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Optimize generate_piece_blocking_evasions()

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Rewrite as in generate_piece_moves() using a for
loop instead of the slower serializing of the
bitboard with pop_1st_bit()

This will allow also to merge with generate_piece_moves()
when we will drop legality constrain on generate_evasions()

Generated moves are not changed, but are generated in a
different order, this changes the number of nodes at fixed
depth test.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2009-02-11 12:58:45 +01:00
parent 67535711e8
commit 1dc1cecf01
1 changed files with 24 additions and 21 deletions
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45
src/movegen.cpp
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@ -102,11 +102,11 @@ namespace {
template<> template<>
inline MoveStack* generate_piece_blocking_evasions<PAWN>(const Position& p, MoveStack* m, Color us, inline MoveStack* generate_piece_blocking_evasions<PAWN>(const Position& p, MoveStack* m, Color us,
Bitboard np, Bitboard bs) { Bitboard pnd, Bitboard bs) {
if (us == WHITE) if (us == WHITE)
return generate_pawn_blocking_evasions<WHITE, RANK_8, Rank3BB, DELTA_N>(p, np, bs, m); return generate_pawn_blocking_evasions<WHITE, RANK_8, Rank3BB, DELTA_N>(p, pnd, bs, m);
else else
return generate_pawn_blocking_evasions<BLACK, RANK_1, Rank6BB, DELTA_S>(p, np, bs, m); return generate_pawn_blocking_evasions<BLACK, RANK_1, Rank6BB, DELTA_S>(p, pnd, bs, m);
} }
} }
@ -265,14 +265,13 @@ int generate_evasions(const Position& pos, MoveStack* mlist, Bitboard pinned) {
if (!(checkers & (checkers - 1))) // Only one bit set? if (!(checkers & (checkers - 1))) // Only one bit set?
{ {
Square checksq = first_1(checkers); Square checksq = first_1(checkers);
Bitboard not_pinned = ~pinned;
assert(pos.color_of_piece_on(checksq) == them); assert(pos.color_of_piece_on(checksq) == them);
// Generate captures of the checking piece // Generate captures of the checking piece
// Pawn captures // Pawn captures
b1 = pos.pawn_attacks(them, checksq) & pos.pawns(us) & not_pinned; b1 = pos.pawn_attacks(them, checksq) & pos.pawns(us) & ~pinned;
while (b1) while (b1)
{ {
from = pop_1st_bit(&b1); from = pop_1st_bit(&b1);
@ -289,7 +288,7 @@ int generate_evasions(const Position& pos, MoveStack* mlist, Bitboard pinned) {
// Pieces captures // Pieces captures
b1 = ( (pos.piece_attacks<KNIGHT>(checksq) & pos.knights(us)) b1 = ( (pos.piece_attacks<KNIGHT>(checksq) & pos.knights(us))
| (pos.piece_attacks<BISHOP>(checksq) & pos.bishops_and_queens(us)) | (pos.piece_attacks<BISHOP>(checksq) & pos.bishops_and_queens(us))
| (pos.piece_attacks<ROOK>(checksq) & pos.rooks_and_queens(us)) ) & not_pinned; | (pos.piece_attacks<ROOK>(checksq) & pos.rooks_and_queens(us)) ) & ~pinned;
while (b1) while (b1)
{ {
@ -298,7 +297,7 @@ int generate_evasions(const Position& pos, MoveStack* mlist, Bitboard pinned) {
} }
// Blocking check evasions are possible only if the checking piece is // Blocking check evasions are possible only if the checking piece is
// a slider // a slider.
if (checkers & pos.sliders()) if (checkers & pos.sliders())
{ {
Bitboard blockSquares = squares_between(checksq, ksq); Bitboard blockSquares = squares_between(checksq, ksq);
