untabify Makefile, cosmetic change in pos_set_checkers_pinners_blockers()

simplify pos_set_checkers_pinners_blockers() (cont'd)
Makefile: add -ginline-points
2024-04-10 17:12:20 +02:00 · 2024-04-10 15:59:24 +02:00 · 2024-04-10 13:02:23 +02:00 · 2024-04-10 12:57:39 +02:00 · 2024-04-10 12:57:08 +02:00 · 2024-04-10 12:54:47 +02:00
38 changed files with 4397 additions and 1813 deletions
--- a/.dir-locals.el
+++ b/.dir-locals.el
@@ -1,3 +1,3 @@
 ((nil . ((compile-command . (concat "make -C "
                                       (vc-root-dir)
-                                       " -k -j2")))))
+                                       " -k -j2 testing")))))
--- a/.gitignore
+++ b/.gitignore
@@ -4,6 +4,7 @@ vgcore.*
 *.i
 *.old
 *.save
+perf.data
 /GPATH
 /GRTAGS
 /GTAGS
@@ -17,4 +18,5 @@ vgcore.*
 /tmp/
 /notused/
 valgrind.out
+gmon.out
 compile_commands.json
--- a/199
+++ b/199
@@ -1,6 +1,6 @@
-# Makefile - GNU make only.
+# 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.
 #
@@ -12,6 +12,7 @@

 SHELL     := /bin/bash
 CC        := gcc
+#CC        := clang
 LD        := ld
 BEAR      := bear
 TOUCH     := touch
@@ -20,10 +21,11 @@ RMDIR     := rmdir
 MAKE      := make

 SRCDIR    := ./src
-INCDIR    := ./src
+INCDIR    := ./src                                          # used by ./test sources
 OBJDIR    := ./obj
 BINDIR    := ./bin
 DEPDIR    := ./dep
+TSTDIR    := ./test

 BRLIB     := ./brlib
 BRINCDIR  := $(BRLIB)/include
@@ -36,54 +38,97 @@ SRC       := $(wildcard $(SRCDIR)/*.c)                      # project sources
 SRC_FN    := $(notdir $(SRC))                               # source basename
 OBJ       := $(addprefix $(OBJDIR)/,$(SRC_FN:.c=.o))

-LIB       := br_$(shell uname -m)			     # library name
+TSTSRC    := $(wildcard $(TSTDIR)/*.c)

-DEP_FN    := $(SRC_FN) $(LIBSRC_FN)
+LIB       := br_$(shell uname -m)                           # library name
+LIBS      := $(strip -l$(LIB) -lreadline)
+
+DEP_FN    := $(SRC_FN)
 DEP       := $(addprefix $(DEPDIR)/,$(DEP_FN:.c=.d))

 TARGET_FN := brchess
 TARGET    := $(addprefix $(BINDIR)/,$(TARGET_FN))

-LDFLAGS   := -L$(BRLIBDIR)
-LIBS      := $(strip -l$(LIB) -lreadline)
+ASMFILES  := $(SRC:.c=.s) $(TSTSRC:.c=.s)
+CPPFILES  := $(SRC:.c=.i) $(TSTSRC:.c=.i)

 ##################################### pre-processor flags
 CPPFLAGS  := -I$(BRINCDIR) -I$(INCDIR)
-CPPFLAGS  += -DBUG_ON
-CPPFLAGS  += -DWARN_ON
-CPPFLAGS  += -NDEBUG                         #

-#CPPFLAGS  += -DDEBUG                         # global
-CPPFLAGS  += -DDEBUG_DEBUG                   # enable log() functions
-#CPPFLAGS  += -DDEBUG_DEBUG_C                # enable verbose log() settings
-CPPFLAGS  += -DDEBUG_POOL                    # memory pools management
-#CPPFLAGS  += -DDEBUG_FEN                     # FEN decoding
-CPPFLAGS  += -DDEBUG_MOVE                    # move generation
-CPPFLAGS  += -DDEBUG_EVAL                    # eval functions
-CPPFLAGS  += -DDEBUG_PIECE                   # piece list management
-CPPFLAGS  += -DDEBUG_SEARCH                  # move search
+CPPFLAGS  += -DNDEBUG                                       # assert
+CPPFLAGS  += -DBUG_ON                                       # brlib bug.h
+CPPFLAGS  += -DWARN_ON                                      # brlib bug.h
+
+#CPPFLAGS  += -DDEBUG                                        # global - unused
+#CPPFLAGS  += -DDEBUG_DEBUG                                  # enable log() functions
+#CPPFLAGS  += -DDEBUG_DEBUG_C                                # enable log() settings
+#CPPFLAGS  += -DDEBUG_POOL                                   # memory pools management
+#CPPFLAGS  += -DDEBUG_POS                                    # position.c
+#CPPFLAGS  += -DDEBUG_MOVE                                   # move generation
+
+# fen.c
+#CPPFLAGS  += -DDEBUG_FEN                                    # FEN decoding
+
+# attack.c
+#CPPFLAGS  += -DDEBUG_ATTACK_ATTACKERS1                      # sq_attackers details
+CPPFLAGS  += -DDEBUG_ATTACK_ATTACKERS                       # sq_attackers
+CPPFLAGS  += -DDEBUG_ATTACK_PINNERS                         # sq_pinners details
+
+#CPPFLAGS  += -DDEBUG_EVAL                                   # eval functions
+#CPPFLAGS  += -DDEBUG_PIECE                                  # piece list management
+#CPPFLAGS  += -DDEBUG_SEARCH                                 # move search
+
+CPPFLAGS  += -DDIAGRAM_SYM                                  # diagram with symbols

 # remove extraneous spaces (due to spaces before comments)
 CPPFLAGS  := $(strip $(CPPFLAGS))

 ##################################### compiler flags
 CFLAGS    := -std=gnu11
-CFLAGS    += -O3
-CFLAGS    += -g
+
+### dev OR release
+
+# dev
+# CFLAGS    += -O1
+CFLAGS    += -g                                             # symbols (gdb, perf, etc.)
+CFLAGS    += -ginline-points                                # inlined funcs debug info
+# for gprof
+#CFLAGS += -pg
+# Next one may be useful for valgrind (when invalid instructions)
+#CFLAGS += -mno-tbm
+
+# release
+CFLAGS    += -Ofast
+
+CFLAGS    += -march=native
+CFLAGS    += -flto
 CFLAGS    += -Wall
 CFLAGS    += -Wextra
-CFLAGS    += -march=native
 CFLAGS    += -Wmissing-declarations
-# for gprof
-# 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   := --static
+LDFLAGS   += -L$(BRLIBDIR)
+LDFLAGS   += -flto
+
+LDFLAGS   := $(strip $(LDFLAGS))
+
 ##################################### archiver/dependency flags
 ARFLAGS   := rcs
-DEPFLAGS  = -MMD -MP -MF $(DEPDIR)/$*.d
+DEPFLAGS   = -MMD -MP -MF $(DEPDIR)/$*.d
+
+##################################### archiver/dependency flags
+ALL_CFLAGS  = $(DEPFLAGS) $(CPPFLAGS) $(CFLAGS)
+ALL_LDFLAGS = $(LDFLAGS) $(LIBS)

 ##################################### General targets
 .PHONY: all compile clean cleanall
@@ -94,15 +139,14 @@ compile: brlib objs

 libs: brlib

-clean: cleandep cleanobj cleanbin
+clean: cleandep cleanasmcpp cleanobj cleanbin

 cleanall: clean cleandepdir cleanobjdir cleanallbrlib cleanbindir

 ##################################### cleaning functions
-# rmfiles - deletes a list of files in a directory if they exist.
+# rmfiles - delete a list of files if they exist.
 # $(1): the directory
-# $(2): the list of files to delete
-# $(3): The string to include in action output - "cleaning X files."
+# $(2): The string to include in action output - "cleaning X files."
 # see: https://stackoverflow.com/questions/6783243/functions-in-makefiles
 #
 # Don't use wildcard like "$(DIR)/*.o", so we can control mismatches between
@@ -118,7 +162,7 @@ define rmfiles
 	fi
 endef

-# rmdir - deletes a directory if it exists.
+# rmdir - delete a directory if it exists.
 # $(1): the directory
 # $(2): The string to include in action output - "removing X dir."
 #
@@ -179,19 +223,18 @@ cleanobjdir: cleanobj
 # "normal" ones, but do not imply to rebuild target.
 $(OBJDIR)/%.o: $(SRCDIR)/%.c | $(OBJDIR) $(DEPDIR)
 	@echo compiling brchess module: $< "->" $@.
-	@$(CC) -c $(DEPFLAGS) $(CPPFLAGS) $(CFLAGS) $< -o $@
+	@$(CC) -c $(ALL_CFLAGS) $< -o $@

 ##################################### brlib libraries
-.PHONY: cleanbrlib cleanallbrlib libs brlib
+.PHONY: cleanbrlib cleanallbrlib brlib

 cleanbrlib:
 	$(MAKE) -C $(BRLIB) clean
-	@#$(call rmfiles,$(DLIB) $(SLIB),library)

 cleanallbrlib:
 	$(MAKE) -C $(BRLIB) cleanall

-brlib: libs
+brlib:
 	$(MAKE) -C $(BRLIB) libs

 ##################################### brchess binaries
@@ -205,19 +248,22 @@ cleanbin:
 cleanbindir:
 	$(call rmdir,$(BINDIR),binaries)

-# We don't use static lib, but we could build it here
-#$(TARGET): $(DLIB) $(OBJ) | $(BINDIR) $(SLIB)
-$(TARGET): libs $(OBJ) | $(BINDIR) $(SLIB)
-	@echo generating $@ executable.
+$(TARGET): libs $(OBJ) | $(BINDIR)
+	@echo generating $@.
 	$(CC) $(LDFLAGS) $(OBJ) $(LIBS) -o $@

 ##################################### pre-processed (.i) and assembler (.s) output
+.PHONY: cleanasmcpp
+
+cleanasmcpp:
+	@$(call rmfiles,$(ASMFILES) $(CPPFILES),asm and pre-processed)
+
 %.i: %.c
-	@echo generating $@
+	@echo "generating $@ (cpp processed)."
 	@$(CC) -E $(CPPFLAGS) $(CFLAGS) $< -o $@

 %.s: %.c
-	@echo generating $@
+	@echo "generating $@ (asm)."
 	@$(CC) -S -fverbose-asm $(CPPFLAGS) $(CFLAGS) $< -o $@

 ##################################### LSP (ccls)
@@ -230,17 +276,13 @@ $(CCLSROOT):
 	@$(TOUCH) $@

 # generate compile_commands.json.
-# Need to add includes and Makefile dependencies.
+# TODO: add Makefile dependencies.
 # also, if cclsfile is newer than sources, no need to clean objects file
 # (and to run bear).
 # maybe run cleanobj cleanlibobj in commands ?
-$(CCLSFILE): cleanobj cleanbrlib $(SRC) $(LIBSRC) | $(CCLSROOT)
+$(CCLSFILE): cleanobj cleanbrlib libs | $(CCLSROOT)
 	@echo "Generating ccls compile commands file ($@)."
-	@$(BEAR) -- $(MAKE) compile
-
-#.PHONY: bear
-#bear: cleanobj cleanlibobj Makefile | $(CCLSROOT)
-#    @$(BEAR) -- make compile
+	@$(BEAR) -- $(MAKE) testing

 ##################################### valgrind (mem check)
 .PHONY: memcheck
@@ -258,20 +300,63 @@ memcheck: targets
 	@$(VALGRIND) $(VALGRINDFLAGS) $(BINDIR)/brchess

 ##################################### test binaries
-TEST        = bin/fen-test bin/bitboard-test
+.PHONY: testing test

-FENTESTOBJS = obj/fen.o obj/position.o obj/piece.o obj/util.o obj/bitboard.o
-BITBOARDOBJS = obj/position.o obj/piece.o obj/bitboard.o obj/fen.o \
-	obj/hyperbola-quintessence.o
+TEST          := piece-test fen-test bitboard-test movegen-test attack-test
+TEST          += movedo-test perft-test
+
+PIECE_OBJS    := piece.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 misc.o
+
+TEST          := $(addprefix $(BINDIR)/,$(TEST))
+
+PIECE_OBJS    := $(addprefix $(OBJDIR)/,$(PIECE_OBJS))
+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=$(TEST)
+	echo FEN_OBJS=$(FEN_OBJS)

 testing: $(TEST)

-bin/fen-test: test/fen-test.c $(FENTESTOBJS)
-	$(CC) $(CPPFLAGS) $(CFLAGS) $< $(FENTESTOBJS)  $(LDFLAGS) $(LIBS) -o $@
+bin/piece-test: test/piece-test.c $(FEN_OBJS)
+	@echo compiling $@ test executable.
+	@$(CC) $(ALL_CFLAGS) $< $(FEN_OBJS) $(ALL_LDFLAGS) -o $@

-bin/bitboard-test: test/bitboard-test.c $(BITBOARDOBJS)
-	$(CC) $(CPPFLAGS) $(CFLAGS) $< $(BITBOARDOBJS) $(LDFLAGS) $(LIBS) -o $@
+bin/fen-test: test/fen-test.c test/common-test.h $(FEN_OBJS)
+	@echo compiling $@ test executable.
+	@$(CC) $(ALL_CFLAGS) $< $(FEN_OBJS) $(ALL_LDFLAGS) -o $@

+bin/bitboard-test: test/bitboard-test.c test/common-test.h $(BB_OBJS)
+	@echo compiling $@ test executable.
+	@$(CC) $(ALL_CFLAGS) $< $(BB_OBJS) $(ALL_LDFLAGS) -o $@
+
+bin/movegen-test: test/movegen-test.c test/common-test.h $(MOVEGEN_OBJS)
+	@echo compiling $@ test executable.
+	@$(CC) $(ALL_CFLAGS) $< $(MOVEGEN_OBJS) $(ALL_LDFLAGS) -o $@
+
+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/2
+++ b/2
--- a/src/attack.c
+++ b/src/attack.c
@@ -0,0 +1,214 @@
+/* attack.c - attack functions.
+ *
+ * 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 <stdarg.h>
+
+#include "chessdefs.h"
+#include "bitboard.h"
+#include "position.h"
+#include "hyperbola-quintessence.h"
+#include "attack.h"
+
+
+/**
+ * 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)
+{
+    color_t opp = OPPONENT(c);
+
+    /* 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 (bb_pawn_attacks[opp][sq] & 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
+ * @pos: position
+ * @occ: occupation mask used
+ * @sq:  square to test
+ * @c:   attacker color
+ *
+ * Find all @c attacks on @sq. En-passant is not considered.
+ *
+ * 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: a bitboard of attackers.
+ */
+bitboard_t sq_attackers(const pos_t *pos, const bitboard_t occ, const square_t sq, const color_t c)
+{
+    bitboard_t attackers = 0, tmp;
+    bitboard_t sqbb = mask(sq);
+    //bitboard_t occ = pos_occ(pos);
+    bitboard_t to;
+    color_t opp = OPPONENT(c);
+
+    /* pawn */
+    to =  pos->bb[c][PAWN];
+    tmp = pawn_shift_upleft(sqbb, opp) & to;
+    attackers |= tmp;
+#   ifdef DEBUG_ATTACK_ATTACKERS1
+    bb_print("att pawn upleft", tmp);
+#   endif
+    tmp = pawn_shift_upright(sqbb, opp) & to;
+    attackers |= tmp;
+#   ifdef DEBUG_ATTACK_ATTACKERS1
+    bb_print("att pawn upright", tmp);
+#   endif
+
+    /* knight & king */
+    to = pos->bb[c][KNIGHT];
+    tmp = bb_knight_moves(to, sq);
+    attackers |= tmp;
+#   ifdef DEBUG_ATTACK_ATTACKERS1
+    bb_print("att knight", tmp);
+#   endif
+    to = pos->bb[c][KING];
+    tmp = bb_king_moves(to, sq);
+    attackers |= tmp;
+#   ifdef DEBUG_ATTACK_ATTACKERS1
+    bb_print("att king", tmp);
+#   endif
+
+    /* bishop / queen */
+    to = pos->bb[c][BISHOP] | pos->bb[c][QUEEN];
+    tmp = hyperbola_bishop_moves(occ, sq) & to;
+    attackers |= tmp;
+#   ifdef DEBUG_ATTACK_ATTACKERS1
+    bb_print("att bishop/queen", tmp);
+#   endif
+
+    /* rook / queen */
+    to = pos->bb[c][ROOK] | pos->bb[c][QUEEN];
+    tmp = hyperbola_rook_moves(occ, sq) & to;
+    attackers |= tmp;
+#   ifdef DEBUG_ATTACK_ATTACKERS1
+    bb_print("att rook/queen", tmp);
+    bb_print("ATTACKERS", attackers);
+    printf("attackers=%lx\n", attackers);
+#   endif
+
+    return attackers;
+}
+
+/**
+ * sq_pinners() - get "pinners" on a square
+ * @pos: position
+ * @sq:  square to test
+ * @color:   attacker color
+ *
+ * Find all @c pieces which are separated from @sq by only one piece (of
+ * any color).
+ *
+ * @Return: bitboard of pinners.
+ */
+bitboard_t sq_pinners(const pos_t *pos, const square_t sq, const color_t color)
+{
+    bitboard_t attackers, pinners = 0;
+    bitboard_t occ = pos_occ(pos);
+    bitboard_t maybe_pinner, tmp, lines;
+
+    /* bishop type */
+    attackers = pos->bb[color][BISHOP] | pos->bb[color][QUEEN];
+    /* occupancy on sq diag and antidiag */
+    lines = (bb_sqdiag[sq] | bb_sqanti[sq]) & occ;
+    bit_for_each64(maybe_pinner, tmp, attackers) {
+        bitboard_t between = bb_between_excl[maybe_pinner][sq];
+        /* keep only squares between AND on sq diag/anti */
+        if (popcount64(between & lines) == 1)
+            pinners |= mask(maybe_pinner);
+    }
+
+    /* same for rook type */
+    attackers = pos->bb[color][ROOK] | pos->bb[color][QUEEN];
+    lines = (bb_sqrank[sq] | bb_sqfile[sq]) & occ;
+    bit_for_each64(maybe_pinner, tmp, attackers) {
+        bitboard_t between = bb_between_excl[maybe_pinner][sq];
+        if (popcount64(between & lines) == 1)
+            pinners |= mask(maybe_pinner);
+    }
+#   ifdef DEBUG_ATTACK_ATTACKERS1
+    char str[32];
+    printf("pinners : %s\n", pos_pinners2str(pos, str, sizeof(str)));
+    printf("pinners : %lx\n", pinners);
+#   endif
+    return pinners;
+}
+
+/**
+ * sq_attackers() - find all attackers on a square
+ * @pos: position
+ * @sq:  square to test
+ *
+ * Find all attacks on @sq. En-passant is not considered.
+ * Just a wrapper over @sq_attackers().
+ *
+ * @Return: a bitboard of attackers.
+ */
+bitboard_t sq_attackers_all(const pos_t *pos, const square_t sq)
+{
+    bitboard_t occ = pos_occ(pos);
+    return sq_attackers(pos, occ, sq, WHITE) | sq_attackers(pos, occ, sq, BLACK);
+}
--- a/src/attack.h
+++ b/src/attack.h
@@ -0,0 +1,26 @@
+/* attack.h - attack functions.
+ *
+ * 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>
+ *
+ */
+
+#ifndef _ATTACK_H
+#define _ATTACK_H
+
+#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);
+#endif
--- a/src/bitboard.c
+++ b/src/bitboard.c
@@ -20,7 +20,14 @@
 #include "piece.h"
 #include "board.h"
 #include "bitboard.h"
-#include "position.h"
+
+bitboard_t bb_sq[64];
+bitboard_t bb_sqrank[64], bb_sqfile[64], bb_sqdiag[64], bb_sqanti[64];
+bitboard_t bb_between_excl[64][64];
+bitboard_t bb_between[64][64];
+bitboard_t bb_line[64][64];
+
+bitboard_t bb_knight[64], bb_king[64], bb_pawn_attacks[2][64];

