[8] = {
- 45, 45, 30, 0, 0, 0, 0, 0
- };
+} // namespace
- const int QStormOpenFileBonus[8] = {
- 0, 0, 0, 0, 0, 30, 45, 30
- };
+namespace Pawns {
-}
+/// Pawns::init() initializes some tables needed by evaluation. Instead of using
+/// hard-coded tables, when makes sense, we prefer to calculate them with a formula
+/// to reduce independent parameters and to allow easier tuning and better insight.
+void init() {
-////
-//// Functions
-////
+ static const int Seed[RANK_NB] = { 0, 13, 24, 18, 76, 100, 175, 330 };
-/// Constructor
+ for (int opposed = 0; opposed <= 1; ++opposed)
+ for (int phalanx = 0; phalanx <= 1; ++phalanx)
+ for (int support = 0; support <= 2; ++support)
+ for (Rank r = RANK_2; r < RANK_8; ++r)
+ {
+ int v = 17 * support;
+ v += (Seed[r] + (phalanx ? (Seed[r + 1] - Seed[r]) / 2 : 0)) >> opposed;
-PawnInfoTable::PawnInfoTable(unsigned numOfEntries) {
- size = numOfEntries;
- entries = new PawnInfo[size];
- if(entries == NULL) {
- std::cerr << "Failed to allocate " << (numOfEntries * sizeof(PawnInfo))
- << " bytes for pawn hash table." << std::endl;
- exit(EXIT_FAILURE);
+ Connected[opposed][phalanx][support][r] = make_score(v, v * (r - 2) / 4);
}
- this->clear();
}
-/// Destructor
+/// Pawns::probe() looks up the current position's pawns configuration in
+/// the pawns hash table. It returns a pointer to the Entry if the position
+/// is found. Otherwise a new Entry is computed and stored there, so we don't
+/// have to recompute all when the same pawns configuration occurs again.
-PawnInfoTable::~PawnInfoTable() {
- delete [] entries;
-}
+Entry* probe(const Position& pos) {
+ Key key = pos.pawn_key();
+ Entry* e = pos.this_thread()->pawnsTable[key];
-/// PawnInfoTable::clear() clears the pawn hash table by setting all
-/// entries to 0.
+ if (e->key == key)
+ return e;
-void PawnInfoTable::clear() {
- memset(entries, 0, size * sizeof(PawnInfo));
+ e->key = key;
+ e->scores[WHITE] = evaluate<WHITE>(pos, e);
+ e->scores[BLACK] = evaluate<BLACK>(pos, e);
+ e->openFiles = popcount(e->semiopenFiles[WHITE] & e->semiopenFiles[BLACK]);
+ e->asymmetry = popcount( (e->passedPawns[WHITE] | e->passedPawns[BLACK])
+ | (e->semiopenFiles[WHITE] ^ e->semiopenFiles[BLACK]));
+
+ return e;
}
-/// PawnInfoTable::get_pawn_info() takes a position object as input, computes
-/// a PawnInfo object, and returns a pointer to it. The result is also
-/// stored in a hash table, so we don't have to recompute everything when
-/// the same pawn structure occurs again.
-
-PawnInfo *PawnInfoTable::get_pawn_info(const Position &pos) {
- assert(pos.is_ok());
-
- Key key = pos.get_pawn_key();
- int index = int(key & (size - 1));
- PawnInfo *pi = entries + index;
-
- // If pi->key matches the position's pawn hash key, it means that we
- // have analysed this pawn structure before, and we can simply return the
- // information we found the last time instead of recomputing it:
- if(pi->key == key)
- return pi;
-
- // Clear the PawnInfo object, and set the key:
- pi->clear();
- pi->key = key;
-
- Value mgValue[2] = {Value(0), Value(0)};
- Value egValue[2] = {Value(0), Value(0)};
-
- // Loop through the pawns for both colors:
- for(Color us = WHITE; us <= BLACK; us++) {
- Color them = opposite_color(us);
- Bitboard ourPawns = pos.pawns(us);
- Bitboard theirPawns = pos.pawns(them);
- Bitboard pawns = ourPawns;
-
- // Initialize pawn storm scores by giving bonuses for open files:
- if(EvaluatePawnStorms)
- for(File f = FILE_A; f <= FILE_H; f++)
- if(pos.file_is_half_open(us, f)) {
- pi->ksStormValue[us] += KStormOpenFileBonus[f];
- pi->qsStormValue[us] += QStormOpenFileBonus[f];
- }
+/// Entry::shelter_storm() calculates shelter and storm penalties for the file
+/// the king is on, as well as the two closest files.
