magic bitboards via AI

1 files changed, 6 insertions, 44 deletions

diff --git a/src/engine/moves/rook.c b/src/engine/moves/rook.c
index abbc784..0938de9 100644
--- a/src/engine/moves/rook.c
+++ b/src/engine/moves/rook.c
@@ -7,53 +7,15 @@ void __forloop_rook_moves_gen(
   bitboard_t friendly_pieces,
   bitboard_t enemy_pieces
 ) {
+  bitboard_t all_occupied = friendly_pieces | enemy_pieces;
   while (friendly_type) {
     int from = __builtin_ctzll(friendly_type);
     friendly_type &= friendly_type - 1;
-
-    int og_rank = from / 8; // range: [0, 7]
-    int og_file = from % 8; // range: [0, 7]
-    int rank = og_rank + 1, file = og_file, index = rank * 8 + file;
-
-
-    bitboard_t occupied;
-    while (rank < 8 && !occupied_by(friendly_pieces, index)) {
-      occupied = occupied_by(enemy_pieces, index);
-      add_move(moves, from, index, .flags = occupied ? MOVE_CAPTURE : 0);
-      if (occupied) {
-        break;
-      }
-      index = ++rank * 8 + file;
-    }
-
-    rank = og_rank - 1, file = og_file, index = rank * 8 + file;
-    while (rank >= 0 && !occupied_by(friendly_pieces, index)) {
-      occupied = occupied_by(enemy_pieces, index);
-      add_move(moves, from, index, .flags = occupied ? MOVE_CAPTURE : 0);
-      if (occupied) {
-        break;
-      }
-      index = --rank * 8 + file;
-    }
-
-    rank = og_rank, file = og_file + 1, index = rank * 8 + file;
-    while (file < 8 && !occupied_by(friendly_pieces, index)) {
-      occupied = occupied_by(enemy_pieces, index);
-      add_move(moves, from, index, .flags = occupied ? MOVE_CAPTURE : 0);
-      if (occupied) {
-        break;
-      }
-      index = rank * 8 + ++file;
-    }
-    
-    rank = og_rank, file = og_file - 1, index = rank * 8 + file;
-    while (file >= 0 && !occupied_by(friendly_pieces, index)) {
-      occupied = occupied_by(enemy_pieces, index);
-      add_move(moves, from, index, .flags = occupied ? MOVE_CAPTURE : 0);
-      if (occupied) {
-        break;
-      }
-      index = rank * 8 + --file;
+    bitboard_t attacks = get_rook_attacks(from, all_occupied) & ~friendly_pieces;
+    while (attacks) {
+      int to = __builtin_ctzll(attacks);
+      attacks &= attacks - 1;
+      add_move(moves, from, to, .flags = ((enemy_pieces >> to) & 1) ? MOVE_CAPTURE : 0);
     }
   }
 }