add movedo-test

Makefile

@@ -286,7 +286,7 @@ memcheck: targets
 ##################################### test binaries
 .PHONY: testing test
 
-TEST          :=piece-test fen-test bitboard-test movegen-test attack-test
+TEST          := piece-test fen-test bitboard-test movegen-test attack-test movedo-test
 
 PIECE_OBJS    := piece.o
 FEN_OBJS      := fen.o position.o piece.o bitboard.o board.o hyperbola-quintessence.o \
@@ -297,6 +297,8 @@ MOVEGEN_OBJS  := fen.o position.o piece.o bitboard.o board.o hyperbola-quintesse
 	attack.o move.o move-gen.o
 ATTACK_OBJS   := fen.o position.o piece.o bitboard.o board.o hyperbola-quintessence.o \
 	 attack.o move.o move-gen.o
+MOVEDO_OBJS   := fen.o position.o piece.o bitboard.o board.o hyperbola-quintessence.o \
+	 attack.o move.o move-gen.o move-do.o
 
 TEST          := $(addprefix $(BINDIR)/,$(TEST))
 
@@ -305,6 +307,7 @@ FEN_OBJS      := $(addprefix $(OBJDIR)/,$(FEN_OBJS))
 BB_OBJS       := $(addprefix $(OBJDIR)/,$(BB_OBJS))
 MOVEGEN_OBJS  := $(addprefix $(OBJDIR)/,$(MOVEGEN_OBJS))
 ATTACK_OBJS   := $(addprefix $(OBJDIR)/,$(ATTACK_OBJS))
+MOVEDO_OBJS   := $(addprefix $(OBJDIR)/,$(MOVEDO_OBJS))
 
 test:
 	echo TEST=$(TEST)
@@ -332,6 +335,10 @@ bin/attack-test: test/attack-test.c test/common-test.h $(ATTACK_OBJS)
 	@echo compiling $@ test executable.
 	@$(CC) $(ALL_CFLAGS) $< $(ATTACK_OBJS) $(ALL_LDFLAGS) -o $@
 
+bin/movedo-test: test/movedo-test.c test/common-test.h $(MOVEDO_OBJS)
+	@echo compiling $@ test executable.
+	@$(CC) $(ALL_CFLAGS) $< $(MOVEDO_OBJS) $(ALL_LDFLAGS) -o $@
+
 ##################################### Makefile debug
 .PHONY: showflags wft
 

src/bitboard.h

@@ -173,10 +173,6 @@ static __always_inline bitboard_t bb_rank(int rank)
 {
     return RANK_1bb << (rank * 8);
 }
-static __always_inline bitboard_t bb_file(int file)
-{
-    return FILE_Abb << file;
-}
 static __always_inline bitboard_t bb_rel_rank(int rank, color)
 {
     return RANK_1bb << (rank * 8);
@@ -187,11 +183,13 @@ static __always_inline bitboard_t bb_file(int file)
 }
 */
 
-#define BB_RANK(r)        ((u64) RANK_1bb << ((r) * 8))
+#define bb_rank(r)        ((u64) RANK_1bb << ((r) * 8))
 #define BB_FILE(f)        ((u64) FILE_Abb << (f))
 
-#define BB_REL_RANK(r, c) (RANK_1bb << (SQ_REL_RANK((r), (c)) * 8))
-#define BB_REL_FILE(f, c) (FILE_Abb << (SQ_REL_RANK((f), (c))))
+#define bb_rel_rank(r, c) bb_rank(sq_rel_rank(r, c))
+
+//#define BB_REL_RANK(r, c) (RANK_1bb << (SQ_REL_RANK(r, c) * 8))
+//#define BB_REL_FILE(f, c) (FILE_Abb << (SQ_REL_RANK((f), (c))))
 
 /**
  * bb_sq_aligned() - check if two squares are aligned (same file or rank).

src/chessdefs.h

@@ -21,8 +21,30 @@
 #define mask(i)            ( (u64) (ONE << (i)) )
 
 #define BOARDSIZE          (8*8)
-/* relative rank */
-#define SQ_REL_RANK(r, c)  (rank_t)((7 * (c)) ^ r)
+
+/**
+ * sq_rel - get relative square
+ * @sq: white point of view square
+ * @c:  color
+ *
+ * Get relative (mirrored if @c is BLACK) square.
+ * Example: sq_rel(A1, WHITE) = A1, sq_rel(B2, BLACK) = B7
+ *
+ * @return: Relative square.
+ */
+#define sq_rel(sq, c)      ((square_t)((sq) ^ (56 * (c))))
+
+/**
+ * sq_rel_rank - get relative rank
+ * @rank: white point of view rank
+ * @c:  color
+ *
+ * Get relative (mirrored if @c is BLACK) rank.
+ * Example: sq_rel(RANK_2, WHITE) = RANK_2, sq_rel(RANK_6, BLACK) = RANK_3
+ *
+ * @return: Relative rank.
+ */
+#define sq_rel_rank(rank, c)  ((rank_t)((7 * (c)) ^ rank))
 
 /* castle_t bits structure
  */
@@ -35,16 +57,23 @@ typedef enum {
     CASTLE_W  = (CASTLE_WK | CASTLE_WQ),          /* 00000011 W castle mask */
     CASTLE_B  = (CASTLE_BK | CASTLE_BQ),          /* 00001100 B castle mask */
 
-    CASTLE_K  = (1 << 0),                         /* generic K/Q, after doing : */
-    CASTLE_Q  = (1 << 1),                         /* flags >> (2 * color)       */
+    CASTLE_K  = (1 << 0),                         /* generic K/Q, bits 0 and 1 */
+    CASTLE_Q  = (1 << 1),
+    CASTLE_KQ = (CASTLE_K |CASTLE_Q)
 } castle_rights_t;
 