+
+template<Color Us>
+Value Entry::shelter_storm(const Position& pos, Square ksq) {
+
+ constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Bitboard ShelterMask =
+ Us == WHITE ? make_bitboard(SQ_A2, SQ_B3, SQ_C2, SQ_F2, SQ_G3, SQ_H2)
+ : make_bitboard(SQ_A7, SQ_B6, SQ_C7, SQ_F7, SQ_G6, SQ_H7);
+ constexpr Bitboard StormMask =
+ Us == WHITE ? make_bitboard(SQ_A3, SQ_C3, SQ_F3, SQ_H3)
+ : make_bitboard(SQ_A6, SQ_C6, SQ_F6, SQ_H6);
+
+ enum { BlockedByKing, Unopposed, BlockedByPawn, Unblocked };
+
+ File center = std::max(FILE_B, std::min(FILE_G, file_of(ksq)));
+ Bitboard b = pos.pieces(PAWN)
+ & (forward_ranks_bb(Us, ksq) | rank_bb(ksq))
+ & (adjacent_files_bb(center) | file_bb(center));
+ Bitboard ourPawns = b & pos.pieces(Us);
+ Bitboard theirPawns = b & pos.pieces(Them);
+ Value safety = MaxSafetyBonus;
+
+ for (File f = File(center - 1); f <= File(center + 1); ++f)
+ {
+ b = ourPawns & file_bb(f);
+ Rank rkUs = b ? relative_rank(Us, backmost_sq(Us, b)) : RANK_1;
+
+ b = theirPawns & file_bb(f);
+ Rank rkThem = b ? relative_rank(Us, frontmost_sq(Them, b)) : RANK_1;
+
+ int d = std::min(f, ~f);
+ safety -= ShelterWeakness[f == file_of(ksq)][d][rkUs]
+ + StormDanger
+ [f == file_of(ksq) && rkThem == relative_rank(Us, ksq) + 1 ? BlockedByKing :
+ rkUs == RANK_1 ? Unopposed :
+ rkThem == rkUs + 1 ? BlockedByPawn : Unblocked]
+ [d][rkThem];
+ }
- // Loop through all pawns of the current color and score each pawn:
- while(pawns) {
- Square s = pop_1st_bit(&pawns);
- File f = square_file(s);
- Rank r = square_rank(s);
- bool passed, doubled, isolated, backward, chain, candidate;
- int bonus;
-
- assert(pos.piece_on(s) == pawn_of_color(us));
-
- // The file containing the pawn is not half open:
- pi->halfOpenFiles[us] &= ~(1 << f);
-
- // Passed, isolated or doubled pawn?
- passed = pos.pawn_is_passed(us, s);
- isolated = pos.pawn_is_isolated(us, s);
- doubled = pos.pawn_is_doubled(us, s);
-
- if(EvaluatePawnStorms) {
- // We calculate kingside and queenside pawn storm
- // scores for both colors. These are used when evaluating
- // middle game positions with opposite side castling.
- //
- // Each pawn is given a base score given by a piece square table
- // (KStormTable[] or QStormTable[]). This score is increased if
- // there are enemy pawns on adjacent files in front of the pawn.
- // This is because we want to be able to open files against the
- // enemy king, and to avoid blocking the pawn structure (e.g. white
- // pawns on h6, g5, black pawns on h7, g6, f7).
-
- // Kingside pawn storms:
- bonus = KStormTable[relative_square(us, s)];
- if(bonus > 0 && outpost_mask(us, s) & theirPawns) {
- switch(f) {
-
- case FILE_F:
- bonus += bonus / 4;
- break;
-
- case FILE_G:
- bonus += bonus / 2 + bonus / 4;
- break;
-
- case FILE_H:
- bonus += bonus / 2;
- break;
-
- default:
- break;
- }
- }
- pi->ksStormValue[us] += bonus;
+ if (popcount((ourPawns & ShelterMask) | (theirPawns & StormMask)) == 5)
+ safety += Value(300);
- // Queenside pawn storms:
- bonus = QStormTable[relative_square(us, s)];
- if(bonus > 0 && passed_pawn_mask(us, s) & theirPawns) {
- switch(f) {
+ return safety;
+}
- case FILE_A:
- bonus += bonus / 2;
- break;
- case FILE_B:
- bonus += bonus / 2 + bonus / 4;
- break;
+/// Entry::do_king_safety() calculates a bonus for king safety. It is called only
+/// when king square changes, which is about 20% of total king_safety() calls.
- case FILE_C:
- bonus += bonus / 2;
- break;
+template<Color Us>
+Score Entry::do_king_safety(const Position& pos, Square ksq) {
- default:
- break;
- }
- }
- pi->qsStormValue[us] += bonus;
- }
-
- // Member of a pawn chain? We could speed up the test a little by
- // introducing an array of masks indexed by color and square for doing
- // the test, but because everything is hashed, it probably won't make
- // any noticable difference.
- chain = (us == WHITE)?
