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Add Pseudo Move Generator #12

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Josh merged 17 commits from 7-add-pseudo-move-generator into main 2025-08-18 00:28:00 +00:00
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1 changed files with 61 additions and 61 deletions
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engine/src/bitboard.c
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@@ -146,11 +146,11 @@ void push_move(struct Move *out, int *count, int from, int to, uint8_t piece, ui
most complicated movement patterns and behaviors in the game. Separating out the logic should most complicated movement patterns and behaviors in the game. Separating out the logic should
hopefully make debugging easier. hopefully make debugging easier.
*/ */
void gen_white_pawn_quiet_pushes(const struct Board *b, struct Move *out, int *count) { void gen_white_pawn_quiet_pushes(const struct Board *board, struct Move *out, int *count) {
const uint64_t occ = b->occ[BOTH]; const uint64_t occ = board->occ[BOTH];
const uint64_t empty = ~occ; const uint64_t empty = ~occ;
const uint64_t pawns = b->pieces[P]; const uint64_t pawns = board->pieces[P];
// One-step pushes: shift pawns up by 8 onto empty squares // One-step pushes: shift pawns up by 8 onto empty squares
uint64_t one_step = (pawns << 8) & empty; uint64_t one_step = (pawns << 8) & empty;
@@ -177,11 +177,11 @@ void gen_white_pawn_quiet_pushes(const struct Board *b, struct Move *out, int *c
} }
} }
void gen_black_pawn_quiet_pushes(const struct Board *b, struct Move *out, int *count) { void gen_black_pawn_quiet_pushes(const struct Board *board, struct Move *out, int *count) {
const uint64_t occ = b->occ[BOTH]; const uint64_t occ = board->occ[BOTH];
const uint64_t empty = ~occ; const uint64_t empty = ~occ;
const uint64_t pawns = b->pieces[p]; const uint64_t pawns = board->pieces[p];
// One-step pushes: shift pawns down by 8 onto empty squares // One-step pushes: shift pawns down by 8 onto empty squares
uint64_t one_step = (pawns >> 8) & empty; uint64_t one_step = (pawns >> 8) & empty;
@@ -208,10 +208,10 @@ void gen_black_pawn_quiet_pushes(const struct Board *b, struct Move *out, int *c
// We will only allow pawns to promote to queen. Technically, they should be allowed // We will only allow pawns to promote to queen. Technically, they should be allowed
// to promote to any of the following: Rook, Bishop, Knight, Queen. // to promote to any of the following: Rook, Bishop, Knight, Queen.
void gen_white_pawn_push_promotions(const struct Board *b, struct Move *out, int *count) { void gen_white_pawn_push_promotions(const struct Board *board, struct Move *out, int *count) {
const uint64_t occ = b->occ[BOTH]; const uint64_t occ = board->occ[BOTH];
const uint64_t empty = ~occ; const uint64_t empty = ~occ;
const uint64_t pawns = b->pieces[P]; const uint64_t pawns = board->pieces[P];
// destinations on rank 8 reachable by a single push // destinations on rank 8 reachable by a single push
uint64_t promos = ((pawns << 8) & empty) & RANK_8; uint64_t promos = ((pawns << 8) & empty) & RANK_8;
@@ -223,10 +223,10 @@ void gen_white_pawn_push_promotions(const struct Board *b, struct Move *out, int
} }
} }
void gen_black_pawn_push_promotions(const struct Board *b, struct Move *out, int *count) { void gen_black_pawn_push_promotions(const struct Board *board, struct Move *out, int *count) {
const uint64_t occ = b->occ[BOTH]; const uint64_t occ = board->occ[BOTH];
const uint64_t empty = ~occ; const uint64_t empty = ~occ;
const uint64_t pawns = b->pieces[p]; const uint64_t pawns = board->pieces[p];