 /* determine is oo or ooo is possible with castle flags f and color c
  */
-#define NORM_CASTLE(f, c) ((f) >> (2 * (c)))      /* shift  flags to bits 0/1 */
-#define CAN_OO(f, c)     (NORM_CASTLE(f, c) & CASTLE_K)
-#define CAN_OOO(f, c)    (NORM_CASTLE(f, c) & CASTLE_Q)
-#define CAN_CASTLE(f, c) (CAN_OO(f, c) | CAN_OOO(f, c))
+//#define NORM_CASTLE(f, c)  ((f) >> (2 * (c)))      /* shift  flags to bits 0/1 */
+//#define
+//(NORM_CASTLE(f, c) & CASTLE_Q)
+#define can_oo(f, c)     ((f) & (CASTLE_K  << ((c) * 2)))
+#define can_ooo(f, c)    ((f) & (CASTLE_Q  << ((c) * 2)))
+#define can_castle(f, c) ((f) & (CASTLE_KQ << ((c) * 2)))
+
+#define clr_oo(f, c)     ((f) & ~(CASTLE_K  << (2 * (c))))
+#define clr_ooo(f, c)    ((f) & ~(CASTLE_Q  << (2 * (c))))
+#define clr_castle(f, c) ((f) & ~(CASTLE_KQ << (2 * (c)) ))
 
 /* game phases
  */

src/fen.c

@@ -81,9 +81,9 @@ static int fen_check(pos_t *pos)
     if (pos->en_passant != SQUARE_NONE) {
         rank_t eprank = sq_rank(pos->en_passant);
         file_t epfile = sq_file(pos->en_passant);
-        rank_t rank5 = SQ_REL_RANK(RANK_5, pos->turn);
-        rank_t rank6 = SQ_REL_RANK(RANK_6, pos->turn);
-        rank_t rank7 = SQ_REL_RANK(RANK_7, pos->turn);
+        rank_t rank5 = sq_rel_rank(RANK_5, pos->turn);
+        rank_t rank6 = sq_rel_rank(RANK_6, pos->turn);
+        rank_t rank7 = sq_rel_rank(RANK_7, pos->turn);
         piece_t pawn = pos->turn == WHITE? B_PAWN: W_PAWN;
         if (warn(eprank != rank6 ||
                  pos->board[sq_make(epfile, rank5)] != pawn ||

src/move-do.c

@@ -1,6 +1,6 @@
 /* move-do.c - move do/undo.
  *
- * Copyright (C) 2021 Bruno Raoult ("br")
+ * Copyright (C) 2021-2024 Bruno Raoult ("br")
  * Licensed under the GNU General Public License v3.0 or later.
  * Some rights reserved. See COPYING.
  *
@@ -15,146 +15,158 @@
 #include <ctype.h>
 #include <stdlib.h>
 
+#include "brlib.h"
+#include "likely.h"
+
 #include "chessdefs.h"
 #include "move.h"
 #include "position.h"
 
