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