brchess func calls changes, always run perft() & perft2()

movegen: don't separate promotions, perft: loop uses next_legal()
move_{do,undo}: do not save/restore pos state
2024-03-27 12:53:42 +01:00 · 2024-03-27 12:52:39 +01:00 · 2024-03-27 12:42:45 +01:00 · 2024-03-27 12:41:38 +01:00 · 2024-03-27 12:40:16 +01:00 · 2024-03-26 17:43:59 +01:00
25 changed files with 1450 additions and 651 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -17,4 +17,5 @@ vgcore.*
 /tmp/
 /notused/
 valgrind.out
+gmon.out
 compile_commands.json
--- a/53
+++ b/53
@@ -1,6 +1,6 @@
 # Makefile - brchess Makefile, **GNU make only**
 #
-# Copyright (C) 2021-2023 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.
 #
@@ -86,23 +86,36 @@ CPPFLAGS  := $(strip $(CPPFLAGS))

 ##################################### compiler flags
 CFLAGS    := -std=gnu11
-#CFLAGS    += -flto
+
+### dev OR release
+# dev
 CFLAGS    += -O1
-CFLAGS    += -g
+#CFLAGS    += -g
+# release
+#CFLAGS    += -Ofast
+
+CFLAGS    += -march=native
+CFLAGS    += -flto
 CFLAGS    += -Wall
 CFLAGS    += -Wextra
-CFLAGS    += -march=native
 CFLAGS    += -Wmissing-declarations
 # for gprof
-# CFLAGS += -pg
+CFLAGS += -pg
 # Next one may be useful for valgrind (when invalid instructions)
 # CFLAGS += -mno-tbm

 CFLAGS    := $(strip $(CFLAGS))

+# development CFLAGS - unused - TODO
+#DEV_CFLAGS := -O1
+#DEV_CFLAGS += -g
+
+# release CFLAGS - unused - TODO
+#REL_CFLAGS := -Ofast
+
 ##################################### linker flags
 LDFLAGS   := -L$(BRLIBDIR)
-#LDFLAGS   += -flto
+LDFLAGS   += -flto

 LDFLAGS   := $(strip $(LDFLAGS))

@@ -286,17 +299,17 @@ 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
+TEST          += movedo-test perft-test

 PIECE_OBJS    := piece.o
-FEN_OBJS      := fen.o position.o piece.o bitboard.o board.o hyperbola-quintessence.o \
-	attack.o
-BB_OBJS       := fen.o position.o piece.o bitboard.o board.o hyperbola-quintessence.o \
-	attack.o
-MOVEGEN_OBJS  := fen.o position.o piece.o bitboard.o board.o hyperbola-quintessence.o \
-	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
+FEN_OBJS      := $(PIECE_OBJS) fen.o position.o bitboard.o board.o \
+	hyperbola-quintessence.o attack.o
+BB_OBJS       := $(FEN_OBJS)
+MOVEGEN_OBJS  := $(BB_OBJS) move.o move-gen.o
+ATTACK_OBJS   := $(MOVEGEN_OBJS)
+MOVEDO_OBJS   := $(ATTACK_OBJS) move-do.o
+PERFT_OBJS    := $(MOVEDO_OBJS) search.o

 TEST          := $(addprefix $(BINDIR)/,$(TEST))

@@ -305,6 +318,8 @@ 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))
+PERFT_OBJS    := $(addprefix $(OBJDIR)/,$(PERFT_OBJS))

 test:
 	echo TEST=$(TEST)
@@ -332,6 +347,14 @@ 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 $@
+
+bin/perft-test: test/perft-test.c test/common-test.h $(PERFT_OBJS)
+	@echo compiling $@ test executable.
+	@$(CC) $(ALL_CFLAGS) $< $(PERFT_OBJS) $(ALL_LDFLAGS) -o $@
+
 ##################################### Makefile debug
 .PHONY: showflags wft

--- a/src/attack.c
+++ b/src/attack.c
@@ -21,7 +21,68 @@
 #include "attack.h"


-// #define DEBUG_ATTACK_ATTACKERS1
+/**
+ * sq_is_attacked() - find if a square is attacked
+ * @pos: position
+ * @occ: occupation mask used
+ * @sq:  square to test
+ * @c:   attacker color
+ *
+ * Find if a @c piece attacks @sq.
+ *
+ * Algorithm:  We perform a reverse attack, and check if any given
+ * piece type on @sq can attack a @c piece of same type.
+ *
+ * For example, if @c is white, we test for all T in P,N,B,R,Q,K if
+ * T on @sq could attack a white T piece.
+ *
+ * @Return: true if @sq is attacked by a @c piece, false otherwise.
+ */
+bool sq_is_attacked(const pos_t *pos, const bitboard_t occ, const square_t sq, const color_t c)
+{
+    bitboard_t sqbb = mask(sq);
+    color_t opp = OPPONENT(c);
+
+
+    //pos_print_raw(pos, 1);
+
+    /* bishop / queen */
+    if (hyperbola_bishop_moves(occ, sq) & (pos->bb[c][BISHOP] | pos->bb[c][QUEEN]))
+        return true;
+
+    /* rook / queen */
+    if (hyperbola_rook_moves(occ, sq) & (pos->bb[c][ROOK] | pos->bb[c][QUEEN]))
+        return true;
+
+    /* pawn */
+    if ((pawn_shift_upleft(sqbb, opp) | pawn_shift_upright(sqbb, opp)) & pos->bb[c][PAWN])
+        return true;
+
+    /* knight */
+    if (bb_knight_moves(pos->bb[c][KNIGHT], sq))
+        return true;
+
+    /* king */
+    if (bb_king_moves(pos->bb[c][KING], sq))
+        return true;
+
+    return false;
+}
+
+/**
+ * is_in_check() - find if a king is in check.
+ * @pos:   position
+ * @color: king color
+ *
+ * Find if a @c king is in check. This function is a wrapper over @sq_is_attacked().
+ *
+ * @Return: true if @sq is attacked by a @c piece, false otherwise.
+ */
+bool is_in_check(const pos_t *pos, const color_t color)
+{
+    bitboard_t occ = pos_occ(pos);
+    return sq_is_attacked(pos, occ, pos->king[color], OPPONENT(color));
+}

 /**
 * sq_attackers() - find attackers on a square
--- a/src/attack.h
+++ b/src/attack.h
@@ -17,6 +17,9 @@
 #include "chessdefs.h"
 #include "bitboard.h"

+bool sq_is_attacked(const pos_t *pos, const bitboard_t occ, const square_t sq, const color_t c);
+bool is_in_check(const pos_t *pos, const color_t color);
+
 bitboard_t sq_attackers(const pos_t *pos, const bitboard_t occ, const square_t sq, const color_t c);
 bitboard_t sq_attackers_all(const pos_t *pos, const square_t sq);
 bitboard_t sq_pinners(const pos_t *pos, const square_t sq, const color_t c);
--- a/src/bitboard.c
+++ b/src/bitboard.c
@@ -190,8 +190,6 @@ void bitboard_init(void)
 */
 bitboard_t bb_knight_moves(bitboard_t notmine, square_t sq)
 {
-    //bitboard_print("bb_knight_move mask", bb_knight[sq]);
-    //bitboard_print("bb_knight_move  res", bb_knight[sq] & notmine);
    return bb_knight[sq] & notmine;
 }

--- a/src/bitboard.h
+++ b/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).
@@ -274,15 +272,15 @@ static __always_inline bitboard_t shift_nw(const bitboard_t bb)
 #define pawn_push_upleft(sq, c)   ((sq) + ((c) == WHITE ? NORTH_WEST: SOUTH_EAST))
 #define pawn_push_upright(sq, c)  ((sq) + ((c) == WHITE ? NORTH_EAST: SOUTH_WEST))

-extern bitboard_t bitboard_between_excl(square_t sq1, square_t sq2);
-extern void bitboard_init(void);
+bitboard_t bitboard_between_excl(square_t sq1, square_t sq2);
+void bitboard_init(void);

-extern bitboard_t bb_knight_moves(bitboard_t occ, square_t sq);
-extern bitboard_t bb_king_moves(bitboard_t occ, square_t sq);
+bitboard_t bb_knight_moves(bitboard_t notmine, square_t sq);
+bitboard_t bb_king_moves(bitboard_t notmine, square_t sq);

-extern void bb_print(const char *title, const bitboard_t bitboard);
-extern void bb_print_multi(const char *title, const int n, ...);
-extern char *bb_rank_sprint(char *str, const uchar bb8);
-extern char *bb_sq2str(const bitboard_t bb, char *str, int len);
+void bb_print(const char *title, const bitboard_t bitboard);
+void bb_print_multi(const char *title, const int n, ...);
+char *bb_rank_sprint(char *str, const uchar bb8);
+char *bb_sq2str(const bitboard_t bb, char *str, int len);

 #endif  /* _BITBOARD_H */
--- a/src/chessdefs.h
+++ b/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
 */
--- a/src/fen.c
+++ b/src/fen.c
@@ -75,15 +75,15 @@ static const char *castle_str = "KQkq";
 static int fen_check(pos_t *pos)
 {
    char *colstr[2] = { "white", "black"};
-    int error = 0, warning = 0;
+    int warning = 0;

    /* en passant, depends on who plays next */
    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 ||
@@ -130,13 +130,7 @@ static int fen_check(pos_t *pos)
            }
        }
    }
-    if (!(error = pos_check(pos, 0))) {
-        /* TODO: Should it really be here ? */
-        pos->checkers = pos_checkers(pos, pos->turn);
-        pos->pinners = pos_king_pinners(pos, pos->turn);
-        pos->blockers = pos_king_blockers(pos, pos->turn, pos->pinners);
-    }
-    return error ? -1: warning;
+    return pos_ok(pos, 0) ? warning: -1;
 }

 /**
--- a/src/hyperbola-quintessence.h
+++ b/src/hyperbola-quintessence.h
@@ -17,17 +17,17 @@
 #include "board.h"
 #include "bitboard.h"

-extern void hyperbola_init(void);
+void hyperbola_init(void);

-extern bitboard_t hyperbola_rank_moves(const bitboard_t occ, const square_t sq);
-extern bitboard_t hyperbola_moves(const bitboard_t pieces, const square_t sq,
-                                  const bitboard_t mask);
-extern bitboard_t hyperbola_file_moves(const bitboard_t occ, const square_t sq);
-extern bitboard_t hyperbola_diag_moves(const bitboard_t occ, const square_t sq);
-extern bitboard_t hyperbola_anti_moves(const bitboard_t occ, const square_t sq);
+bitboard_t hyperbola_rank_moves(const bitboard_t occ, const square_t sq);
+bitboard_t hyperbola_moves(const bitboard_t pieces, const square_t sq,
+                           const bitboard_t mask);
+bitboard_t hyperbola_file_moves(const bitboard_t occ, const square_t sq);
+bitboard_t hyperbola_diag_moves(const bitboard_t occ, const square_t sq);
+bitboard_t hyperbola_anti_moves(const bitboard_t occ, const square_t sq);

-extern bitboard_t hyperbola_bishop_moves(const bitboard_t occ, const square_t sq);
-extern bitboard_t hyperbola_rook_moves(const bitboard_t occ, const square_t sq);
-extern bitboard_t hyperbola_queen_moves(const bitboard_t occ, const square_t sq);
+bitboard_t hyperbola_bishop_moves(const bitboard_t occ, const square_t sq);
+bitboard_t hyperbola_rook_moves(const bitboard_t occ, const square_t sq);
+bitboard_t hyperbola_queen_moves(const bitboard_t occ, const square_t sq);

