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Code style tweaks to pawns.cpp

Browse source 
Also a small speedup.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2010-05-14 09:47:11 +02:00
parent 6c27bf1880
commit 0b49ec9822
1 changed files with 41 additions and 39 deletions
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80
src/pawns.cpp
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@ -100,6 +100,7 @@ namespace {
// Pawn storm lever bonuses by file
const int StormLeverBonus[8] = { -8, -8, -13, 0, 0, -13, -8, -8 };
#undef S
}
@ -107,11 +108,10 @@ namespace {
//// Functions
////
/// Constructor
/// PawnInfoTable c'tor and d'tor instantiated one each thread
PawnInfoTable::PawnInfoTable(unsigned numOfEntries) {
PawnInfoTable::PawnInfoTable(unsigned numOfEntries) : size(numOfEntries) {
size = numOfEntries;
entries = new PawnInfo[size];
if (!entries)
{
@ -122,9 +122,8 @@ PawnInfoTable::PawnInfoTable(unsigned numOfEntries) {
}
/// Destructor
PawnInfoTable::~PawnInfoTable() {
delete [] entries;
}
@ -140,9 +139,9 @@ void PawnInfo::clear() {
/// 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.
/// 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) {
@ -180,11 +179,12 @@ PawnInfo* PawnInfoTable::get_pawn_info(const Position& pos) {
template<Color Us>
Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
Bitboard theirPawns, PawnInfo* pi) {
Square s;
Bitboard b;
Square s, s2;
File f;
Rank r;
Rank r, r2;
bool passed, isolated, doubled, opposed, chain, backward, candidate;
int bonus;
int bonus, v;
Score value = make_score(0, 0);
const Square* ptr = pos.piece_list_begin(Us, PAWN);
@ -205,31 +205,26 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
assert(pos.piece_on(s) == piece_of_color_and_type(Us, PAWN));
// Passed, isolated or doubled pawn?
passed = !(theirPawns & passed_pawn_mask(Us, s));
isolated = !(ourPawns & neighboring_files_bb(s));
doubled = ourPawns & squares_behind(Us, s);
opposed = theirPawns & squares_in_front_of(Us, s);
// We calculate kingside and queenside pawn storm
// scores for both colors. These are used when evaluating
// middle game positions with opposite side castling.
// 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[]). Pawns which seem to have good
// chances of creating an open file by exchanging itself against an
// enemy pawn on an adjacent file gets an additional bonus.
// chances of creating an open file by exchanging itself against
// an enemy pawn on an adjacent file gets an additional bonus.
// Kingside pawn storms
bonus = KStormTable[relative_square(Us, s)];
if (f >= FILE_F)
{
Bitboard b = outpost_mask(Us, s) & theirPawns & (FileFBB | FileGBB | FileHBB);
b = outpost_mask(Us, s) & theirPawns & (FileFBB | FileGBB | FileHBB);
while (b)
{
// Give a bonus according to the distance of the nearest enemy pawn
Square s2 = pop_1st_bit(&b);
int v = StormLeverBonus[f] - 2 * square_distance(s, s2);
s2 = pop_1st_bit(&b);
r2 = square_rank(s2);
v = StormLeverBonus[f] - 2 * rank_distance(r, r2);
// If enemy pawn has no pawn beside itself is particularly vulnerable.
// Big bonus, especially against a weakness on the rook file
@ -245,12 +240,13 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
bonus = QStormTable[relative_square(Us, s)];
if (f <= FILE_C)
{
Bitboard b = outpost_mask(Us, s) & theirPawns & (FileABB | FileBBB | FileCBB);
b = outpost_mask(Us, s) & theirPawns & (FileABB | FileBBB | FileCBB);
while (b)
{
// Give a bonus according to the distance of the nearest enemy pawn
Square s2 = pop_1st_bit(&b);
int v = StormLeverBonus[f] - 4 * square_distance(s, s2);
s2 = pop_1st_bit(&b);
r2 = square_rank(s2);
v = StormLeverBonus[f] - 4 * rank_distance(r, r2);
// If enemy pawn has no pawn beside itself is particularly vulnerable.
// Big bonus, especially against a weakness on the rook file
@ -262,13 +258,16 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
}
pi->qsStormValue[Us] += bonus;
// Member of a pawn chain (but not the backward one)? 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 = ourPawns
& neighboring_files_bb(f)
& (rank_bb(r) | rank_bb(r - (Us == WHITE ? 1 : -1)));
// Our rank and previous one. Used for chain detection.
b = rank_bb(r) | rank_bb(r + (Us == WHITE ? -1 : 1));
// Passed, isolated, doubled or member of a pawn
// chain (but not the backward one) ?
passed = !(theirPawns & passed_pawn_mask(Us, s));
doubled = ourPawns & squares_behind(Us, s);
opposed = theirPawns & squares_in_front_of(Us, s);
isolated = !(ourPawns & neighboring_files_bb(f));
chain = ourPawns & neighboring_files_bb(f) & b;
// Test for backward pawn
//
@ -277,7 +276,7 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
// there are friendly pawns behind on neighboring files it cannot
// be backward either.
if ( (passed | isolated | chain)
|| (ourPawns & behind_bb(Us, r) & neighboring_files_bb(f))
|| (ourPawns & outpost_mask(opposite_color(Us), s))
|| (pos.attacks_from<PAWN>(s, Us) & theirPawns))
backward = false;
else
@ -286,7 +285,7 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
// 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 = pos.attacks_from<PAWN>(s, Us);
b = pos.attacks_from<PAWN>(s, Us);
// Note that we are sure to find something because pawn is not passed
// nor isolated, so loop is potentially infinite, but it isn't.
@ -311,10 +310,12 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
if (passed && (ourPawns & squares_in_front_of(Us, s)))
passed = false;
// Score this pawn
// Mark the pawn as passed. Pawn will be properly scored in evaluation
// because we need full attack info to evaluate passed pawns.
if (passed)
set_bit(&(pi->passedPawns), s);
// Score this pawn
if (isolated)
{
value -= IsolatedPawnPenalty[f];
@ -345,9 +346,10 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
/// only when king square changes, about 20% of total get_king_shelter() calls.
int PawnInfo::updateShelter(const Position& pos, Color c, Square ksq) {
unsigned shelter = 0;
Bitboard pawns = pos.pieces(PAWN, c) & this_and_neighboring_files_bb(ksq);
unsigned shelter = 0;
unsigned r = ksq & (7 << 3);
for (int i = 1, k = (c ? -8 : 8); i < 4; i++)
{
r += k;