-/*
-  /\**
- *  * move_do() - execute move in a duplicated position.
- *  * @pos: &pos_t struct on which move will be applied
- *  * @move: &move_t struct to apply
- *  *
- *  * @return: &new position
- *  *\/
- * pos_t *move_do(pos_t *pos, move_t *move)
- * {
- * #   ifdef DEBUG_MOVE
- *     //log(1, "new move: ");
- *     //move_print(0, move, M_PR_NL | M_PR_LONG);
- * #   endif
+/**
+ * move_do() - do move.
+ * @pos:    &pos_t position
+ * @move:   move to apply
+ * @state:  &state_t address where irreversible changes will be saved
  *
- *     pos_t *new = pos_dup(pos);
- *     piece_t piece = PIECE(move->piece), newpiece = piece, captured = move->capture;
- *     int color = COLOR(move->piece);
- *     square_t from = move->from, to = move->to;
- *     u64 bb_from = SQ88_2_BB(from), bb_to = SQ88_2_BB(to);
+ * @move is applied to @pos:
+ * - bitboards and board are updated
+ * - counters are updated:
+ *   - move count
+ *   - 50-moves rule count
+ * - flags are possibly updated:
+ *   - castling
+ *   - en-passant
+ * - captured piece (excl. en-passant)
  *
- *     if (move->capture || piece == PAWN)    /\* 50 moves *\/
- *         new->clock_50 = 0;
- *     else
- *         new->clock_50++;
- *
- *     if (move->flags & M_CAPTURE) {                            /\* capture *\/
- *         if (move->flags & M_EN_PASSANT) {
- *             uchar ep_file = F88(pos->en_passant);
- *             square_t ep_grab = color == WHITE ? SQ88(ep_file, 4): SQ88(ep_file, 3);
- *             u64 bb_ep_grab = SQ88_2_BB(ep_grab);
- *
- *             log_f(5, "en-passant=%d,%d\n", ep_file, color == WHITE ? 4 : 3);
- *             piece_del(&new->board[ep_grab].s_piece->list);
- *             new->board[ep_grab].piece = 0;
- *             new->occupied[OPPONENT(color)] &= ~bb_ep_grab;
- *             new->bb[OPPONENT(color)][BB_PAWN] &= ~bb_ep_grab;
- *
- *         } else {
- *             piece_del(&new->board[to].s_piece->list);
- *             new->board[to].piece = 0;
- *             new->occupied[OPPONENT(color)] &= ~bb_to;
- *             new->bb[OPPONENT(color)][PIECETOBB(captured)] &= ~bb_to;
- *         }
- *
- *     } else if (move->flags & M_CASTLE_Q) {
- *         uchar row = R88(from);
- *         square_t rook_from = SQ88(0, row);
- *         square_t rook_to = SQ88(3, row);
- *         u64 bb_rook_from = SQ88_2_BB(rook_from);
- *         u64 bb_rook_to = SQ88_2_BB(rook_to);
- *
- *         new->board[rook_to] = new->board[rook_from];
- *         new->board[rook_to].s_piece->square = rook_to;
- *         new->occupied[color] &= ~bb_rook_from;
- *         new->occupied[color] |= bb_rook_to;
- *         new->bb[color][PIECETOBB(BB_ROOK)] &= ~bb_rook_from;
- *         new->bb[color][PIECETOBB(BB_ROOK)] |= bb_rook_to;
- *         new->board[rook_from].piece = 0;
- *         new->board[rook_from].s_piece = NULL;
- *         //new->castle &= color == WHITE? ~CASTLE_W: ~CASTLE_B;
- *
- *     } else if (move->flags & M_CASTLE_K) {
- *         uchar row = R88(from);
- *         square_t rook_from = SQ88(7, row);
- *         square_t rook_to = SQ88(5, row);
- *         u64 bb_rook_from = SQ88_2_BB(rook_from);
- *         u64 bb_rook_to = SQ88_2_BB(rook_to);
- *
- *         new->board[rook_to] = new->board[rook_from];
- *         new->board[rook_to].s_piece->square = rook_to;
- *         new->occupied[color] &= ~bb_rook_from;
- *         new->occupied[color] |= bb_rook_to;
- *         new->bb[color][PIECETOBB(BB_ROOK)] &= ~bb_rook_from;
- *         new->bb[color][PIECETOBB(BB_ROOK)] |= bb_rook_to;
- *         new->board[rook_from].piece = 0;
- *         new->board[rook_from].s_piece = NULL;
- *         // new->castle &= color == WHITE? ~CASTLE_W: ~CASTLE_B;
- *     }
- *
- *     new->board[to] = new->board[from];
- *     /\* fix dest square *\/
- *     new->board[to].s_piece->square = to;
- *     if (move->flags & M_PROMOTION) {
- *         log_f(5, "promotion to %s\n", P_SYM(move->promotion));
- *         log_f(5, "newpiece=%#x p=%#x\n", move->promotion, PIECE(move->promotion));
- *         newpiece = PIECE(move->promotion);
- *         new->board[to].piece = move->promotion;
- *         new->board[to].s_piece->piece = move->promotion;
- *     }
- *     /\* replace old occupied bitboard by new one *\/
- *     new->occupied[color] &= ~bb_from;
- *     new->occupied[color] |= bb_to;
- *     new->bb[color][PIECETOBB(piece)] &= ~bb_from;
- *     new->bb[color][PIECETOBB(newpiece)] |= bb_to;
- *     if (move->flags & M_PROMOTION) {
- *         log_f(5, "promotion color=%d bbpiece=%d\n", color, PIECETOBB(newpiece));
- *         //bitboard_print(new->bb[color][PIECETOBB(newpiece)]);
- *     }
- *     /\* set en_passant *\/
- *     new->en_passant = 0;
- *     if (piece == PAWN) {
- *         if (R88(from) == 1 && R88(to) == 3)
- *             pos->en_passant = SQ88(F88(from), 2);
- *         else if  (R88(from) == 6 && R88(to) == 4)
- *             pos->en_passant = SQ88(F88(from), 5);
- *     }
- *
- *     /\* always make "from" square empty *\/
- *     new->board[from].piece = 0;
- *     new->board[from].s_piece = NULL;
- *
- *     //printf("old turn=%d ", color);
- *     //printf("new turn=%d\n", new->turn);
- *     //fflush(stdout);
- *     /\* adjust castling flags *\/
- *     if ((bb_from | bb_to) & E1bb)
- *         new->castle &= ~(CASTLE_WQ | CASTLE_WK);
- *     else if ((bb_from | bb_to) & A1bb)
- *         new->castle &= ~CASTLE_WQ;
- *     else if ((bb_from | bb_to) & H1bb)
- *         new->castle &= ~CASTLE_WK;
- *
- *     if ((bb_from | bb_to) & E8bb)
- *         new->castle &= ~(CASTLE_BQ | CASTLE_BK);
- *     else if ((bb_from | bb_to) & A8bb)
- *         new->castle &= ~CASTLE_BQ;
- *     else if ((bb_from | bb_to) & H8bb)
- *         new->castle &= ~CASTLE_BK;
- *
- *     SET_COLOR(new->turn, OPPONENT(color));        /\* pos color *\/
- *     return new;
- * }
- *
- * void move_undo(pos_t *pos, __unused move_t *move)
- * {
- *     pos_del(pos);
- * }
+ * @return: pos.
  */
+pos_t *move_do(pos_t *pos, move_t move, state_t *state)
+{
+//#   ifdef DEBUG_MOVE_DO
+//    move_print(move, M_PR_NL | M_PR_LONG);
+//#   endif
+    *state = pos->state;                          /* save irreversible changes */
+
+    color_t us = pos->turn, them = OPPONENT(us);
+    square_t from = move_from(move), to = move_to(move);
+    piece_t piece = pos->board[from];
+    piece_t new_piece = piece;
+
+    ++pos->clock_50;
+    ++pos->plycount;
+    pos->en_passant = SQUARE_NONE;
+    pos->turn = them;
+
+    if (is_promotion(move))
+        new_piece = MAKE_PIECE(move_promoted(move), us);
+
+    if (is_capture(move)) {
+        pos->clock_50 = 0;
+        pos->captured = pos->board[to];           /* save capture info */
+        pos_clr_sq(pos, to);                      /* clear square */
+    } else if (is_castle(move)) {                 /* handle rook move */
+        square_t rookfrom, rookto;
+        if (is_castle_K(move)) {
+            rookfrom = sq_rel(H1, us);
+            rookto = sq_rel(F1, us);
+        } else {
+            rookfrom = sq_rel(A1, us);
+            rookto = sq_rel(D1, us);
+        }
+        pos_set_sq(pos, rookto, pos->board[rookfrom]);
+        pos_clr_sq(pos, rookfrom);
+        pos->castle = clr_castle(pos->castle, us);
+    } else if (PIECE(piece) == PAWN) {            /* pawn non capture or e.p. */
+        pos->clock_50 = 0;
+        if (is_dpush(move))                       /* if pawn double push, set e.p. */
+            pos->en_passant = pawn_push_up(from, us);
+        else if (is_enpassant(move)) {            /* clear grabbed pawn */
+            square_t grabbed = pawn_push_up(to, them);
+            pos_clr_sq(pos, grabbed);
+        }
+    }
+
+    pos_clr_sq(pos, from);                        /* always clear "from" and set "to" */
+    pos_set_sq(pos, to, new_piece);
+
+    /* update castling flags
+     * As we always consider flags are valid, we :
+     * - adjust our flags if relative from is "E1", "A1", H1"
+     * - adjust opp flags if relative to   if "A8", H8"
+     */
+    if (can_castle(pos->castle, us)) {            /* do we save time with this test ? */
+        square_t rel_e1 = sq_rel(E1, us);
+        square_t rel_a1 = sq_rel(A1, us); square_t rel_h1 = sq_rel(H1, us);
+        if (from == rel_e1)
+            pos->castle = clr_castle(pos->castle, us);
+        else if (from == rel_a1)
+            pos->castle = clr_ooo(pos->castle, us);
+        else if (from == rel_h1)
+            pos->castle = clr_oo(pos->castle, us);
+    }
+    if (can_castle(pos->castle, them)) {          /* do we save time with this test ? */
+        square_t rel_a8 = sq_rel(A8, us); square_t rel_h8 = sq_rel(H8, us);
+        if (to == rel_a8)
+            pos->castle = clr_ooo(pos->castle, them);
+        else if (to == rel_h8)
+            pos->castle = clr_oo(pos->castle, them);
+    }
+
+    return pos;
+}
+
+/**
+ * move_undo() - undo move.
+ * @pos:    &pos_t position
+ * @move:   move to undo
+ * @state:  &state_t address where irreversible changes were saved
+ *
+ * @move is applied to @pos:
+ * - bitboards and board are updated
+ * - previous information is restored:
+ *   - castling
+ *   - en-passant
+ *   - captured piece (excl. en-passant)
+ *   - move count
+ *   - 50-moves rule count
+ *
+ * @return: pos.
+ */
+pos_t *move_undo(pos_t *pos, const move_t move, const state_t *state)
+{
+//#   ifdef DEBUG_MOVE
+    //log(1, "new move: ");
+    //move_print(0, move, M_PR_NL | M_PR_LONG);
+//#   endif
+    color_t them = pos->turn, us = OPPONENT(them);
+    square_t from = move_from(move), to = move_to(move);
+    piece_t piece = pos->board[to];
+
+    pos->state = *state;                          /* restore irreversible changes */
+
+    if (is_promotion(move))
+        piece = MAKE_PIECE(PAWN, us);
+
+    pos_clr_sq(pos, to);                          /* always clear "to" and set "from" */
+    pos_set_sq(pos, from, piece);
+
+    if (is_capture(move)) {
+        pos_set_sq(pos, to, pos->captured);       /* restore captured piece */
+    } else if (is_castle(move)) {                 /* make reverse rook move */
+        square_t rookfrom, rookto;
+        if (is_castle_K(move)) {
+            rookfrom = sq_rel(F1, us);
+            rookto = sq_rel(H1, us);
+        } else {
+            rookfrom = sq_rel(D1, us);
+            rookto = sq_rel(A1, us);
+        }
+        pos_set_sq(pos, rookto, pos->board[rookfrom]);
+        pos_clr_sq(pos, rookfrom);
+    } else if (is_enpassant(move)) {              /* restore grabbed pawn */
+        square_t grabbed = pawn_push_up(to, them);
+        pos_set_sq(pos, grabbed, MAKE_PIECE(PAWN, them));
+    }
+
+    return pos;
+}

