1 files changed, 101 insertions, 0 deletions
diff --git a/src/engine/moves/knight.c b/src/engine/moves/knight.c
new file mode 100644
index 0000000..c48b48e
--- /dev/null
+++ b/src/engine/moves/knight.c
@@ -0,0 +1,101 @@
+#include "../moves.h"
+
+bitboard_t knight_moves[64] = {
+  132096ULL,
+  329728ULL,
+  659712ULL,
+  659712ULL >> 1,
+  659712ULL >> 2,
+  659712ULL >> 3,
+  10489856ULL,
+  4202496ULL,
+
+  33816580ULL,
+  84410376ULL,
+  168886289ULL,
+  168886289ULL >> 1,
+  168886289ULL >> 2,
+  168886289ULL >> 3,
+  2685403152ULL,
+  1075839008ULL,
+
+  8657044482ULL,
+  21609056261ULL,
+  43234889994ULL,
+  43234889994ULL >> 1,
+  43234889994ULL >> 2,
+  43234889994ULL >> 3,
+  687463207072ULL,
+  275414786112ULL,
+
+  8657044482ULL >> 8,
+  21609056261ULL >> 8,
+  43234889994ULL >> 8,
+  43234889994ULL >> (8 + 1),
+  43234889994ULL >> (8 + 2),
+  43234889994ULL >> (8 + 3),
+  687463207072ULL >> 8,
+  275414786112ULL >> 8,
+  
+  8657044482ULL >> 16,
+  21609056261ULL >> 16,
+  43234889994ULL >> 16,
+  43234889994ULL >> (16 + 1),
+  43234889994ULL >> (16 + 2),
+  43234889994ULL >> (16 + 3),
+  687463207072ULL >> 16,
+  275414786112ULL >> 16,
+
+  8657044482ULL >> 24,
+  21609056261ULL >> 24,
+  43234889994ULL >> 24,
+  43234889994ULL >> (24 + 1),
+  43234889994ULL >> (24 + 2),
+  43234889994ULL >> (24 + 3),
+  687463207072ULL >> 24,
+  275414786112ULL >> 24,
+
+  288234782788157440ULL,
+  576469569871282176ULL,
+  1224997833292120064ULL,
+  1224997833292120064ULL >> 1,
+  1224997833292120064ULL >> 2,
+  1224997833292120064ULL >> 3,
+  1152939783987658752ULL,
+  2305878468463689728ULL,
+
+  1128098930098176ULL,
+  2257297371824128ULL,
+  4796069720358912ULL,
+  4796069720358912ULL >> 1,
+  4796069720358912ULL >> 2,
+  4796069720358912ULL >> 3,
+  4679521487814656ULL,
+  9077567998918656ULL,
+};
+
+void get_knight_moves(moves_t* moves, position_t position) {
+  assert_valid_position(position);
+
+  bitboard_t friendly_knights;
+  bitboard_t friendly_pieces;
+  if (position.turn == WHITE_TURN) {
+    friendly_pieces = whites(position);
+    friendly_knights = position.bitboards[WHITE_KNIGHT];
+  } else {
+    friendly_pieces = blacks(position);
+    friendly_knights = position.bitboards[BLACK_KNIGHT];
+  }
+
+  while (friendly_knights) {
+    int from = __builtin_ctzll(friendly_knights);
+    friendly_knights &= friendly_knights - 1;
+    bitboard_t ATTACK_MASK = knight_moves[from];
+    ATTACK_MASK &= ~friendly_pieces;
+    while (ATTACK_MASK) {
+      int to = __builtin_ctzll(ATTACK_MASK);
+      ATTACK_MASK &= ATTACK_MASK - 1;
+      add_move(moves, from, to);
+    }
+  }
+}