 #endif  /* _HYPERBOLA_QUINTESSENCE_H */
--- a/src/move-do.c
+++ b/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 +15,176 @@
 #include <ctype.h>
 #include <stdlib.h>

+#include "brlib.h"
+#include "likely.h"
+#include "bug.h"
+
 #include "chessdefs.h"
 #include "move.h"
 #include "position.h"
+#include "move-do.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, const 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_type_t ptype = PIECE(piece);
+    color_t pcolor = COLOR(piece);
+    piece_t new_piece = piece;
+
+    ++pos->clock_50;
+    ++pos->plycount;
+    pos->en_passant = SQUARE_NONE;
+    pos->turn = them;
+
+    bug_on(pcolor != us);
+
+    if (is_promotion(move)) {
+        bug_on(sq_rank(to) != sq_rel_rank(RANK_8, us));
+        new_piece = MAKE_PIECE(move_promoted(move), us);
+    }
+
+    if (is_capture(move)) {
+        pos->clock_50 = 0;
+        pos->captured = pos->board[to];           /* save capture info */
+        bug_on(pos->board[to] == EMPTY || COLOR(pos->captured) != them);
+        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 (ptype == 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);
+
+    if (ptype == KING)
+        pos->king[us] = to;
+
+    /* 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];
+
+
+    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 (PIECE(piece) == KING)
+        pos->king[us] = from;
+
+    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));
+    }
+
+    //pos->state = *state;                          /* restore irreversible changes */
+    pos->turn = us;
+    return pos;
+}
--- a/src/move-do.h
+++ b/src/move-do.h
@@ -14,7 +14,9 @@
 #ifndef MOVE_DO_H
 #define MOVE_DO_H

-//extern pos_t *move_do(pos_t *pos, move_t *move);
-//extern void move_undo(pos_t *pos, move_t *move);
+#include "position.h"
+
+pos_t *move_do(pos_t *pos, const move_t move);//, state_t *state);
+pos_t *move_undo(pos_t *pos, const move_t move);//, const state_t *state);

 #endif  /* MOVE_DO_H */
--- a/src/move-gen.c
+++ b/src/move-gen.c
@@ -40,6 +40,7 @@ bool pseudo_is_legal(const pos_t *pos, const move_t move)
    square_t from = move_from(move), to = move_to(move), king = pos->king[us], sq;
    piece_type_t piece = PIECE(pos->board[from]);
    bitboard_t kingbb = pos->bb[us][KING], tmp;
+    u64 pinned = mask(from) & pos->blockers & pos->bb[us][ALL_PIECES];

    /* (1) - King
     * For castling, we already tested intermediate squares attacks
@@ -53,14 +54,22 @@ bool pseudo_is_legal(const pos_t *pos, const move_t move)

    /* (2) - King is in check
     * Double-check is already handled, as only K moves were generated.
-     * Here, allowed moves are only on King-attacker line, including
-     * attacker.We can move a piece on
-     * in pseudo move generation, so we only care destination square here.
+     * Here, allowed dest squares are only on King-checker line, or on checker
+     * square.
+     * attacker.
+     * Special cases:
+     *   e.p., legal if the taken pawn is giving check
+     *   pinned piece: always illegal
     */
    if (pos->checkers) {
        if (popcount64(pos->checkers) == 1) {     /* one checker */
            square_t checker = ctz64(pos->checkers);
-            bitboard_t between = bb_between[king][checker];
+            if (pinned)
+                return false;
+            if (is_enpassant(move)) {
+                return pawn_push_up(pos->en_passant, them) == checker;
+            }
+            bitboard_t between = bb_between[king][checker] | pos->checkers;
            return mask(to) & between;
        }
        return false;                             /* double check */
@@ -69,7 +78,8 @@ bool pseudo_is_legal(const pos_t *pos, const move_t move)
    /* (3) - pinned pieces
     * We verify here that pinned piece P stays on line King-P.
     */
-    if (mask(from) & pos->blockers & pos->bb[us][ALL_PIECES]) {
+    //if (mask(from) & pos->blockers & pos->bb[us][ALL_PIECES]) {
+    if (pinned) {
        bitboard_t line = bb_line[from][king];
        return line & mask(to);                   /* to is not on pin line */
    }
@@ -79,7 +89,7 @@ bool pseudo_is_legal(const pos_t *pos, const move_t move)
     * 5th relative rank. To do so, we create an occupation bb without
     * the 2 pawns.
     */
-    if (IS_CAPTURE(move) && PIECE(pos->board[to]) == EMPTY) {
+    if (is_enpassant(move)) {
         /* from rank bitboard */
        bitboard_t rank5 = bb_sqrank[from];
        /* enemy rooks/queens on from rank */
@@ -103,18 +113,19 @@ bool pseudo_is_legal(const pos_t *pos, const move_t move)
 /**
 * pos_next_legal() - get next legal move in position.
 * @pos:  position
- * @start:  &int, starting position in move list
+ * @movelist: &pseudo-legal movelist
+ * @start:  &int, starting position in @movelist
 *
 * Get next valid move in @pos move list, from move @start, or MOVE_NONE.
 * @start is set to next non-checked move in pseudo-legal list.
 * Position pseudo-legal moves must be already calculated before calling this function.
 *
- * @return: move, or -1 if no move.
+ * @return: move, or MOVE_NONE if no move.
 */
-move_t pos_next_legal(const pos_t *pos, int *start)
+move_t pos_next_legal(const pos_t *pos, movelist_t *movelist, int *start)
 {
-    const int nmoves = pos->moves.nmoves;
-    const move_t *moves = pos->moves.move;
+    const int nmoves = movelist->nmoves;
+    const move_t *moves = movelist->move;
    move_t move;

    while (*start < nmoves) {
@@ -127,20 +138,20 @@ move_t pos_next_legal(const pos_t *pos, int *start)
 /**
 * pos_all_legal() - get the list of legal moves from pseudo-legal.
 * @pos:  position
- * @dest: destination &movelist_t
+ * @movelist: &pseudo-legal movelist_t
+ * @dest: &destination movelist_t
 *
 * The pseudo-legal moves must be already calculated before calling this function.
 * No check is done on @dest limits.
 *
 * @Return: @dest
 */
-movelist_t *pos_all_legal(const pos_t *pos, movelist_t *dest)
+movelist_t *pos_all_legal(const pos_t *pos, movelist_t *movelist, movelist_t *dest)
 {
    int tmp = dest->nmoves = 0;
    move_t move;
-    //int tmp = 0;

-    while ((move = pos_next_legal(pos, &tmp)) != MOVE_NONE)
+    while ((move = pos_next_legal(pos, movelist, &tmp)) != MOVE_NONE)
        dest->move[dest->nmoves++] = move;
    return dest;
 }
@@ -148,16 +159,19 @@ movelist_t *pos_all_legal(const pos_t *pos, movelist_t *dest)
 /**
 * pos_gen_pseudomoves() - generate position pseudo-legal moves
 * @pos: position
+ * @movelist: &movelist_t array to store pseudo-moves
 *
 * Generate all @pos pseudo moves for player-to-move.
- * The @pos->moves table is filled with the moves.
+ * @movelist is filled with the moves.
 *
 * Only a few validity checks are done here (i.e. moves are not generated):
 *  - castling, if king is in check
 *  - 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
+ *  - capture (excl. en-passant): M_CAPTURE
+ *  - en-passant: M_EN_PASSANT
+ *  - pawn double push: M_DPUSH
 *  - promotion: M_PROMOTION
 *  - promotion and capture
 *
@@ -165,7 +179,7 @@ movelist_t *pos_all_legal(const pos_t *pos, movelist_t *dest)
 *
 * @Return: The total number of moves.
 */
-int pos_gen_pseudomoves(pos_t *pos)
+int pos_gen_pseudomoves(pos_t *pos, movelist_t *movelist)
 {
    color_t us               = pos->turn;
    color_t them             = OPPONENT(us);
@@ -173,165 +187,150 @@ 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;

    bitboard_t movebits, from_pawns;
    bitboard_t tmp1, tmp2;
-
-    move_t *moves            = pos->moves.move;
-    int nmoves               = pos->moves.nmoves;
-
+    move_t *moves            = movelist->move;
+    int *nmoves              = &movelist->nmoves;
    int from, to;

-    /* king - MUST BE FIRST ! */
+    *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, tmp2, movebits) {
-        moves[nmoves++] = move_make(from, to);
+    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);
+        return *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) {
-            moves[nmoves++] = move_make(from, to);
+        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]) {
-        // printf("rook=%d/%s\n", from, sq_to_string(from));
+    bit_for_each64(from, tmp1, pos->bb[us][ROOK] | pos->bb[us][QUEEN]) {
        movebits = hyperbola_rook_moves(occ, from) & not_my_pieces;
-        bit_for_each64(to, tmp2, movebits) {
-            moves[nmoves++] = move_make(from, to);
+        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) {
-            moves[nmoves++] = move_make(from, to);
+        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);
-    int en_passant = pos->en_passant == SQUARE_NONE? 0: pos->en_passant;
-    bitboard_t enemy_avail = bb_sq[en_passant] | enemy_pieces;
+    bitboard_t rel_rank8 = bb_rel_rank(RANK_8, 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;
-    bit_for_each64(to, tmp1, movebits) {
+    movebits = pawn_shift_up(pos->bb[us][PAWN], us) & empty;
+    bit_for_each64(to, tmp1, movebits & ~rel_rank8) {
        from = pawn_push_up(to, them);              /* reverse push */
-        //printf("push %d->%d %s->%s", from, to, sq_to_string(from), sq_to_string(to));
-        moves[nmoves++] = move_make(from, to);
+        moves[(*nmoves)++] = move_make(from, to);
    }
+    bit_for_each64(to, tmp1, movebits & rel_rank8) { /* promotions */
+        from = pawn_push_up(to, them);              /* reverse push */
+        moves[(*nmoves)++] = move_make_promote(from, to, QUEEN);
+        moves[(*nmoves)++] = move_make_promote(from, to, ROOK);
+        moves[(*nmoves)++] = move_make_promote(from, to, BISHOP);
+        moves[(*nmoves)++] = move_make_promote(from, to, KNIGHT);
+    }
+
    /* possible second push */
    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, including en-passant */
-    from_pawns = pos->bb[us][PAWN] & ~rel_rank7; // & ~rel_filea;
-    movebits = pawn_shift_upleft(from_pawns, us) & enemy_avail;
-    bit_for_each64(to, tmp1, movebits) {
+    /* pawn: captures left */
+    movebits = pawn_shift_upleft(pos->bb[us][PAWN], us) & enemy_pieces;
+    bit_for_each64(to, tmp1, movebits & ~rel_rank8) {
        from = pawn_push_upleft(to, them);         /* reverse capture */
-        moves[nmoves++] = move_make_capture(from, to);
+        moves[(*nmoves)++] = move_make_capture(from, to);
    }
-    /* pawn: ranks 2-6 captures right, including en-passant */
-    from_pawns = pos->bb[us][PAWN] & ~rel_rank7; // & ~rel_fileh;
-    movebits = pawn_shift_upright(from_pawns, us) & enemy_avail;
-    bit_for_each64(to, tmp1, movebits) {
-        from = pawn_push_upright(to, them);
-        moves[nmoves++] = move_make_capture(from, to);
+    bit_for_each64(to, tmp1, movebits & rel_rank8) {
+        from = pawn_push_upleft(to, them);         /* reverse capture */
+        moves[(*nmoves)++] = move_make_promote_capture(from, to, QUEEN);
+        moves[(*nmoves)++] = move_make_promote_capture(from, to, ROOK);
+        moves[(*nmoves)++] = move_make_promote_capture(from, to, BISHOP);
+        moves[(*nmoves)++] = move_make_promote_capture(from, to, KNIGHT);
    }