src/move-gen.c

@@ -157,8 +157,9 @@ movelist_t *pos_all_legal(const pos_t *pos, movelist_t *dest)
  *  - castling, if king passes an enemy-controlled square (not final square).
  * When immediately known, a few move flags are also applied in these cases:
  *  - castling: M_CASTLE_{K,Q}
- *  - pawn capture (incl. en-passant): M_CAPTURE
- *                         en-passant: M_EN_PASSANT
+ *  - pawn capture (excl. en-passant): M_CAPTURE
+ *  - en-passant: M_EN_PASSANT
+ *  - pawn double push: M_DPUSH
  *  - promotion: M_PROMOTION
  *  - promotion and capture
  *
@@ -174,7 +175,6 @@ int pos_gen_pseudomoves(pos_t *pos)
     bitboard_t my_pieces     = pos->bb[us][ALL_PIECES];
     bitboard_t not_my_pieces = ~my_pieces;
     bitboard_t enemy_pieces  = pos->bb[them][ALL_PIECES];
-
     bitboard_t occ           = my_pieces | enemy_pieces;
     bitboard_t empty         = ~occ;
 
@@ -183,59 +183,58 @@ int pos_gen_pseudomoves(pos_t *pos)
 
     move_t *moves            = pos->moves.move;
     int nmoves               = pos->moves.nmoves;
-
     int from, to;
 