 /*  vectors are clockwise from N */
 static int knight_vector[] = {
@@ -34,32 +41,63 @@ static int king_vector[8] = {
    SOUTH, SOUTH_WEST, WEST, NORTH_WEST
 };

-bitboard_t bb_sq[SQUARE_MAX];
-bitboard_t bb_rank[64], bb_file[64], bb_diagonal[64], bb_antidiagonal[64];
+/**
+ * bitboard_between_excl() - get bitboard of squares between two squares.
+ * @sq1, @sq2: The two square_t squares
+ *
+ * From: http://www.talkchess.com/forum3/viewtopic.php?f=7&t=12499&start=14
+ * This function may be used instead of bb_XXX arrays if cache pressure is high.
+ *
+ * @Return: bitboard_t, squares between @sq1 and @sq2 (excl. @sq1 and @sq2).
+ */
+bitboard_t bitboard_between_excl(square_t sq1, square_t sq2)
+{
+    const bitboard_t m1 = -1;
+    const bitboard_t a2a7 = C64(0x0001010101010100);
+    const bitboard_t b7h1 = C64(0x0002040810204080);
+    bitboard_t btwn_bits, ray_bits;
+    u32 rank_diff, file_diff, anti_diff, diag_diff;

-bitboard_t bb_knight[64], bb_king[64];
-bitboard_t bb_pawn_push[2][64], bb_bpawn_attack[2][64], bb_pawn_ep[2][64];
+    btwn_bits  =  (m1 << sq1) ^ (m1 << sq2);      /* includes sq1 and sq2 */
+    rank_diff  = ((sq2 | 7) - sq1) >> 3,          /* signed */
+        file_diff  =  (sq2 & 7) - (sq1 & 7);          /* signed */
+
+    anti_diff  =  rank_diff  + file_diff;
+    rank_diff  =  rank_diff  & 15;
+    file_diff  =  file_diff  & 15;
+    anti_diff  =  anti_diff  & 15;
+    diag_diff  =  rank_diff  ^ file_diff;
+    ray_bits   =  2 * ((rank_diff - 1) >> 26);
+
+    ray_bits  |=  bswap64((m1 + diag_diff) & b7h1);
+    ray_bits  |=  (m1 + anti_diff) & b7h1;
+    ray_bits  |=  (m1 + file_diff) & a2a7;
+    ray_bits  *=  btwn_bits  &  -btwn_bits;
+    return ray_bits & btwn_bits;
+}

 /**
 * bitboard_init() - initialize general bitboards
 *
 * Generate the following bitboards :
 *   bb_sq[64]: square to bitboard
- *   bb_rank[64]: square to rank
- *   bb_file[64]: square to file
- *   bb_diagonal[64]: square to diagonal
- *   bb_antidiagonal[64]: square to antidiagonal
+ *   bb_sqrank[64]: square to rank
+ *   bb_sqfile[64]: square to file
+ *   bb_sqdiag[64]: square to diagonal
+ *   bb_sqanti[64]: square to antidiagonal
+ *
+ *   bb_between_excl[64][64]: strict squares between two squares
+ *   bb_between[64][64]: squares between two squares including second square
 *
 * And the following pseudo move masks:
 *   bb_knight[64]: knight moves
 *   bb_king[64]: king moves
- *   bb_pawn[2][64]: white pawn moves (not attacks)
- *   bb_pawn_att[2][64]: white pawn attacks
+ *
 */
 void bitboard_init(void)
 {
    /*  for each square, the 4 masks: file, rank, diagonal, antidiagonal */
-    struct { int df, dr; } dirs[4] = {
+    struct { int df, dr; } vecs[4] = {
        { 0,  1 },                                /* vertical/file */
        { 1,  0 },                                /* horizontal/rank */
        { 1,  1 },                                /* diagonal */
@@ -67,33 +105,66 @@ void bitboard_init(void)
    } ;
    bitboard_t tmpbb[64][4] = { 0 };

-    /* 1) square to bitboard */
-    for (square_t sq = A1; sq <= H8; ++sq)
-        bb_sq[sq] = mask(sq);
+    /* 1) square to bitboard
+     *    in-between, sq2 excluded
+     */
+    for (square_t sq1 = A1; sq1 <= H8; ++sq1) {
+        bb_sq[sq1] = mask(sq1);
+        for (square_t sq2 = A1; sq2 <= H8; ++sq2)
+            bb_between_excl[sq1][sq2] = bitboard_between_excl(sq1, sq2);
+    }

-    /* 2) square to rank/file/diagonal/antidiagonal */
+    /* 2) sq1-to-sq2 mask, sq2 included
+     *    square to file/rank/dia/anti bitmaps
+     */
    for (square_t sq = 0; sq < 64; ++sq) {
-        int r = sq_rank(sq), f = sq_file(sq);
-        for (int mult = -7; mult < 8; ++mult) {
-            for (int dir = 0; dir < 4; ++dir) {
-                int dst_f = f + mult * dirs[dir].df;
-                int dst_r = r + mult * dirs[dir].dr;
-                if (sq_coord_ok(dst_f) && sq_coord_ok(dst_r)) {
-                    int dst = sq_make(dst_f, dst_r);
-                    tmpbb[sq][dir] |= mask(dst);
+        file_t f = sq_file(sq);
+        rank_t r = sq_rank(sq);
+        for (int vec = 0; vec < 4; ++vec) {
+            tmpbb[sq][vec] |= mask(sq_make(f, r));
+            for (int dir = -1; dir <= 1; dir += 2) {
+                file_t df = dir * vecs[vec].df, f2 = f + df;
+                rank_t dr = dir * vecs[vec].dr, r2 = r + dr;
+                bitboard_t mask_between = 0;
+                while (sq_coord_ok(f2) && sq_coord_ok(r2)) {
+                    square_t dest = sq_make(f2, r2);
+                    tmpbb[sq][vec] |= mask(dest);
+                    mask_between |= mask(dest);
+                    bb_between[sq][dest] = mask_between;
+                    f2 += df, r2 += dr;
                }
            }
        }
    }
    for (square_t sq = 0; sq < 64; ++sq) {
-        bb_file[sq] = tmpbb[sq][0];
-        bb_rank[sq] = tmpbb[sq][1];
-        bb_diagonal[sq] = tmpbb[sq][2];
-        bb_antidiagonal[sq] = tmpbb[sq][3];
+        bb_sqfile[sq] = tmpbb[sq][0];
+        bb_sqrank[sq] = tmpbb[sq][1];
+        bb_sqdiag[sq] = tmpbb[sq][2];
+        bb_sqanti[sq] = tmpbb[sq][3];
+    }
+    for (square_t sq1 = 0; sq1 < 64; ++sq1) {
+        for (square_t sq2 = 0; sq2 < 64; ++sq2) {
+            if (sq1 != sq2) {
+                if (bb_sqfile[sq1] == bb_sqfile[sq2])
+                    bb_line[sq1][sq2] = bb_sqfile[sq1];
+                else if (bb_sqrank[sq1] == bb_sqrank[sq2])
+                    bb_line[sq1][sq2] = bb_sqrank[sq1];
+                else if (bb_sqdiag[sq1] == bb_sqdiag[sq2])
+                    bb_line[sq1][sq2] = bb_sqdiag[sq1];
+                else if (bb_sqanti[sq1] == bb_sqanti[sq2])
+                    bb_line[sq1][sq2] = bb_sqanti[sq1];
+            }
+        }
    }

-    /* 3) knight and king moves */
+    /* 3) pawn, knight and king attacks
+     */
    for (square_t sq = A1; sq <= H8; ++sq) {
+        if (sq >= A2)
+            bb_pawn_attacks[BLACK][sq] = pawn_attacks_bb(mask(sq), BLACK);
+        if (sq <= H7)
+            bb_pawn_attacks[WHITE][sq] = pawn_attacks_bb(mask(sq), WHITE);
+
        for (int vec = 0; vec < 8; ++vec) {
            int dst = sq + knight_vector[vec];
            if (sq_ok(dst)) {
@@ -111,21 +182,37 @@ void bitboard_init(void)
    }
 }

+
+/**
+ * bb_knight_moves() - get bitboard of knight pseudo-moves
+ * @notmine: bitboard_t of squares not occupied by own pieces
+ * @sq: knight square
+ *
+ * @Return: bitboard of available moves.
+ */
 bitboard_t bb_knight_moves(bitboard_t notmine, square_t sq)
 {
    return bb_knight[sq] & notmine;
 }
+
+/**
+ * bb_king_moves() - get bitboard of king pseudo-moves
+ * @notmine: bitboard_t of squares not occupied by own pieces
+ * @sq: king square
+ *
+ * @Return: bitboard of available moves.
+ */
 bitboard_t bb_king_moves(bitboard_t notmine, square_t sq)
 {
    return bb_king[sq] & notmine;
 }

 /**
- * bitboard_print() - print simple bitboard representation
+ * bb_print() - print simple bitboard representation
 * @title: a string or NULL
 * @bitboard: the bitboard
 */
-void bitboard_print(const char *title, const bitboard_t bitboard)
+void bb_print(const char *title, const bitboard_t bitboard)
 {
    //char c = p? p: 'X';
    if (title)
@@ -142,19 +229,19 @@ void bitboard_print(const char *title, const bitboard_t bitboard)
 }

 /**
- * bitboard_print_multi() - print multiple bitboards horizontally
+ * bb_print_multi() - print multiple bitboards horizontally
 * @title: a string or NULL
 * @n: number of bitboards
 * @bb_ptr...: pointers to bitboards
 *
- * @n is the number of bitboards to print. If @n -s > 8, it is reduced to 8;
+ * @n is the number of bitboards to print. If @n > 10, it is reduced to 10
 */
-void bitboard_print_multi(const char *title, int n, ...)
+void bb_print_multi(const char *title, int n, ...)
 {
    bitboard_t bb[8];
    va_list ap;

-    n = min(n, 8);
+    n = min(n, 10);

    va_start(ap, n);
    for (int i = 0; i < n; ++i) {                 /* save all bitboards */
@@ -184,16 +271,60 @@ void bitboard_print_multi(const char *title, int n, ...)
 }

 /**
- * bitboard_rank_sprint() - print an u8 rank binary representation
+ * bb_rank_sprint() - print an u8 rank binary representation
 * @str: the destination string
 * @bb8: the uchar to print
+ *
+ * @return: @str, filled with ascii representation
 */
-char *bitboard_rank_sprint(char *str, const uchar bb8)
+char *bb_rank_sprint(char *str, const uchar bb8)
 {
-    for (file_t f = FILE_A; f <= FILE_H; ++f) {
-        *(str+f) = bb8 & mask(f) ? '1': '.';
+    file_t f;
+    for (f = FILE_A; f <= FILE_H; ++f) {
+        *(str + f) = bb8 & mask(f) ? '1': '.';
    }
+    *(str + f) = 0;
    //printf(" 0 1 2 3 4 5 6 7\n");
    //printf("\n");
    return str;
 }
+
+/**
+ * bb_sq2str() - convert bitboard to a string with a list of squares.
+ * @bb:  bitboard
+ * @str: destination string
+ * @len: max @str length
+ *
+ * @str will be filled with the list of string representation of @bb, up to @len
+ * characters.
+ * 3 characters are used per square, so, for example, @str len should be :
+ * - For a valid position checkers (two checkers max): 2*3 + 1 = 7.
+ * - For a valid position pinners (8 pinners): 8*3 + 1 = 25.
+ * - for a full bitboard: 64*3 + 1 = 193.
+ *
+ * If @len is not enough to fill all moves, the last fitting move is replaced by "...".
+ *
+ * @return: The string.
+ */
+char *bb_sq2str(const bitboard_t bb, char *str, const int len)
+{
+    bitboard_t tmp, sq;
+    int nocc = popcount64(bb);
+    int needed = 3 * nocc + 1;
+    int willdo = (int) len >= needed ? nocc: (len - 1) / 3 - 1;
+    int current = 0;
+
+    //printf("sq2str bb=%lx len=%d willdo=%d\n", bb, len, willdo);
+    bit_for_each64(sq, tmp, bb) {
+        if (current == willdo) {
+            strcpy(str + current * 3, "...");
+        } else {
+            strcpy(str + current * 3, sq_to_string(sq));
+            str[current * 3 + 2] = ' ';
+        }
+        if (++current > willdo)
+            break;
+    }
+    str[current * 3] = 0;
+    return str;
+}
--- a/src/bitboard.h
+++ b/src/bitboard.h
@@ -14,50 +14,266 @@
 #ifndef _BITBOARD_H
 #define _BITBOARD_H

-#include "brlib.h"
-#include "bitops.h"
+#include <brlib.h>
+#include <bitops.h>

 #include "chessdefs.h"
 #include "board.h"
-
-typedef u64 bitboard_t;
+#include "piece.h"

 /* mapping square -> bitboard */
 extern bitboard_t bb_sq[64];
+/* squares between sq1 and sq2, exclusing both */
+extern bitboard_t bb_between_excl[64][64];
+/* squares between sq1 and sq2, including sq2 */
+extern bitboard_t bb_between[64][64];