-    /* pawn: rank 7 push */
-    movebits = pawn_shift_up(pos->bb[us][PAWN] & rel_rank7, us) & empty;
-    bit_for_each64(to, tmp1, movebits) {
-        from = pawn_push_up(to, them);              /* reverse push */
-        moves[nmoves++] = move_make_promote(from, to, QUEEN);
-        moves[nmoves++] = move_make_promote(from, to, ROOK);
-        moves[nmoves++] = move_make_promote(from, to, BISHOP);
-        moves[nmoves++] = move_make_promote(from, to, KNIGHT);
+    /* pawn: captures right */
+    movebits = pawn_shift_upright(pos->bb[us][PAWN], us) & enemy_pieces;
+    bit_for_each64(to, tmp1, movebits & ~rel_rank8) {
+        from = pawn_push_upright(to, them);       /* reverse capture */
+        moves[(*nmoves)++] = move_make_capture(from, to);
    }
-    /* pawn promotion: rank 7 captures left */
-    from_pawns = pos->bb[us][PAWN] & rel_rank7; // & ~rel_filea;
-    movebits = pawn_shift_upleft(from_pawns, us) & enemy_avail;
-    bit_for_each64(to, tmp1, movebits) {
-        from = pawn_push_upleft(to, them);         /* reverse capture */
-        moves[nmoves++] = move_make_promote_capture(from, to, QUEEN);
-        moves[nmoves++] = move_make_promote_capture(from, to, ROOK);
-        moves[nmoves++] = move_make_promote_capture(from, to, BISHOP);
-        moves[nmoves++] = move_make_promote_capture(from, to, KNIGHT);
+    bit_for_each64(to, tmp1, movebits & rel_rank8) {
+        from = pawn_push_upright(to, them);       /* reverse capture */
+        moves[(*nmoves)++] = move_make_promote_capture(from, to, QUEEN);
+        moves[(*nmoves)++] = move_make_promote_capture(from, to, ROOK);
+        moves[(*nmoves)++] = move_make_promote_capture(from, to, BISHOP);
+        moves[(*nmoves)++] = move_make_promote_capture(from, to, KNIGHT);
    }
-    /* pawn: rank 7 captures right */
-    from_pawns = pos->bb[us][PAWN] & rel_rank7; // & ~rel_fileh;
-    movebits = pawn_shift_upright(from_pawns, us) & enemy_pieces;
-    bit_for_each64(to, tmp1, movebits) {
-        from = pawn_push_upright(to, them);         /* reverse capture */
-        moves[nmoves++] = move_make_promote_capture(from, to, QUEEN);
-        moves[nmoves++] = move_make_promote_capture(from, to, ROOK);
-        moves[nmoves++] = move_make_promote_capture(from, to, BISHOP);
-        moves[nmoves++] = move_make_promote_capture(from, to, KNIGHT);
+
+    /* pawn: en-passant */
+    if ((to = pos->en_passant) != SQUARE_NONE) {
+        movebits = mask(to);
+        from_pawns = pos->bb[us][PAWN]
+            & (pawn_shift_upleft(movebits, them) | pawn_shift_upright(movebits, them));
+        bit_for_each64(from, tmp1, from_pawns) {
+            moves[(*nmoves)++] = move_make_enpassant(from, to);
+        }
    }

    /* 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);
+                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 */
-                moves[nmoves++] = move_make_flags(from, from - 2, M_CASTLE_Q);
+                moves[(*nmoves)++] = move_make_flags(from, from - 2, M_CASTLE_Q);
            }
        }
    }
-    /* TODO
-     * DONE. pawn ranks 2-6 advance (1 push, + 2 squares for rank 2)
-     * DONE. pawns rank 7 advance + promotions
-     * DONE. pawns ranks 2-6 captures, left and right
-     * DONE. pawns en-passant (with capture)
-     * DONE. pawns rank 7 capture + promotion
-     * DONE. castle
-     *
-     * add function per piece, and type, for easier debug
-     *
+    /* TODO: add function per piece, and type, for easier debug
     */
-    return (pos->moves.nmoves = nmoves);
+    return *nmoves;
 }
--- a/src/move-gen.h
+++ b/src/move-gen.h
@@ -22,8 +22,8 @@
 #include "move.h"

 bool pseudo_is_legal(const pos_t *pos, const move_t move);
-move_t pos_next_legal(const pos_t *pos, int *start);
-movelist_t *pos_all_legal(const pos_t *pos, movelist_t *dest);
-int pos_gen_pseudomoves(pos_t *pos);
+move_t pos_next_legal(const pos_t *pos, movelist_t *movelist, int *start);
+movelist_t *pos_all_legal(const pos_t *pos, movelist_t *movelist, movelist_t *dest);
+int pos_gen_pseudomoves(pos_t *pos, movelist_t *movelist);

 #endif  /* MOVEGEN_H */
--- a/src/move.c
+++ b/src/move.c
@@ -109,8 +109,8 @@ char *move_str(char *dst, const move_t move, __unused const int flags)
    int len;
    sprintf(dst, "%s%s%n", sq_to_string(from), sq_to_string(to), &len);

-    if (IS_PROMOTION(move)) {
-        piece_t promoted = move_promoted(move);
+    if (is_promotion(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 */
--- a/src/move.h
+++ b/src/move.h
@@ -19,59 +19,59 @@
 #include "board.h"

 /* 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
+ * 3 3     2 2    1 1 1 1 1 1
+ * 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
- * ffffff    6    0    0-5      square_t           077       &63   from
- * tttttt    6    6   6-11      square_t         07700  (>>6)&63   to
- * ppp       3   12  12-14  piece_type_t        070000  (>>12)&7   promoted
- * ccc       3   15  15-17  piece_type_t       0700000  (>>15)&7   captured
- * FFFFFF    6   18  18-23  move_flags_t     077000000 (>>18)&63   N/A  flags
- * UUUUUUU   7   24  24-30        unused  017700000000             future usage
- * S         1   31  31-31             -  020000000000             sign
+ * bits    len off range         type         mask        get  desc
+ * ffffff    6   0   0-5     square_t          077        &077 from
+ * tttttt    6   6  6-11     square_t        07700 (>>6)  &077 to
+ * ppp       3  12 12-14 piece_type_t       070000 (>>12) &07  promoted
+ * ccc       3  15 15-17 piece_type_t      0700000 (>>15) &07  captured
+ * FFFFFF    6  18 18-23 move_flags_t    077000000 (>>18) &077 N/A  flags
+ * UUUUUUU   7  24 24-30       unused 017700000000             future usage
+ * S         1  31 31-31            - 020000000000             sign
 */
 typedef s32 move_t;

 /* special move_t values */
-#define MOVE_NONE (-1)
-#define MOVE_NULL (0)                             /* hack: from = to = A1 */
+#define MOVE_NONE ((move_t) -1)
+#define MOVE_NULL ((move_t) 0)                    /* hack: from = to = A1 */

 enum {
-    M_OFF_FROM  = 0,
-    M_OFF_TO    = 6,
-    M_OFF_PROM  = 12,
-    M_OFF_CAPT  = 15,
-    M_OFF_FLAGS = 18
+    M_OFF_FROM     = 0,
+    M_OFF_TO       = 6,
+    M_OFF_PROMOTED = 12,
+    M_OFF_CAPTURED = 15,
+    M_OFF_FLAGS    = 18
 };

 typedef enum {
-    //M_INVALID   = -1,
-    //M_START     = 18,
-    M_CAPTURE   = mask(0),
-    M_ENPASSANT = mask(1),
-    M_PROMOTION = mask(2),
-    M_CASTLE_K  = mask(3),                        /* maybe only one ? */
-    M_CASTLE_Q  = mask(5),                        /* maybe only one ? */
-    M_CHECK     = mask(6)                         /* maybe unknown/useless ? */
+    M_CAPTURE   = mask(M_OFF_FLAGS + 0),
+    M_ENPASSANT = mask(M_OFF_FLAGS + 1),
+    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_DPUSH     = mask(M_OFF_FLAGS + 7)           /* pawn double push */
 } move_flags_t;

-#define MOVE_FLAGS(m)   ((m) >> M_OFF_FLAGS)
-#define IS_CAPTURE(m)   (MOVE_FLAGS(m) & M_CAPTURE)
-#define IS_ENPASSANT(m) (MOVE_FLAGS(m) & M_ENPASSANT)
-#define IS_PROMOTION(m) (MOVE_FLAGS(m) & M_PROMOTION)
-#define IS_CASTLE(m)    (MOVE_FLAGS(m) & (M_CASTLE_K | M_CASTLE_Q))
-#define IS_CASTLE_K(m)  (MOVE_FLAGS(m) & M_CASTLE_K)
-#define IS_CASTLE_Q(m)  (MOVE_FLAGS(m) & M_CASTLE_Q)
-#define IS_CHECK(m)     (MOVE_FLAGS(m) & M_CHECK)
+#define move_set_flags(move, flags) ((move) | (flags))
+
+#define is_capture(m)   ((m) & M_CAPTURE)
+#define is_enpassant(m) ((m) & M_ENPASSANT)
+#define is_promotion(m) ((m) & M_PROMOTION)
+#define is_castle(m)    ((m) & (M_CASTLE_K | M_CASTLE_Q))
+#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

 typedef struct __movelist_s {
    move_t move[MOVES_MAX];
    int nmoves;                                   /* total moves (fill) */
-    int curmove;                                  /* current move (use) */
 } movelist_t;

 static inline square_t move_from(move_t move)
@@ -84,14 +84,14 @@ 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_PROM) & 07;
+    return (move >> M_OFF_PROMOTED) & 07;
 }

 static inline piece_type_t move_captured(move_t move)
 {
-    return (move >> M_OFF_CAPT) & 07;
+    return (move >> M_OFF_CAPTURED) & 07;
 }

 static inline move_t move_make(square_t from, square_t to)
@@ -101,7 +101,7 @@ static inline move_t move_make(square_t from, square_t to)

 static inline move_t move_make_flags(square_t from, square_t to, move_flags_t flags)
 {
-    return move_make(from, to) | (flags << M_OFF_FLAGS);
+    return move_set_flags(move_make(from, to), flags);
 }

 static inline move_t move_make_capture(square_t from, square_t to)
@@ -109,16 +109,26 @@ static inline move_t move_make_capture(square_t from, square_t to)
    return move_make_flags(from, to, M_CAPTURE);
 }

+static inline move_t move_make_enpassant(square_t from, square_t to)
+{
+    return move_make_flags(from, to, M_ENPASSANT);
+}
+
 static inline move_t move_make_promote(square_t from, square_t to,
                                       piece_type_t promoted)
 {
-    return move_make_flags(from, to, M_PROMOTION) | (promoted << M_OFF_PROM);
+    return move_make_flags(from, to, M_PROMOTION) | (promoted << M_OFF_PROMOTED);
 }

 static inline move_t move_make_promote_capture(square_t from, square_t to,
                                               piece_type_t promoted)
 {
-    return move_make_flags(from, to, M_CAPTURE | M_PROMOTION) | (promoted << M_OFF_PROM);
+    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
--- a/src/piece.c
+++ b/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)
 {
--- a/src/position.c
+++ b/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)
 {
@@ -95,27 +83,93 @@ pos_t *pos_clear(pos_t *pos)
 #   endif
    pos->node_count = 0;
    pos->turn = WHITE;
-    pos->clock_50 = 0;
-    pos->plycount = 0;
+
+    /* 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;