-    /* king - MUST BE FIRST ! */
+    bug_on(nmoves != 0);
+
+    /* king - MUST BE FIRST (we stop if doubler check) */
     from = pos->king[us];
     movebits = bb_king_moves(not_my_pieces, from);
-    bit_for_each64(to, tmp1, movebits) {
+    bit_for_each64(to, tmp1, movebits & empty) {
         moves[nmoves++] = move_make(from, to);
     }
+    bit_for_each64(to, tmp1, movebits & enemy_pieces) {
+        moves[nmoves++] = move_make_capture(from, to);
+    }
+
     if (popcount64(pos->checkers) > 1)            /* double check, we stop here */
         return (pos->moves.nmoves = nmoves);
 
     /* sliding pieces */
-    bit_for_each64(from, tmp1, pos->bb[us][BISHOP]) {
+    bit_for_each64(from, tmp1, pos->bb[us][BISHOP] | pos->bb[us][QUEEN]) {
         movebits = hyperbola_bishop_moves(occ, from) & not_my_pieces;
-        bit_for_each64(to, tmp2, movebits) {
+        bit_for_each64(to, tmp2, movebits & empty) {
             moves[nmoves++] = move_make(from, to);
         }
+        bit_for_each64(to, tmp2, movebits & enemy_pieces) {
+            moves[nmoves++] = move_make_capture(from, to);
         }
-    bit_for_each64(from, tmp1, pos->bb[us][ROOK]) {
+    }
+    bit_for_each64(from, tmp1, pos->bb[us][ROOK] | pos->bb[us][QUEEN]) {
         // printf("rook=%d/%s\n", from, sq_to_string(from));
         movebits = hyperbola_rook_moves(occ, from) & not_my_pieces;
-        bit_for_each64(to, tmp2, movebits) {
+        bit_for_each64(to, tmp2, movebits & empty) {
             moves[nmoves++] = move_make(from, to);
         }
-    }
-    /* TODO: remove this one, after movegen is validated */
-    bit_for_each64(from, tmp1, pos->bb[us][QUEEN]) {
-        movebits = hyperbola_queen_moves(occ, from) & not_my_pieces;
-        bit_for_each64(to, tmp2, movebits) {
-            moves[nmoves++] = move_make(from, to);
+        bit_for_each64(to, tmp2, movebits & enemy_pieces) {
+            moves[nmoves++] = move_make_capture(from, to);
         }
     }
 
     /* knight */
     bit_for_each64(from, tmp1, pos->bb[us][KNIGHT]) {
         movebits = bb_knight_moves(not_my_pieces, from);
-        bit_for_each64(to, tmp2, movebits) {
+        bit_for_each64(to, tmp2, movebits & empty) {
             moves[nmoves++] = move_make(from, to);
         }
+        bit_for_each64(to, tmp2, movebits & enemy_pieces) {
+            moves[nmoves++] = move_make_capture(from, to);
+        }
     }
 
     /* pawn: relative rank and files */
-    bitboard_t rel_rank7 = us == WHITE ? RANK_7bb : RANK_2bb;
-    bitboard_t rel_rank3 = us == WHITE ? RANK_3bb : RANK_6bb;
-    //printf("r7_o = %016lx\nr7_n = %016lx\nsize=%lu\n", rel_rank7, BB_REL_RANK(RANK_7, me),
-    //       sizeof(RANK_3bb));
-    //printf("r3_o = %016lx\nr3_n = %016lx\nsize=%lu\n", rel_rank3, BB_REL_RANK(RANK_3, me),
-    //       sizeof(RANK_3bb));
-    //printf("fc_o = %016lx\nfc_n = %016lx\nsize=%lu\n", FILE_Cbb, BB_REL_FILE(FILE_C, me),
-    //       sizeof(RANK_3bb));
-    //bitboard_t rel_filea = (me == WHITE ? FILE_Abb : FILE_Hbb);
-    //bitboard_t rel_fileh = (me == WHITE ? FILE_Hbb : FILE_Abb);
+    bitboard_t rel_rank7 = bb_rel_rank(RANK_7, us);
+    bitboard_t rel_rank3 = bb_rel_rank(RANK_3, us);
 
     /* pawn: ranks 2-6 push 1 and 2 squares */
     movebits = pawn_shift_up(pos->bb[us][PAWN] & ~rel_rank7, us) & empty;
@@ -248,7 +247,7 @@ int pos_gen_pseudomoves(pos_t *pos)
     movebits = pawn_shift_up(movebits & rel_rank3, us) & empty;
     bit_for_each64(to, tmp1, movebits) {
         from = pawn_push_up(pawn_push_up(to, them), them);
-        moves[nmoves++] = move_make(from, to);
+        moves[nmoves++] = move_make_flags(from, to, M_DPUSH);
     }
 
     /* pawn: ranks 2-6 captures left */
@@ -309,21 +308,21 @@ int pos_gen_pseudomoves(pos_t *pos)
     /* castle - Attention ! Castling flags are assumed correct
      */
     if (!pos->checkers) {
-        bitboard_t rel_rank1 = BB_REL_RANK(RANK_1, us);
+        bitboard_t rel_rank1 = bb_rel_rank(RANK_1, us);
         from = pos->king[us];
         square_t from_square[2] = { E1, E8 };     /* verify king is on E1/E8 */
-        bug_on(CAN_CASTLE(pos->castle, us) && from != from_square[us]);
+        bug_on(can_castle(pos->castle, us) && from != from_square[us]);
         /* For castle, we check the opponent attacks on squares between from and to.
          * To square attack check will be done in gen_is_legal.
          */
-        if (CAN_OO(pos->castle, us)) {
+        if (can_oo(pos->castle, us)) {
             bitboard_t occmask = rel_rank1 & (FILE_Fbb | FILE_Gbb);
             if (!(occ & occmask) &&
                 !sq_attackers(pos, occ, from+1, them)) { /* f1/f8 */
                 moves[nmoves++] = move_make_flags(from, from + 2, M_CASTLE_K);
             }
         }
-        if (CAN_OOO(pos->castle, us)) {
+        if (can_ooo(pos->castle, us)) {
             bitboard_t occmask = rel_rank1 & (FILE_Bbb | FILE_Cbb | FILE_Dbb);
             if (!(occ & occmask) &&
                 !sq_attackers(pos, occ, from-1, them)) { /* d1/d8 */