// destinations on rank 1 reachable by a single push // destinations on rank 1 reachable by a single push
uint64_t promos = ((pawns >> 8) & empty) & RANK_1; uint64_t promos = ((pawns >> 8) & empty) & RANK_1;
@@ -238,17 +238,17 @@ void gen_black_pawn_push_promotions(const struct Board *b, struct Move *out, int
} }
} }
void gen_white_pawn_capture_promotions(const struct Board *b, struct Move *out, int *count) { void gen_white_pawn_capture_promotions(const struct Board *board, struct Move *out, int *count) {
const uint64_t opp = b->occ[BLACK]; const uint64_t opp = board->occ[BLACK];
// left capture (from white view): +7, mask off file A // left capture (from white view): +7, mask off file A
uint64_t left = ((b->pieces[P] & ~FILE_A) << 7) & opp & RANK_8; uint64_t left = ((board->pieces[P] & ~FILE_A) << 7) & opp & RANK_8;
while (left) { while (left) {
int to = pop_lsb_index(&left); int to = pop_lsb_index(&left);
int from = to - 7; int from = to - 7;
push_move(out, count,from, to, P, Q, MF_CAPTURE | MF_PROMO); push_move(out, count,from, to, P, Q, MF_CAPTURE | MF_PROMO);
} }
// right capture: +9, mask off file H // right capture: +9, mask off file H
uint64_t right = ((b->pieces[P] & ~FILE_H) << 9) & opp & RANK_8; uint64_t right = ((board->pieces[P] & ~FILE_H) << 9) & opp & RANK_8;
while (right) { while (right) {
int to = pop_lsb_index(&right); int to = pop_lsb_index(&right);
int from = to - 9; int from = to - 9;
@@ -256,17 +256,17 @@ void gen_white_pawn_capture_promotions(const struct Board *b, struct Move *out,
} }
} }
void gen_black_pawn_capture_promotions(const struct Board *b, struct Move *out, int *count) { void gen_black_pawn_capture_promotions(const struct Board *board, struct Move *out, int *count) {
const uint64_t opp = b->occ[WHITE]; const uint64_t opp = board->occ[WHITE];
// from black view, “left” is -7 (mask off file H before shifting) // from black view, “left” is -7 (mask off file H before shifting)
uint64_t left = ((b->pieces[p] & ~FILE_H) >> 7) & opp & RANK_1; uint64_t left = ((board->pieces[p] & ~FILE_H) >> 7) & opp & RANK_1;
while (left) { while (left) {
int to = pop_lsb_index(&left); int to = pop_lsb_index(&left);
int from = to + 7; int from = to + 7;
push_move(out, count,from, to, p, q, MF_CAPTURE | MF_PROMO); push_move(out, count,from, to, p, q, MF_CAPTURE | MF_PROMO);
} }
// “right” is -9 (mask off file A) // “right” is -9 (mask off file A)
uint64_t right = ((b->pieces[p] & ~FILE_A) >> 9) & opp & RANK_1; uint64_t right = ((board->pieces[p] & ~FILE_A) >> 9) & opp & RANK_1;
while (right) { while (right) {
int to = pop_lsb_index(&right); int to = pop_lsb_index(&right);
int from = to + 9; int from = to + 9;
@@ -274,9 +274,9 @@ void gen_black_pawn_capture_promotions(const struct Board *b, struct Move *out,
} }
} }
void gen_white_pawn_captures(const struct Board *b, struct Move *out, int *count) { void gen_white_pawn_captures(const struct Board *board, struct Move *out, int *count) {
const uint64_t pawns = b->pieces[P]; const uint64_t pawns = board->pieces[P];
const uint64_t opp = b->occ[BLACK]; const uint64_t opp = board->occ[BLACK];
// Normal captures (exclude promotion rank) // Normal captures (exclude promotion rank)
uint64_t left_caps = ((pawns & ~FILE_A) << 7) & opp & ~RANK_8; uint64_t left_caps = ((pawns & ~FILE_A) << 7) & opp & ~RANK_8;
@@ -295,24 +295,24 @@ void gen_white_pawn_captures(const struct Board *b, struct Move *out, int *count
} }
// En passant (destination is ep_square) // En passant (destination is ep_square)
if (b->ep_square >= 0) { if (board->ep_square >= 0) {
uint64_t ep = 1ULL << b->ep_square; uint64_t ep = 1ULL << board->ep_square;