-/* mapping square -> rank/file/diagonal/antidiagonal */
-extern bitboard_t bb_rank[64], bb_file[64], bb_diagonal[64], bb_antidiagonal[64];
-extern bitboard_t bb_knight[64], bb_king[64];
-
-#define mask(i)        ( 1ULL << (i) )
-
-enum {
-    FILE_Abb = 0x0101010101010101ULL,
-    FILE_Bbb = 0x0202020202020202ULL,
-    FILE_Cbb = 0x0404040404040404ULL,
-    FILE_Dbb = 0x0808080808080808ULL,
-    FILE_Ebb = 0x1010101010101010ULL,
-    FILE_Fbb = 0x2020202020202020ULL,
-    FILE_Gbb = 0x4040404040404040ULL,
-    FILE_Hbb = 0x8080808080808080ULL,
-};
-
-enum {
-    RANK_1bb = 0x00000000000000ffULL,
-    RANK_2bb = 0x000000000000ff00ULL,
-    RANK_3bb = 0x0000000000ff0000ULL,
-    RANK_4bb = 0x00000000ff000000ULL,
-    RANK_5bb = 0x000000ff00000000ULL,
-    RANK_6bb = 0x0000ff0000000000ULL,
-    RANK_7bb = 0x00ff000000000000ULL,
-    RANK_8bb = 0xff00000000000000ULL
-};
-
-/* https://www.chessprogramming.org/Flipping_Mirroring_and_Rotating#Rotation
+/**
+ * bb_sqrank[64]: square to rank
+ * bb_sqfile[64]: square to file
+ * bb_sqdiag[64]: square to diagonal
+ * bb_sqanti[64]: square to antidiagonal
 */
-static __always_inline bitboard_t bb_rotate_90(bitboard_t b)
+extern bitboard_t bb_sqrank[64], bb_sqfile[64], bb_sqdiag[64], bb_sqanti[64];
+
+/* line (rank, file, diagonal or anti-diagonal) between two squares */
+extern bitboard_t bb_line[64][64];
+
+/* pawn, knight and king attacks */
+extern bitboard_t bb_knight[64], bb_king[64], bb_pawn_attacks[2][64];
+
+/* TODO (maybe C23?) when we can ensure an enum can be u64
+ *
+ * enum {
+ *     A1bb = mask(A1), A2bb = mask(A2), A3bb = mask(A3), A4bb = mask(A4),
+ *     A5bb = mask(A5), A6bb = mask(A6), A7bb = mask(A7), A8bb = mask(A8),
+ *     B1bb = mask(B1), B2bb = mask(B2), B3bb = mask(B3), B4bb = mask(B4),
+ *     B5bb = mask(B5), B6bb = mask(B6), B7bb = mask(B7), B8bb = mask(B8),
+ *     C1bb = mask(C1), C2bb = mask(C2), C3bb = mask(C3), C4bb = mask(C4),
+ *     C5bb = mask(C5), C6bb = mask(C6), C7bb = mask(C7), C8bb = mask(C8),
+ *     D1bb = mask(D1), D2bb = mask(D2), D3bb = mask(D3), D4bb = mask(D4),
+ *     D5bb = mask(D5), D6bb = mask(D6), D7bb = mask(D7), D8bb = mask(D8),
+ *     E1bb = mask(E1), E2bb = mask(E2), E3bb = mask(E3), E4bb = mask(E4),
+ *     E5bb = mask(E5), E6bb = mask(E6), E7bb = mask(E7), E8bb = mask(E8),
+ *     F1bb = mask(F1), F2bb = mask(F2), F3bb = mask(F3), F4bb = mask(F4),
+ *     F5bb = mask(F5), F6bb = mask(F6), F7bb = mask(F7), F8bb = mask(F8),
+ *     G1bb = mask(G1), G2bb = mask(G2), G3bb = mask(G3), G4bb = mask(G4),
+ *     G5bb = mask(G5), G6bb = mask(G6), G7bb = mask(G7), G8bb = mask(G8),
+ *     H1bb = mask(H1), H2bb = mask(H2), H3bb = mask(H3), H4bb = mask(H4),
+ *     H5bb = mask(H5), H6bb = mask(H6), H7bb = mask(H7), H8bb = mask(H8),
+ * };
+ *
+ * enum {
+ *     FILE_Abb = 0x0101010101010101ull, FILE_Bbb = 0x0202020202020202ull,
+ *     FILE_Cbb = 0x0404040404040404ull, FILE_Dbb = 0x0808080808080808ull,
+ *     FILE_Ebb = 0x1010101010101010ull, FILE_Fbb = 0x2020202020202020ull,
+ *     FILE_Gbb = 0x4040404040404040ull, FILE_Hbb = 0x8080808080808080ull,
+ *
+ *     RANK_1bb = 0x00000000000000ffull, RANK_2bb = 0x000000000000ff00ull,
+ *     RANK_3bb = 0x0000000000ff0000ull, RANK_4bb = 0x00000000ff000000ull,
+ *     RANK_5bb = 0x000000ff00000000ull, RANK_6bb = 0x0000ff0000000000ull,
+ *     RANK_7bb = 0x00ff000000000000ull, RANK_8bb = 0xff00000000000000ull
+ * };
+ */
+
+/* generated with bash:
+ * R="ABCDEFGH"
+ * F="12345678"
+ * for i in {0..63}; do
+ *   printf "#define  %c%cbb %#018llxull\n" ${R:i/8:1} ${F:i%8:1} $((1 << i))
+ * done
+ */
+#define A1bb     0x0000000000000001ull
+#define A2bb     0x0000000000000002ull
+#define A3bb     0x0000000000000004ull
+#define A4bb     0x0000000000000008ull
+#define A5bb     0x0000000000000010ull
+#define A6bb     0x0000000000000020ull
+#define A7bb     0x0000000000000040ull
+#define A8bb     0x0000000000000080ull
+#define B1bb     0x0000000000000100ull
+#define B2bb     0x0000000000000200ull
+#define B3bb     0x0000000000000400ull
+#define B4bb     0x0000000000000800ull
+#define B5bb     0x0000000000001000ull
+#define B6bb     0x0000000000002000ull
+#define B7bb     0x0000000000004000ull
+#define B8bb     0x0000000000008000ull
+#define C1bb     0x0000000000010000ull
+#define C2bb     0x0000000000020000ull
+#define C3bb     0x0000000000040000ull
+#define C4bb     0x0000000000080000ull
+#define C5bb     0x0000000000100000ull
+#define C6bb     0x0000000000200000ull
+#define C7bb     0x0000000000400000ull
+#define C8bb     0x0000000000800000ull
+#define D1bb     0x0000000001000000ull
+#define D2bb     0x0000000002000000ull
+#define D3bb     0x0000000004000000ull
+#define D4bb     0x0000000008000000ull
+#define D5bb     0x0000000010000000ull
+#define D6bb     0x0000000020000000ull
+#define D7bb     0x0000000040000000ull
+#define D8bb     0x0000000080000000ull
+#define E1bb     0x0000000100000000ull
+#define E2bb     0x0000000200000000ull
+#define E3bb     0x0000000400000000ull
+#define E4bb     0x0000000800000000ull
+#define E5bb     0x0000001000000000ull
+#define E6bb     0x0000002000000000ull
+#define E7bb     0x0000004000000000ull
+#define E8bb     0x0000008000000000ull
+#define F1bb     0x0000010000000000ull
+#define F2bb     0x0000020000000000ull
+#define F3bb     0x0000040000000000ull
+#define F4bb     0x0000080000000000ull
+#define F5bb     0x0000100000000000ull
+#define F6bb     0x0000200000000000ull
+#define F7bb     0x0000400000000000ull
+#define F8bb     0x0000800000000000ull
+#define G1bb     0x0001000000000000ull
+#define G2bb     0x0002000000000000ull
+#define G3bb     0x0004000000000000ull
+#define G4bb     0x0008000000000000ull
+#define G5bb     0x0010000000000000ull
+#define G6bb     0x0020000000000000ull
+#define G7bb     0x0040000000000000ull
+#define G8bb     0x0080000000000000ull
+#define H1bb     0x0100000000000000ull
+#define H2bb     0x0200000000000000ull
+#define H3bb     0x0400000000000000ull
+#define H4bb     0x0800000000000000ull
+#define H5bb     0x1000000000000000ull
+#define H6bb     0x2000000000000000ull
+#define H7bb     0x4000000000000000ull
+#define H8bb     0x8000000000000000ull
+
+#define FILE_Abb 0x0101010101010101ull
+#define FILE_Bbb 0x0202020202020202ull
+#define FILE_Cbb 0x0404040404040404ull
+#define FILE_Dbb 0x0808080808080808ull
+#define FILE_Ebb 0x1010101010101010ull
+#define FILE_Fbb 0x2020202020202020ull
+#define FILE_Gbb 0x4040404040404040ull
+#define FILE_Hbb 0x8080808080808080ull
+
+#define RANK_1bb 0x00000000000000ffull
+#define RANK_2bb 0x000000000000ff00ull
+#define RANK_3bb 0x0000000000ff0000ull
+#define RANK_4bb 0x00000000ff000000ull
+#define RANK_5bb 0x000000ff00000000ull
+#define RANK_6bb 0x0000ff0000000000ull
+#define RANK_7bb 0x00ff000000000000ull
+#define RANK_8bb 0xff00000000000000ull
+
+
+/*
+static __always_inline bitboard_t bb_rank(int rank)
 {
-    return b;
+    return RANK_1bb << (rank * 8);
+}
+static __always_inline bitboard_t bb_rel_rank(int rank, color)
+{
+    return RANK_1bb << (rank * 8);
+}
+static __always_inline bitboard_t bb_file(int file)
+{
+    return FILE_Abb << file;
+}
+*/
+
+/**
+ * bb_first_bb() - return bitboard of first square of a bitboard.
+ * @bb: bitboard
+ *
+ * bb must be non-zero.
+ *
+ * @return: bitboard of first square (lsb) of @bb.
+ */
+static __always_inline square_t bb_first_bb(bitboard_t bb)
+{
+    return bb & -bb;
+}
+
+/**
+ * bb_next() - clear and return next (lsb) square of a bitboard.
+ * @bb: &bitboard
+ *
+ * The bitboard addressed by @bb must be non-zero.
+ *
+ * @return: first bit (lsb) of @bb.
+ */
+static __always_inline square_t bb_next(bitboard_t *bb)
+{
+    square_t sq = ctz64(*bb);
+    *bb &= *bb - 1;
+    return sq;
+}
+
+/**
+ * bb_multiple() - test if a bitboard has multiple bits.
+ * @bb: bitboard
+ *
+ * @return: true if @bb has more than 1 bit, false otherwise.
+ */
+static __always_inline bool bb_multiple(bitboard_t bb)
+{
+    return !!(bb & (bb - 1));
+}
+
+/**
+ * bb_shift() - shift bitboard
+ * @bb: bitboard
+ *
+ * No control is done on off-board shifting (i.e. shifting -1 from A2 gives H3).
+ *
+ * @return: true if @bb has more than 1 bit, false otherwise.
+ */
+static __always_inline bitboard_t bb_shift(bitboard_t bb, int shift)
+{
+   return shift >= 0 ? bb << shift : bb >> -shift;
+}
+
+
+#define bb_rank(r)        ((u64) RANK_1bb << ((r) * 8))
+#define bb_file(f)        ((u64) FILE_Abb << (f))
+
+#define bb_rel_rank(r, c) bb_rank(sq_rel_rank(r, c))
+#define bb_rel_file(f, c) bb_file(sq_rel_rank(f, c))
+
+/**
+ * bb_sq_aligned() - check if two squares are aligned (same file or rank).
+ * @sq1, @sq2:  the two squares.
+ *
+ * @return: true if @sq1 and @sq2 are on same line, false otherwise.
+ */
+static __always_inline bool bb_sq_aligned(square_t sq1, square_t sq2)
+{
+    return bb_line[sq1][sq2];
+}
+
+/**
+ * bb_sq_aligned3() - check if 3 squares are aligned (same file or rank).
+ * @sq1, @sq2, @sq3:  the three squares.
+ *
+ * @return: true if @sq1, @sq2, and @sq3 are aligned, false otherwise.
+ */
+static __always_inline bool bb_sq_aligned3(square_t sq1, square_t sq2, square_t sq3)
+{
+    return bb_line[sq1][sq2] & mask(sq3);
+}
+
+/**
+ * bb_sq_between() - check if a square is between two squares
+ * @sq:  the possibly "in-between" square
+ * @sq1: square 1
+ * @sq2: square 2
+ *
+ * @return: bitboard of @sq if between @sq1 and @sq2.
+ */
+static __always_inline bitboard_t bb_sq_between(square_t sq, square_t sq1, square_t sq2)
+{
+    return bb_between_excl[sq1][sq2] & mask(sq);
 }

 /* TODO: when OK, replace with macros */
@@ -94,13 +310,30 @@ static __always_inline bitboard_t shift_nw(const bitboard_t bb)
    return (bb & ~FILE_Abb) << NORTH_WEST;
 }

-extern void bitboard_init(void);
+/* pawn moves/attacks (for bitboards) */
+#define pawn_shift_up(bb, c)      ((c) == WHITE ? shift_n(bb): shift_s(bb))
+#define pawn_shift_upleft(bb, c)  ((c) == WHITE ? shift_nw(bb): shift_se(bb))
+#define pawn_shift_upright(bb, c) ((c) == WHITE ? shift_ne(bb): shift_sw(bb))

-extern bitboard_t bb_knight_moves(bitboard_t occ, square_t sq);
-extern bitboard_t bb_king_moves(bitboard_t occ, square_t sq);
+#define pawn_attacks_bb(bb, c)    (pawn_shift_upleft(bb, c) |                   \
+                                   pawn_shift_upright(bb, c))

-extern void bitboard_print(const char *title, const bitboard_t bitboard);
-extern void bitboard_print_multi(const char *title, const int n, ...);
-extern char *bitboard8_sprint(char *str, const uchar bb8);
+/* pawn move (for single pawn) - NO SQUARE CONTROL HERE !
+ * Need to make functions with control instead.
+ */
+#define pawn_push_up(sq, c)       ((sq) + ((c) == WHITE ? NORTH:      SOUTH))
+//#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))
+
+bitboard_t bitboard_between_excl(square_t sq1, square_t sq2);
+void bitboard_init(void);
+
+bitboard_t bb_knight_moves(bitboard_t notmine, square_t sq);
+bitboard_t bb_king_moves(bitboard_t notmine, square_t sq);
+
+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/board.c
+++ b/src/board.c
@@ -1,4 +1,4 @@
-/* board.c - 8x8 board.
+/* board.c - 8x8 functions.
 *
 * Copyright (C) 2024 Bruno Raoult ("br")
 * Licensed under the GNU General Public License v3.0 or later.
@@ -11,10 +11,14 @@
 *
 */

+#include <stdio.h>
+#include <ctype.h>
+
 #include "brlib.h"
 #include "board.h"
+#include "bitboard.h"

-char *sq_strings[] = {
+static const char *sq_strings[] = {
    "a1", "b1", "c1", "d1", "e1", "f1", "g1", "h1",
    "a2", "b2", "c2", "d2", "e2", "f2", "g2", "h2",
    "a3", "b3", "c3", "d3", "e3", "f3", "g3", "h3",
@@ -25,7 +29,100 @@ char *sq_strings[] = {
    "a8", "b8", "c8", "d8", "e8", "f8", "g8", "h8",
 };

-const char *sq_string(const int sq)
+/**
+ * sq_to_string() - return a square string
+ * @square: square (0-64)
+ *
+ * @Return: Pointer to @square string representation ("a1"-"h8").
+ */
+const char *sq_to_string(const square_t square)
 {
-    return sq_strings[sq];
+    return sq_strings[square];
+}
+
+/**
+ * sq_from_string() - return a square from a string
+ * @sqstr: the square representation (a1-h8)
+ *
+ * @Return: square_t representation of str.
+ */
+square_t sq_from_string(const char *sqstr)
+{
+    file_t f = C2FILE(sqstr[0]);
+    rank_t r = C2RANK(sqstr[1]);
+    return sq_coord_ok(f) && sq_coord_ok(r) ? sq_make(f, r): SQUARE_NONE;
+}
+
+/**
+ * board_print() - Print a board
+ * @board:  &board_t to print
+ */
+void board_print(const piece_t *board)
+{
+    printf("  +---+---+---+---+---+---+---+---+\n");
+    for (int rank = 7; rank >= 0; --rank) {
+        printf("%c |", rank + '1');
+        for (int file = 0; file < 8; ++file) {
+            piece_t pc = board[sq_make(file, rank)];
+#           ifdef DIAGRAM_SYM
+            printf(" %s |", pc? piece_to_sym(pc): " ");
+#           else
+            printf(" %s |", pc? piece_to_fen(pc): " ");
+#           endif
+        }
+        printf("\n  +---+---+---+---+---+---+---+---+\n");
+    }
+    printf("    A   B   C   D   E   F   G   H\n");
+}
+
+/**
+ * board_print_mask() - Print a board position with some reversed squares
+ * @board:  &board_t to print
+ * @mask:   a bitboard indicating reverse color displayed squares
+ *
+ * Squares corresponding to @mask will be displayed in reverse colors.
+ */
+void board_print_mask(const piece_t *board, const bitboard_t mask)
+{
+    // 6: blink
+#   define REVERSE "\e[7m▌"
+#   define RESET   "▐\e[0m"
+    printf("  +---+---+---+---+---+---+---+---+\n");
+    for (int rank = 7; rank >= 0; --rank) {
+        printf("%c |", rank + '1');
+        for (int file = 0; file < 8; ++file) {
+            square_t sq = sq_make(file, rank);
+            piece_t pc = board[sq];
+            bitboard_t set = mask(sq) & mask;
+            printf("%s", set? REVERSE : " ");
+#           ifdef DIAGRAM_SYM
+            printf("%s", pc? piece_to_sym(pc): " ");
+#           else
+            printf("%s", pc? piece_to_char_color(pc): " ");
+#           endif
+            printf("%s|", set? RESET : " ");
+        }
+        printf("\n  +---+---+---+---+---+---+---+---+\n");
+    }
+    printf("    A   B   C   D   E   F   G   H\n");
+}
+
+/**
+ * board_print_raw - print raw (octal or FEN symbol) board
+ * @bb: the bitboard
+ * @type: int, 0 for octal, 1 for fen symbol
+ */
+void board_print_raw(const piece_t *board, const int type)
+{
+    for (rank_t r = RANK_8; r >= RANK_1; --r) {
+        for (file_t f = FILE_A; f <= FILE_H; ++f) {
+            piece_t p = board[sq_make(f, r)];
+            if (type) {
+                printf("%s ", p == EMPTY? ".": piece_to_char(p));
+            } else {
+                printf("%02o ", p);
+            }
+        }
+        printf("\n");
+    }
 }
--- a/src/board.h
+++ b/src/board.h
@@ -11,12 +11,21 @@
 *
 */

-#ifndef BOARD_H
-#define BOARD_H
+#ifndef _BOARD_H
+#define _BOARD_H

 #include "brlib.h"

 #include "chessdefs.h"
+#include "piece.h"
+#include "bitboard.h"
+
+/* from human to machine */
+#define C2FILE(c)          (tolower(c) - 'a')
+#define C2RANK(c)          (tolower(c) - '1')
+/* from machine to human */
+#define FILE2C(f)          ((f) + 'a')
+#define RANK2C(r)          ((r) + '1')

 /* a square is defined as
 * rrrfff
@@ -24,43 +33,6 @@
 #define SQ_FILEMASK (007)                         /* warning, octal */
 #define SQ_RANKMASK (070)

-typedef enum {
-    _SSQUARE_ = -1,                               /* force signed enum */
-    A1 = 0, B1, C1, D1, E1, F1, G1, H1,
-    A2,     B2, C2, D2, E2, F2, G2, H2,
-    A3,     B3, C3, D3, E3, F3, G3, H3,
-    A4,     B4, C4, D4, E4, F4, G4, H4,
-    A5,     B5, C5, D5, E5, F5, G5, H5,
-    A6,     B6, C6, D6, E6, F6, G6, H6,
-    A7,     B7, C7, D7, E7, F7, G7, H7,
-    A8,     B8, C8, D8, E8, F8, G8, H8,
-    SQUARE_MAX = 64,
-    SQUARE_NONE = 64
-} square_t;
-
-typedef enum {
-    _SFILE_ = -1,                                 /* force signed enum */
-    FILE_A = 0, FILE_B, FILE_C, FILE_D, FILE_E, FILE_F, FILE_G, FILE_H,
-    FILE_MAX,
-} file_t;
-
-typedef enum {
-    _SRANK_ = -1,                                 /* force signed enum */
-    RANK_1 = 0, RANK_2, RANK_3, RANK_4, RANK_5, RANK_6, RANK_7, RANK_8,
-    RANK_MAX,
-} rank_t;
-
-typedef enum {
-    NORTH = 8,
-    EAST =  1,
-    SOUTH = -NORTH,
-    WEST = -EAST,
-
-    NORTH_EAST = (NORTH + EAST),
-    SOUTH_EAST = (SOUTH + EAST),
-    SOUTH_WEST = (SOUTH + WEST),
-    NORTH_WEST = (NORTH + WEST),
-} dir_t;