src/move.c

@@ -110,7 +110,7 @@ char *move_str(char *dst, const move_t move, __unused const int flags)
     sprintf(dst, "%s%s%n", sq_to_string(from), sq_to_string(to), &len);
 
     if (is_promotion(move)) {
-        piece_t promoted = move_promoted(move);
+        piece_t promoted = (piece_t) move_promoted(move);
         sprintf(dst + len, "%s", piece_to_low(promoted));
     }
     return dst;
@@ -147,8 +147,8 @@ static int _moves_cmp_bysquare(const void *p1, const void *p2)
     square_t t1 = move_to(m1);
     square_t f2 = move_from(m2);
     square_t t2 = move_to(m2);
-    piece_t prom1 = move_promoted(m1);
-    piece_t prom2 = move_promoted(m2);
+    piece_type_t prom1 = move_promoted(m1);
+    piece_type_t prom2 = move_promoted(m2);
     if (f1 < f2) return -1;
     if (f1 > f2) return 1;
     /* f1 == f2 */

src/move.h

@@ -20,7 +20,7 @@
 
 /* move structure:
  * 3 3     2 2    1 1 1 1 1 1
- * 1 0    5 3    8 7 5 4 2 1    6 5    0
+ * 1 0     4 3    8 7 5 4 2 1    6 5    0
  * S UUUUUUU FFFFFF ccc ppp tttttt ffffff
  *
  * bits    len off range         type         mask        get  desc
@@ -52,7 +52,8 @@ typedef enum {
     M_PROMOTION = mask(M_OFF_FLAGS + 2),
     M_CASTLE_K  = mask(M_OFF_FLAGS + 3),          /* maybe only one ? */
     M_CASTLE_Q  = mask(M_OFF_FLAGS + 5),          /* maybe only one ? */
-    M_CHECK     = mask(M_OFF_FLAGS + 6)           /* maybe unknown/useless ? */
+    M_CHECK     = mask(M_OFF_FLAGS + 6),          /* maybe unknown/useless ? */
+    M_DPUSH     = mask(M_OFF_FLAGS + 7)           /* pawn double push */
 } move_flags_t;
 
 #define move_set_flags(move, flags) ((move) | (flags))
@@ -64,7 +65,7 @@ typedef enum {
 #define is_castle_K(m)  ((m) & M_CASTLE_K)
 #define is_castle_Q(m)  ((m) & M_CASTLE_Q)
 #define is_check(m)     ((m) & M_CHECK)
-
+#define is_dpush(m)     ((m) & M_DPUSH)
 
 #define MOVES_MAX   256
 
@@ -83,7 +84,7 @@ static inline square_t move_to(move_t move)
     return (move >> M_OFF_TO) & 077;
 }
 
-static inline piece_t move_promoted(move_t move)
+static inline piece_type_t move_promoted(move_t move)
 {
     return (move >> M_OFF_PROMOTED) & 07;
 }
@@ -93,7 +94,6 @@ static inline piece_type_t move_captured(move_t move)
     return (move >> M_OFF_CAPTURED) & 07;
 }
 
-
 static inline move_t move_make(square_t from, square_t to)
 {
     return (to << M_OFF_TO) | from;
@@ -111,7 +111,7 @@ static inline move_t move_make_capture(square_t from, square_t to)
 
 static inline move_t move_make_enpassant(square_t from, square_t to)
 {
-    return move_make_flags(from, to, M_CAPTURE | M_ENPASSANT);
+    return move_make_flags(from, to, M_ENPASSANT);
 }
 
 static inline move_t move_make_promote(square_t from, square_t to,
@@ -126,6 +126,11 @@ static inline move_t move_make_promote_capture(square_t from, square_t to,
     return move_make_promote(from, to, promoted) | M_CAPTURE;
 }
 
+static inline move_t move_set_captured(move_t move, piece_type_t captured)
+{
+    return move | (captured << M_OFF_CAPTURED);
+}
+
 /* moves_print flags
  */
 #define M_PR_CAPT      0x01

src/piece.c

@@ -65,10 +65,6 @@ char *piece_to_low(piece_t p)
 {
     return piece_details[p].low;
 }
-//char *piece_to_sym(piece_t p)
-//{
-//    return piece_details[PIECE(p)].sym;
-//}
 
 char *piece_to_sym(piece_t p)
 {

src/position.c

@@ -47,14 +47,7 @@ pos_t *pos_new(void)
  * pos_dup() - duplicate a position.
  * @pos: &position to duplicate.
  *
- * New position is the same as source one (with duplicated pieces list),
- * except:
- * - moves list is empty
- * - bestmove is NULL
- * - nodecount is set to zero
- * - eval is set to EVAL_INVALID
- * - moves_generated ans moves_counted are unset
- * - check is set to zero
+ * Return a copy, allocated with malloc(1), of @pos.
  *
  * @Return: The new position.
  *
@@ -64,14 +57,7 @@ pos_t *pos_dup(const pos_t *pos)
 {
     pos_t *newpos = safe_malloc(sizeof(pos_t));
 
-    //board = new->board;
     *newpos = *pos;
-    //new->bestmove = NULL;
-    newpos->node_count = 0;
-    //new->eval = EVAL_INVALID;
-    //new->moves_generated = false;
-    //new->moves_counted = false;
-    //new->check[WHITE] = new->check[BLACK] = 0;
     return newpos;
 }
 