    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;
    }

-    for (square_t sq = A1; sq <= H8; ++sq)
-        pos->board[sq] = EMPTY;
-    pos->moves.curmove = 0;
-    pos->moves.nmoves = 0;
    pos->checkers = 0;
    pos->pinners = 0;
+    pos->blockers = 0;
+
+    //pos->moves.nmoves = 0;
    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
@@ -132,6 +186,49 @@ bitboard_t pos_checkers(const pos_t *pos, const color_t color)
    return sq_attackers(pos, occ, pos->king[color], OPPONENT(color));
 }

+/**
+ * pos_set_checkers_pinners_blockers() - calculate checkers, pinners and blockers.
+ * @pos:   &position
+ *
+ * Set position checkers, pinners and blockers on player-to-play king.
+ * It should be faster than @pos_checkers + @pos_set_pinners_blockers, as
+ * some calculation will be done once.
+ */
+/*
+ * void pos_set_checkers_pinners_blockers(pos_t *pos)
+ * {
+ *     bitboard_t b_bb = pos->bb[WHITE][BISHOP] | pos->bb[BLACK][BISHOP];
+ *     bitboard_t r_bb = pos->bb[WHITE][ROOK] | pos->bb[BLACK][ROOK];
+ *     bitboard_t q_bb = pos->bb[WHITE][QUEEN] | pos->bb[BLACK][QUEEN];
+ *
+ *     /\* find out first piece on every diagonal *\/
+ *
+ * }
+ */
+
+/**
+ * pos_set_pinners_blockers() - set position pinners and blockers.
+ * @pos:   &position
+ *
+ * set position pinners and blockers on player-to-play king.
+ */
+void pos_set_pinners_blockers(pos_t *pos)
+{
+    color_t color = pos->turn;
+    square_t king = pos->king[color];
+    bitboard_t tmp, occ = pos_occ(pos), blockers = 0;
+    int pinner;
+
+    pos->pinners = sq_pinners(pos, king, OPPONENT(pos->turn));
+    bit_for_each64(pinner, tmp, pos->pinners) {
+        //bitboard_t blocker =
+        // warn_on(popcount64(blocker) != 1);
+        blockers |= bb_between_excl[pinner][king] & occ;
+    }
+    pos->blockers = blockers;
+    return;
+}
+
 /**
 * pos_king_pinners() - get the "pinners" on a king "pinners".
 * @pos:   &position
@@ -164,19 +261,18 @@ bitboard_t pos_king_blockers(const pos_t *pos, const color_t color, const bitboa
    square_t pinner, king = pos->king[color];

    bit_for_each64(pinner, tmp, pinners) {
-        bitboard_t blocker = bb_between_excl[pinner][king] & occ;
-        warn_on(popcount64(blocker) != 1);
-        if (popcount64(blocker) != 1) {
-            printf("n blockers = %d\n", popcount64(blocker));
-            bb_print("blockers", blocker);
-        }
-        blockers |= blocker;
+        //warn_on(popcount64(blocker) != 1);
+        //if (popcount64(blocker) != 1) {
+        //    printf("n blockers = %d\n", popcount64(blocker));
+        //    bb_print("blockers", blocker);
+        //}
+        blockers |= bb_between_excl[pinner][king] & occ;
    }
    return blockers;
 }

 /**
- * pos_check() - extensive position consistency check.
+ * pos_ok() - extensive position consistency check.
 * @pos:    &position
 * @strict: if true, call bug_on() on any error.
 *
@@ -201,9 +297,9 @@ bitboard_t pos_king_blockers(const pos_t *pos, const color_t color, const bitboa
 * TODO: add more checks:
 * - kings attacking each other
 *
- * @Return: Number of detected error (only if @strict is false).
+ * @return: (if @strict is false) return true if check is ok, false otherwise.
 */
-int pos_check(const pos_t *pos, const bool strict)
+bool pos_ok(const pos_t *pos, const bool strict)
 {
    int n, count = 0, bbcount = 0, error = 0;
    bitboard_t tmp;
@@ -247,7 +343,7 @@ int pos_check(const pos_t *pos, const bool strict)
    error += warn_on(sq_dist(pos->king[WHITE], pos->king[BLACK]) < 2);

    bug_on(strict && error);
-    return error;
+    return error? false: true;
 }

 /**
@@ -279,7 +375,7 @@ void pos_print_mask(const pos_t *pos, const bitboard_t mask)
 }

 /**
- * pos_print_board_raw - print simple position board (octal/FEN symbol values)
+ * pos_print_raw - print simple position board (octal/FEN symbol values)
 * @bb: the bitboard
 * @type: int, 0 for octal, 1 for fen symbol
 */
@@ -295,7 +391,7 @@ 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;
@@ -304,12 +400,12 @@ 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++;
                }
            }
--- a/src/position.h
+++ b/src/position.h
@@ -18,6 +18,7 @@

 #include "brlib.h"
 #include "bitops.h"
+#include "struct-group.h"

 #include "chessdefs.h"
 #include "bitboard.h"
@@ -28,22 +29,34 @@
 typedef struct __pos_s {
    u64 node_count;                               /* evaluated nodes */
    int turn;                                     /* WHITE or BLACK */
-    u16 clock_50;
-    u16 plycount;                                 /* plies so far, start is 0 */

-    square_t king[2];                             /* dup with bb, faster retrieval */
-    square_t en_passant;
-    castle_rights_t castle;
+    /* data which cannot be recovered by move_undo (like castle_rights, ...),
+     * or would be expensive to recover (checkers, ...)
+     * following data can be accessed either directly, either via "movesave"
+     * structure name.
+     * For example, pos->en_passant and pos->state.en_passant are the same.
+     * This allows a memcpy on this data (to save/restore position state).
+     */
+    struct_group_tagged(state_s, state,
+                        square_t en_passant;
+                        castle_rights_t castle;
+                        u16 clock_50;
+                        u16 plycount;             /* plies so far, start from 1 */
+                        piece_t captured;         /* only for move_undo */
+                        bitboard_t checkers;      /* opponent checkers */
+                        bitboard_t pinners;       /* opponent pinners */
+                        bitboard_t blockers;      /* pieces blocking pin */
+        );

-    bitboard_t bb[2][PIECE_TYPE_MAX];             /* bb[0][PAWN], bb[1][ALL_PIECES] */
-    bitboard_t controlled[2];                     /* unsure */
-    bitboard_t checkers;                          /* opponent checkers */
-    bitboard_t pinners;                           /* opponent pinners */
-    bitboard_t blockers;                          /* pieces blocking pin */
    piece_t board[BOARDSIZE];
-    movelist_t moves;
+    bitboard_t bb[2][PIECE_TYPE_MAX];             /* bb[0][PAWN], bb[1][ALL_PIECES] */
+    //bitboard_t controlled[2];                     /* unsure */
+    square_t king[2];                             /* dup with bb, faster retrieval */
+    //movelist_t moves;
 } pos_t;

+typedef struct state_s state_t;
+
 #define pos_pinned(p)                  (p->blockers & p->bb[p->turn][ALL_PIECES])

 /**
@@ -80,6 +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;
 }

 /**
@@ -118,7 +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));
 }

 /**
@@ -138,25 +153,25 @@ 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 set_king_pinners_blockers(pos_t *pos);
+void pos_set_pinners_blockers(pos_t *pos);
+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 );

-extern int pos_check(const pos_t *pos, const bool strict);
+bool pos_ok(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 */
--- a/src/search.c
+++ b/src/search.c
@@ -1,6 +1,6 @@
 /* search.c - search good moves.
 *
- * Copyright (C) 2023 Bruno Raoult ("br")
+ * Copyright (C) 2023-2024 Bruno Raoult ("br")
 * Licensed under the GNU General Public License v3.0 or later.
 * Some rights reserved. See COPYING.
 *
@@ -11,14 +11,98 @@
 *
 */

+#include <stdio.h>

-#include <br.h>
-#include <list.h>
-#include "debug.h"
+#include "brlib.h"

-#include "move.h"
-#include "eval.h"
+#include "position.h"
+#include "move-gen.h"
+#include "move-do.h"
 #include "search.h"
+#include "attack.h"
+
+//#include "move.h"
+//#include "eval.h"
+
+/**
+ * perft() - Perform perft on position
+ * @pos:   &position to search
+ * @depth: Wanted depth.
+ * @ply:   Depth level where perft is consolidated.
+ *
+ * Print perftCalculate the negamax value of @pos. This is an extensive search, with
+ * absolutely no cutoff.
+ *
+ * @return: The @pos negamax evaluation.
+ */
+u64 perft(pos_t *pos, int depth, int ply)
+{
+    int subnodes, movetmp = 0;
+    u64 nodes = 0;
+    movelist_t pseudo = { .nmoves = 0 };
+    move_t move;
+    state_t state;
+
+    if (depth == 0)
+        return 1;
+    pos->checkers = pos_checkers(pos, pos->turn);
+    pos_set_pinners_blockers(pos);
+    state = pos->state;
+
+    pos_gen_pseudomoves(pos, &pseudo);
+    while ((move =  pos_next_legal(pos, &pseudo, &movetmp)) != MOVE_NONE) {
+        move_do(pos, move);
+        subnodes = perft(pos, depth - 1, ply + 1);
+        if (ply == 1) {
+            char movestr[8];
+            printf("%s: %d\n", move_str(movestr, move, 0), subnodes);
+        }
+        nodes += subnodes;
+        move_undo(pos, move);
+        pos->state = state;
+    }
+
+    if (ply == 1)
+        printf("\nTotal: %lu\n", nodes);
+    return nodes;
+}
+
+u64 perft2(pos_t *pos, int depth, int ply)
+{
+    int subnodes, nmove = 0;
+    u64 nodes = 0;
+    movelist_t pseudo = { .nmoves = 0 };
+    move_t move;
+    state_t state;
+
+    if (is_in_check(pos, OPPONENT(pos->turn)))
+        return 0;
+    if (depth == 0)
+        return 1;
+    pos->checkers = pos_checkers(pos, pos->turn);
+    pos_set_pinners_blockers(pos);
+    state = pos->state;
+
+    pos_gen_pseudomoves(pos, &pseudo);
+
+    for (nmove = 0; nmove < pseudo.nmoves; ++nmove ) {
+        move = pseudo.move[nmove];
+        move_do(pos, move);
+        //if (!is_in_check(pos, OPPONENT(pos->turn))) {
+        subnodes = perft2(pos, depth - 1, ply + 1);
+        nodes += subnodes;
+        if (ply == 1) {
+            char movestr[8];
+            printf("%s: %d\n", move_str(movestr, move, 0), subnodes);
+        }
+            //}
+        move_undo(pos, move);
+        pos->state = state;
+    }
+    if (ply == 1)
+        printf("\nTotal: %lu\n", nodes);
+    return nodes;
+}

