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is_legal: fix check+pinned and knight check; perft-test + perft2()

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Bruno Raoult
2024-03-26 17:37:18 +01:00
parent 7637bdad10
commit 08ba989170
7 changed files with 457 additions and 87 deletions
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20
src/move-gen.c
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@@ -40,6 +40,7 @@ bool pseudo_is_legal(const pos_t *pos, const move_t move)
square_t from = move_from(move), to = move_to(move), king = pos->king[us], sq;
piece_type_t piece = PIECE(pos->board[from]);
bitboard_t kingbb = pos->bb[us][KING], tmp;
u64 pinned = mask(from) & pos->blockers & pos->bb[us][ALL_PIECES];
/* (1) - King
* For castling, we already tested intermediate squares attacks
@@ -53,14 +54,22 @@ bool pseudo_is_legal(const pos_t *pos, const move_t move)
/* (2) - King is in check
* Double-check is already handled, as only K moves were generated.
* Here, allowed moves are only on King-attacker line, including
* attacker.We can move a piece on
* in pseudo move generation, so we only care destination square here.
* Here, allowed dest squares are only on King-checker line, or on checker
* square.
* attacker.
* Special cases:
* e.p., legal if the taken pawn is giving check
* pinned piece: always illegal
*/
if (pos->checkers) {
if (popcount64(pos->checkers) == 1) { /* one checker */
square_t checker = ctz64(pos->checkers);
bitboard_t between = bb_between[king][checker];
if (pinned)
return false;
if (is_enpassant(move)) {
return pawn_push_up(pos->en_passant, them) == checker;
}
bitboard_t between = bb_between[king][checker] | pos->checkers;
return mask(to) & between;
}
return false; /* double check */
@@ -69,7 +78,8 @@ bool pseudo_is_legal(const pos_t *pos, const move_t move)
/* (3) - pinned pieces
* We verify here that pinned piece P stays on line King-P.
*/
if (mask(from) & pos->blockers & pos->bb[us][ALL_PIECES]) {
//if (mask(from) & pos->blockers & pos->bb[us][ALL_PIECES]) {
if (pinned) {
bitboard_t line = bb_line[from][king];
return line & mask(to); /* to is not on pin line */
}