Fri, 04 Apr 2014 17:36:42 +0200
NEED TESTING: implemented check and checkmate - TODO: avoid checkmate by moving another piece in between
1 /*
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3 *
4 * Copyright 2014 Mike Becker. All rights reserved.
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16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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28 */
30 #include "pawn.h"
31 #include "rules.h"
33 _Bool pawn_chkrules(GameState *gamestate, Move *move) {
34 int8_t d = ((move->piece & COLOR_MASK) == WHITE ? -1 : 1);
36 if (move->torow == (d < 0 ? 7 : 0)) {
37 if (move->promotion) {
38 uint8_t promopiece = move->promotion & PIECE_MASK;
39 if (!promopiece || promopiece == PAWN || promopiece == KING) {
40 return 0;
41 }
42 } else {
43 return 0;
44 }
45 } else {
46 if (move->promotion) {
47 return 0;
48 }
49 }
51 if (move->capture) {
52 if (move->fromrow == move->torow + d && (
53 move->fromfile == move->tofile + 1 ||
54 move->fromfile == move->tofile - 1)) {
56 return mdst(gamestate->board, move) ||
57 (gamestate->board[move->fromrow][move->tofile]
58 & ENPASSANT_THREAT);
59 } else {
60 return 0;
61 }
62 } else {
63 if (move->fromfile == move->tofile) {
64 return (move->fromrow == move->torow + d) ||
65 (move->fromrow == (d < 0 ? 1 : 6) && /* advanced first move */
66 move->fromrow == move->torow + d*2);
67 } else {
68 return 0;
69 }
70 }
71 }
73 _Bool pawn_isblocked(GameState *gamestate, Move *move) {
74 return mdst(gamestate->board, move) && !move->capture;
75 }
77 int pawn_getlocation(GameState *gamestate, Move *move) {
78 int8_t d = ((move->piece & COLOR_MASK) == WHITE ? -1 : 1);
80 if (move->fromfile == POS_UNSPECIFIED) {
81 move->fromfile = move->tofile;
82 }
83 move->fromrow = move->torow + d;
84 if (move->fromrow > 6) {
85 return INVALID_POSITION;
86 } else {
87 /* advanced first move */
88 if (move->fromrow == (d < 0 ? 2 : 5) &&
89 msrc(gamestate->board,move) != move->piece) {
91 move->fromrow += d;
92 if (move->fromrow > 6) {
93 return INVALID_POSITION;
94 }
95 }
96 }
97 return VALID_MOVE_SYNTAX;
98 }