Retire direction.cpp

Move the code to bitboard.cpp

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

src/Makefile

@@ -35,7 +35,7 @@ PGOBENCH = ./$(EXE) bench 32 1 10 default depth
 ### Object files
 OBJS = bitboard.o pawns.o material.o endgame.o evaluate.o main.o \
 	misc.o move.o movegen.o history.o movepick.o search.o position.o \
-	direction.o tt.o uci.o ucioption.o book.o bitbase.o san.o benchmark.o timeman.o
+	tt.o uci.o ucioption.o book.o bitbase.o san.o benchmark.o timeman.o
 
 
 ### ==========================================================================

src/bitboard.cpp

@@ -236,6 +236,7 @@ Bitboard RookPseudoAttacks[64];
 Bitboard QueenPseudoAttacks[64];
 
 uint8_t BitCount8Bit[256];
+int8_t  DirectionTable[64][64];
 
 
 ////
@@ -244,6 +245,8 @@ uint8_t BitCount8Bit[256];
 
 namespace {
 
+  SquareDelta get_direction(Square orig, Square dest);
+  void init_direction_table();
   void init_masks();
   void init_attacks();
   void init_between_bitboards();
@@ -285,6 +288,7 @@ void init_bitboards() {
   int rookDeltas[4][2] = {{0,1},{0,-1},{1,0},{-1,0}};
   int bishopDeltas[4][2] = {{1,1},{-1,1},{1,-1},{-1,-1}};
 
+  init_direction_table();
   init_masks();
   init_attacks();
   init_between_bitboards();
@@ -380,6 +384,36 @@ namespace {
   // understand, but they all seem to work correctly, and it should never
   // be necessary to touch any of them.
 
+  SquareDelta get_direction(Square orig, Square dest) {
+
+    const SquareDelta directions[] = {
+        DELTA_E, DELTA_N, DELTA_NE, DELTA_NW, DELTA_W, DELTA_S, DELTA_SW, DELTA_SE
+    };
+
+    for (int idx = 0; idx < 8; idx++)
+    {
+        Square from = orig;
+        Square to = from + directions[idx];
+
+        while (to != dest && square_distance(to, from) == 1 && square_is_ok(to))
+        {
+            from = to;
+            to += directions[idx];
+        }
+
+        if (to == dest && square_distance(from, to) == 1)
+            return directions[idx];
+    }
+    return DELTA_NONE;
+  }
+
+  void init_direction_table() {
+
+    for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++)
+        for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++)
+            DirectionTable[s1][s2] = uint8_t(get_direction(s1, s2));
+  }
+
   void init_masks() {
 
     SetMaskBB[SQ_NONE] = 0ULL;

src/bitboard.h

@@ -90,6 +90,7 @@ extern Bitboard RookPseudoAttacks[64];
 extern Bitboard QueenPseudoAttacks[64];
 
 extern uint8_t BitCount8Bit[256];
+extern int8_t DirectionTable[64][64];
 
 
 ////
@@ -297,6 +298,24 @@ inline Bitboard attack_span_mask(Color c, Square s) {
 }
 
 
+/// squares_aligned returns true if the squares s1, s2 and s3 are aligned
+/// either on a straight or on a diagonal line.
+
+inline bool squares_aligned(Square s1, Square s2, Square s3) {
+  return   DirectionTable[s1][s2] != DELTA_NONE
+        && abs(DirectionTable[s1][s2]) ==  abs(DirectionTable[s2][s3]);
+}
+
+
+/// squares_straight_aligned returns true if the squares s1 and s2 are aligned
+/// on a straight line, either veritical or horizontal.
+
+inline bool squares_straight_aligned(Square s1, Square s2) {
+  return   abs(DirectionTable[s1][s2]) == DELTA_N
+        || abs(DirectionTable[s1][s2]) == DELTA_E;
+}
+
+
 /// first_1() finds the least significant nonzero bit in a nonzero bitboard.
 /// pop_1st_bit() finds and clears the least significant nonzero bit in a
 /// nonzero bitboard.

src/direction.cpp

@@ -1,60 +0,0 @@
-/*
-  Stockfish, a UCI chess playing engine derived from Glaurung 2.1
-  Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
-
-  Stockfish is free software: you can redistribute it and/or modify
-  it under the terms of the GNU General Public License as published by
-  the Free Software Foundation, either version 3 of the License, or
-  (at your option) any later version.
-
-  Stockfish is distributed in the hope that it will be useful,
-  but WITHOUT ANY WARRANTY; without even the implied warranty of
-  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-  GNU General Public License for more details.
-
-  You should have received a copy of the GNU General Public License
-  along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*/
-
-
-////
-//// Includes
-////
-
-#include "square.h"
-
-int8_t DirectionTable[64][64];
-
-
-static SquareDelta direction(Square orig, Square dest) {
-
-  const SquareDelta directions[] = {
-      DELTA_E, DELTA_N, DELTA_NE, DELTA_NW, DELTA_W, DELTA_S, DELTA_SW, DELTA_SE
-  };
-
-  Square from, to;
-
-  for (int idx = 0; idx < 8; idx++)
-  {
-      from = orig;
-      to = from + directions[idx];
-
-      while (to != dest && square_distance(to, from) == 1 && square_is_ok(to))
-      {
-          from = to;
-          to += directions[idx];
-      }
-
-      if (to == dest && square_distance(from, to) == 1)
-          return directions[idx];
-  }
-  return DELTA_NONE;
-}
-
-void init_direction_table() {
-
-  for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++)
-      for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++)
-          DirectionTable[s1][s2] = uint8_t(direction(s1, s2));
-}

src/main.cpp

@@ -59,7 +59,6 @@ int main(int argc, char* argv[]) {
   cin.rdbuf()->pubsetbuf(NULL, 0);
 
   // Startup initializations
-  init_direction_table();
   init_bitboards();
   init_uci_options();
   Position::init_zobrist();

src/movegen.cpp

@@ -244,7 +244,7 @@ MoveStack* generate_evasions(const Position& pos, MoveStack* mlist) {
       case QUEEN:
           // In case of a queen remove also squares attacked in the other direction to
           // avoid possible illegal moves when queen and king are on adjacent squares.
-          if (direction_is_straight(checksq, ksq))
+          if (squares_straight_aligned(checksq, ksq))
               sliderAttacks |= RookPseudoAttacks[checksq] | pos.attacks_from<BISHOP>(checksq);
           else
               sliderAttacks |= BishopPseudoAttacks[checksq] | pos.attacks_from<ROOK>(checksq);

src/square.h

@@ -81,9 +81,6 @@ ENABLE_OPERATORS_ON(SquareDelta);
 const int FlipMask = 56;
 const int FlopMask =  7;
 
-extern int8_t DirectionTable[64][64];
-
-
 ////
 //// Inline functions
 ////
@@ -183,20 +180,4 @@ inline bool square_is_ok(Square s) {
   return file_is_ok(square_file(s)) && rank_is_ok(square_rank(s));
 }
 
-inline bool squares_aligned(Square s1, Square s2, Square s3) {
-  return   DirectionTable[s1][s2] != DELTA_NONE
-        && abs(DirectionTable[s1][s2]) ==  abs(DirectionTable[s2][s3]);
-}
-
-inline bool direction_is_straight(Square s1, Square s2) {
-  return   abs(DirectionTable[s1][s2]) == DELTA_N
-        || abs(DirectionTable[s1][s2]) == DELTA_E;
-}
-
-////
-//// Prototypes
-////
-
-extern void init_direction_table();
-
 #endif // !defined(SQUARE_H_INCLUDED)