 /* flip a 0-63 square:
 * Vertical:   G8 (62) becomes G1 (6)
@@ -73,7 +45,7 @@ typedef enum {
 /* TODO: revert to macros after bitboard migration */
 static __always_inline square_t sq_make(file_t file, rank_t rank)
 {
-    return (rank << 6) + file;
+    return (rank << 3) + file;
 }
 static __always_inline file_t sq_file(square_t square)
 {
@@ -81,22 +53,41 @@ static __always_inline file_t sq_file(square_t square)
 }
 static __always_inline rank_t sq_rank(square_t square)
 {
-    return square >> 6;
+    return square >> 3;
 }

 #define sq_ok(sq)       ((sq) >= A1 && (sq) <= H8)
 #define sq_coord_ok(c)  ((c) >= 0 && (c) < 8)

-/* Chebyshev distance: max( |r2 - r1|, |f2 - f1| )
+/**
+ * sq_dist() - Chebyshev (king) distance between two squares (macro).
+ * @sq1, @sq2: The two squares.
+ *
 * See: https://www.chessprogramming.org/Distance
+ * Distance is max( |r2 - r1|, |f2 - f1| )
+ *
+ * @Return: the Chebyshev distance.
 */
 #define sq_dist(sq1, sq2) (max(abs(sq_file(sq2) - sq_file(sq1)),  \
                               abs(sq_rank(sq2) - sq_rank(sq1))))
-/* Manhattan distance: |r2 - r1| + |f2 - f1|
+
+/**
+ * sq_taxi() - Manhattan (taxi) distance between two squares (macro).
+ * @sq1, @sq2: The two squares.
+ *
+ * See: https://www.chessprogramming.org/Distance
+ * Distance is |r2 - r1| + |f2 - f1|.
+ *
+ * @Return: the Manhattan distance.
 */
-#define sq_manh(sq1, sq2) (abs(sq_file(sq2) - sq_file(sq1)) +     \
+#define sq_taxi(sq1, sq2) (abs(sq_file(sq2) - sq_file(sq1)) +     \
                           abs(sq_rank(sq2) - sq_rank(sq1)))

-extern const char *sq_string(const square_t sq);
+extern const char *sq_to_string(const square_t sq);
+extern square_t sq_from_string(const char *sq_string);

-#endif  /* BOARD_H */
+extern void board_print(const piece_t *board);
+extern void board_print_mask(const piece_t *board, const bitboard_t mask);
+extern void board_print_raw(const piece_t *board, const int type);
+
+#endif  /* _BOARD_H */
--- a/src/chessdefs.h
+++ b/src/chessdefs.h
@@ -1,6 +1,6 @@
-/* chessdefs.h - generic chess definitions.
+/* chessdefs.h - generic/catchall chess definitions.
 *
- * 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.
 *
@@ -16,18 +16,36 @@

 #include "brlib.h"                                /* brlib types */

-#define C64(const_u64) const_u64##ULL
-#define U64(const_s64) const_s64##LL
+#define ONE                1ull
+#define C64(const_u64)     const_u64##ULL
+#define mask(i)            ( (u64) (ONE << (i)) )

-//typedef ushort board;
+#define BOARDSIZE          (8*8)

-#define BOARDSIZE    (8*8)
-/* from human to machine */
-#define C2FILE(c)    (tolower(c) - 'a')
-#define C2RANK(c)    (tolower(c) - '1')
-/* from machine to human */
-#define FILE2C(f)    ((f) + 'a')
-#define RANK2C(r)    ((r) + '1')
+/**
+ * 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))
+#define sq_rel_file(file, c)  ((file_t)((7 * (c)) ^ file))

 /* castle_t bits structure
 */
@@ -36,10 +54,27 @@ typedef enum {
    CASTLE_WQ = (1 << 1),                         /* 0x02 00000010 */
    CASTLE_BK = (1 << 2),                         /* 0x04 00000100 */
    CASTLE_BQ = (1 << 3),                         /* 0x08 00001000 */
+
+    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, bits 0 and 1 */
+    CASTLE_Q  = (1 << 1),
+    CASTLE_KQ = (CASTLE_K |CASTLE_Q)
 } castle_rights_t;

-#define CASTLE_W        (CASTLE_WK | CASTLE_WQ)   /* 00000011 W castle mask */
-#define CASTLE_B        (CASTLE_BK | CASTLE_BQ)   /* 00001100 B castle mask */
+/* 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
+//(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
 */
@@ -47,19 +82,93 @@ typedef enum {
 #define MIDDLEGAME 1
 #define ENDGAME    2

-/* bitboard
+/* forward defs */
+typedef struct __pos_s pos_t;
+typedef struct __movelist_s movelist_t;
+
+/* basic types
 */
-//typedef u64 bitboard_t;
+typedef u64 bitboard_t;

 /* eval type
 */
 //typedef s32 eval_t;

-/* forward typedefs
+/* forward enum definition is impossible in C11, to simplify
+ * cross-dependancies, all important enum are moved here.
 */
-//typedef struct piece_list_s piece_list_t;
-//typedef struct board_s board_t;
-//typedef struct pos_s pos_t;
-//typedef struct move_s move_t;
+typedef enum {
+    _SSQUARE_ = -1,                               /* force signed enum */
+    A1 = 0, B1, C1, D1, E1, F1, G1, H1,
+    A2,     B2, C2, D2, E2, F2, G2, H2,
+    A3,     B3, C3, D3, E3, F3, G3, H3,
+    A4,     B4, C4, D4, E4, F4, G4, H4,
+    A5,     B5, C5, D5, E5, F5, G5, H5,
+    A6,     B6, C6, D6, E6, F6, G6, H6,
+    A7,     B7, C7, D7, E7, F7, G7, H7,
+    A8,     B8, C8, D8, E8, F8, G8, H8,
+    SQUARE_MAX = 64,
+    SQUARE_NONE = 64
+} square_t;
+
+typedef enum {
+    _SFILE_ = -1,                                 /* force signed enum */
+    FILE_A = 0, FILE_B, FILE_C, FILE_D, FILE_E, FILE_F, FILE_G, FILE_H,
+    FILE_MAX,
+} file_t;
+
+typedef enum {
+    _SRANK_ = -1,                                 /* force signed enum */
+    RANK_1 = 0, RANK_2, RANK_3, RANK_4, RANK_5, RANK_6, RANK_7, RANK_8,
+    RANK_MAX,
+} rank_t;
+
+typedef enum {
+    NORTH = 8,
+    EAST =  1,
+    SOUTH = -NORTH,
+    WEST = -EAST,
+
+    NORTH_EAST = (NORTH + EAST),
+    SOUTH_EAST = (SOUTH + EAST),
+    SOUTH_WEST = (SOUTH + WEST),
+    NORTH_WEST = (NORTH + WEST),
+} dir_t;
+
+/* define diff for relative squares */
+#define sq_up(c)          ((c) == WHITE ? NORTH: SOUTH)
+#define sq_upleft(c)      ((c) == WHITE ? NORTH_WEST: SOUTH_EAST)
+#define sq_upright(c)     ((c) == WHITE ? NORTH_EAST: SOUTH_WEST)
+
+#include <time.h>
+
+typedef struct mclock {
+    clockid_t clocktype;
+    ulong elapsed_l;
+    double elapsed_f;
+    struct timespec start;
+} mclock_t;
+
+#define CLOCK_WALL    CLOCK_REALTIME
+#define CLOCK_SYSTEM  CLOCK_MONOTONIC_RAW
+#define CLOCK_PROCESS CLOCK_PROCESS_CPUTIME_ID
+#define CLOCK_THREAD  CLOCK_THREAD_CPUTIME_ID
+
+/**
+ * CLOCK_DEFINE - define a clock type.
+ * @name: clock name
+ * @type: clock type
+ *
+ * This macro is equivalent to:
+ *   mclock_t name;
+ *   clock_init(&name, type);
+ */
+#define CLOCK_DEFINE(name, type) struct mclock name = { .clocktype = type }
+
+void clock_init(mclock_t *clock, clockid_t type);
+void clock_start(mclock_t *clock);
+s64 clock_elapsed_μs(mclock_t *clock);
+s64 clock_elapsed_ms(mclock_t *clock);
+double clock_elapsed_sec(mclock_t *clock);

 #endif  /* _CHESSDEFS_H */
--- a/src/fen.c
+++ b/src/fen.c
@@ -1,4 +1,4 @@
-/* fen.c - fen notation.
+/* fen.c - fen parsing/generation/test.
 *
 * Copyright (C) 2021-2024 Bruno Raoult ("br")
 * Licensed under the GNU General Public License v3.0 or later.
@@ -21,10 +21,11 @@
 #include <bug.h>

 #include "chessdefs.h"
+#include "util.h"
+//#include "piece.h"
+//#include "bitboard.h"
 #include "position.h"
 #include "fen.h"
-#include "piece.h"
-#include "util.h"

 /* FEN description:
 * 1 : pieces on board (no space allowed):
@@ -59,6 +60,79 @@ static const char *castle_str = "KQkq";

 #define SKIP_BLANK(p) for(;isspace(*(p)); (p)++)

+/**
+ * fen_check(pos_t *pos) - test (and try to fix) fen-generated position.
+ * @pos: position
+ *
+ * Test and fix the following:
+ * - inconsistent castle flags (if K & R are not in correct position)
+ * - inconsistent en-passant square (turn, bad pawn position)
+ *
+ * pos_check() is also called, leading to fatal errors if something is wrong.
+ *
+ * @return: 0 if OK, 1 if OK after fix, -1 if fatal issue.
+ */
+static int fen_check(pos_t *pos)
+{
+    char *colstr[2] = { "white", "black"};
+    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);
+        piece_t pawn = pos->turn == WHITE? B_PAWN: W_PAWN;
+        if (warn(eprank != rank6 ||
+                 pos->board[sq_make(epfile, rank5)] != pawn ||
+                 pos->board[sq_make(epfile, rank6)] != EMPTY ||
+                 pos->board[sq_make(epfile, rank7)] != EMPTY,
+                 "fen warn: wrong en-passant settings. (fixed)\n")) {
+#           ifdef DEBUG_FEN
+            printf("ep5=%o ep6=%o ep7=%o\n", sq_make(epfile, rank5),
+                   sq_make(epfile, rank6), sq_make(epfile, rank7));
+#           endif
+            warning++;
+            pos->en_passant = SQUARE_NONE;
+        }
+    }
+
+    for (int color = WHITE; color <= BLACK; ++color) {
+        rank_t rank1 = color == WHITE? RANK_1: RANK_8;
+
+        /* castling */
+        /* where K and R should be for valid castle flag */
+        bitboard_t k    = bb_sq[sq_make(FILE_E, rank1)];
+        bitboard_t r_k  = bb_sq[sq_make(FILE_H, rank1)];
+        bitboard_t r_q  = bb_sq[sq_make(FILE_A, rank1)];
+
+       /* where they are */
+        bitboard_t kings = pos->bb[color][KING];
+        bitboard_t rooks = pos->bb[color][ROOK];
+        castle_rights_t castle_k = color == WHITE? CASTLE_WK: CASTLE_BK;
+        castle_rights_t castle_q = color == WHITE? CASTLE_WQ: CASTLE_BQ;
+        if (pos->castle & castle_k) {
+            if (warn(!(k & kings && r_k & rooks),
+                     "fen warn: wrong %s short castling K or R position (fixed)\n",
+                     colstr[color])) {
+                warning++;
+                pos->castle &= ~castle_k;
+            }
+        }
+        if (pos->castle & castle_q) {
+            if (warn(!(k & kings && r_q & rooks),
+                     "fen warn: wrong %s long castling K or R position (fixed)\n",
+                     colstr[color])) {
+                warning++;
+                pos->castle &= ~castle_q;
+            }
+        }
+    }
+    return pos_ok(pos, 0) ? warning: -1;
+}
+
 /**
 * startpos - create a game start position
 * @pos: a position pointer or NULL
@@ -92,7 +166,6 @@ pos_t *fen2pos(pos_t *pos, const char *fen)
    pos_t tmppos;

    pos_clear(&tmppos);
-
    /* 1) get piece placement information
     */
    for (rank = 7, file = 0; *cur && !isspace(*cur); ++cur) {
@@ -105,9 +178,9 @@ pos_t *fen2pos(pos_t *pos, const char *fen)
            file += *cur - '0';
            continue;
        }
-        if ((piece = char_color_to_piece(*cur)) != EMPTY) {
+        if ((piece = piece_from_fen(*cur)) != EMPTY) {
 #           ifdef DEBUG_FEN
-            log_i(5, "f=%d r=%d *p=%c piece=%#04x t=%d c=%d\n", file, rank, *cur,
+            printf("f=%d r=%d *p=%c piece=%#04x t=%d c=%d\n", file, rank, *cur,
                  piece, PIECE(piece), COLOR(piece));
 #           endif
            pos_set_sq(&tmppos, sq_make(file, rank), piece);
@@ -142,42 +215,50 @@ pos_t *fen2pos(pos_t *pos, const char *fen)

    /* 4) en passant
     */
-    tmppos.en_passant = 0;
    if (*cur == '-') {
        cur++;
    } else {
-        tmppos.en_passant = sq_make(C2FILE(*cur), C2RANK(*(cur+1)));
+        tmppos.en_passant = sq_from_string(cur);
        cur += 2;
    }
    SKIP_BLANK(cur);

    /* 5) half moves since last capture or pawn move (50 moves rule)
     */
-    sscanf(cur, "%hd%n", &tmppos.clock_50, &consumed);
+    tmppos.clock_50 = 0;
+    tmppos.plycount = 1;
+    if (sscanf(cur, "%hd%n", &tmp, &consumed) != 1)
+        goto end;                                 /* early end, ignore w/o err */
+
+    tmppos.clock_50 = tmp;
    cur += consumed;
    SKIP_BLANK(cur);

    /* 6) current full move number, starting with 1
     */
-    sscanf(cur, "%hd", &tmp);
+    if (sscanf(cur, "%hd", &tmp) != 1)
+        goto end;
    if (tmp <= 0)                                 /* fix faulty numbers*/
        tmp = 1;
    tmp = 2 * (tmp - 1) + (tmppos.turn == BLACK); /* plies, +1 if black turn */
-
    tmppos.plycount = tmp;

-#   ifdef DEBUG_FEN
-    raw_board_print(&tmppos);
-#   endif
-
 end:
    if (warn(err_line, "FEN error line %d: charpos=%d char=%#x(%c)\n",
             err_line, err_pos, err_char, err_char)) {
        return NULL;
    }
+    if (fen_check(&tmppos) < 0)
+        return NULL;
    if (!pos)
-        pos = pos_new();
-    *pos = tmppos;
+        pos = pos_dup(&tmppos);
+    //puts("prout 1");
+    //pos_print_raw(&tmppos, 1);
+    //puts("prout 2");
+#   ifdef DEBUG_FEN
+    pos_print_raw(&tmppos, 1);
+#   endif
+
    return pos;
 }

@@ -209,13 +290,23 @@ char *pos2fen(const pos_t *pos, char *fen)
        for (file_t f = FILE_A; f <= FILE_H;) {
            square_t sq = sq_make(f, r);
            piece_t piece = pos->board[sq];
-            if (pos->board[sq] == EMPTY) {
+#           ifdef DEBUG_FEN
+            printf("r=%d f=%d p=%d pos=%d\n", r, f, piece, cur);
+#           endif
+            if (piece == EMPTY) {
                int len = 0;
                for (; f <= FILE_H && pos->board[sq_make(f, r)] == EMPTY; f++)
                    len++;
+#               ifdef DEBUG_FEN
+                printf("empty=%d char=%c\n", len, '0' + len);
+#               endif
                fen[cur++] = '0' + len;
            } else {
-                fen[cur++] = piece_to_char_color(piece);
+                fen[cur++] = *piece_to_fen(piece);
+#               ifdef DEBUG_FEN
+                printf("f1=%d r=%d c=%c t=%d c=%d \n", f, r,
+                       *(piece_to_fen(piece)), PIECE(piece), COLOR(piece));
+#               endif
                f++;
            }
        }
@@ -240,7 +331,7 @@ char *pos2fen(const pos_t *pos, char *fen)

    /* 4) en passant
     */
-    if (!pos->en_passant) {
+    if (pos->en_passant == SQUARE_NONE) {
        fen[cur++] = '-';
    } else {
        fen[cur++] = FILE2C(sq_file(pos->en_passant));
--- a/src/fen.h
+++ b/src/fen.h
@@ -14,7 +14,7 @@
 #ifndef FEN_H
 #define FEN_H

-#include "position.h"
+#include "chessdefs.h"

 #define FENSTRLEN 92                              /* secure FEN string size */

--- a/src/hyperbola-quintessence.c
+++ b/src/hyperbola-quintessence.c
@@ -44,11 +44,10 @@ uchar bb_rank_attacks[64 * 8];
 *   2) shift left result 2 more bits, as bit 0 is unused and already cleared:
 *      (O <<= 2)
 *
- * TODO ? create masks excluding slider (eg. bb_diagonal ^ bb_sq[square]),
+ * TODO ? create masks excluding slider (eg. bb_diag ^ bb_sq[square]),
 * to save one operation in hyperbola_moves().
 * TODO ? replace rank attack with this idea, mapping rank to diagonal ?
 * See http://timcooijmans.blogspot.com/2014/04/
- *
 */
 void hyperbola_init()
 {
@@ -56,7 +55,8 @@ void hyperbola_init()
     */
    for (int occ = 0; occ < 64; ++occ) {
        for (int file = 0; file < 8; ++file) {
-            uchar attacks = 0;
+            int attacks = 0;
+            //int o = mask << 1;                    /* skip right square */