- (ourPawns & neighboring_files_bb(f) & (rank_bb(r) | rank_bb(r-1))) :
- (ourPawns & neighboring_files_bb(f) & (rank_bb(r) | rank_bb(r+1)));
-
-
- // Test for backward pawn.
-
- // If the pawn is isolated, passed, or member of a pawn chain, it cannot
- // be backward:
- if(passed || isolated || chain)
- backward = false;
- // If the pawn can capture an enemy pawn, it's not backward:
- else if(pos.pawn_attacks(us, s) & theirPawns)
- backward = false;
- // Check for friendly pawns behind on neighboring files:
- else if(ourPawns & in_front_bb(them, r) & neighboring_files_bb(f))
- backward = false;
- else {
- // We now know that there is no friendly pawns beside or behind this
- // pawn on neighboring files. We now check whether the pawn is
- // backward by looking in the forward direction on the neighboring
- // files, and seeing whether we meet a friendly or an enemy pawn first.
- Bitboard b;
- if(us == WHITE) {
- for(b=pos.pawn_attacks(us, s); !(b&(ourPawns|theirPawns)); b<<=8);
- backward = (b | (b << 8)) & theirPawns;
- }
- else {
- for(b=pos.pawn_attacks(us, s); !(b&(ourPawns|theirPawns)); b>>=8);
- backward = (b | (b >> 8)) & theirPawns;
- }
- }
-
- // Test for candidate passed pawn.
- candidate =
- (!passed && pos.file_is_half_open(them, f) &&
- count_1s_max_15(neighboring_files_bb(f)
- & (in_front_bb(them, r) | rank_bb(r))
- & ourPawns)
- - count_1s_max_15(neighboring_files_bb(f) & in_front_bb(us, r)
- & theirPawns)
- >= 0);
-
- // In order to prevent doubled passed pawns from receiving a too big
- // bonus, only the frontmost passed pawn on each file is considered as
- // a true passed pawn.
- if(passed && (ourPawns & squares_in_front_of(us, s))) {
- // candidate = true;
- passed = false;
- }
-
- // Score this pawn:
- Value mv = Value(0), ev = Value(0);
- if(isolated) {
- mv -= IsolatedPawnMidgamePenalty[f];
- ev -= IsolatedPawnEndgamePenalty[f];
- if(pos.file_is_half_open(them, f)) {
- mv -= IsolatedPawnMidgamePenalty[f] / 2;
- ev -= IsolatedPawnEndgamePenalty[f] / 2;
- }
- }
- if(doubled) {
- mv -= DoubledPawnMidgamePenalty[f];
- ev -= DoubledPawnEndgamePenalty[f];
- }
- if(backward) {
- mv -= BackwardPawnMidgamePenalty[f];
- ev -= BackwardPawnEndgamePenalty[f];
- if(pos.file_is_half_open(them, f)) {
- mv -= BackwardPawnMidgamePenalty[f] / 2;
- ev -= BackwardPawnEndgamePenalty[f] / 2;
- }
- }
- if(chain) {
- mv += ChainMidgameBonus[f];
- ev += ChainEndgameBonus[f];
- }
- if(candidate) {
- mv += CandidateMidgameBonus[relative_rank(us, s)];
- ev += CandidateEndgameBonus[relative_rank(us, s)];
- }
-
- mgValue[us] += mv;
- egValue[us] += ev;
-
- // If the pawn is passed, set the square of the pawn in the passedPawns
- // bitboard:
- if(passed)
- set_bit(&(pi->passedPawns), s);
- }
- }
+ kingSquares[Us] = ksq;
+ castlingRights[Us] = pos.can_castle(Us);
+ int minKingPawnDistance = 0;
- pi->mgValue = int16_t(mgValue[WHITE] - mgValue[BLACK]);
- pi->egValue = int16_t(egValue[WHITE] - egValue[BLACK]);
+ Bitboard pawns = pos.pieces(Us, PAWN);
+ if (pawns)
+ while (!(DistanceRingBB[ksq][minKingPawnDistance++] & pawns)) {}
- return pi;
+ Value bonus = shelter_storm<Us>(pos, ksq);
+
+ // If we can castle use the bonus after the castling if it is bigger
+ if (pos.can_castle(MakeCastling<Us, KING_SIDE>::right))
+ bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_G1)));
+
+ if (pos.can_castle(MakeCastling<Us, QUEEN_SIDE>::right))
+ bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_C1)));
+
+ return make_score(bonus, -16 * minKingPawnDistance);
}
+
+// Explicit template instantiation
+template Score Entry::do_king_safety<WHITE>(const Position& pos, Square ksq);
+template Score Entry::do_king_safety<BLACK>(const Position& pos, Square ksq);
+
+} // namespace Pawns
projects / stockfish / blobdiff