 /**
 * negamax() - search position negamax.
@@ -31,32 +115,34 @@
 *
 * @return: The @pos negamax evaluation.
 */
-eval_t negamax(pos_t *pos, int depth, int color)
-{
-    move_t *move;
-    pos_t *newpos;
-    eval_t best = EVAL_MIN, score;
-
-    pos->node_count++;
-    if (depth == 0) {
-        moves_gen_all_nomoves(pos);
-        score = eval(pos) * color;
-        return score;
-    }
-    moves_gen_all(pos);
-    list_for_each_entry(move, &pos->moves[pos->turn], list) {
-        newpos = move_do(pos, move);
-        score = -negamax(newpos, depth - 1, -color);
-        pos->node_count += newpos->node_count;
-        move->negamax = score;
-        if (score > best) {
-            best = score;
-            pos->bestmove = move;
-        }
-        move_undo(newpos, move);
-    }
-    return best;
-}
+/*
+ * eval_t negamax(pos_t *pos, int depth, int color)
+ * {
+ *     move_t *move;
+ *     pos_t *newpos;
+ *     eval_t best = EVAL_MIN, score;
+ *
+ *     pos->node_count++;
+ *     if (depth == 0) {
+ *         moves_gen_all_nomoves(pos);
+ *         score = eval(pos) * color;
+ *         return score;
+ *     }
+ *     moves_gen_all(pos);
+ *     list_for_each_entry(move, &pos->moves[pos->turn], list) {
+ *         newpos = move_do(pos, move);
+ *         score = -negamax(newpos, depth - 1, -color);
+ *         pos->node_count += newpos->node_count;
+ *         move->negamax = score;
+ *         if (score > best) {
+ *             best = score;
+ *             pos->bestmove = move;
+ *         }
+ *         move_undo(newpos, move);
+ *     }
+ *     return best;
+ * }
+ */


 /**
@@ -74,74 +160,76 @@ eval_t negamax(pos_t *pos, int depth, int color)
 *
 * @return: The @pos PVS evaluation.
 */
-eval_t pvs(pos_t *pos, int depth, int alpha, int beta, int color)
-{
-    move_t *move;
-    pos_t *newpos;
-    eval_t score = EVAL_INVALID;
-    bool firstchild = true;
-
-    pos->node_count++;
-
-    if (depth == 0) {
-        //return quiesce(p, alpha, beta);           /* leaf node */
-        moves_gen_all_nomoves(pos);
-        score = eval(pos) * color;
-        log_f(2, "Terminal: depth=%d ", depth);
-        log_f(2, "score=%d alpha=%d beta=%d\n", score, alpha, beta);
-        return score;
-    }
-
-    moves_gen_all(pos);
-    //moves_print(pos, M_PR_EVAL);
-    /* do the full search for first child */
-    //move = list_first_entry_or_null(&pos->moves[pos->turn], move_t, list);
-
-    list_for_each_entry(move, &pos->moves[pos->turn], list) {
-        newpos = move_do(pos, move);
-        log(2, "%.*s", 5 - depth, "                ");
-        if (firstchild) {                               /* first child */
-            score = -pvs(newpos, depth - 1, -beta, -alpha, -color);
-            log_f(2, "First child depth=%d move=", depth);
-            //move_print(0, move, 0);
-            log(2, "score=%d alpha=%d beta=%d\n", score, alpha, beta);
-            pos->bestmove = move;
-        } else {
-            /* search with a null window */
-            score = -pvs(newpos, depth - 1, -alpha - 1, -alpha, -color);
-            log_f(2, "Other child depth=%d move=", depth);
-            //move_print(0, move, 0);
-            log_f(2, "score=%d alpha=%d beta=%d ", score, alpha, beta);
-            /* for fail-soft:  if (score > alpha && score < beta) */
-            if (score > alpha) {
-                /* if failed high, do a full re-search */
-                log_f(2, "doing full search.");
-                score = -pvs(newpos, depth - 1, -beta, -alpha, -color);
-            }
-            log(2, "\n");
-        }
-        pos->node_count += newpos->node_count;
-        move_undo(newpos, move);
-        if (score >= beta) {                      /* fail-hard hard beta cut-off */
-            log(2, "%.*s", 5 - depth, "                ");
-            log_f(2, "depth=%d score=%d alpha=%d beta=%d beta cut-off.\n",
-                  depth, score, alpha, beta);
-            return beta;
-        }
-        if (score > alpha) {
-            log(2, "%.*s", 5 - depth, "                ");
-            log_f(2, "depth=%d setting new alpha from %d to %d\n",
-                  depth, alpha, score);
-            alpha = score;
-            pos->bestmove = move;
-        }
-        move->pos = NULL;
-        move->negamax = score;
-        firstchild = false;
-    }
-
-    return alpha;
-}
+/*
+ * eval_t pvs(pos_t *pos, int depth, int alpha, int beta, int color)
+ * {
+ *     move_t *move;
+ *     pos_t *newpos;
+ *     eval_t score = EVAL_INVALID;
+ *     bool firstchild = true;
+ *
+ *     pos->node_count++;
+ *
+ *     if (depth == 0) {
+ *         //return quiesce(p, alpha, beta);           /\* leaf node *\/
+ *         moves_gen_all_nomoves(pos);
+ *         score = eval(pos) * color;
+ *         log_f(2, "Terminal: depth=%d ", depth);
+ *         log_f(2, "score=%d alpha=%d beta=%d\n", score, alpha, beta);
+ *         return score;
+ *     }
+ *
+ *     moves_gen_all(pos);
+ *     //moves_print(pos, M_PR_EVAL);
+ *     /\* do the full search for first child *\/
+ *     //move = list_first_entry_or_null(&pos->moves[pos->turn], move_t, list);
+ *
+ *     list_for_each_entry(move, &pos->moves[pos->turn], list) {
+ *         newpos = move_do(pos, move);
+ *         log(2, "%.*s", 5 - depth, "                ");
+ *         if (firstchild) {                               /\* first child *\/
+ *             score = -pvs(newpos, depth - 1, -beta, -alpha, -color);
+ *             log_f(2, "First child depth=%d move=", depth);
+ *             //move_print(0, move, 0);
+ *             log(2, "score=%d alpha=%d beta=%d\n", score, alpha, beta);
+ *             pos->bestmove = move;
+ *         } else {
+ *             /\* search with a null window *\/
+ *             score = -pvs(newpos, depth - 1, -alpha - 1, -alpha, -color);
+ *             log_f(2, "Other child depth=%d move=", depth);
+ *             //move_print(0, move, 0);
+ *             log_f(2, "score=%d alpha=%d beta=%d ", score, alpha, beta);
+ *             /\* for fail-soft:  if (score > alpha && score < beta) *\/
+ *             if (score > alpha) {
+ *                 /\* if failed high, do a full re-search *\/
+ *                 log_f(2, "doing full search.");
+ *                 score = -pvs(newpos, depth - 1, -beta, -alpha, -color);
+ *             }
+ *             log(2, "\n");
+ *         }
+ *         pos->node_count += newpos->node_count;
+ *         move_undo(newpos, move);
+ *         if (score >= beta) {                      /\* fail-hard hard beta cut-off *\/
+ *             log(2, "%.*s", 5 - depth, "                ");
+ *             log_f(2, "depth=%d score=%d alpha=%d beta=%d beta cut-off.\n",
+ *                   depth, score, alpha, beta);
+ *             return beta;
+ *         }
+ *         if (score > alpha) {
+ *             log(2, "%.*s", 5 - depth, "                ");
+ *             log_f(2, "depth=%d setting new alpha from %d to %d\n",
+ *                   depth, alpha, score);
+ *             alpha = score;
+ *             pos->bestmove = move;
+ *         }
+ *         move->pos = NULL;
+ *         move->negamax = score;
+ *         firstchild = false;
+ *     }
+ *
+ *     return alpha;
+ * }
+ */

 /*
 * int negascout (pos_t *pos, int depth, int alpha, int beta )
--- a/src/search.h
+++ b/src/search.h
@@ -1,6 +1,6 @@
 /* search.h - search for perfect move.
 *
- * 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.
 *
@@ -16,7 +16,10 @@

 #include "position.h"

-eval_t negamax(pos_t *pos, int depth, int color);
-eval_t pvs(pos_t *pos, int depth, int alpha, int beta, int color);
+//eval_t negamax(pos_t *pos, int depth, int color);
+//eval_t pvs(pos_t *pos, int depth, int alpha, int beta, int color);
+
+u64 perft(pos_t *pos, int depth, int ply);
+u64 perft2(pos_t *pos, int depth, int ply);

 #endif  /* SEARCH_H */
--- a/test/common-test.h
+++ b/test/common-test.h
@@ -14,19 +14,23 @@
 #include <stdio.h>
 #include "chessdefs.h"
 /* when below FENs are in a struct with selection per test */
-#define NOTEST   0
-#define FEN      1
-#define BITBOARD 2
-#define MOVEGEN  4
-#define ATTACK   8
+#define NOTEST      0
+#define FEN         1
+#define BITBOARD    2
+#define MOVEGEN     4
+#define ATTACK      8
+#define MOVEDO     16
+#define PERFT      32

 struct fentest {
+    int line;
    uint modules;
    char *comment;
    char *fen;
 } fentest[] = {
    /*
-    { ATTACK,
+    { __LINE__.
+      ATTACK,
      "checkers: ",
      ""
    },
@@ -35,144 +39,177 @@ struct fentest {
     */
    //"4k3/pppppppp/8/8/8/8/PPPPPPPP/2BRK3 w - - 0 1",
    //"4k3/pppppppp/8/8/8/8/PPPPPPPP/1B1R1K2 w - - 0 1",
-    { MOVEGEN,
-      "illegal white e.p.",
-      "3k4/8/8/2qpPK2/8/8/8/8 w - d6 0 1",
-    },
-    { MOVEGEN,
-      "illegal black e.p.",
-      "8/8/8/8/2QPpk2/8/8/3K4 b - d3 0 1",
-    },
-
-    { MOVEGEN,
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
      "illegal white e.p.",
      "3k4/8/5K2/3pP3/8/2b5/8/8 w - d6 0 1",
    },
-    { MOVEGEN,
+    { __LINE__, PERFT,
+      "only K, pawn push and ep moves",
+      "3k4/8/8/3pPK2/8/8/8/8 w - d6 0 1"
+    },
+
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
+      "illegal white e.p.",
+      "3k4/8/8/2qpPK2/8/8/8/8 w - d6 0 1",
+    },
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
+      "illegal black e.p.",
+      "8/8/8/8/2QPpk2/8/8/3K4 b - d3 0 1",
+    },
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
      "illegal black e.p.",
      "8/8/2B5/8/3Pp3/5k2/8/3K4 b - d3 0 1",
    },