            /* set f left attacks */
            for (int slide = file - 1; slide >= 0; --slide) {
@@ -69,43 +69,60 @@ void hyperbola_init()
            for (int slide = file + 1; slide < 8; ++slide) {
                int b = bb_sq[slide];
                attacks |= b;
-                if ((occ << 1) & b)
+                if ((occ << 1) & b)               /* piece on b, we stop */
+                    //if ((o & b) == b)
                    break;
            }
-            bb_rank_attacks[occ * 8 + file] = attacks;
+            bb_rank_attacks[(occ << 3) + file] = attacks;
+
+            //if (((occ << 3) + file) == 171) {
+            //char str[64], str2[64];
+               //printf("mask=%x=%s file=%d att=%x=%s\n",
+               //       occ, bitboard_rank_sprint(str, occ), file,
+               //       attacks, bitboard_rank_sprint(str2, attacks));
+            //}
        }
    }
 }

 /**
- * hyperbola_rank_moves() - generate rank moves for a sliding piece.
+ * hyperbola_rank_moves() - get rank moves for a sliding piece.
 * @pieces: occupation bitboard
 * @sq: piece square
 *
- * Rank attacks are not handled by HQ, so we do it with a
+ * Rank attacks are not handled by HQ, so this function uses a pre-calculated
+ * rank attacks table (@bb_rank_attacks).
 *
- * @Return: The moves mask for piece
+ * @Return: bitboard of @piece available pseudo-moves.
 */
-static bitboard_t hyperbola_rank_moves(bitboard_t occ, square_t sq)
+bitboard_t hyperbola_rank_moves(bitboard_t occ, square_t sq)
 {
-    uint32_t rank = sq & SQ_FILEMASK;
-    uint32_t file = sq & SQ_RANKMASK;
-    uint64_t o = (occ >> rank) & 0x7e;            /* 01111110 clear bits 0 & 7 */
-
-    return ((bitboard_t)bb_rank_attacks[o * 4 + file]) << rank;
+    u32 rank = sq & SQ_RANKMASK;
+    u32 file = sq & SQ_FILEMASK;
+    u64 o = (occ >> rank) & 0176;                 /* 01111110 clear bits 0 & 7 */
+    //char zob[128], zob2[128];
+    //printf("rank_moves: occ=%lx=%s file=%d o=%lx=%s index=%ld=%ld attack=%lx=%s\n", occ,
+    //       bitboard_rank_sprint(zob, occ), file, o,
+    //       bitboard_rank_sprint(zob, o), (o << 2) + file, (o * 4) + file,
+    //       (bitboard_t)bb_rank_attacks[(o << 2) + file] << rank,
+    //       bitboard_rank_sprint(zob2, (bitboard_t)bb_rank_attacks[(o << 2) + file] << rank));
+    return ((bitboard_t)bb_rank_attacks[(o << 2) + file]) << rank;
 }

 /**
- * hyperbola_moves() - generate hyperbola moves mask for a given sliding piece
+ * hyperbola_moves() - get hyperbola pseudo-moves for a sliding piece
 * @pieces: occupation bitboard
 * @sq: piece square
- * @mask: mask considered
+ * @mask: the appropriate mask (pre-calculated)
 *
- * See https://www.chessprogramming.org/Hyperbola_Quintessence
+ * This function can be used for files, diagonal, and anti-diagonal attacks.
+ * @mask is the corresponding pre-calculated table (@bb_sqfile, @bb_sqdiag,
+ * or @bb_sqanti).
+ * See https://www.chessprogramming.org/Hyperbola_Quintessence for details.
 *
- * @Return: The moves mask for piece
+ * @Return: bitboard of piece available pseudo-moves.
 */
-static bitboard_t hyperbola_moves(const bitboard_t pieces, const square_t sq,
+bitboard_t hyperbola_moves(const bitboard_t pieces, const square_t sq,
                                   const bitboard_t mask)
 {
    bitboard_t o = pieces & mask;
@@ -117,32 +134,77 @@ static bitboard_t hyperbola_moves(const bitboard_t pieces, const square_t sq,
        & mask;
 }

-static bitboard_t hyperbola_file_moves(bitboard_t occ, square_t sq)
+/**
+ * hyperbola_file_moves() - get file pseudo-moves for a sliding piece.
+ * @pieces: occupation bitboard
+ * @sq: piece square
+ *
+ * @Return: bitboard of piece available pseudo-moves on its file.
+ */
+bitboard_t hyperbola_file_moves(const bitboard_t occ, const square_t sq)
 {
-    return hyperbola_moves(occ, bb_file[sq], sq);
+    return hyperbola_moves(occ, sq, bb_sqfile[sq]);
 }

-static bitboard_t hyperbola_diagonal_moves(bitboard_t occ, square_t sq)
+/**
+ * hyperbola_diag_moves() - get diagonal pseudo-moves for a sliding piece.
+ * @pieces: occupation bitboard
+ * @sq: piece square
+ *
+ * @Return: bitboard of piece available pseudo-moves on its diagonal.
+ */
+bitboard_t hyperbola_diag_moves(const bitboard_t occ, const square_t sq)
 {
-    return hyperbola_moves(occ, bb_diagonal[sq], sq);
+    return hyperbola_moves(occ, sq, bb_sqdiag[sq]);
 }

-static bitboard_t hyperbola_antidiagonal_moves(bitboard_t occ, square_t sq)
+/**
+ * hyperbola_anti_moves() - get anti-diagonal pseudo-moves for a sliding piece.
+ * @pieces: occupation bitboard
+ * @sq: piece square
+ *
+ * @Return: bitboard of piece available pseudo-moves on its anti-diagonal.
+ */
+bitboard_t hyperbola_anti_moves(const bitboard_t occ, const square_t sq)
 {
-    return hyperbola_moves(occ, bb_antidiagonal[sq], sq);
+    return hyperbola_moves(occ, sq, bb_sqanti[sq]);
 }

-bitboard_t hyperbola_bishop_moves(bitboard_t occ, square_t sq)
+/**
+ * hyperbola_bishop_moves() - get bitboard of bishop pseudo-moves
+ * @occ: occupation bitboard
+ * @sq: bishop square
+ *
+ * @Return: bitboard of bishop available pseudo-moves.
+ */
+bitboard_t hyperbola_bishop_moves(const bitboard_t occ, const square_t sq)
 {
-    return hyperbola_diagonal_moves(occ, sq) + hyperbola_antidiagonal_moves(occ, sq);
+    return hyperbola_diag_moves(occ, sq) | hyperbola_anti_moves(occ, sq);
 }

-bitboard_t hyperbola_rook_moves(bitboard_t occ, square_t sq)
+/**
+ * hyperbola_rook_moves() - get bitboard of rook pseudo-moves
+ * @occ: occupation bitboard
+ * @sq: rook square
+ *
+ * @Return: bitboard of rook available pseudo-moves.
+ */
+bitboard_t hyperbola_rook_moves(const bitboard_t occ, const square_t sq)
 {
-    return hyperbola_file_moves(occ, sq) + hyperbola_rank_moves(occ, sq);
+    return hyperbola_file_moves(occ, sq) | hyperbola_rank_moves(occ, sq);
 }

-bitboard_t hyperbola_queen_moves(bitboard_t occ, square_t sq)
+/**
+ * hyperbola_queen_moves() - get bitboard of queen pseudo-moves
+ * @occ: occupation bitboard
+ * @sq: queen square
+ *
+ * This function is a wrapper over @hyperbola_bishop_moves() and
+ * @hyperbola_rook_moves().
+ *
+ * @Return: bitboard of queen available pseudo-moves.
+ */
+bitboard_t hyperbola_queen_moves(const bitboard_t occ, const square_t sq)
 {
-    return hyperbola_bishop_moves(occ, sq) + hyperbola_rook_moves(occ, sq);
+    return hyperbola_bishop_moves(occ, sq) | hyperbola_rook_moves(occ, sq);
 }
--- a/src/hyperbola-quintessence.h
+++ b/src/hyperbola-quintessence.h
@@ -18,8 +18,16 @@
 #include "bitboard.h"