@@ -87,6 +73,8 @@ void pos_del(pos_t *pos)
 /**
  * pos_clear() - clear a position.
  * @pos: &position.
+ *
+ * @return: @pos.
  */
 pos_t *pos_clear(pos_t *pos)
 {
@@ -96,10 +84,12 @@ pos_t *pos_clear(pos_t *pos)
     pos->node_count = 0;
     pos->turn = WHITE;
 
+    /* move_do/undo position state */
     pos->en_passant = SQUARE_NONE;
     pos->castle = 0;
     pos->clock_50 = 0;
     pos->plycount = 0;
+    pos->captured = NO_PIECE;
 
     for (square_t sq = A1; sq <= H8; ++sq)
         pos->board[sq] = EMPTY;
@@ -107,7 +97,7 @@ pos_t *pos_clear(pos_t *pos)
     for (color_t color = WHITE; color <= BLACK; ++color) {
         for (piece_type_t piece = 0; piece <= KING; ++piece)
             pos->bb[color][piece] = 0;
-        pos->controlled[color] = 0;
+        //pos->controlled[color] = 0;
         pos->king[color] = SQUARE_NONE;
     }
 
@@ -120,6 +110,65 @@ pos_t *pos_clear(pos_t *pos)
     return pos;
 }
 
+/**
+ * pos_cmp() - compare two positions..
+ * @pos1, @pos2: The two &position.
+ *
+ * @return: true if equal, false otherwise.
+ */
+bool pos_cmp(const pos_t *pos1, const pos_t *pos2)
+{
+#define _cmpf(a) (pos1->a != pos2->a)
+    bool ret = false;
+    if (warn_on(_cmpf(node_count)))
+        goto end;
+    if (warn_on(_cmpf(turn)))
+        goto end;
+
+    /* move_do/undo position state */
+    if (warn_on(_cmpf(en_passant)))
+        goto end;
+    if (warn_on(_cmpf(castle)))
+        goto end;
+    if (warn_on(_cmpf(clock_50)))
+        goto end;
+    if (warn_on(_cmpf(plycount)))
+        goto end;
+    if (warn_on(_cmpf(captured)))
+        goto end;
+
+    for (square_t sq = A1; sq <= H8; ++sq)
+        if (warn_on(_cmpf(board[sq])))
+            goto end;
+
+    for (color_t color = WHITE; color <= BLACK; ++color) {
+        for (piece_type_t piece = 0; piece <= KING; ++piece)
+            if (warn_on(_cmpf(bb[color][piece])))
+                goto end;
+        //pos->controlled[color] = 0;
+        if (warn_on(_cmpf(king[color])))
+            goto end;
+    }
+
+    if (warn_on(_cmpf(checkers)))
+        goto end;
+    if (warn_on(_cmpf(pinners)))
+        goto end;
+    if (warn_on(_cmpf(blockers)))
+        goto end;
+
+    if (warn_on(_cmpf(moves.nmoves)))
+        goto end;
+    for (int i = 0; i < pos1->moves.nmoves; ++i)
+        if (warn_on(_cmpf(moves.move[i])))
+            goto end;
+
+    ret = true;
+end:
+    return ret;
+#undef _cmpf
+}
+
 /**
  * pos_checkers() - find all checkers on a king.
  * @pos:   &position
@@ -299,7 +348,7 @@ void pos_print_raw(const pos_t *pos, const int type)
  */
 void pos_print_pieces(const pos_t *pos)
 {
-    int bit, count, cur;
+    int sq, count, cur;
     char *pname;
     u64 tmp;
     bitboard_t p;
@@ -308,12 +357,12 @@ void pos_print_pieces(const pos_t *pos)
             p = pos->bb[color][piece];
             count = popcount64(p);
             cur = 0;
-            pname = piece_to_cap(piece);
-            printf("%s(0)%s", pname, count? ":": "");
+            pname = piece_to_char(p);
+            printf("%s(%d)%s", pname, count, count? ":": "");
             if (count) {
-                bit_for_each64(bit, tmp, p) {
-                    char cf = sq_file(bit), cr = sq_rank(bit);
-                    printf("%s%c%c", cur? ",": "", FILE2C(cf), RANK2C(cr));
+                bit_for_each64(sq, tmp, p) {
+                    // char cf = sq_file(bit), cr = sq_rank(bit);
+                    printf("%s%s", cur? ",": "", sq_to_string(sq));
                     cur++;
                 }
             }

src/position.h

@@ -41,12 +41,13 @@ typedef struct __pos_s {
                         castle_rights_t castle;
                         u16 clock_50;
                         u16 plycount;             /* plies so far, start from 1 */
+                        piece_t captured;         /* only for move_undo */
         );
 
     piece_t board[BOARDSIZE];
 
     bitboard_t bb[2][PIECE_TYPE_MAX];             /* bb[0][PAWN], bb[1][ALL_PIECES] */
-    bitboard_t controlled[2];                     /* unsure */
+    //bitboard_t controlled[2];                     /* unsure */
     square_t king[2];                             /* dup with bb, faster retrieval */
     bitboard_t checkers;                          /* opponent checkers */
     bitboard_t pinners;                           /* opponent pinners */
@@ -92,6 +93,8 @@ static __always_inline void pos_clr_sq(pos_t *pos, square_t square)
     pos->board[square] = EMPTY;
     pos->bb[color][type] &= ~mask(square);
     pos->bb[color][ALL_PIECES] &= ~mask(square);
+    if (type == KING)
+        pos->king[color] = SQUARE_NONE;
 }
 
 /**
@@ -130,7 +133,7 @@ static __always_inline bitboard_t pos_between_occ(const pos_t *pos,
 static __always_inline int pos_between_count(const pos_t *pos,
                                              const square_t sq1, const square_t sq2)
 {
-    return bb_between_excl[sq1][sq2] & pos_occ(pos);
+    return popcount64(pos_between_occ(pos, sq1, sq2));
 }
 