@ -306,11 +305,11 @@ int generate_evasions(const Position& pos, MoveStack* mlist, Bitboard pinned) {
assert((pos.occupied_squares() & blockSquares) == EmptyBoardBB); assert((pos.occupied_squares() & blockSquares) == EmptyBoardBB);
// Pieces moves // Pieces moves
mlist = generate_piece_blocking_evasions<PAWN>(pos, mlist, us, not_pinned, blockSquares); mlist = generate_piece_blocking_evasions<PAWN>(pos, mlist, us, pinned, blockSquares);
mlist = generate_piece_blocking_evasions<KNIGHT>(pos, mlist, us, not_pinned, blockSquares); mlist = generate_piece_blocking_evasions<KNIGHT>(pos, mlist, us, pinned, blockSquares);
mlist = generate_piece_blocking_evasions<BISHOP>(pos, mlist, us, not_pinned, blockSquares); mlist = generate_piece_blocking_evasions<BISHOP>(pos, mlist, us, pinned, blockSquares);
mlist = generate_piece_blocking_evasions<ROOK>(pos, mlist, us, not_pinned, blockSquares); mlist = generate_piece_blocking_evasions<ROOK>(pos, mlist, us, pinned, blockSquares);
mlist = generate_piece_blocking_evasions<QUEEN>(pos, mlist, us, not_pinned, blockSquares); mlist = generate_piece_blocking_evasions<QUEEN>(pos, mlist, us, pinned, blockSquares);
} }
// Finally, the ugly special case of en passant captures. An en passant // Finally, the ugly special case of en passant captures. An en passant
@ -325,7 +324,7 @@ int generate_evasions(const Position& pos, MoveStack* mlist, Bitboard pinned) {
assert(b1 != EmptyBoardBB); assert(b1 != EmptyBoardBB);
b1 &= not_pinned; b1 &= ~pinned;
while (b1) while (b1)
{ {
from = pop_1st_bit(&b1); from = pop_1st_bit(&b1);
@ -587,14 +586,18 @@ namespace {
template<PieceType Piece> template<PieceType Piece>
MoveStack* generate_piece_blocking_evasions(const Position& pos, MoveStack* mlist, Color us, MoveStack* generate_piece_blocking_evasions(const Position& pos, MoveStack* mlist, Color us,
Bitboard not_pinned, Bitboard blockSquares) { Bitboard pinned, Bitboard blockSquares) {
Square from;
Bitboard b;
Bitboard b = pos.pieces_of_color_and_type(us, Piece) & not_pinned; for (int i = 0, e = pos.piece_count(us, Piece); i < e; i++)
while (b)
{ {
Square from = pop_1st_bit(&b); from = pos.piece_list(us, Piece, i);
Bitboard bb = pos.piece_attacks<Piece>(from) & blockSquares; if (pinned && bit_is_set(pinned, from))
SERIALIZE_MOVES(bb); continue;
b = pos.piece_attacks<Piece>(from) & blockSquares;
SERIALIZE_MOVES(b);
} }
return mlist; return mlist;
} }
@ -821,12 +824,12 @@ namespace {
} }
template<Color Us, Rank TRANK_8, Bitboard TRank3BB, SquareDelta TDELTA_N> template<Color Us, Rank TRANK_8, Bitboard TRank3BB, SquareDelta TDELTA_N>
MoveStack* generate_pawn_blocking_evasions(const Position& pos, Bitboard not_pinned, MoveStack* generate_pawn_blocking_evasions(const Position& pos, Bitboard pinned,
Bitboard blockSquares, MoveStack* mlist) { Bitboard blockSquares, MoveStack* mlist) {
Square to; Square to;
// Find non-pinned pawns // Find non-pinned pawns
Bitboard b1 = pos.pawns(Us) & not_pinned; Bitboard b1 = pos.pawns(Us) & ~pinned;
// Single pawn pushes. We don't have to AND with empty squares here, // Single pawn pushes. We don't have to AND with empty squares here,
// because the blocking squares will always be empty. // because the blocking squares will always be empty.