 void hyperbola_init(void);
-extern bitboard_t hyperbola_bishop_moves(bitboard_t occ, square_t sq);
-extern bitboard_t hyperbola_rook_moves(bitboard_t occ, square_t sq);
-extern bitboard_t hyperbola_queen_moves(bitboard_t occ, 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);
+
+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/misc.c
+++ b/src/misc.c
@@ -0,0 +1,112 @@
+/* misc.c - generic/catchall functions.
+ *
+ * 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 <time.h>
+
+#include "chessdefs.h"
+
+/*
+ * 1 sec      = 1000 millisec
+ * 1 millisec = 1000 microsec
+ * 1 microsec = 1000 nanosec
+ * milli = sec * 1000 + nanosec / 1000000
+ *
+ */
+
+/* We use microsec for all intermediate calcluation */
+#define NANO_IN_MICRO  1000ll                     /* nanosecond in millisecond */
+#define MICRO_IN_SEC   1000000ll                  /* millisecond in second */
+
+#define MILLI_IN_SEC   1000ll                     /* millisecond in second */
+
+#define MICRO_IN_MILLI 1000ll
+
+//#define NANO_IN_MILLI  1000000ll                         /* nanosecond in millisecond */
+//#define NANO_IN_SEC    (NANOS_IN_MS * MS_IN_SEC)
+
+
+/**
+ * clock_start - start or restart a clock.
+ * @clock: &mclock_t clock
+ *
+ * Save current time according to @clock type.
+ */
+void clock_start(mclock_t *clock)
+{
+    clock_gettime(clock->clocktype, &clock->start);
+}
+
+/**
+ * clock_init - initializes a clock type.
+ * @clock: &mclock_t clock
+ * @type: clock type
+ *
+ * See the clock_gettime(2) for details.
+ * CLOCK_WALL (a.k.a CLOCK_REALTIME): Wall clock.
+ * CLOCK_SYSTEM (a.k.a CLOCK_MONOTONIC_RAW): System clock.
+ * CLOCK_PROCESS (a.k.a CLOCK_PROCESS_CPUTIME_ID): Process CPU clock (incl. threads).
+ * CLOCK_THREAD  (a.k.a CLOCK_THREAD_CPUTIME_ID): Thread CPU clock.
+ */
+void clock_init(mclock_t *clock, clockid_t type)
+{
+    clock->clocktype = type;
+    clock_start(clock);
+}
+
+/**
+ * clock_elapsed_μs - return a mclock_t elapsed time in microseconds.
+ * @clock: &mclock_t clock
+ *
+ * The elapsed time is calculated between current time and last clock_start(@clock)
+ * call time.
+ *
+ * @return: microseconds elapsed since last clock_start().
+ */
+s64 clock_elapsed_μs(mclock_t *clock)
+{
+    struct timespec current;
+    s64 μs;
+
+    clock_gettime(clock->clocktype, &current);
+    μs = ((s64)current.tv_sec - (s64)clock->start.tv_sec) * MICRO_IN_SEC +
+        ((s64)current.tv_nsec - (s64)clock->start.tv_nsec) / NANO_IN_MICRO ;
+    return μs;
+}
+
+/**
+ * clock_elapsed_ms - return a mclock_t elapsed time in milliseconds.
+ * @clock: &mclock_t clock
+ *
+ * The elapsed time is calculated between current time and last clock_start(@clock)
+ * call time.
+ *
+ * @return: milliseconds elapsed since last clock_start().
+ */
+s64 clock_elapsed_ms(mclock_t *clock)
+{
+    return clock_elapsed_μs(clock) / MICRO_IN_MILLI;
+}
+
+/**
+ * clock_elapsed_sec - return a mclock_t elapsed time in seconds.
+ * @clock: &mclock_t clock
+ *
+ * The elapsed time is calculated between current time and last clock_start(@clock)
+ * call time.
+ *
+ * @return: seconds elapsed since last clock_start().
+ */
+double clock_elapsed_sec(mclock_t *clock)
+{
+    return (double) clock_elapsed_μs(clock) / (double) MICRO_IN_SEC;
+}
--- a/src/move-do.c
+++ b/src/move-do.c
@@ -0,0 +1,193 @@
+/* move-do.c - move do/undo.
+ *
+ * Copyright (C) 2021-2024 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 <malloc.h>
+#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() - do move.
+ * @pos:    &pos_t position
+ * @move:   move to apply
+ * @state:  &state_t address where irreversible changes will be saved
+ *
+ * @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)
+ *
+ * @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_t captured = pos->board[to];
+    piece_type_t ptype = PIECE(piece);
+    color_t pcolor = COLOR(piece);
+    piece_t new_piece = piece;
+    int up = sq_up(us);
+
+    ++pos->clock_50;
+    ++pos->plycount;
+    pos->en_passant = SQUARE_NONE;
+    pos->turn = them;
+    pos->captured = captured;
+
+    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 (captured != EMPTY) {
+        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 = from + up;
+        else if (is_enpassant(move)) {            /* clear grabbed pawn */
+            square_t grabbed = to - up;
+            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];
+    int up = sq_up(them);
+
+    if (is_promotion(move))
+        piece = MAKE_PIECE(PAWN, us);
+
+    pos_clr_sq(pos, to);                          /* always clear "to" ... */
+    pos_set_sq(pos, from, piece);                 /* ... and set "from" */
+
+    if (PIECE(piece) == KING)
+        pos->king[us] = from;
+
+    if (pos->captured != EMPTY) {
+        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 = to + up;
+        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
@@ -0,0 +1,22 @@
+/* move-do.h - move do/undo.
+ *
+ * Copyright (C) 2021-2024 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>
+ *
+ */
+
+#ifndef MOVE_DO_H
+#define MOVE_DO_H
+
+#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
@@ -0,0 +1,480 @@
+/* move-gen.c - move generation
+ *
+ * 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 "bitops.h"
+#include "bug.h"
+
+#include "chessdefs.h"
+#include "board.h"
+#include "bitboard.h"
+#include "piece.h"
+#include "position.h"
+#include "move.h"
+#include "hyperbola-quintessence.h"
+#include "attack.h"
+#include "move-gen.h"
+
+
+/**
+ * pseudo_is_legal() - check if a move is legal.
+ * @pos:  position
+ * @move: move_t to verify
+ *
+ * @return: true if move is valid, false otherwise.
+ */
+bool pseudo_is_legal(const pos_t *pos, const move_t move)
+{
+    color_t  us = pos->turn, them = OPPONENT(us);
+    square_t from = move_from(move), to = move_to(move);
+    square_t king = pos->king[us];
+    bitboard_t kingbb = pos->bb[us][KING];
+    bitboard_t occ = pos_occ(pos);
+    u64 pinned = mask(from) & pos->blockers;
+    u64 checkers = pos->checkers;
+
+    /* (1) - Castling & King
+     * For castling, we need to check intermediate squares attacks only.
+     * Attention: To test if K is in check after moving, we need to exclude
+     * king from occupation bitboard (to catch king moving away from checker
+     * on same line) !
+     */
+    if (unlikely(from == king)) {
+        if (unlikely(is_castle(move))) {
+            square_t dir = to > from? 1: -1;
+            if (sq_attackers(pos, occ, from + dir, them))
+                return false;
+        }
+        return !sq_attackers(pos, occ ^ kingbb, to, them);
+    }
+
+    /* (2) - King is in check
+     * Double-check is already handled in (1), as only K moves were generated
+     * by pseudo legal move generator.
+     * Here, allowed dest squares are only on King-checker line, or on checker
+     * square.
+     * attacker.
+     * Special cases:
+     *   e.p., legal if the grabbed pawn is giving check
+     *   pinned piece: always illegal
+     */
+    if (checkers) {
+        if (pinned)
+            return false;
+        if (bb_multiple(checkers))
+            return false;
+        square_t checker = ctz64(checkers);
+        if (is_enpassant(move)) {
+            return pos->en_passant + sq_up(them) == checker;
+        }
+        return true;
+        //bitboard_t between = bb_between[king][checker] | pos->checkers;
+        //return mask(to) & between;
+    }
+
+    /* (3) - pinned pieces
+     * We verify here that pinned piece P stays on line King-P.
+     */
+    if (mask(from) & pos->blockers) {
+        return bb_line[from][king] & mask(to);    /* is to on pinner line ? */
+    }
+
+    /* (4) - En-passant
+     * pinned pieces are handled in pinned section.
+     * One case not handled anywhere else: when the two "disappearing" pawns
+     * would discover a R/Q horizontal check.
+     */
+    if (is_enpassant(move)) {
+        bitboard_t rank5 = us == WHITE? RANK_5bb: RANK_4bb;
+
+        if ((pos->bb[us][KING] & rank5)) {
+            bitboard_t exclude = mask(pos->en_passant - sq_up(us)) | mask(from);
+            bitboard_t rooks = (pos->bb[them][ROOK] | pos->bb[them][QUEEN]) & rank5;
+
+            while (rooks) {
+                square_t rook = bb_next(&rooks);
+                if (hyperbola_rank_moves(occ ^ exclude, rook) & kingbb)
+                    return false;
+            }
+        }
+    }
+    return true;
+}
+
+/**
+ * pos_next_legal() - get next legal move in position.
+ * @pos:  position
+ * @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 MOVE_NONE if no move.
+ */
+move_t pos_next_legal(const pos_t *pos, movelist_t *movelist, int *start)
+{
+    const int nmoves = movelist->nmoves;
+    const move_t *moves = movelist->move;
+    move_t move;
+
+    while (*start < nmoves) {
+        if (pseudo_is_legal(pos, (move = moves[(*start)++] )))
+            return  move;
+    }
+    return MOVE_NONE;
+}
+
+/**
+ * pos_all_legal() - get the list of legal moves from pseudo-legal.
+ * @pos:  position
+ * @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 *movelist, movelist_t *dest)
+{
+    int tmp = dest->nmoves = 0;
+    move_t move;
+
+    while ((move = pos_next_legal(pos, movelist, &tmp)) != MOVE_NONE)
+        dest->move[dest->nmoves++] = move;
+    return dest;
+}
+
+/**
+ * gen_pseudo_king() - generate king pseudo-legal moves.
+ * @pos: position
+ * @movelist: &movelist_t array to store pseudo-moves
+ *
+ */
+static inline __unused move_t *gen_pseudo_king(move_t *moves, square_t from,
+                                               bitboard_t mask)
+{
+    //color_t us    = pos->turn;
+    //square_t from = pos->king[us];
+    //bitboard_t not_my_pieces     = ~pos->bb[us][ALL_PIECES];
+    bitboard_t to_bb = bb_king_moves(mask, from);
+    square_t to;
+    while (moves) {
+        to = bb_next(&to_bb);
+        *moves++ = move_make(from, to);
+    }
+    return moves;
+}
+
+/**
+ * pos_gen_check_pseudomoves() - generate position pseudo-legal moves when in check
+ * @pos: position
+ * @movelist: &movelist_t array to store pseudo-moves
+ *
+ * Generate all @pos pseudo moves for player-to-move.
+ * @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}
+ *  - capture (excl. en-passant): M_CAPTURE
+ *  - en-passant: M_EN_PASSANT
+ *  - pawn double push: M_DPUSH
+ *  - promotion: M_PROMOTION
+ *  - promotion and capture
+ *
+ * TODO: move code to specific functions (especially castling, pawn push/capture)
+ *
+ * @Return: The total number of moves.
+ */
+
+/**
+ * gen_pseudo_escape() - generate position pseudo-legal moves when in check
+ * @pos: square_t king position
+ * @mask: possible destinations to consider
+ * @moves: &move_t array to store pseudo-moves
+ *
+ * Generate all @pos pseudo moves for player-to-move, when in check.
+ * @movelist is filled with the moves.
+ *
+ * If king is doubles-checked, only King moves will be generated.
+ * Otherwise, only moves where destination in between King or checker, or checker
+ * square.
+ *
+ */
+/*
+ * static void __always_inline gen_pseudo_escape(pos_t *pos, movelist_t *movelist)
+ * {
+ *     color_t us               = pos->turn;
+ *     color_t them             = OPPONENT(us);
+ *     square_t king            = pos->king[us];
+ *
+ *     gen_pseudo_king(pos, movelist);
+ *
+ * }
+ */
+
+/**
+ * move_make_promotions() - generate all promotions for given pawn and dest.
+ * @moves: &move_t array where to store moves
+ * @from: pawn position
+ * @to: promotion square
+ *
+ * Generate all (Q/R/B/N) promotion moves on @to for pawn @from.
+ *
+ * @Return: New @moves (incremented by 4).
+ */
+static inline move_t *move_make_promotions(move_t *moves, square_t from, square_t to)
+{
+    for (piece_type_t pt = QUEEN; pt >= KNIGHT; --pt)
+        *moves++ = move_make_promote(from, to, pt);
+    return moves;
+}
+
+/**
+ * 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.
+ * @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}
+ *  - capture (excl. en-passant): M_CAPTURE
+ *  - en-passant: M_EN_PASSANT
+ *  - pawn double push: M_DPUSH
+ *  - promotion: M_PROMOTION
+ *  - promotion and capture
+ *
+ * TODO: move code to specific functions (especially castling, pawn push/capture)
+ *
+ * @Return: The total number of moves.
+ */
+int pos_gen_pseudomoves(pos_t *pos, movelist_t *movelist)
+{
+    color_t us               = pos->turn;
+    color_t them             = OPPONENT(us);
+
+    bitboard_t my_pieces     = pos->bb[us][ALL_PIECES];
+    bitboard_t enemy_pieces  = pos->bb[them][ALL_PIECES];
+    bitboard_t dest_squares  = ~my_pieces;
+    bitboard_t occ           = my_pieces | enemy_pieces;
+    bitboard_t empty         = ~occ;
+
+    bitboard_t from_bb, to_bb;
+    bitboard_t tmp_bb;
+    move_t *moves            = movelist->move;
+    //int *nmoves              = &movelist->nmoves;
+    square_t from, to;
+    square_t king = pos->king[us];
+
+    //*nmoves = 0;
+
+    /* king - MUST BE FIRST (we stop if doubler check) */
+    to_bb = bb_king_moves(dest_squares, king);
+    while(to_bb) {
+        to = bb_next(&to_bb);
+        *moves++ = move_make(king, to);
+    }
+
+    if (bb_multiple(pos->checkers))               /* double check, we stop here */
+        goto finish;
+
+    if (pos->checkers) {
+        /* one checker: we limit destination squares to line between
+         * checker and king + checker square (think: knight).
+         */
+        square_t checker = ctz64(pos->checkers);
+        dest_squares &= bb_between[king][checker] | pos->checkers;
+        enemy_pieces &= dest_squares;
+    } else {
+        /* no checker: castling moves
+         * Attention ! Castling flags are assumed correct
+         */
+        bitboard_t rel_rank1 = bb_rel_rank(RANK_1, 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]);
+        /* 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)) {
+            bitboard_t occmask = rel_rank1 & (FILE_Fbb | FILE_Gbb);
+            if (!(occ & occmask)) {
+                *moves++ = move_make_flags(king, king + 2, M_CASTLE_K);
+            }
+        }
+        if (can_ooo(pos->castle, us)) {
+            bitboard_t occmask = rel_rank1 & (FILE_Bbb | FILE_Cbb | FILE_Dbb);
+            if (!(occ & occmask)) { // &&
+                *moves++ = move_make_flags(king, king - 2, M_CASTLE_Q);
+            }
+        }
+    }
+    /* sliding pieces */
+    from_bb = pos->bb[us][BISHOP] | pos->bb[us][QUEEN];
+    while (from_bb) {
+        from = bb_next(&from_bb);
+        to_bb = hyperbola_bishop_moves(occ, from) & dest_squares;
+        while(to_bb) {
+            to = bb_next(&to_bb);
+            *moves++ = move_make(from, to);
+        }
+    }
+    from_bb = pos->bb[us][ROOK] | pos->bb[us][QUEEN];
+    while (from_bb) {
+        from = bb_next(&from_bb);
+        to_bb = hyperbola_rook_moves(occ, from) & dest_squares;
+        while(to_bb) {
+            to = bb_next(&to_bb);
+            *moves++ = move_make(from, to);
+        }
+    }
+
+    /* knight */
+    from_bb = pos->bb[us][KNIGHT];
+    while (from_bb) {
+        from = bb_next(&from_bb);
+        to_bb = bb_knight_moves(dest_squares, from);
+        while(to_bb) {
+            to = bb_next(&to_bb);
+            *moves++ = move_make(from, to);
+        }
+    }
+
+    /* pawn: relative rank and files */
+    bitboard_t rel_rank8 = bb_rel_rank(RANK_8, us);
+    bitboard_t rel_rank3 = bb_rel_rank(RANK_3, us);
+
+    /* pawn: push */
+    int shift = sq_up(us);
+    tmp_bb = bb_shift(pos->bb[us][PAWN], shift) & empty;
+
+    to_bb = tmp_bb & ~rel_rank8 & dest_squares;   /* non promotion */
+    while(to_bb) {
+        to = bb_next(&to_bb);
+        from = to - shift;
+        *moves++ = move_make(from, to);
+    }
+    to_bb = tmp_bb & rel_rank8 & dest_squares;           /* promotions */
+    while(to_bb) {
+        to = bb_next(&to_bb);
+        from = to - shift;
+        moves = move_make_promotions(moves, from, to);
+    }
+
+    /* possible second push */
+    to_bb = bb_shift(tmp_bb & rel_rank3, shift) & empty & dest_squares;
+    while(to_bb) {
+        to = bb_next(&to_bb);
+        from = to - shift - shift;
+        *moves++ = move_make_flags(from, to, M_DPUSH);
+    }
+
+    /* pawn: captures */
+    /*
+     * tmp_bb = pawn_attacks_bb(pos->bb[us][PAWN], us) & enemy_pieces;
+     * //bb_print("FAIL", tmp_bb);
+     * to_bb = tmp_bb & ~rel_rank8;
+     * while (to_bb) {
+     *     to = bb_next(&to_bb);
+     *     from_bb = bb_pawn_attacks[them][to] & pos->bb[us][PAWN];
+     *     while (from_bb) {
+     *         from = bb_next(&from_bb);
+     *         *moves++ = move_make(from, to);
+     *     }
+     * }
+     * to_bb = tmp_bb & rel_rank8;
+     * while (to_bb) {
+     *     to = bb_next(&to_bb);
+     *     from_bb = bb_pawn_attacks[them][to] & pos->bb[us][PAWN];
+     *     while (from_bb) {
+     *         from = bb_next(&from_bb);
+     *         moves = move_make_promotions(moves, from, to);
+     *     }
+     * }
+     */
+
+    /* pawn: captures left */
+    bitboard_t filter = ~bb_rel_file(FILE_A, us);
+    shift = sq_upleft(us);
+    tmp_bb = bb_shift(pos->bb[us][PAWN] & filter, shift) & enemy_pieces;
+
+    to_bb = tmp_bb & ~rel_rank8;
+    while (to_bb) {
+        to = bb_next(&to_bb);
+        from = to - shift;
+        *moves++ = move_make(from, to);
+    }
+    to_bb = tmp_bb & rel_rank8;
+    while (to_bb) {
+        to = bb_next(&to_bb);
+        from = to - shift;
+        moves = move_make_promotions(moves, from, to);
+    }
+
+    /* pawn: captures right */
+    filter = ~bb_rel_file(FILE_H, us);
+    shift = sq_upright(us);
+    tmp_bb = bb_shift(pos->bb[us][PAWN] & filter, shift) & enemy_pieces;
+    to_bb = tmp_bb & ~rel_rank8;
+    while (to_bb) {
+        to = bb_next(&to_bb);
+        from = to - shift;
+        *moves++ = move_make(from, to);
+    }
+    to_bb = tmp_bb & rel_rank8;
+    while (to_bb) {
+        to = bb_next(&to_bb);
+        from = to - shift;
+        moves = move_make_promotions(moves, from, to);
+    }
+
+    /* pawn: en-passant
+     * TODO: special case when in-check here ?
+     */
+    if ((to = pos->en_passant) != SQUARE_NONE) {
+        from_bb = bb_pawn_attacks[them][to] & pos->bb[us][PAWN];
+        while (from_bb) {
+            from = bb_next(&from_bb);
+            *moves++ = move_make_enpassant(from, to);
+        }
+    }
+    /*
+     * to_bb = mask(to);
+     *     /\* if e.p not on file H, we may add an e.p move to "up-left" *\/
+     *     filter = ~bb_rel_file(FILE_A, us);
+     *     shift = sq_upleft(us);
+     *     if (bb_shift(pos->bb[us][PAWN] & filter, shift) & to_bb)
+     *         *moves++ = move_make_enpassant(to - shift, to);
+     *
+     *     filter = ~bb_rel_file(FILE_H, us);
+     *     shift = sq_upright(us);
+     *     if (bb_shift(pos->bb[us][PAWN] & filter, shift) & to_bb)
+     *         *moves++ = move_make_enpassant(to - shift, to);
+     * }
+     */
+
+    /* TODO: add function per piece, and type, for easier debug
+     */
+finish:
+    return movelist->nmoves = moves - movelist->move;
+}
--- a/src/move-gen.h
+++ b/src/move-gen.h
@@ -1,4 +1,4 @@
-/* movegen.h - move generation
+/* move-gen.h - move generation
 *
 * Copyright (C) 2024 Bruno Raoult ("br")
 * Licensed under the GNU General Public License v3.0 or later.
@@ -21,10 +21,9 @@
 #include "piece.h"
 #include "move.h"

-/**
- * gen_all_pseudomoves() - generate all pseudo moves
- *
- */
-int gen_all_pseudomoves(pos_t *pos);
+bool pseudo_is_legal(const pos_t *pos, const move_t move);
+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
--- a/src/move.h
+++ b/src/move.h
@@ -1,6 +1,6 @@
 /* move.h - move management.
 *
- * 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.
 *
@@ -15,50 +15,120 @@
 #define MOVE_H

 #include "chessdefs.h"
-#include "position.h"
-//#include "pool.h"
 #include "piece.h"
+#include "board.h"

 /* move structure:
- * 3     2 2     1 1 1 1 1 1
- * 1     5 4     8 7 5 4 2 1    6 5    0
- * UUUUUUU FFFFFFF ppp ccc tttttt ffffff
+ * 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    range         type     mask        get   desc
- * ffffff    0-5     square_t       3f        &63   from
- * tttttt   6-11     square_t      fc0   (>>6)&63   to
- * ccc     12-14 piece_type_t     7000   (>>12)&7   captured
- * ppp     15-17 piece_type_t    38000   (>>15)&7   promoted
- * FFFFFFF 18-24          N/A  1fc0000        N/A   flags
- * UUUUUUU 25-31       unused fe000000        N/A   future usage ?
+ * 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
 */
-#define move_t u32
+typedef s32 move_t;

-#define M_
-/* move flags */
-#define M_FLAGS_BEG 18
-#define M_HAS_FLAGS mask(_M_FLAGS_BEG + 0)            /* probably unused */
-#define M_CAPTURE   mask(_M_FLAGS_BEG + 1)
-#define M_ENPASSANT mask(_M_FLAGS_BEG + 2)
-#define M_PROMOTION mask(_M_FLAGS_BEG + 3)
-#define M_CASTLE_K  mask(_M_FLAGS_BEG + 4)
-#define M_CASTLE_Q  mask(_M_FLAGS_BEG + 5)
-#define M_CHECK     mask(_M_FLAGS_BEG + 6)            /* probably unknown/useless */
+/* special move_t values */
+#define MOVE_NONE ((move_t) -1)
+#define MOVE_NULL ((move_t) 0)                    /* hack: from = to = A1 */

-#define M_FLAGS     (M_CAPTURE | M_ENPASSANT | M_PROMOTION | \
-                     M_CASTLE_K | M_CASTLE_Q | M_CHECK)
-#define M_NORMAL    (~M_FLAGS)
+enum {
+    M_OFF_FROM     = 0,
+    M_OFF_TO       = 6,
+    M_OFF_PROMOTED = 12,
+    M_OFF_CAPTURED = 15,
+    M_OFF_FLAGS    = 18
+};
+
+typedef enum {
+    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_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

-static inline move_t move_make(square_t from, square_t to)
+typedef struct __movelist_s {
+    move_t move[MOVES_MAX];
+    int nmoves;                                   /* total moves (fill) */
+} movelist_t;
+
+static inline square_t move_from(move_t move)
 {
-    return (to << 3) | from;
+    return move & 077;
 }

-static inline move_t move_from(move_t move)
+static inline square_t move_to(move_t move)
 {
-    return move & 56;
+    return (move >> M_OFF_TO) & 077;
+}
+
+static inline piece_type_t move_promoted(move_t move)
+{
+    return (move >> M_OFF_PROMOTED) & 07;
+}
+
+static inline piece_type_t move_captured(move_t move)
+{
+    return (move >> M_OFF_CAPTURED) & 07;
+}
+
+static inline move_t move_make(square_t from, square_t to)
+{
+    return (to << M_OFF_TO) | from;
+}
+
+static inline move_t move_make_flags(square_t from, square_t to, move_flags_t flags)
+{
+    return move_set_flags(move_make(from, to), flags);
+}
+
+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_PROMOTED);
+}
+
+static inline move_t move_make_promote_capture(square_t from, square_t to,
+                                               piece_type_t promoted)
+{
+    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
@@ -67,37 +137,14 @@ static inline move_t move_from(move_t move)
 #define M_PR_NCAPT     0x02
 #define M_PR_NUM       0x04
 #define M_PR_NL        0x08
+#define M_UCI          0x10                       /* UCI style - e7e8q */
 #define M_PR_EVAL      0x20                       /* separate captures */
 #define M_PR_SEPARATE  0x40                       /* separate captures */
 #define M_PR_LONG      0x80

-typedef struct {
-    move_t move[MOVES_MAX];
-    int nmoves;                                   /* total moves (fill) */
-    int curmove;                                  /* current move (use) */
-} movelist_t;
-
-//pool_t *moves_pool_init();
-//void moves_pool_stats();
 //int move_print(int movenum, move_t *move, move_flags_t flags);
-//void moves_print(pos_t *move, move_flags_t flags);
-
-//void move_del(struct list_head *ptr);
-//int moves_del(pos_t *pos);
-
-int pseudo_moves_castle(pos_t *pos, bool color, bool doit, bool do_king);
-//int pseudo_moves_gen(pos_t *pos, piece_list_t *piece, bool doit, bool do_king);
-//int pseudo_moves_pawn(pos_t *pos, piece_list_t *piece, bool doit);
-int moves_gen(pos_t *pos, bool color, bool doit, bool do_king);
-int moves_gen_king_moves(pos_t *pos, bool color, bool doit);
-
-void moves_sort(pos_t *pos);
-void moves_gen_eval_sort(pos_t *pos);
-
-void moves_gen_all(pos_t *pos);
-void moves_gen_all_nomoves(pos_t *pos);
-
-pos_t *move_do(pos_t *pos, move_t *move);
-void move_undo(pos_t *pos, move_t *move);
+char *move_str(char *dst, const move_t move, __unused const int flags);
+void moves_print(movelist_t *moves, int flags);
+void move_sort_by_sq(movelist_t *moves);