// From-squares that can capture onto ep (reverse of +7/+9) // From-squares that can capture onto ep (reverse of +7/+9)
uint64_t ep_from = (((ep & ~FILE_H) >> 7) | ((ep & ~FILE_A) >> 9)) & pawns; uint64_t ep_from = (((ep & ~FILE_H) >> 7) | ((ep & ~FILE_A) >> 9)) & pawns;
while (ep_from) { while (ep_from) {
int from = pop_lsb_index(&ep_from); int from = pop_lsb_index(&ep_from);
int to = b->ep_square; int to = board->ep_square;
// EP never promotes, so no promo piece; still a capture // EP never promotes, so no promo piece; still a capture
push_move(out, count,from, to, P, 0, MF_CAPTURE | MF_ENPASSANT); push_move(out, count,from, to, P, 0, MF_CAPTURE | MF_ENPASSANT);
} }
} }
} }
void gen_black_pawn_captures(const struct Board *b, struct Move *out, int *count) { void gen_black_pawn_captures(const struct Board *board, struct Move *out, int *count) {
const uint64_t pawns = b->pieces[p]; const uint64_t pawns = board->pieces[p];
const uint64_t opp = b->occ[WHITE]; const uint64_t opp = board->occ[WHITE];
// Normal captures (exclude promotion rank) // Normal captures (exclude promotion rank)
uint64_t left_caps = ((pawns & ~FILE_H) >> 7) & opp & ~RANK_1; // from black POV, "left" is -7 uint64_t left_caps = ((pawns & ~FILE_H) >> 7) & opp & ~RANK_1; // from black POV, "left" is -7
@@ -330,15 +330,15 @@ void gen_black_pawn_captures(const struct Board *b, struct Move *out, int *count
} }
// En passant // En passant
if (b->ep_square >= 0) { if (board->ep_square >= 0) {
uint64_t ep = 1ULL << b->ep_square; uint64_t ep = 1ULL << board->ep_square;
// From-squares that can capture onto ep (reverse of -7/-9) // From-squares that can capture onto ep (reverse of -7/-9)
uint64_t ep_from = (((ep & ~FILE_A) << 7) | ((ep & ~FILE_H) << 9)) & pawns; uint64_t ep_from = (((ep & ~FILE_A) << 7) | ((ep & ~FILE_H) << 9)) & pawns;
while (ep_from) { while (ep_from) {
int from = pop_lsb_index(&ep_from); int from = pop_lsb_index(&ep_from);
int to = b->ep_square; int to = board->ep_square;
push_move(out, count,from, to, p, 0, MF_CAPTURE | MF_ENPASSANT); push_move(out, count,from, to, p, 0, MF_CAPTURE | MF_ENPASSANT);
} }
} }
@@ -351,12 +351,12 @@ void gen_black_pawn_captures(const struct Board *b, struct Move *out, int *count
*/ */
void gen_knight_moves(const struct Board *b, struct Move *out, int *count, bool captures_only) { void gen_knight_moves(const struct Board *board, struct Move *out, int *count, bool captures_only) {
enum Color side = b->side_to_move; enum Color side = board->side_to_move;
uint64_t own = b->occ[side]; uint64_t own = board->occ[side];
uint64_t opp = b->occ[side ^ 1]; uint64_t opp = board->occ[side ^ 1];
uint8_t pid = (side == WHITE) ? N : n; uint8_t pid = (side == WHITE) ? N : n;
uint64_t bb = (side == WHITE) ? b->pieces[N] : b->pieces[n]; uint64_t bb = (side == WHITE) ? board->pieces[N] : board->pieces[n];
while (bb) { while (bb) {
int from = pop_lsb_index(&bb); int from = pop_lsb_index(&bb);
@@ -404,13 +404,13 @@ void gen_bishop_moves(const struct Board *board, struct Move *out, int *count, b
} }
} }
void gen_rook_moves(const struct Board *b, struct Move *out, int *count, bool captures_only) { void gen_rook_moves(const struct Board *board, struct Move *out, int *count, bool captures_only) {
enum Color side = b->side_to_move; enum Color side = board->side_to_move;
uint64_t own = b->occ[side]; uint64_t own = board->occ[side];
uint64_t opp = b->occ[side ^ 1]; uint64_t opp = board->occ[side ^ 1];
uint64_t occ = b->occ[BOTH]; uint64_t occ = board->occ[BOTH];
uint8_t pid = (side == WHITE) ? R : r; uint8_t pid = (side == WHITE) ? R : r;
uint64_t bb = (side == WHITE) ? b->pieces[R] : b->pieces[r]; uint64_t bb = (side == WHITE) ? board->pieces[R] : board->pieces[r];
