/*
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
+ Copyright (C) 2008-2012 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
S(34,68), S(83,166), S(0, 0), S( 0, 0)
};
+ const Score PawnStructureWeight = S(233, 201);
+
#undef S
+
+ inline Score apply_weight(Score v, Score w) {
+ return make_score((int(mg_value(v)) * mg_value(w)) / 0x100,
+ (int(eg_value(v)) * eg_value(w)) / 0x100);
+ }
}
-/// PawnInfoTable::get_pawn_info() takes a position object as input, computes
+/// PawnInfoTable::pawn_info() takes a position object as input, computes
/// a PawnInfo object, and returns a pointer to it. The result is also stored
/// in an 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) const {
+PawnInfo* PawnInfoTable::pawn_info(const Position& pos) const {
- assert(pos.is_ok());
-
- Key key = pos.get_pawn_key();
- PawnInfo* pi = find(key);
+ Key key = pos.pawn_key();
+ PawnInfo* pi = probe(key);
// 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
pi->pawnAttacks[WHITE] = ((wPawns << 9) & ~FileABB) | ((wPawns << 7) & ~FileHBB);
pi->pawnAttacks[BLACK] = ((bPawns >> 7) & ~FileABB) | ((bPawns >> 9) & ~FileHBB);
- // Evaluate pawns for both colors
+ // Evaluate pawns for both colors and weight the result
pi->value = evaluate_pawns<WHITE>(pos, wPawns, bPawns, pi)
- evaluate_pawns<BLACK>(pos, bPawns, wPawns, pi);
+
+ pi->value = apply_weight(pi->value, PawnStructureWeight);
+
return pi;
}
Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
Bitboard theirPawns, PawnInfo* pi) {
- const BitCountType Max15 = CpuIs64Bit ? CNT64_MAX15 : CNT32_MAX15;
const Color Them = (Us == WHITE ? BLACK : WHITE);
Bitboard b;
Rank r;
bool passed, isolated, doubled, opposed, chain, backward, candidate;
Score value = SCORE_ZERO;
- const Square* ptr = pos.piece_list_begin(Us, PAWN);
+ const Square* pl = pos.piece_list(Us, PAWN);
// Loop through all pawns of the current color and score each pawn
- while ((s = *ptr++) != SQ_NONE)
+ while ((s = *pl++) != SQ_NONE)
{
assert(pos.piece_on(s) == make_piece(Us, PAWN));
- f = square_file(s);
- r = square_rank(s);
+ f = file_of(s);
+ r = rank_of(s);
// This file cannot be half open
pi->halfOpenFiles[Us] &= ~(1 << f);
passed = !(theirPawns & passed_pawn_mask(Us, s));
doubled = ourPawns & squares_in_front_of(Us, s);
opposed = theirPawns & squares_in_front_of(Us, s);
- isolated = !(ourPawns & neighboring_files_bb(f));
- chain = ourPawns & neighboring_files_bb(f) & b;
+ isolated = !(ourPawns & adjacent_files_bb(f));
+ chain = ourPawns & adjacent_files_bb(f) & b;
// Test for backward pawn
backward = false;
// If the pawn is passed, isolated, or member of a pawn chain it cannot
- // be backward. If there are friendly pawns behind on neighboring files
+ // be backward. If there are friendly pawns behind on adjacent files
// or if can capture an enemy pawn it cannot be backward either.
if ( !(passed | isolated | chain)
&& !(ourPawns & attack_span_mask(Them, s))
&& !(pos.attacks_from<PAWN>(s, Us) & theirPawns))
{
// We now know that there are 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
+ // pawn on adjacent files. We now check whether the pawn is
+ // backward by looking in the forward direction on the adjacent
// files, and seeing whether we meet a friendly or an enemy pawn first.
b = pos.attacks_from<PAWN>(s, Us);
// A not passed pawn is a candidate to become passed if it is free to
// advance and if the number of friendly pawns beside or behind this
- // pawn on neighboring files is higher or equal than the number of
- // enemy pawns in the forward direction on the neighboring files.
+ // pawn on adjacent files is higher or equal than the number of
+ // enemy pawns in the forward direction on the adjacent files.
candidate = !(opposed | passed | backward | isolated)
- && (b = attack_span_mask(Them, s + pawn_push(Us)) & ourPawns) != EmptyBoardBB
- && count_1s<Max15>(b) >= count_1s<Max15>(attack_span_mask(Us, s) & theirPawns);
+ && (b = attack_span_mask(Them, s + pawn_push(Us)) & ourPawns) != 0
+ && popcount<Max15>(b) >= popcount<Max15>(attack_span_mask(Us, s) & theirPawns);
// Passed pawns will be properly scored in evaluation because we need
// full attack info to evaluate passed pawns. Only the frontmost passed
// pawn on each file is considered a true passed pawn.
if (passed && !doubled)
- set_bit(&(pi->passedPawns[Us]), s);
+ pi->passedPawns[Us] |= s;
// Score this pawn
if (isolated)
if (relative_rank(Us, ksq) <= RANK_4)
{
- pawns = pos.pieces(PAWN, Us) & this_and_neighboring_files_bb(ksq);
+ pawns = pos.pieces(PAWN, Us) & this_and_adjacent_files_bb(file_of(ksq));
r = ksq & (7 << 3);
for (int i = 0; i < 3; i++)
{
r += Shift;
- shelter += BitCount8Bit[(pawns >> r) & 0xFF] * (64 >> i);
+ shelter += BitCount8Bit[(pawns >> r) & 0xFF] << (6 - i);
}
}
kingSquares[Us] = ksq;
projects / stockfish / blobdiff