diff --git a/src/Makefile b/src/Makefile
index 7eef3416..c836fd42 100644
--- a/src/Makefile
+++ b/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
### ==========================================================================
diff --git a/src/bitboard.cpp b/src/bitboard.cpp
index 01c9954a..72e208ff 100644
--- a/src/bitboard.cpp
+++ b/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;
diff --git a/src/bitboard.h b/src/bitboard.h
index b8eb3220..599d0120 100644
--- a/src/bitboard.h
+++ b/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.
diff --git a/src/direction.cpp b/src/direction.cpp
deleted file mode 100644
index ebff65b1..00000000
--- a/src/direction.cpp
+++ /dev/null
@@ -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 .
-*/
-
-
-////
-//// 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));
-}
diff --git a/src/main.cpp b/src/main.cpp
index 70359fdf..01b032c2 100644
--- a/src/main.cpp
+++ b/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();
diff --git a/src/movegen.cpp b/src/movegen.cpp
index d6710d1c..0db293cc 100644
--- a/src/movegen.cpp
+++ b/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(checksq);
else
sliderAttacks |= BishopPseudoAttacks[checksq] | pos.attacks_from(checksq);
diff --git a/src/square.h b/src/square.h
index 7a59e078..1c4a3902 100644
--- a/src/square.h
+++ b/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)