 #endif  /* MOVE_H */
--- a/src/movegen.c
+++ b/src/movegen.c
@@ -1,74 +0,0 @@
-/* movegen.c - move generation
- *
- * 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 "bitops.h"
-
-#include "bitboard.h"
-#include "hyperbola-quintessence.h"
-#include "piece.h"
-#include "move.h"
-
-//void add_pseudo_move(move_t *pmove, square_t from, square_t to)
-//{
-//    pmov
-//}
-
-/**
- * gen_all_pseudomoves() - generate all pseudo moves
- *
- */
-int gen_all_pseudomoves(pos_t *pos)
-{
-    int me = pos->turn, other = OPPONENT(me);
-    bitboard_t my_pieces = pos->bb[me][ALL_PIECES], notmine = ~my_pieces,
-        other_pieces = pos->bb[other][ALL_PIECES],
-        occ = my_pieces | other_pieces, movebits;
-    int tmp1, tmp2, from, to;
-    movelist_t moves = pos->moves;
-
-    /* sliding pieces */
-    bit_for_each64(from, tmp1, pos->bb[me][BISHOP]) {
-        movebits = hyperbola_bishop_moves(occ, from) & notmine;
-        bit_for_each64(to, tmp2, movebits) {
-            moves.move[moves.nmoves++] = move_make(from, to);
-        }
-
-    }
-    bit_for_each64(from, tmp1, pos->bb[me][ROOK]) {
-        movebits = hyperbola_rook_moves(occ, from) & notmine;
-        bit_for_each64(to, tmp2, movebits) {
-            moves.move[moves.nmoves++] = move_make(from, to);
-        }
-    }
-    bit_for_each64(from, tmp1, pos->bb[me][QUEEN]) {
-        movebits = hyperbola_queen_moves(occ, from) & notmine;
-        bit_for_each64(to, tmp2, movebits) {
-            moves.move[moves.nmoves++] = move_make(from, to);
-        }
-    }
-
-    /* knight */
-    bit_for_each64(from, tmp1, pos->bb[me][KNIGHT]) {
-        movebits = bb_knight_moves(occ, from) & notmine;
-        bit_for_each64(to, tmp2, movebits) {
-            moves.move[moves.nmoves++] = move_make(from, to);
-        }
-    }
-
-    /* king */
-    movebits = bb_king_moves(occ, pos->king[me]) & notmine;
-    bit_for_each64(to, tmp2, movebits) {
-        moves.move[moves.nmoves++] = move_make(from, to);
-    }
-    /* TODO  */
-}
--- a/src/piece.c
+++ b/src/piece.c
@@ -25,22 +25,22 @@
 * piece_details
 */
 const struct piece_details piece_details[PIECE_MAX] = {
-    /*             Abb  AbbC Sym  SymC Name   start value */
-    [EMPTY]    = { ' ', ' ', " ", " ", " ", 0, 0, 0 },
-    [W_PAWN]   = { 'P', 'P', "♟", "♙", "Pawn",   P_VAL_OPN, P_VAL_MID, P_VAL_END },
-    [W_KNIGHT] = { 'N', 'N', "♞", "♘", "Knight", N_VAL_OPN, N_VAL_MID, N_VAL_END },
-    [W_BISHOP] = { 'B', 'B', "♝", "♗", "Bishop", B_VAL_OPN, B_VAL_MID, B_VAL_END },
-    [W_ROOK]   = { 'R', 'R', "♜", "♖", "Rook",   R_VAL_OPN, R_VAL_MID, R_VAL_END },
-    [W_QUEEN]  = { 'Q', 'Q', "♛", "♕", "Queen",  Q_VAL_OPN, Q_VAL_MID, Q_VAL_END },
-    [W_KING]   = { 'K', 'K', "♚", "♔", "King",   K_VAL_OPN, K_VAL_MID, K_VAL_END },
-    [7]        = { '7', '7', "<EFBFBD>", "<EFBFBD>", "Inv 7",  0, 0, 0 },
-    [8]        = { '8', '8', "<EFBFBD>", "<EFBFBD>", "Inv 8",  0, 0, 0 },
-    [B_PAWN]   = { 'P', 'p', "♟", "♟", "Pawn",   P_VAL_OPN, P_VAL_MID, P_VAL_END },
-    [B_KNIGHT] = { 'N', 'n', "♞", "♞", "Knight", P_VAL_OPN, N_VAL_MID, N_VAL_END },
-    [B_BISHOP] = { 'B', 'b', "♝", "♝", "Bishop", P_VAL_OPN, B_VAL_MID, B_VAL_END },
-    [B_ROOK]   = { 'R', 'r', "♜", "♜", "Rook",   P_VAL_OPN, R_VAL_MID, R_VAL_END },
-    [B_QUEEN]  = { 'Q', 'q', "♛", "♛", "Queen",  P_VAL_OPN, Q_VAL_MID, Q_VAL_END },
-    [B_KING]   = { 'K', 'k', "♚", "♚", "King",   P_VAL_OPN, K_VAL_MID, K_VAL_END },
+    /*             cap  low  fen  sym  name      values */
+    [EMPTY]    = { "",  "",  "",  "",  "",       0, 0, 0 },
+    [W_PAWN]   = { "",  "",  "P", "♙", "Pawn",   P_VAL_OPN, P_VAL_MID, P_VAL_END },
+    [W_KNIGHT] = { "N", "n", "N", "♘", "Knight", N_VAL_OPN, N_VAL_MID, N_VAL_END },
+    [W_BISHOP] = { "B", "b", "B", "♗", "Bishop", B_VAL_OPN, B_VAL_MID, B_VAL_END },
+    [W_ROOK]   = { "R", "r", "R", "♖", "Rook",   R_VAL_OPN, R_VAL_MID, R_VAL_END },
+    [W_QUEEN]  = { "Q", "q", "Q", "♕", "Queen",  Q_VAL_OPN, Q_VAL_MID, Q_VAL_END },
+    [W_KING]   = { "K", "k", "K", "♔", "King",   K_VAL_OPN, K_VAL_MID, K_VAL_END },
+    [7]        = { "",  "",  "",  "",  "",       0, 0, 0 },
+    [8]        = { "",  "",  "",  "",  "",       0, 0, 0 },
+    [B_PAWN]   = { "",  "",  "p", "♟", "Pawn",   P_VAL_OPN, P_VAL_MID, P_VAL_END },
+    [B_KNIGHT] = { "N", "n", "n", "♞", "Knight", P_VAL_OPN, N_VAL_MID, N_VAL_END },
+    [B_BISHOP] = { "B", "b", "b", "♝", "Bishop", P_VAL_OPN, B_VAL_MID, B_VAL_END },
+    [B_ROOK]   = { "R", "r", "r", "♜", "Rook",   P_VAL_OPN, R_VAL_MID, R_VAL_END },
+    [B_QUEEN]  = { "Q", "q", "q", "♛", "Queen",  P_VAL_OPN, Q_VAL_MID, Q_VAL_END },
+    [B_KING]   = { "K", "k", "k", "♚", "King",   P_VAL_OPN, K_VAL_MID, K_VAL_END },
 };

 const char pieces_str[6+6+1] = "PNBRQKpnbrqk";
@@ -51,24 +51,24 @@ bool piece_ok(piece_t p)
    return !(p & ~(MASK_COLOR | MASK_PIECE)) && pt && (pt <= KING);
 }

-char piece_to_char(piece_t p)
+char *piece_to_cap(piece_t p)
 {
-    return piece_details[p].abbr;
+    return piece_details[p].cap;
 }

-char piece_to_char_color(piece_t p)
+char *piece_to_char(piece_t p)
 {
-    return piece_details[p].abbr_color;
+    return piece_details[p].fen;
+}
+
+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_color(piece_t p)
-{
-    return piece_details[p].sym_color;
+    return piece_details[p].sym;
 }

 char *piece_to_name(piece_t p)
@@ -76,98 +76,20 @@ char *piece_to_name(piece_t p)
    return piece_details[p].name;
 }

-piece_t char_to_piece(char c)
+piece_type_t piece_t_from_char(char c)
 {
    char *p = strchr(pieces_str, c);
-    return p? (p - pieces_str) % 6 + 1: EMPTY;
+    return p? (p - pieces_str) % 6 + 1: NO_PIECE_TYPE;
 }

-piece_t char_color_to_piece(char c)
+//piece_type_t piece_from_promotion(char c, color_t color)
+//{
+//    piece_type_t piece = piece_t_from_char(c);
+//    return piece? SET_COLOR()p? (p - pieces_str) % 6 + 1: NO_PIECE_TYPE;
+//}
+
+piece_t piece_from_char(char c)
 {
-    piece_t piece = char_to_piece(c);
-    return isupper(c)? piece: SET_BLACK(piece);
+    piece_type_t piece = piece_t_from_char(c);
+    return isupper(c)? SET_WHITE(piece): SET_BLACK(piece);
 }
-
-
-/*
- * void piece_list_print(struct list_head *list)
- * {
- *     struct list_head *p_cur, *tmp;
- *     piece_list_t *piece;
- *
- *     list_for_each_safe(p_cur, tmp, list) {
- *         piece = list_entry(p_cur, piece_list_t, list);
- *
- *         printf("%s%c%c ", P_SYM(piece->piece),
- *                FILE2C(F88(piece->square)),
- *                RANK2C(R88(piece->square)));
- *     }
- *     printf("\n");
- * }
- *
- * pool_t *piece_pool_init()
- * {
- *     if (!pieces_pool)
- *         pieces_pool = pool_create("pieces", 128, sizeof(piece_list_t));
- *     return pieces_pool;
- * }
- *
- * void piece_pool_stats()
- * {
- *     if (pieces_pool)
- *         pool_stats(pieces_pool);
- * }
- *
- * piece_list_t *piece_add(pos_t *pos, piece_t piece, square_t square)
- * {
- *     piece_list_t *new;
- *     short color = COLOR(piece);
- *
- * #   ifdef DEBUG_PIECE
- *     log_f(3, "piece=%02x square=%02x\n", piece, square);
- *     log_f(5, "Adding %s %s on %c%c\n", color? "Black": "White",
- *           P_NAME(piece), FILE2C(F88(square)), RANK2C(R88(square)));
- * #   endif
- *     if ((new = pool_get(pieces_pool))) {
- *         /\* first piece is always king *\/
- *         if (PIECE(piece) == KING)
- *             list_add(&new->list, &pos->pieces[color]);
- *         else
- *             list_add_tail(&new->list, &pos->pieces[color]);
- *         new->piece = piece;
- *         new->square = square;
- *         new->castle = 0;
- *         new-> value = piece_details[PIECE(piece)].value;
- *     }
- *
- *     return new;
- * }
- *
- * void piece_del(struct list_head *ptr)
- * {
- *     piece_list_t *piece = list_entry(ptr, piece_list_t, list);
- * #   ifdef DEBUG_PIECE
- *     log_f(3, "piece=%02x square=%02x\n", piece->piece, piece->square);
- * #   endif
- *     list_del(ptr);
- *     pool_add(pieces_pool, piece);
- *     return;
- * }
- *
- * int pieces_del(pos_t *pos, short color)
- * {
- *     struct list_head *p_cur, *tmp, *head;
- *     int count = 0;
- *
- *     head = &pos->pieces[color];
- *
- *     list_for_each_safe(p_cur, tmp, head) {
- *         piece_del(p_cur);
- *         count++;
- *     }
- * #   ifdef DEBUG_PIECE
- *     log_f(3, "color=%d removed=%d\n", color, count);
- * #   endif
- *     return count;
- * }
- */
--- a/src/piece.h
+++ b/src/piece.h
@@ -31,11 +31,12 @@ typedef enum {

 typedef enum {
    ALL_PIECES = 0,                               /* 'all pieces' bitboard */
+    NO_PIECE_TYPE = 0,
    PAWN = 1, KNIGHT, BISHOP, ROOK, QUEEN, KING,
    PIECE_TYPE_MAX = 7                            /* bit 4 */
 } piece_type_t;

-typedef enum {
+typedef enum __piece_e {
    EMPTY = 0,
    NO_PIECE = 0,
    W_PAWN = PAWN, W_KNIGHT, W_BISHOP, W_ROOK, W_QUEEN, W_KING,
@@ -70,13 +71,21 @@ typedef enum {
 #define K_VAL_END    20000

 /* some default values for pieces
+ * @abbr:   char, piece capital letter (used for game notation)
+ * @abbr_c: char, capital for white, lowercase for black
+ * char *sym;
+ *  char *sym_c;
+ *  char *name;
+ *  s64  opn_value;
+ *  s64  mid_value;
+ *  s64  end_value;
 */
 extern const struct piece_details {
-    char abbr;                                    /* used for game notation */
-    char abbr_color;                              /* lowercase = black */
-    char *sym;                                    /* used for game notation */
-    char *sym_color;                              /* different W & B */
-    char *name;
+    char *cap;                                    /* used for game notation */
+    char *low;                                    /* used also for UCI promotion */
+    char *fen;                                    /* cap=white, low=black */
+    char *sym;                                    /* UTF-8 symbol */
+    char *name;                                   /* piece name */
    s64  opn_value;                               /* value opening */
    s64  mid_value;                               /* value midgame */
    s64  end_value;                               /* value endgame */
@@ -84,7 +93,7 @@ extern const struct piece_details {

 extern const char pieces_str[6+6+1];              /* to search from fen/user input */

-#define OPPONENT(p)       !(p)
+#define OPPONENT(color)   !(color)

 #define MASK_PIECE        0x07                      /* 00000111 */
 #define MASK_COLOR        0x08                      /* 00001000 */
@@ -96,20 +105,26 @@ extern const char pieces_str[6+6+1];              /* to search from fen/user inp
 #define IS_WHITE(p)       (!COLOR(p))
 #define IS_BLACK(p)       (COLOR(p))

-#define SET_WHITE(p)      ((p) &= ~MASK_COLOR)
-#define SET_BLACK(p)      ((p) |= MASK_COLOR)
-#define SET_COLOR(p, c)   (!(c)? SET_WHITE(p): SET_BLACK(p))
+#define SET_WHITE(p)      (piece_t)((p) &= ~MASK_COLOR)
+#define SET_BLACK(p)      (piece_t)((p) |= MASK_COLOR)
+#define SET_COLOR(p, c)   (piece_t)(!(c)? SET_WHITE(p): SET_BLACK(p))

-extern bool piece_ok(piece_t p);
+bool piece_ok(piece_t p);

-extern char piece_to_char(piece_t p);
-extern char piece_to_char_color(piece_t p);
-extern char *piece_to_sym(piece_t p);
-extern char *piece_to_sym_color(piece_t p);
-extern char *piece_to_name(piece_t p);
+char *piece_to_cap(piece_t p);
+char *piece_to_low(piece_t p);
+char *piece_to_fen(piece_t p);
+char *piece_to_sym(piece_t p);
+char *piece_to_name(piece_t p);

-extern piece_t char_to_piece(char c);
-extern piece_t char_color_to_piece(char c);
+#define piece_to_char(c) piece_to_fen(c)
+//#define piece_to_char_t(p) piece_to_uci(p)
+
+//piece_type_t char_to_piece(char c);
+piece_type_t piece_t_from_char(char c);
+piece_t piece_from_fen(char c);
+
+#define piece_from_char(c) piece_from_fen(c)

 /* use short name or symbol - no effect
 */
--- a/src/position.c
+++ b/src/position.c
@@ -24,32 +24,20 @@
 #include "chessdefs.h"
 #include "position.h"
 #include "bitboard.h"
+#include "hyperbola-quintessence.h"
 #include "fen.h"
 #include "piece.h"
 #include "util.h"
-//#include "eval.h"
-
-//static pool_t *pos_pool;
-
-//const char *rankstr = "12345678";
-//const char *filestr = "ABCDEFGH";
-
-/****************************************************
- * #define BYTE_PRINT "%c%c%c%c%c%c%c%c"            *
- * #define BYTE2BIN(b) ((b) & 0x01 ? '1' : '0'),  \ *
- *         ((b) & 0x02 ? '1' : '0'),              \ *
- *         ((b) & 0x04 ? '1' : '0'),              \ *
- *         ((b) & 0x08 ? '1' : '0'),              \ *
- *         ((b) & 0x10 ? '1' : '0'),              \ *
- *         ((b) & 0x20 ? '1' : '0'),              \ *
- *         ((b) & 0x40 ? '1' : '0'),              \ *
- *         ((b) & 0x80 ? '1' : '0')                 *
- ****************************************************/
+#include "board.h"
+#include "attack.h"

 /**
 * pos_new() - allocate a new position
 *
- * position is not initialized
+ * Position is not initialized.
+ * If BUG_ON compilation is defined, the program will fail.
+ *
+ * @Return: The new position or NULL.
 */
 pos_t *pos_new(void)
 {
@@ -60,31 +48,17 @@ 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.
+ * @Return: The new position.
 *
 * TODO: merge with pos_new - NULL for init, non null for duplicate
 */
-pos_t *pos_dup(pos_t *pos)
+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;
 }

@@ -100,92 +74,379 @@ void pos_del(pos_t *pos)
 /**
 * pos_clear() - clear a position.
 * @pos: &position.
+ *
+ * @return: @pos.
 */
 pos_t *pos_clear(pos_t *pos)
 {
+#   ifdef DEBUG_POS
    printf("size(pos_board=%lu elt=%lu\n", sizeof(pos->board), sizeof(int));
-    //for (square square = A1; square <= H8; ++square)
-    //    pos->board[square] = EMPTY;
-
-    SET_WHITE(pos->turn);
+#   endif
    pos->node_count = 0;
-    pos->turn = 0;
+    pos->turn = WHITE;
+
+    /* move_do/undo position state */
+    pos->en_passant = SQUARE_NONE;
+    pos->castle = 0;
    pos->clock_50 = 0;
    pos->plycount = 0;
-    pos->en_passant = 0;
-    pos->castle = 0;
-    memset(pos->board, 0, sizeof(pos->board));
-    //pos->curmove = 0;
-    //pos->eval = 0;
-    //pos->occupied[WHITE] = 0;
-    //pos->occupied[BLACK] = 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[WHITE] = 0;
-        pos->controlled[BLACK] = 0;
+        //pos->controlled[color] = 0;
+        pos->king[color] = SQUARE_NONE;
    }
-    //pos->mobility[WHITE] = 0;
-    //pos->mobility[BLACK] = 0;
-    //pos->moves_generated = false;
-    //pos->moves_counted = false;
-    /* remove pieces / moves */
-    //pieces_del(pos, WHITE);
-    //pieces_del(pos, BLACK);
-    //moves_del(pos);

