2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008 Marco Costalba
6 Stockfish is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 Stockfish is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
25 #include "direction.h"
33 uint8_t DirectionTable[64][64];
34 uint8_t SignedDirectionTable[64][64];
41 void init_direction_table() {
42 SquareDelta deltas[8] = {
43 DELTA_E, DELTA_W, DELTA_N, DELTA_S, DELTA_NE, DELTA_SW, DELTA_NW, DELTA_SE
45 for(Square s1 = SQ_A1; s1 <= SQ_H8; s1++)
46 for(Square s2 = SQ_A1; s2 <= SQ_H8; s2++) {
47 DirectionTable[s1][s2] = uint8_t(DIR_NONE);
48 SignedDirectionTable[s1][s2] = uint8_t(SIGNED_DIR_NONE);
49 if(s1 == s2) continue;
50 for(SignedDirection d = SIGNED_DIR_E; d <= SIGNED_DIR_SE; d++) {
51 SquareDelta delta = deltas[d];
53 for(s4 = s1 + delta, s3 = s1;
54 square_distance(s4, s3) == 1 && s4 != s2 && square_is_ok(s4);
55 s3 = s4, s4 += delta);
56 if(s4 == s2 && square_distance(s4, s3) == 1) {
57 SignedDirectionTable[s1][s2] = uint8_t(d);
58 DirectionTable[s1][s2] = uint8_t(d/2);