-    { MOVEGEN,
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
      "legal white e.p.",
      "1K1k4/8/8/3pP3/8/6b1/8/8 w - d6 0 1",
    },
-    { MOVEGEN,
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
      "legal black e.p.",
      "8/8/6B1/8/3Pp3/8/8/1k1K4 b - d3 0 1",
    },
-
-    { MOVEGEN,
-      "white mate.",
-      "1nbqkbn1/ppp1pppp/8/r1rpP1K1/8/8/PPPP1PPP/RNBQ1BNR w - d6 0 1",
-    },
-    { MOVEGEN,
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
      "illegal e.p.",
      "1nbqkbn1/ppp1pppp/8/r1rpP1K1/8/8/PPPP1PPP/RNBQ1BNR w - d6 0 1",
    },
-    { ATTACK,
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
+      "illegal e.p. bug perft at depth 4",
+      "1nbqkbn1/ppp2ppp/4p3/r1rpP3/6K1/P7/1PPP1PPP/RNBQ1BNR b - - 1 2"
+    },
+    /*
+     * { __LINE__, MOVEGEN | MOVEDO | PERFT,
+     *   "illegal e.p. bug perft depth 3",
+     *   "1nbqkbn1/ppp2ppp/4p3/2rpP3/r5K1/P7/1PPP1PPP/RNBQ1BNR w - - 2 3"
+     * },
+     * { __LINE__, MOVEGEN | MOVEDO | PERFT,
+     *   "illegal e.p. bug perft depth 2",
+     *   "1nbqkbn1/ppp2ppp/4p3/2rpP3/r4PK1/P7/1PPP2PP/RNBQ1BNR b - - 0 3"
+     * },
+     * { __LINE__, MOVEGEN | MOVEDO | PERFT | PERFT,
+     *   "illegal e.p. bug perft depth 1 - fixed",
+     *   "1nb1kbn1/ppp2ppp/4p3/2rpP1q1/r4PK1/P7/1PPP2PP/RNBQ1BNR w - - 1 4"
+     * },
+     */
+    { __LINE__, ATTACK,
      "checkers: a1 h1",
      "1k6/8/8/8/8/8/8/r2K3r w - - 1 1"
    },
-    { ATTACK,
+    { __LINE__, ATTACK,
      "checkers: a8 h8",
      "R2k3R/8/8/8/8/8/8/1K6 b - - 1 1"
    },
-    { ATTACK,
+    { __LINE__, ATTACK,
      "checkers: b3 g3",
      "1k6/8/8/8/8/1r1K2r1/8/8 w - - 1 1"
    },

-    { ATTACK,
+    { __LINE__, ATTACK,
      "checkers: b6 g6",
      "8/8/1R1k2R1/8/8/8/8/1K6 b - - 1 1"
    },

-    { ATTACK,
+    { __LINE__, ATTACK,
      "checkers: g2 g7",
      "8/k5r1/8/8/6K1/8/6r1/8 w - - 1 1"
    },
-    { ATTACK,
+    { __LINE__, ATTACK,
      "checkers: g2 g7",
      "8/6R1/8/6k1/8/8/K5R1/8 b - - 1 1"
    },
-    { ATTACK,
+    { __LINE__, ATTACK,
      "checkers: d5 e3, pinners: none (2 pieces between attacker & K)",
      "3k4/8/8/3r3b/b7/1N2nn2/2n1B3/rNBK1Rbr w - - 1 1"
    },

-    { ATTACK,
+    { __LINE__, ATTACK,
      "checkers: d4 e6 pinners: h4 a5 a8 h8",
      "Rn1k1r1R/4b3/1n2N3/B7/3R3B/8/8/3K4 b - - 1 1"
    },
-    { ATTACK,
+    { __LINE__, ATTACK,
      "checkers: d5 e3, pinners: a1 h1 a4 h5",
      "3k4/8/8/3r3b/b7/1N2n3/4B3/rN1K1R1r w - - 1 0"
    },

-    { MOVEGEN,
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
      "only pawn captures",
      "4k3/8/2p1p3/2PpP3/8/pp4pp/PP4PP/4K3 w - d6 0 1"
    },

-    { FEN | ATTACK,
+    { __LINE__, FEN | ATTACK,
      "checker: h4",
      "4k3/8/8/8/7b/8/8/4K3 w - - 0 1"
    },
 // First game moves
-    { FEN | MOVEGEN,
-      "initial pos",
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "startpos",
      "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
    },
-    { FEN | MOVEGEN,
+    //{ __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+    //  "1.e3 - perft bug",
+    //  "rnbqkbnr/pppppppp/8/8/8/4P3/PPPP1PPP/RNBQKBNR b KQkq - 0 1"
+    //},
+    //{ __LINE__, FEN | MOVEGEN | MOVEDO | PERFT | PERFT,
+    //  "1.e3 Nc6 - perft bug",
+    //  "r1bqkbnr/pppppppp/2n5/8/8/4P3/PPPP1PPP/RNBQKBNR w KQkq - 1 2"
+    //},
+    //{ __LINE__, FEN | MOVEGEN | MOVEDO | PERFT | PERFT,
+    //  "1.e3 Nc6 2.Ke2 - perft bug",
+    //  "r1bqkbnr/pppppppp/2n5/8/8/4P3/PPPPKPPP/RNBQ1BNR b kq - 2 2"
+    //},
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "1.e3 Nc6 2.Ke2 Nd4+ - perft bug",
+      "r1bqkbnr/pppppppp/8/8/3n4/4P3/PPPPKPPP/RNBQ1BNR w kq - 3 3"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "1.e4",
      "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "1.Nh3",
      "rnbqkbnr/pppppppp/8/8/8/7N/PPPPPPPP/RNBQKB1R b KQkq - 1 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "1.e4 e5 2.Nf3 Nc6",
      "r1bqkbnr/pp1ppppp/2n5/2p5/4P3/5N2/PPPP1PPP/RNBQKB1R w KQkq - 0 1"
    },

    // castling test
    // both can castle queen only
-    { FEN | MOVEGEN,
-      "",
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "no Q castling",
      "r3k2r/8/3B4/8/8/3b4/8/R3K2R w KQkq - 0 1"
    },
-    { FEN | MOVEGEN,
-      "",
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "no castling, 2 mates in 1",
      "r3k2r/8/3BB3/8/8/3bb3/8/R3K2R w KQkq - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "r2bkb1r/8/8/8/8/3bb3/8/R2BKB1R w KQkq - 0 1"
    },
    //
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "4 castle possible, only K+R",
      "r3k2r/8/8/8/8/8/8/R3K2R w KQkq - 0 1"
    },
    //
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "only kings on A1/A8, white to play",
      "k7/8/8/8/8/8/8/K7 w - - 0 1"
    },
    //
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "only one move possible (Pf2xBg3)",
      "k7/8/8/1p1p4/pPpPp3/P1PpPpb1/NBNP1P2/KBB1B3 w - - 0 1"
    },
    //
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "only 2 moves possible (Ph5xg6 e.p., Ph5-h6)",
      "k7/8/8/1p1p2pP/pPpPp3/P1PpPp2/NBNP1P2/KBB1B3 w - g6 0 1"
    },
    //
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "2 Kings, W/B/ pawns on 7th for promotion",
      "k4n2/4P3/8/8/8/8/4p3/K4N2 w - - 0 1"
    },
@@ -180,20 +217,20 @@ struct fentest {
    // white is a pawn down
    // white has 36 moves: P=11 + 1 e.p. N=6+3 B=5+5 R=1 Q=3 K=1 + 1 e.p.
    // black has 33 moves: P=11 N=2+7 B=5 R=3 Q=3 K=1 + castle
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "rnbqk2r/pp1pbpp1/7p/2pPp3/4n3/3B1N2/PPP2PPP/RNBQ1RK1 w kq c6 0 7"
    },

-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "4k3/4p3/8/b7/1BR1p2p/1Q3P2/5N2/4K3 w - - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "r1bq1rk1/pppp1ppp/2n2n2/4p3/2B1P3/3PPN2/PPP3PP/RN1QK2R b KQ - 1 7"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "6k1/6pp/R2p4/p1p5/8/1P1r3P/6P1/6K1 b - - 3 3"
    },
@@ -201,186 +238,202 @@ struct fentest {
    // some of tests below are from:
    // - Rodent IV
    // - https://www.chessprogramming.net/perfect-perft/
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "8/2p5/3p4/Kp5r/1R3p1k/8/4P1P1/8 w - - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "4rrk1/pp1n3p/3q2pQ/2p1pb2/2PP4/2P3N1/P2B2PP/4RRK1 b - - 7 19"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "rq3rk1/ppp2ppp/1bnpb3/3N2B1/3NP3/7P/PPPQ1PP1/2KR3R w - - 7 14"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "r1bq1r1k/1pp1n1pp/1p1p4/4p2Q/4Pp2/1BNP4/PPP2PPP/3R1RK1 w - - 2 14"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "r3r1k1/2p2ppp/p1p1bn2/8/1q2P3/2NPQN2/PPP3PP/R4RK1 b - - 2 15"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "1rbqk1nr/p3ppbp/2np2p1/2p5/1p2PP2/3PB1P1/PPPQ2BP/R2NK1NR b KQk - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "r1bqk2r/pp1p1ppp/2n1pn2/2p5/1bPP4/2NBP3/PP2NPPP/R1BQK2R b KQkq - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "rnb1kb1r/ppp2ppp/1q2p3/4P3/2P1Q3/5N2/PP1P1PPP/R1B1KB1R b KQkq - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "r1b2rk1/pp2nppp/1b2p3/3p4/3N1P2/2P2NP1/PP3PBP/R3R1K1 b - - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "n1q1r1k1/3b3n/p2p1bp1/P1pPp2p/2P1P3/2NBB2P/3Q1PK1/1R4N1 b - - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "r1bq1r1k/b1p1npp1/p2p3p/1p6/3PP3/1B2NN2/PP3PPP/R2Q1RK1 w - - 1 16"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "3r1rk1/p5pp/bpp1pp2/8/q1PP1P2/b3P3/P2NQRPP/1R2B1K1 b - - 6 22"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "r1q2rk1/2p1bppp/2Pp4/p6b/Q1PNp3/4B3/PP1R1PPP/2K4R w - - 2 18"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "4k2r/1pb2ppp/1p2p3/1R1p4/3P4/2r1PN2/P4PPP/1R4K1 b - - 3 22"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "3q2k1/pb3p1p/4pbp1/2r5/PpN2N2/1P2P2P/5PP1/Q2R2K1 b - - 4 26"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "2r5/8/1n6/1P1p1pkp/p2P4/R1P1PKP1/8/1R6 w - - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "r2q1rk1/1b1nbppp/4p3/3pP3/p1pP4/PpP2N1P/1P3PP1/R1BQRNK1 b - - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "6k1/5pp1/7p/p1p2n1P/P4N2/6P1/1P3P1K/8 w - - 0 35"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "r4rk1/1pp1q1pp/p2p4/3Pn3/1PP1Pp2/P7/3QB1PP/2R2RK1 b - - 0 1"
    },

-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "r3k2r/Pppp1ppp/1b3nbN/nP6/BBP1P3/q4N2/Pp1P2PP/R2Q1RK1 w kq - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "",
      "1k6/1b6/8/8/7R/8/8/4K2R b K - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "Illegal ep move #1",
      "3k4/3p4/8/K1P4r/8/8/8/8 b - - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "Illegal ep move #2",
      "8/8/4k3/8/2p5/8/B2P2K1/8 w - - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "EP Capture Checks Opponent",
      "8/8/1k6/2b5/2pP4/8/5K2/8 b - d3 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "Short Castling Gives Check",
      "5k2/8/8/8/8/8/8/4K2R w K - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "Long Castling Gives Check",
      "3k4/8/8/8/8/8/8/R3K3 w Q - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "Castle Rights",
      "r3k2r/1b4bq/8/8/8/8/7B/R3K2R w KQkq - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "Castling Prevented",
      "r3k2r/8/3Q4/8/8/5q2/8/R3K2R b KQkq - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "Promote out of Check",
      "2K2r2/4P3/8/8/8/8/8/3k4 w - - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "Discovered Check",
      "8/8/1P2K3/8/2n5/1q6/8/5k2 b - - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "Promote to give check",
      "4k3/1P6/8/8/8/8/K7/8 w - - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "Under Promote to give check",
      "8/P1k5/K7/8/8/8/8/8 w - - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "Self Stalemate",
      "K1k5/8/P7/8/8/8/8/8 w - - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "Stalemate & Checkmate",
      "8/k1P5/8/1K6/8/8/8/8 w - - 0 1"
    },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
      "Stalemate & Checkmate",
      "8/8/2k5/5q2/5n2/8/5K2/8 b - - 0 1"
    },
-
-    { FEN,
+    { __LINE__, MOVEDO | PERFT,
+      "simple movedo/undo: only 2 W knights",
+      "8/1k6/8/8/8/8/6K1/1NN5 w - - 0 1"
+    },
+    { __LINE__, MOVEDO | PERFT,
+      "simple movedo/undo: only 2 W knights",
+      "8/1k6/8/8/8/8/6K1/1NN5 w - - 0 1"
+    },
+    { __LINE__, MOVEDO | PERFT,
+      "simple movedo/undo: only 2 W knights",
+      "5n2/1k6/8/8/5K2/8/P7/1N6 w - - 0 1"
+    },
+    { __LINE__, FEN,
      "illegal EP and castle flags, fix-able by fen parser, SF crash",
      "4k3/8/8/8/7B/8/8/4K3 w KQkq e6 0 1"
    },
-    { FEN,
+    { __LINE__, FEN,
      "illegal, SF crash",
      "4k3/8/8/8/7b/8/8/4K3 b - - 0 1"
    },
-    { FEN,
+    { __LINE__, FEN,
      "illegal, SF crash",
      "2r1k3/3B4/8/8/8/8/8/4K3 w - - 0 1"
    },
-    { FEN,
+    { __LINE__, FEN,
      "illegal, SF crash",
      "2r1k3/3P4/8/8/8/8/8/4K3 w - - 0 1"
    },
-
-    { 0, NULL, NULL }
+    { __LINE__, 0, NULL, NULL }
 };