 /**
@@ -150,25 +153,26 @@ static __always_inline int pos_between_count(const pos_t *pos,
 //void bitboard_print(bitboard_t bb, char *title);
 //void bitboard_print2(bitboard_t bb1, bitboard_t bb2, char *title);
 
-extern pos_t *pos_new();
-extern pos_t *pos_dup(const pos_t *pos);
-extern void pos_del(pos_t *pos);
-extern pos_t *pos_clear(pos_t *pos);
+pos_t *pos_new();
+pos_t *pos_dup(const pos_t *pos);
+void pos_del(pos_t *pos);
+pos_t *pos_clear(pos_t *pos);
+bool pos_cmp(const pos_t *pos1, const pos_t *pos2);
 
-extern bitboard_t pos_checkers(const pos_t *pos, const color_t color);
-extern bitboard_t pos_king_pinners(const pos_t *pos, const color_t color);
-extern bitboard_t pos_king_blockers(const pos_t *pos, const color_t color, const bitboard_t );
-//extern bitboard_t set_king_pinners_blockers(pos_t *pos);
-//extern char *pos_checkers2str(const pos_t *pos, char *str);
-//extern char *pos_pinners2str(const pos_t *pos, char *str);
+bitboard_t pos_checkers(const pos_t *pos, const color_t color);
+bitboard_t pos_king_pinners(const pos_t *pos, const color_t color);
+bitboard_t pos_king_blockers(const pos_t *pos, const color_t color, const bitboard_t );
+//bitboard_t set_king_pinners_blockers(pos_t *pos);
+//char *pos_checkers2str(const pos_t *pos, char *str);
+//char *pos_pinners2str(const pos_t *pos, char *str);
 
-extern int pos_check(const pos_t *pos, const bool strict);
+int pos_check(const pos_t *pos, const bool strict);
 
-extern void pos_print(const pos_t *pos);
-extern void pos_print_mask(const pos_t *pos, const bitboard_t mask);
-extern void pos_print_raw(const pos_t *pos, const int type);
+void pos_print(const pos_t *pos);
+void pos_print_mask(const pos_t *pos, const bitboard_t mask);
+void pos_print_raw(const pos_t *pos, const int type);
 
-extern void pos_print_pieces(const pos_t *pos);
+void pos_print_pieces(const pos_t *pos);
 
 
 #endif  /* POSITION_H */

test/common-test.h

@@ -19,6 +19,7 @@
 #define BITBOARD    2
 #define MOVEGEN     4
 #define ATTACK      8
+#define MOVEDO     16
 
 struct fentest {
     uint modules;
@@ -367,7 +368,18 @@ struct fentest {
       "illegal, SF crash",
       "2r1k3/3P4/8/8/8/8/8/4K3 w - - 0 1"
     },
-
+    { MOVEDO,
+      "simple movedo/undo: only 2 W knights",
+      "8/1k6/8/8/8/8/6K1/1NN5 w - - 0 1"
+    },
+    { MOVEDO,
+      "simple movedo/undo: only 2 W knights",
+      "8/1k6/8/8/8/8/6K1/1NN5 w - - 0 1"
+    },
+    { MOVEDO,
+      "simple movedo/undo: only 2 W knights",
+      "5n2/1k6/8/8/5K2/8/P7/1N6 w - - 0 1"
+    },
     { 0, NULL, NULL }
 };
 

test/movedo-test.c

@@ -0,0 +1,80 @@
+/* movedo-test.c - basic movedo/undo tests.
+ *
+ * Copyright (C) 2024 Bruno Raoult ("br")
+ * Licensed under the GNU General Public License v3.0 or later.
+ * Some rights reserved. See COPYING.
+ *
+ * You should have received a copy of the GNU General Public License along with this
+ * program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.html>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "chessdefs.h"
+#include "fen.h"
+#include "position.h"
+#include "move.h"
+#include "move-do.h"
+#include "move-gen.h"
+
+#include "common-test.h"
+
+int main(int __unused ac, __unused char**av)
+{
+    int i = 1;
+    char *fen, movebuf[8];;
+    pos_t *pos, *savepos;
+    move_t move;
+
+    setlinebuf(stdout);                           /* line-buffered stdout */
+
+    bitboard_init();
+    hyperbola_init();
+
+    while ((fen = next_fen(MOVEGEN | MOVEDO))) {
+        if (!(pos = fen2pos(NULL, fen))) {
+            printf("wrong fen %d: [%s]\n", i, fen);
+            continue;
+        }
+        pos_gen_pseudomoves(pos);
+        savepos = pos_dup(pos);
+        if (pos_cmp(pos, savepos) != true) {
+            printf("*** positions differ 1\n");
+            exit(0);
+        }
+        int tmp = 0, j = 1;
+        while ((move = pos_next_legal(pos, &tmp)) != MOVE_NONE) {
+            state_t state;
+
+            pos_print(pos);
+            printf("i=%d j=%d  turn=%d move=[%s]\n", i, j, pos->turn,
+                   move_str(movebuf, move, 0));
+            //move_p
+            move_do(pos, move, &state);
+            pos_print(pos);
+            fflush(stdout);
+            pos_check(pos, true);
+            printf("%d/%d move_do check ok\n", i, j);
+            move_undo(pos, move, &state);
+            if (pos_cmp(pos, savepos) != true) {
+                printf("*** positions differ 2\n");
+                exit(0);
+            }
+            fflush(stdout);
+            pos_check(pos, true);
+            printf("%d/%d move_undo check ok\n", i, j);
+
+            if (j++ == 1000)
+                exit(0);
+        }
+        pos_del(savepos);
+        pos_del(pos);
+        i++;
+    }
+    return 0;
+}