bitboard: make directional methods take step argument

src/repr/bitboard.rs

@@ -45,43 +45,42 @@ impl BitBoard {
         self.0 == 0
     }
 
-    // Directional shifts with edge masking (prevents wrapping)
-    pub const fn east(&self) -> Self {
-        let mask = !Self::col_mask(Board::BOARD_SIZE - 1).0; // Mask to block column 7 bits
-        Self((self.0 & mask) << 1)
+    pub const fn east(&self, n: usize) -> Self {
+        let mask = !Self::col_mask(Board::BOARD_SIZE - 1).0; // Mask to block column BOARD_SIZE-1 bits
+        Self((self.0 & mask) << n)
     }
 
-    pub const fn west(&self) -> Self {
+    pub const fn west(&self, n: usize) -> Self {
         let mask = !Self::col_mask(0).0;
-        Self((self.0 & mask) >> 1)
+        Self((self.0 & mask) >> n)
     }
 
-    pub const fn north(&self) -> Self {
-        Self(self.0 >> Board::BOARD_SIZE)
+    pub const fn north(&self, n: usize) -> Self {
+        Self(self.0 >> (Board::BOARD_SIZE as usize * n))
     }
 
-    pub const fn south(&self) -> Self {
-        Self(self.0 << Board::BOARD_SIZE)
+    pub const fn south(&self, n: usize) -> Self {
+        Self(self.0 << (Board::BOARD_SIZE as usize * n))
     }
 
-    pub const fn northeast(&self) -> Self {
-        self.north().east()
+    pub const fn northeast(&self, n: usize) -> Self {
+        self.north(n).east(n)
     }
 
-    pub const fn northwest(&self) -> Self {
-        self.north().west()
+    pub const fn northwest(&self, n: usize) -> Self {
+        self.north(n).west(n)
     }
 
-    pub const fn southeast(&self) -> Self {
-        self.south().east()
+    pub const fn southeast(&self, n: usize) -> Self {
+        self.south(n).east(n)
     }
 
-    pub const fn southwest(&self) -> Self {
-        self.south().west()
+    pub const fn southwest(&self, n: usize) -> Self {
+        self.south(n).west(n)
     }
 
     /// All direction methods
-    pub const DIRECTIONS: [fn(&Self) -> Self; 8] = [
+    pub const DIRECTIONS: [fn(&Self, usize) -> Self; 8] = [
         BitBoard::east,
         BitBoard::west,
         BitBoard::north,

src/repr/board.rs

@@ -298,7 +298,7 @@ impl Board {
 
             // Expand in direction until edge or non-opponent piece
             loop {
-                current = dir(&current);
+                current = dir(&current, 1);
                 if current.is_empty() || !current.intersects(*opponent_board) {
                     break;
                 }