-static int cur = 0;
+static int cur = -1;

 static char *next_fen(uint module)
 {
+    cur++;
    while (fentest[cur].fen && !(fentest[cur].modules & module))
        cur++;
-    return fentest[cur].fen ? fentest[cur++].fen: NULL;
+    return fentest[cur].fen;
 }

 static __unused char* cur_comment()
 {
    return fentest[cur].comment;
 }
+
+static __unused int cur_line()
+{
+    return fentest[cur].line;
+}
--- a/test/movedo-test.c
+++ b/test/movedo-test.c
@@ -0,0 +1,93 @@
+/* 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 = 0, test_line;
+    char *fen, movebuf[8];;
+    pos_t *pos, *savepos;
+    movelist_t pseudo;
+    move_t move;
+
+    setlinebuf(stdout);                           /* line-buffered stdout */
+
+    bitboard_init();
+    hyperbola_init();
+
+    while ((fen = next_fen(MOVEDO))) {
+        test_line = cur_line();
+        if (!(pos = fen2pos(NULL, fen))) {
+            printf("wrong fen %d: [%s]\n", i, fen);
+            continue;
+        }
+
+        pos->checkers = pos_checkers(pos, pos->turn);
+        pos_set_pinners_blockers(pos);
+
+        pos_gen_pseudomoves(pos, &pseudo);
+        savepos = pos_dup(pos);
+
+        state_t state = pos->state;
+        int tmp = 0, j = 0;
+        while ((move = pos_next_legal(pos, &pseudo, &tmp)) != MOVE_NONE) {
+            //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);
+            //pos_print(pos);
+            //fflush(stdout);
+            if (!pos_ok(pos, false)) {
+                printf("*** fen %d move %d [%s] invalid position after move_do\n",
+                       test_line, j, movebuf);
+                exit(0);
+            }
+
+            //printf("%d/%d move_do check ok\n", i, j);
+            move_undo(pos, move);
+            pos->state = state;
+            if (!pos_ok(pos, false)) {
+                printf("*** fen %d move %d [%s] invalid position after move_undo\n",
+                       test_line, j, movebuf);
+                exit(0);
+            }
+            if (pos_cmp(pos, savepos) != true) {
+                printf("*** fen %d move %d [%s] position differ after move_{do,undo}\n",
+                       test_line, j, movebuf);
+                exit(0);
+            }
+            //fflush(stdout);
+            //pos_check(pos, true);
+            //printf("%d/%d move_undo check ok\n", i, j);
+            j++;
+        }
+        printf("fen %d line=%d [%s] %d move_{do,undo} OK\n", i, test_line, fen, j);
+        pos_del(savepos);
+        pos_del(pos);
+        i++;
+    }
+    return 0;
+}
--- a/test/movegen-test.c
+++ b/test/movegen-test.c
@@ -76,7 +76,7 @@ static FILE *open_stockfish()
    return out_desc;
 }

-static void send_stockfish_fen(FILE *desc, pos_t *pos, char *fen)
+static void send_stockfish_fen(FILE *desc, pos_t *pos, movelist_t *movelist, char *fen)
 {
    char *buf = NULL;
    int count, __unused mycount = 0, fishcount;
@@ -85,8 +85,9 @@ static void send_stockfish_fen(FILE *desc, pos_t *pos, char *fen)

    pos_clear(pos);

-    move_t *moves = pos->moves.move;
-    int nmoves = pos->moves.nmoves;
+    move_t *moves = movelist->move;
+    int *nmoves = &movelist->nmoves;
+    *nmoves = 0;
    //char nodescount[] = "Nodes searched";
    //printf("nmoves = %d\n", nmoves);
    fflush(stdout);
@@ -109,7 +110,7 @@ static void send_stockfish_fen(FILE *desc, pos_t *pos, char *fen)
            //       buf[0], buf[1], buf[2], buf[3],
            //       sq_to_string(from), sq_to_string(to),
            //       count);
-            moves[nmoves++] = move_make(from, to);
+            moves[(*nmoves)++] = move_make(from, to);

        } else if (sscanf(buf, "%*5s: %d", &count) == 1) {
            square_t from = sq_from_string(buf);
@@ -120,10 +121,10 @@ static void send_stockfish_fen(FILE *desc, pos_t *pos, char *fen)
            //       buf[0], buf[1], buf[2], buf[3],
            //       sq_to_string(from), sq_to_string(to),
            //       count);
-            moves[nmoves++] = move_make_promote(from, to, promoted);
+            moves[(*nmoves)++] = move_make_promote(from, to, promoted);
        }
    }
-    pos->moves.nmoves = nmoves;
+    //pos->moves.nmoves = nmoves;
    // printf("fishcount=%d mycount=%d\n", fishcount, mycount);
    free(buf);
 }
@@ -215,7 +216,7 @@ int main(int __unused ac, __unused char**av)
    FILE *outfd;
    char *fen;
    pos_t *pos, *fishpos = pos_new();
-    movelist_t legal;
+    movelist_t pseudo, legal, fishmoves;
    //bitboard_t wrong = 0x5088000040, tmp, loop;
    //bit_for_each64(loop, tmp, )
    //printf("fishpos 1=%p\n", fishpos);
@@ -235,9 +236,12 @@ int main(int __unused ac, __unused char**av)
            continue;
        }
        /* print movelists */
-        send_stockfish_fen(outfd, fishpos, fen);
-        pos_gen_pseudomoves(pos);
-        pos_all_legal(pos, &legal);
+        send_stockfish_fen(outfd, fishpos, &fishmoves, fen);
+        pos_gen_pseudomoves(pos, &pseudo);
+        //moves_print(&pseudo, 0);
+        pos_all_legal(pos, &pseudo, &legal);
+
+        //moves_print(&legal, 0);
        //printf("Fu ");
        //moves_print(fishpos, 0);
        //fflush(stdout);
@@ -246,7 +250,7 @@ int main(int __unused ac, __unused char**av)
        //fflush(stdout);

        /* sort and print movelists */
-        move_sort_by_sq(&fishpos->moves);
+        move_sort_by_sq(&fishmoves);
        move_sort_by_sq(&legal);
        // printf("\nFs ");
        // moves_print(fishpos, 0);
@@ -256,15 +260,15 @@ int main(int __unused ac, __unused char**av)
        // fflush(stdout);

