return shift<EAST>(file_bb(s)) | shift<WEST>(file_bb(s));
}
+/// line_bb(Square, Square) returns a Bitboard representing an entire line
+/// (from board edge to board edge) that intersects the given squares.
+/// If the given squares are not on a same file/rank/diagonal, return 0.
+/// Ex. line_bb(SQ_C4, SQ_F7) returns a bitboard with the A2-G8 diagonal.
+
+inline Bitboard line_bb(Square s1, Square s2) {
+
+ assert(is_ok(s1) && is_ok(s2));
+ return LineBB[s1][s2];
+}
-/// between_bb() returns squares that are linearly between the given squares
+/// between_bb() returns a Bitboard representing squares that are linearly
+/// between the given squares (excluding the given squares).
/// If the given squares are not on a same file/rank/diagonal, return 0.
+/// Ex. between_bb(SQ_C4, SQ_F7) returns a bitboard with squares D5 and E6.
inline Bitboard between_bb(Square s1, Square s2) {
- Bitboard b = LineBB[s1][s2] & ((AllSquares << s1) ^ (AllSquares << s2));
+ Bitboard b = line_bb(s1, s2) & ((AllSquares << s1) ^ (AllSquares << s2));
return b & (b - 1); //exclude lsb
}
/// straight or on a diagonal line.
inline bool aligned(Square s1, Square s2, Square s3) {
- return LineBB[s1][s2] & s3;
+ return line_bb(s1, s2) & s3;
}
: attacks_bb<Pt>(s, pos.pieces());
if (pos.blockers_for_king(Us) & s)
- b &= LineBB[pos.square<KING>(Us)][s];
+ b &= line_bb(pos.square<KING>(Us), s);
attackedBy2[Us] |= attackedBy[Us][ALL_PIECES] & b;
attackedBy[Us][Pt] |= b;
// the king evasions in order to skip known illegal moves, which avoids any
// useless legality checks later on.
while (sliders)
- sliderAttacks |= LineBB[ksq][pop_lsb(&sliders)] & ~pos.checkers();
+ sliderAttacks |= line_bb(ksq, pop_lsb(&sliders)) & ~pos.checkers();
// Generate evasions for king, capture and non capture moves
Bitboard b = attacks_bb<KING>(ksq) & ~pos.pieces(us) & ~sliderAttacks;