stellar

commit a1e1fde71226015465fd0dacbf438af066a8f5c7
parent 7ee440bb0ac6b207d99d69730ba6002bb908d96c
Author: Dimitrije Dobrota <mail@dimitrijedobrota.com>
Date:   Mon, 19 Sep 2022 19:26:16 +0200

King attack mask

Diffstat:
M
src/engine.c
 | 
17
+++++++++++++++++

1 file changed, 17 insertions(+), 0 deletions(-)
diff --git a/src/engine.c b/src/engine.c
@@ -122,6 +122,9 @@ U64 pawn_attacks[2][64];
 // knight attack table [square]
 U64 knight_attacks[64];
 
+// king attack table [square]
+U64 king_attacks[64];
+
 // generate pawn attack
 U64 mask_pawn_attacks(int side, int square) {
   U64 bitboard = C64(0), attacks;
@@ -149,11 +152,25 @@ U64 mask_knight_attacks(int square) {
   return attacks;
 }
 
+U64 mask_king_attacks(int square) {
+  U64 bitboard = C64(0), attacks = C64(0);
+
+  bit_set(bitboard, square);
+  attacks |= westOne(bitboard) | eastOne(bitboard);
+  attacks |= soutOne(bitboard) | nortOne(bitboard);
+  attacks |= soutOne(bitboard) | nortOne(bitboard);
+  attacks |= soEaOne(bitboard) | noEaOne(bitboard);
+  attacks |= soWeOne(bitboard) | noWeOne(bitboard);
+
+  return attacks;
+}
+
 void init_leapers_attacks(void) {
   for (int square = 0; square < 64; square++) {
     pawn_attacks[WHITE][square] = mask_pawn_attacks(WHITE, square);
     pawn_attacks[BLACK][square] = mask_pawn_attacks(BLACK, square);
     knight_attacks[square] = mask_knight_attacks(square);
+    king_attacks[square] = mask_king_attacks(square);
   }
 }