        /* compare movelists */
-        if (!movelists_equal(&fishpos->moves, &legal)) {
+        if (!movelists_equal(&fishmoves, &legal)) {
            pos_print(pos);
            printf("F: ");
-            moves_print(&fishpos->moves, 0);
+            moves_print(&fishmoves, 0);
            printf("M: ");
            moves_print(&legal, 0);
        } else {
-            printf("[%s]\n\tMoves (OK): ", fen);
-            moves_print(&fishpos->moves, 0);
+            printf("[%s]: OK (%d Moves)\n", fen, legal.nmoves);
+            //moves_print(&fishpos->moves, 0);
        }
        //compare_moves(&fishpos->moves, &legal);
            //} else {
--- a/test/perft-test.c
+++ b/test/perft-test.c
@@ -0,0 +1,303 @@
+/* perft-test.c - perft test.
+ *
+ * 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 <time.h>
+#include <locale.h>
+
+#include "chessdefs.h"
+#include "fen.h"
+#include "position.h"
+#include "move.h"
+#include "move-do.h"
+#include "move-gen.h"
+#include "search.h"
+
+#include "common-test.h"
+
+#define RD 0
+#define WR 1
+
+typedef struct {
+    move_t move;
+    int count;
+} ddperft;
+
+/**
+ * return write pipd fd
+ */
+static FILE *open_stockfish()
+{
+    int rpipe[2], wpipe[2];
+    FILE *out_desc;
+    pid_t pid;
+
+    if ((pipe(rpipe) < 0) || (pipe(wpipe) < 0)) {
+        perror("pipe");
+        return NULL;
+    }
+    if ((pid = fork()) < 0) {
+        perror("fork");
+        return NULL;
+    }
+
+    if (!pid) {                                   /* stockfish */
+        setvbuf(stdin,  NULL, _IOLBF, 0);
+        setvbuf(stdout, NULL, _IOLBF, 0);
+        setvbuf(stderr, NULL, _IOLBF, 0);
+
+        dup2(wpipe[RD], STDIN_FILENO);
+        dup2(rpipe[WR], STDOUT_FILENO);
+        dup2(rpipe[WR], STDERR_FILENO);
+
+        close(wpipe[RD]);
+        close(wpipe[WR]);
+        close(rpipe[RD]);
+        close(rpipe[WR]);
+        if (execlp("stockfish", "stockfish", NULL) == -1) {
+            perror("execlp");
+            return NULL;
+        }
+        return 0;                                 /* not reached */
+    }
+    /* us */
+    dup2(rpipe[RD], STDIN_FILENO);
+    setvbuf(stdin, NULL, _IOLBF, 0);
+
+    close(wpipe[RD]);
+    close(rpipe[RD]);
+    close(rpipe[WR]);
+
+    out_desc = fdopen(wpipe[WR], "w");
+    setvbuf(out_desc, NULL, _IOLBF, 0);
+
+    return out_desc;
+}
+
+static u64 send_stockfish_fen(FILE *desc, pos_t *pos, movelist_t *movelist,
+                               char *fen, int depth)
+{
+    char *buf = NULL;
+    u64 count, mycount = 0, fishcount;
+    size_t alloc = 0;
+    ssize_t buflen;
+
+    pos_clear(pos);
+
+    move_t *moves = movelist->move;
+    int *nmoves = &movelist->nmoves;
+    *nmoves = 0;
+    //char nodescount[] = "Nodes searched";
+    //printf("nmoves = %d\n", nmoves);
+    fflush(stdout);
+    //sprintf(str, "stockfish \"position fen %s\ngo perft depth\n\"", fen);
+    fprintf(desc, "position fen %s\ngo perft %d\n", fen, depth);
+    //fflush(desc);
+    while ((buflen = getline(&buf, &alloc, stdin)) > 0) {
+        buf[--buflen] = 0;
+        if (buflen == 0)
+            continue;
+        if (sscanf(buf, "Nodes searched: %lu", &fishcount) == 1) {
+            break;
+        }
+        //printf("%d: %s\n", line++, buf);
+        if (sscanf(buf, "%*4s: %lu", &count) == 1) {
+            square_t from = sq_from_string(buf);
+            square_t to   = sq_from_string(buf + 2);
+            mycount += count;
+            //printf("move found: %c%c->%c%c %s->%s count=%d\n",
+            //       buf[0], buf[1], buf[2], buf[3],
+            //       sq_to_string(from), sq_to_string(to),
+            //       count);
+            moves[(*nmoves)++] = move_make(from, to);
+
+        } else if (sscanf(buf, "%*5s: %lu", &count) == 1) {
+            square_t from = sq_from_string(buf);
+            square_t to   = sq_from_string(buf + 2);
+            piece_type_t promoted = piece_t_from_char(*(buf + 4));
+            mycount += count;
+            //printf("move found: %c%c->%c%c %s->%s count=%d\n",
+            //       buf[0], buf[1], buf[2], buf[3],
+            //       sq_to_string(from), sq_to_string(to),
+            //       count);
+            moves[(*nmoves)++] = move_make_promote(from, to, promoted);
+        }
+    }
+    //pos->moves.nmoves = nmoves;
+    // printf("fishcount=%d mycount=%d\n", fishcount, mycount);
+    free(buf);
+    return mycount;
+}
+
+static __unused bool movelists_equal(movelist_t *fish, movelist_t *me)
+{
+    move_t *m1 = fish->move, *m2 = me->move;
+    int n1 = fish->nmoves, n2 = me->nmoves;
+    int mask = 077777;
+
+    if (n1 != n2)
+        return false;
+    for (int cur = 0; cur < n1; ++cur) {
+        if ((m1[cur] & mask) != (m2[cur] & mask))
+            return false;
+    }
+    return true;
+}
+
+static __unused void compare_moves(movelist_t *fish, movelist_t *me)
+{
+    char str1[1024] = {0}, str2[1024] = {0}, tmpstr[1024];
+    char *skip = "      ";
+    move_t *m1 = fish->move;
+    move_t *m2 = me->move;
+    int n1 = fish->nmoves;
+    int n2 = me->nmoves;
+
+#define f(c) move_from(c)
+#define t(c) move_to(c)
+
+    for (move_t *c1 = m1, *c2 = m2; (c1 - m1 < n1) || (c2 - m2 < n2);) {
+        // square_t f1 = move_from(*c1); square_t t1 = move_to(*c1);
+        // square_t f2 = move_from(*c2); square_t t2 = move_to(*c2);
+
+        /* no more move in c2 */
+        if (c2 - m2 >= n2) {
+            while (c1 - m1 < n1) {
+                sprintf(tmpstr, " %s-%s", sq_to_string(f(*c1)), sq_to_string(t(*c1)));
+                strcat (str1, tmpstr);
+                c1++;
+            }
+            break;
+        }
+        if (c1 - m1 >= n1) {
+            while (c2 - m2 < n2) {
+                sprintf(tmpstr, " %s-%s", sq_to_string(f(*c2)), sq_to_string(t(*c2)));
+                strcat (str2, tmpstr);
+                c2++;
+            }
+            break;
+        }
+
+        /* missing move in c2 */
+        if (f(*c1) < f(*c2) ||
+            (f(*c1) == f(*c2) && t(*c1) < t(*c2))) {
+            strcat(str2, skip);
+            sprintf(tmpstr, " %s-%s", sq_to_string(f(*c1)), sq_to_string(t(*c1)));
+            strcat (str1, tmpstr);
+            while ((c1 - m1 < n1) && (f(*c1) < f(*c2) ||
+                                      (f(*c1) == f(*c2) && t(*c1) < t(*c2)))) {
+                c1++;
+            }
+            continue;
+        }
+        /* missing move in c1 */
+        if (f(*c1) > f(*c2) ||
+            (f(*c1) == f(*c2) && t(*c1) > t(*c2))) {
+            strcat(str1, skip);
+            sprintf(tmpstr, " %s-%s", sq_to_string(f(*c2)), sq_to_string(t(*c2)));
+            strcat (str2, tmpstr);
+            while ((c2 - m2 < n2) && (f(*c1) > f(*c2) ||
+                                      (f(*c1) == f(*c2) && t(*c1) > t(*c2)))) {
+                c2++;
+            }
+            continue;
+        }
+        sprintf(tmpstr, " %s-%s", sq_to_string(f(*c1)), sq_to_string(t(*c1)));
+        strcat(str1, tmpstr);
+        strcat(str2, tmpstr);
+        c1++, c2++;
+    }
+    printf("F(%2d): %s\nM(%2d): %s\n", n1, str1, n2, str2);
+}
+
+
+int main(int __unused ac, __unused char**av)
+{
+    int i = 0, test_line;
+    u64 sf_count, my_count;
+    char *fen;
+    pos_t *pos, *savepos, *fishpos = pos_new();
+    movelist_t fishmoves;
+    //move_t move;
+    FILE *outfd;
+    int depth = 6;
+
+    if (ac > 1)
+        depth = atoi(av[1]);
+    printf("depth = %d\n", depth);
+
+    setlocale(LC_NUMERIC, "");
+    setlinebuf(stdout);                           /* line-buffered stdout */
+    outfd = open_stockfish();
+
+    bitboard_init();
+    hyperbola_init();
+
+    while ((fen = next_fen(PERFT | MOVEDO))) {
+        test_line = cur_line();
+        if (!(pos = fen2pos(NULL, fen))) {
+            printf("wrong fen %d: [%s]\n", i, fen);
+            continue;
+        }
+        sf_count = send_stockfish_fen(outfd, fishpos, &fishmoves, fen, depth);
+        //pos_gen_pseudomoves(pos, &pseudo);
+        savepos = pos_dup(pos);
+        //int j = 0;
+
+#define NANOSEC  1000000000                       /* nano sec in sec */
+#define MILLISEC 1000000                          /* milli sec in sec */
+
+        // 1 sec = 1000 millisec
+        // 1 millisec = 1000 microsec
+        // 1 microsec = 1000 nanosec
+        // milli = sec * 1000 + nanosec / 1000000
+        struct timespec ts1, ts2;
+        s64 microsecs;
+
+        clock_gettime(CLOCK_MONOTONIC_RAW, &ts1);
+        my_count = perft(pos, depth, 1);
+        clock_gettime(CLOCK_MONOTONIC_RAW, &ts2);
+
+        microsecs = ((s64)ts2.tv_sec - (s64)ts1.tv_sec) * 1000000l
+            + ((s64)ts2.tv_nsec - (s64)ts1.tv_nsec) / 1000l ;
+        if (sf_count == my_count) {
+            printf("pt1 OK : line=%03d perft=%lu ms=%'ldms lps=%'lu \"%s\"\n",
+                   test_line, my_count, microsecs/1000l,
+                   my_count*1000000l/microsecs, fen);
+        } else  {
+            printf("pt1 ERR: line=%03d sf=%lu me=%lu \"%s\"\n",
+                   test_line, sf_count, my_count, fen);
+        }
+
+        clock_gettime(CLOCK_MONOTONIC_RAW, &ts1);
+        my_count = perft2(pos, depth, 1);
+        clock_gettime(CLOCK_MONOTONIC_RAW, &ts2);
+
+        microsecs = ((s64)ts2.tv_sec - (s64)ts1.tv_sec) * 1000000l
+            + ((s64)ts2.tv_nsec - (s64)ts1.tv_nsec) / 1000l ;
+        if (sf_count == my_count) {
+            printf("pt2 OK : line=%03d perft=%lu ms=%'ldms lps=%'lu \"%s\"\n\n",
+                   test_line, my_count, microsecs/1000l,
+                   my_count*1000000l/microsecs, fen);
+        } else  {
+            printf("pt2 ERR: line=%03d sf=%lu me=%lu \"%s\"\n\n",
+                   test_line, sf_count, my_count, fen);
+        }
+        pos_del(savepos);
+        pos_del(pos);
+        i++;
+    }
+    return 0;
+}
--- a/util.c
+++ b/util.c
Author	SHA1	Message	Date
Bruno Raoult	26b9a5b58a	brchess func calls changes, always run perft() & perft2()	2024-03-27 12:53:42 +01:00
Bruno Raoult	65fe74c9c5	movegen: don't separate promotions, perft: loop uses next_legal()	2024-03-27 12:52:39 +01:00
Bruno Raoult	9b2f5ff751	move_{do,undo}: do not save/restore pos state	2024-03-27 12:42:45 +01:00
Bruno Raoult	edcc87be5a	a few more perft debug tests	2024-03-27 12:41:38 +01:00
Bruno Raoult	09afd98971	fen2pos: no more pos_checkers etc... position.c: pos_check -> pos_ok (bool)	2024-03-27 12:40:16 +01:00
Bruno Raoult	08ba989170	is_legal: fix check+pinned and knight check; perft-test + perft2()	2024-03-26 17:43:59 +01:00
Bruno Raoult	7637bdad10	attack.c: sq_is_attacked() and is_in_check()	2024-03-26 17:34:11 +01:00
Bruno Raoult	70d6c23c00	position add: pos_set_pinners_blockers()	2024-03-26 17:31:44 +01:00
Bruno Raoult	aaeab03089	revert captured in position before change to move struct	2024-03-23 19:49:35 +01:00
Bruno Raoult	ce2e0e8459	add forgotten changes in bitboard-switch branch (git is so... difficult)	2024-03-23 17:41:15 +01:00
Bruno Raoult	d0279125ae	move_{do,undo}: FIX forgotten king[] update, add few bug_on()	2024-03-23 17:37:40 +01:00
Bruno Raoult	798047b84d	Merge branch 'bitboard-switch'	2024-03-23 17:26:26 +01:00
Bruno Raoult	856e3e52da	add movedo-test	2024-03-21 07:00:20 +01:00
Bruno Raoult	51a348c1e4	add pos_cmp (as a debug check after move_{do,undo})	2024-03-21 06:58:56 +01:00
Bruno Raoult	51c35e21f4	castling: lowercase macros, nove-{do,undo}: full (untested) version	2024-03-20 10:00:07 +01:00
Bruno Raoult	3a06407d5a	move: exclusive M_CAPTURE / M_EN_PASSANT	2024-03-20 09:58:42 +01:00
Bruno Raoult	ae6328ce26	position: add captured piece	2024-03-20 09:57:10 +01:00
Bruno Raoult	08064dd1a1	start bb-based move_do	2024-03-19 18:30:31 +01:00
Bruno Raoult	49705bc707	rename few macros to lowercase, add M_DPUSH move flag	2024-03-19 18:30:10 +01:00
Bruno Raoult	8527c3dee1	movegen: separate all captures (easier later handling)	2024-03-18 10:21:25 +01:00
Bruno Raoult	dc916f5c56	move.h: revert flags to direct bit mask	2024-03-18 09:15:16 +01:00
Bruno Raoult	748953a767	move-gen: separate pawn capture from en-passant (easier later testing)	2024-03-18 09:13:51 +01:00
Bruno Raoult	9c2e76442d	add a struct_group for move_do() irreversible changes	2024-03-17 17:34:21 +01:00
Bruno Raoult	49302c7a60	lowercase move flags macros	2024-03-17 17:33:48 +01:00
Bruno Raoult	db38b507ff	add gmon.out	2024-03-17 17:30:51 +01:00