while (bb) { while (bb) {
int from = pop_lsb_index(&bb); int from = pop_lsb_index(&bb);
@@ -431,13 +431,13 @@ void gen_rook_moves(const struct Board *b, struct Move *out, int *count, bool ca
} }
} }
void gen_queen_moves(const struct Board *b, struct Move *out, int *count, bool captures_only) { void gen_queen_moves(const struct Board *board, struct Move *out, int *count, bool captures_only) {
enum Color side = b->side_to_move; enum Color side = board->side_to_move;
uint64_t own = b->occ[side]; uint64_t own = board->occ[side];
uint64_t opp = b->occ[side ^ 1]; uint64_t opp = board->occ[side ^ 1];
uint64_t occ = b->occ[BOTH]; uint64_t occ = board->occ[BOTH];
uint8_t pid = (side == WHITE) ? Q : q; uint8_t pid = (side == WHITE) ? Q : q;
uint64_t bb = (side == WHITE) ? b->pieces[Q] : b->pieces[q]; uint64_t bb = (side == WHITE) ? board->pieces[Q] : board->pieces[q];
while (bb) { while (bb) {
int from = pop_lsb_index(&bb); int from = pop_lsb_index(&bb);
@@ -458,12 +458,12 @@ void gen_queen_moves(const struct Board *b, struct Move *out, int *count, bool c
} }
} }
void gen_king_moves(struct Board *b, struct Move *out, int *count, bool captures_only) { void gen_king_moves(struct Board *board, struct Move *out, int *count, bool captures_only) {
enum Color side = b->side_to_move; enum Color side = board->side_to_move;
uint64_t own = b->occ[side]; uint64_t own = board->occ[side];
uint64_t opp = b->occ[side ^ 1]; uint64_t opp = board->occ[side ^ 1];
uint8_t pid = (side == WHITE) ? K : k; uint8_t pid = (side == WHITE) ? K : k;
uint64_t kk = (side == WHITE) ? b->pieces[K] : b->pieces[k]; uint64_t kk = (side == WHITE) ? board->pieces[K] : board->pieces[k];
if (!kk) return; if (!kk) return;
int from = first_set_index(kk); int from = first_set_index(kk);
@@ -483,26 +483,26 @@ void gen_king_moves(struct Board *b, struct Move *out, int *count, bool captures
} }
if (!captures_only) { if (!captures_only) {
uint64_t occ = b->occ[BOTH]; uint64_t occ = board->occ[BOTH];
if (side == WHITE) { if (side == WHITE) {
if ((b->castling_rights & CASTLE_WK) && !(occ & WK_EMPTY_MASK)) { if ((board->castling_rights & CASTLE_WK) && !(occ & WK_EMPTY_MASK)) {
push_move(out, count,E1, WK_TO, K, 0, MF_CASTLE); push_move(out, count,E1, WK_TO, K, 0, MF_CASTLE);
} }
if ((b->castling_rights & CASTLE_WQ) && !(occ & WQ_EMPTY_MASK)) { if ((board->castling_rights & CASTLE_WQ) && !(occ & WQ_EMPTY_MASK)) {
push_move(out, count,E1, WQ_TO, K, 0, MF_CASTLE); push_move(out, count,E1, WQ_TO, K, 0, MF_CASTLE);
} }
} else { } else {
if ((b->castling_rights & CASTLE_BK) && !(occ & BK_EMPTY_MASK)) { if ((board->castling_rights & CASTLE_BK) && !(occ & BK_EMPTY_MASK)) {
push_move(out, count,E8, BK_TO, k, 0, MF_CASTLE); push_move(out, count,E8, BK_TO, k, 0, MF_CASTLE);
} }
if ((b->castling_rights & CASTLE_BQ) && !(occ & BQ_EMPTY_MASK)) { if ((board->castling_rights & CASTLE_BQ) && !(occ & BQ_EMPTY_MASK)) {
push_move(out, count,E8, BQ_TO, k, 0, MF_CASTLE); push_move(out, count,E8, BQ_TO, k, 0, MF_CASTLE);
} }
} }
} }
} }
void print_board(const struct Board *b) { void print_board(const struct Board *board) {
const char PIECE_CH[12] = { const char PIECE_CH[12] = {
'P','N','B','R','Q','K', 'P','N','B','R','Q','K',
'p','n','b','r','q','k' 'p','n','b','r','q','k'
@@ -512,7 +512,7 @@ void print_board(const struct Board *b) {
for (int i = 0; i < 64; ++i) grid[i] = '.'; for (int i = 0; i < 64; ++i) grid[i] = '.';
for (int p = 0; p < 12; ++p) { for (int p = 0; p < 12; ++p) {
uint64_t bb = b->pieces[p]; uint64_t bb = board->pieces[p];
while (bb) { while (bb) {
int sq = pop_lsb_index(&bb); int sq = pop_lsb_index(&bb);
grid[sq] = PIECE_CH[p]; grid[sq] = PIECE_CH[p];