+    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(__unused const pos_t *pos1, __unused 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
+ * @color: king color
+ *
+ * Get a bitboard of all checkers on @color king.
+ * Just a wrapper over @sq_attackers().
+ *
+ * @return: a bitboard of attackers.
+ */
+bitboard_t pos_checkers(const pos_t *pos, const color_t color)
+{
+    bitboard_t occ = pos_occ(pos);
+    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)
+{
+    int us = pos->turn, them = OPPONENT(us);
+    bitboard_t occ = pos_occ(pos);
+    bitboard_t attackers;
+    bitboard_t checkers = 0, blockers = 0, pinners = 0;
+    bitboard_t targets, tmpcheckers, maybeblockers, tmppinners;
+    square_t king = pos->king[us];
+    int pinner;
+
+    /* bishop type - we attack with a bishop from king position */
+    attackers = pos->bb[them][BISHOP] | pos->bb[them][QUEEN];
+
+    /* targets is all "target" pieces if K was a bishop */
+    targets = hyperbola_bishop_moves(occ, king) & occ;
+
+    /* checkers = only opponent B/Q */
+    tmpcheckers = targets & attackers;
+    checkers |= tmpcheckers;
+
+    /* maybe blockers = we remove checkers, to look "behind" */
+    maybeblockers = targets & ~tmpcheckers;
+
+    /* we find second targets, by removing first ones (excl. checkers) */
+    if (maybeblockers) {
+        targets = hyperbola_bishop_moves(occ ^ maybeblockers, king) ^ tmpcheckers;
+
+        /* pinners = only B/Q */
+        tmppinners = targets & attackers;
+
+        /* blockers = we find occupied squares between pinner and king */
+        while (tmppinners) {
+            pinner = bb_next(&tmppinners);
+            pinners |= mask(pinner);
+            blockers |= bb_between[pinner][king] & maybeblockers;
+        }
+    }
+
+    /* same for rook type */
+    attackers = pos->bb[them][ROOK] | pos->bb[them][QUEEN];
+    targets = hyperbola_rook_moves(occ, king) & occ;
+
+    tmpcheckers = targets & attackers;
+    checkers |= tmpcheckers;
+
+    maybeblockers = targets & ~tmpcheckers;
+    if (maybeblockers) {
+        targets = hyperbola_rook_moves(occ ^ maybeblockers, king) ^ tmpcheckers;
+        tmppinners = targets & attackers;
+        while (tmppinners) {
+            pinner = bb_next(&tmppinners);
+            pinners |= mask(pinner);
+            blockers |= bb_between[pinner][king] & maybeblockers;
+        }
+    }
+
+    /* pawns & knights */
+    checkers |= bb_pawn_attacks[us][king] & pos->bb[them][PAWN];
+    checkers |= bb_knight[king] & pos->bb[them][KNIGHT];
+
+    pos->checkers = checkers;
+    pos->pinners = pinners;
+    pos->blockers = blockers;
+}
+
+/**
+ * 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
+ * @color: king color.
+ *
+ * get position "pinners" on @color king. Here, pinner means a piece separated from king
+ * by one piece (any color) only.
+ * This is just a wrapper over @sq_pinners().
+ *
+ * @return: pinners bitboard.
+ */
+bitboard_t pos_king_pinners(const pos_t *pos, const color_t color)
+{
+    return sq_pinners(pos, pos->king[color], OPPONENT(pos->turn));
+}
+
+/**
+ * pos_king_blockers() - get the pin blockers on a king.
+ * @pos:   &position
+ * @color: king color.
+ * @pinners: pinners bitboard.
+ *
+ * get @pinners blockers pieces on @color king.
+ *
+ * @return: blockers bitboard.
+ */
+bitboard_t pos_king_blockers(const pos_t *pos, const color_t color, const bitboard_t pinners)
+{
+    bitboard_t tmp, blockers = 0, occ = pos_occ(pos);
+    square_t pinner, king = pos->king[color];
+
+    bit_for_each64(pinner, tmp, pinners) {
+        //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_ok() - extensive position consistency check.
+ * @pos:    &position
+ * @strict: if true, call bug_on() on any error.
+ *
+ * Perform some validity check on position @pos:
+ * - pawns on 1st or 8th rank
+ * - number of pawns > 8 (per color)
+ * - total number of pieces > 16 or zero (per color)
+ * - number of kings != 1 (per color)
+ * - discrepancy between board and king (per color)
+ * - discrepancy between piece bitboards and ALL_PIECES bitboards (per color)
+ * - discrepancy between bitboards and board (per color)
+ * - side-to-move already checking opponent king
+ * - side-to-move in check more than twice
+ * - kings distance is 1
+ *
+ * In case of errors, and @strict is true, @bug_on() is called, and program will
+ * be terminated.
+ * This function should be called with @strict == false during initialization phase
+ * (eg after fen parsing), and with @strict == true otherwise (as we have some data
+ * corruption).
+ *
+ * TODO: add more checks:
+ * - kings attacking each other
+ *
+ * @return: (if @strict is false) return true if check is ok, false otherwise.
+ */
+bool pos_ok(__unused const pos_t *pos, __unused const bool strict)
+{
+    int n, count = 0, bbcount = 0, error = 0;
+    __unused bitboard_t tmp;
+
+    /* pawns on 1st ot 8th rank */
+    tmp = (pos->bb[WHITE][PAWN] | pos->bb[BLACK][PAWN]) & (RANK_1bb | RANK_8bb);
+    error += warn_on(tmp);
+
+    for (color_t color = WHITE; color <= BLACK; ++color) {
+        /* pawn count */
+        n = popcount64(pos->bb[color][PAWN]);
+        error += warn_on(n > 8);
+        /* king count */
+        n = popcount64(pos->bb[color][KING]);
+        error += warn_on(n != 1);
+        /* king mismatch with board */
+        error += warn_on(PIECE(pos->board[pos->king[color]]) != KING);
+        /* pieces count */
+        n = popcount64(pos->bb[color][ALL_PIECES]);
+        error += warn_on(n == 0 || n > 16);
+        bbcount += n;
+    }
+    for (square_t sq = 0; sq < 64; ++sq) {
+        piece_t piece = pos->board[sq];
+        __unused bitboard_t match;
+        if (piece == EMPTY)
+            continue;
+        color_t c = COLOR(piece);
+        piece_type_t p = PIECE(piece);
+        match = pos->bb[c][p] & mask(sq);
+        error += warn_on(!match);
+        count++;
+    }
+    /* occupied occupation is different from bitboards */
+    error += warn_on(count != bbcount);
+    /* is opponent already in check ? */
+    error += warn_on(pos_checkers(pos, OPPONENT(pos->turn)));
+    /* is color to play in check more than twice ? */
+    error += warn_on(popcount64(pos_checkers(pos, OPPONENT(pos->turn))) > 2);
+    /* kings distance is less than 2 */
+    error += warn_on(sq_dist(pos->king[WHITE], pos->king[BLACK]) < 2);
+
+    bug_on(strict && error);
+    return error? false: true;
+}
+
 /**
 * pos_print() - Print position and fen on stdout.
 * @pos:  &position
 */
-void pos_print(pos_t *pos)
+void pos_print(const pos_t *pos)
 {
-    int rank, file;
-    piece_t pc, *board = pos->board;
-    char fen[92];
+    char str[128];

-    //piece_list_t *wk = list_first_entry(&pos->pieces[WHITE], piece_list_t, list),
-    //    *bk = list_first_entry(&pos->pieces[BLACK], piece_list_t, list);
-
-
-    printf("  +---+---+---+---+---+---+---+---+\n");
-    for (rank = 7; rank >= 0; --rank) {
-        printf("%c |", rank + '1');
-        for (file = 0; file < 8; ++file) {
-            pc = board[sq_make(file, rank)];
-            printf(" %s |", piece_to_sym_color(pc));
-        }
-        printf("\n  +---+---+---+---+---+---+---+---+\n");
-    }
-    printf("    A   B   C   D   E   F   G   H\n");
-    printf("%s\n", pos2fen(pos, fen));
-    //printf("Turn: %s.\n", IS_WHITE(pos->turn) ? "white" : "black");
-    /*
-     * printf("Kings: W:%c%c B:%c%c\n",
-     *        FILE2C(F88(wk->square)),
-     *        RANK2C(R88(wk->square)),
-     *        FILE2C(F88(bk->square)),
-     *        RANK2C(R88(bk->square)));
-     */
-    //printf("plies=%d clock50=%d\n", pos->plycount, pos->clock_50);
-    //printf("Current move = %d\n", pos->curmove);
-    //printf("Squares controlled: W:%d B:%d\n", popcount64(pos->controlled[WHITE]),
-    //       popcount64(pos->controlled[BLACK]));
-    //printf("Mobility: W:%u B:%u\n", pos->mobility[WHITE],
-    //       pos->mobility[BLACK]);
+    board_print(pos->board);
+    printf("fen %s\n", pos2fen(pos, str));
+    printf("checkers: %s\n", pos_checkers2str(pos, str, sizeof(str)));
+    printf("pinners : %s\n", pos_pinners2str(pos, str, sizeof(str)));
+    printf("blockers: %s\n", pos_blockers2str(pos, str, sizeof(str)));
 }

 /**
- * pos_pieces_print() - Print position pieces
+ * pos_print_mask() - Print position and fen on stdout, with highlighted squares.
+ * @pos:  &position
+ * @mask: mask of highlighted squares.
+ */
+void pos_print_mask(const pos_t *pos, const bitboard_t mask)
+{
+    char fen[92];
+
+    board_print_mask(pos->board, mask);
+    printf("fen %s\n", pos2fen(pos, fen));
+}
+
+/**
+ * pos_print_raw - print simple position board (octal/FEN symbol values)
+ * @bb: the bitboard
+ * @type: int, 0 for octal, 1 for fen symbol
+ */
+void pos_print_raw(const pos_t *pos, const int type)
+{
+    board_print_raw(pos->board, type);
+    return;
+}
+
+/**
+ * pos_print_pieces() - Print position pieces
 * @pos:  &position
 */
-void pos_pieces_print(pos_t *pos)
+void pos_print_pieces(const pos_t *pos)
 {
-    int bit, count, cur;
-    char pname;
+    int sq, count, cur;
+    char *pname;
    u64 tmp;
    bitboard_t p;
    for (int color = WHITE; color <= BLACK; ++color) {
@@ -193,123 +454,17 @@ void pos_pieces_print(pos_t *pos)
            p = pos->bb[color][piece];
            count = popcount64(p);
            cur = 0;
-            pname = piece_to_char(piece);
-            printf("%c(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++;
                }
-
            }
            printf(" ");
        }
        printf("\n");
-        //printf("White pieces (%d): \t", popcount64(pos->occupied[WHITE]));
-        //piece_list_print(&pos->pieces[WHITE]);
-        //printf("Black pieces (%d): \t", popcount64(pos->occupied[BLACK]));
-        //piece_list_print(&pos->pieces[BLACK]);
    }
 }
-
-
-/*
-inline void bitboard_print2_raw(bitboard_t bb1, bitboard_t bb2, char *title)
-{
-    int i;
-    printf("%s%s", title? title: "", title? ":\n": "");
-
-    printf("\tW: %#018lx\tB: %#018lx\n", bb1, bb2);
-    for (i=56; i>=0; i-=8)
-        printf("\t"BYTE_PRINT"\t\t"BYTE_PRINT"\n",
-               BYTE2BIN(bb1>>i),
-               BYTE2BIN(bb2>>i));
-}
-*/
-
-/**
- * raw_board_print - print simple board (hex values)
- * @bb: the bitboard
- */
-void raw_board_print(const pos_t *pos)
-{
-
-    for (rank_t r = RANK_8; r >= RANK_1; --r) {
-        for (file_t f = FILE_A; f <= FILE_H; ++f)
-            printf("%02x ", pos->board[sq_make(f, r)]);
-        printf(" \n");
-    }
-    return;
-}
-
-/**
- * pos_bitboards_print() - Print position bitboards
- * @pos:  &position
- */
-//void pos_bitboards_print(pos_t *pos)
-//{
-//    printf("Bitboards occupied :\n");
-//    bitboard_print2(pos->occupied[WHITE], pos->occupied[BLACK]);
-//    printf("Bitboards controlled :\n");
-//    bitboard_print2(pos->controlled[WHITE], pos->controlled[BLACK]);
-//
-//}
-
-/**
- * pos_check() - extensive position consistenci check.
- * @pos:  &position
- */
-/*
- * void pos_check(position *pos)
- * {
- *     int rank, file;
- *     piece_t piece;
- *     board_t *board = pos->board;
- *
- *     /\* check that board and bitboard reflect same information *\/
- *     for (rank = 7; rank >= 0; --rank) {
- *         for (file = 0; file < 8; ++file) {
- *             piece_list_t *ppiece;
- *             printf("checking %c%c ", file+'a', rank+'1');
- *
- *             piece = board[SQ88(file, rank)].piece;
- *             ppiece= board[SQ88(file, rank)].s_piece;
- *             printf("piece=%s ", P_CSYM(piece));
- *             if (ppiece)
- *                 printf("ppiece=%s/sq=%#x ", P_CSYM(ppiece->piece), ppiece->square);
- *             switch(PIECE(piece)) {
- *                 case PAWN:
- *                     printf("pawn" );
- *                     break;
- *                 case KNIGHT:
- *                     printf("knight ");
- *                     break;
- *                 case BISHOP:
- *                     printf("bishop ");
- *                     break;
- *                 case ROOK:
- *                     printf("rook ");
- *                     break;
- *                 case QUEEN:
- *                     printf("queen ");
- *                     break;
- *                 case KING:
- *                     printf("king ");
- *                     break;
- *             }
- *             printf("\n");
- *         }
- *     }
- * }
- */
-
-/*
- * void pos_del(pos_t *pos)
- * {
- *     pieces_del(pos, WHITE);
- *     pieces_del(pos, BLACK);
- *     moves_del(pos);
- *     pool_add(pos_pool, pos);
- * }
- */
--- a/src/position.h
+++ b/src/position.h
@@ -18,39 +18,47 @@

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

-#include "bitboard.h"
 #include "chessdefs.h"
+#include "bitboard.h"
 #include "piece.h"
 #include "move.h"
+#include "board.h"

-typedef struct {
+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 en_passant;
-    castle_rights_t castle;

-    //eval_t eval;
-    //int check[2];
-    //int eval_simple_phase;
-    //eval_t eval_simple;
-    //move_t *bestmove;
-    //bool moves_generated;
-    //bool moves_counted;
+    /* 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] */
-    square_t king[2];                             /* dup with bb, faster retrieval */
-    bitboard_t controlled[2];
-    //u16 mobility[2];
-                                                  //struct list_head pieces[2];                   /* pieces list, King is first */
-    //struct list_head moves[2];
    piece_t board[BOARDSIZE];
-    movelist_t moves;
-    int nmoves;
+    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])
+
 /**
 * pos_set_sq - unconditionally set a piece on a square
 * @pos: position
@@ -59,13 +67,13 @@ typedef struct {
 *
 * Both position board and bitboards are modified.
 */
-static inline void pos_set_sq(pos_t *pos, square_t square, piece_t piece)
+static __always_inline void pos_set_sq(pos_t *pos, square_t square, piece_t piece)
 {
    color_t color = COLOR(piece);
    piece_type_t type = PIECE(piece);
    pos->board[square] = piece;
-    pos->bb[color][type] |= 1 << square;
-    pos->bb[color][ALL_PIECES] |= 1 << square;
+    pos->bb[color][type] |= mask(square);
+    pos->bb[color][ALL_PIECES] |= mask(square);
    if (type == KING)
        pos->king[color] = square;
 }
@@ -77,31 +85,93 @@ static inline void pos_set_sq(pos_t *pos, square_t square, piece_t piece)
 *
 * Both position board and bitboards are modified.
 */
-static inline void pos_clr_sq(pos_t *pos, square_t square)
+static __always_inline void pos_clr_sq(pos_t *pos, square_t square)
 {
    piece_t piece = pos->board[square];
    piece_type_t type = PIECE(piece);
    color_t color = COLOR(piece);
    pos->board[square] = EMPTY;
-    pos->bb[color][type] &= ~(1 << square);
-    pos->bb[color][ALL_PIECES] &= ~(1 << square);
+    pos->bb[color][type] &= ~mask(square);
+    pos->bb[color][ALL_PIECES] &= ~mask(square);
+    if (type == KING)
+        pos->king[color] = SQUARE_NONE;
 }

+/**
+ * pos_occ() - get position occupation (all pieces)
+ * @pos: position
+ *
+ * @return: occupation bitboard.
+ */
+static __always_inline bitboard_t pos_occ(const pos_t *pos)
+{
+    return pos->bb[WHITE][ALL_PIECES] | pos->bb[BLACK][ALL_PIECES];
+}
+
+/**
+ * pos_between_occ() - find occupation between two squares.
+ * @pos:   position
+ * @sq1:   square 1
+ * @sq2:   square 2
+ *
+ * @return: bitboard of @betw if between @sq1 and @sq2.
+ */
+static __always_inline bitboard_t pos_between_occ(const pos_t *pos,
+                                                  const square_t sq1, const square_t sq2)
+{
+    return bb_between_excl[sq1][sq2] & pos_occ(pos);
+}
+
+/**
+ * pos_between_count() - count occupied squares between two squares.
+ * @pos:   position
+ * @sq1:   square 1
+ * @sq2:   square 2
+ *
+ * @return: bitboard of @betw if between @sq1 and @sq2.
+ */
+static __always_inline int pos_between_count(const pos_t *pos,
+                                             const square_t sq1, const square_t sq2)
+{
+    return popcount64(pos_between_occ(pos, sq1, sq2));
+}
+
+/**
+ * pos_checkers2str() - get of string of checkers.
+ * @p:   position
+ * @str:   destination string
+ * @len:   max @str len.
+ *
+ * A wrapper over @bb_sq2str() for checkers bitmap.
+ *
+ * @return: @str.
+ */
+#define pos_checkers2str(p, str, len)  bb_sq2str(p->checkers, str, len)
+#define pos_pinners2str(p, str, len)   bb_sq2str(p->pinners, str, len)
+#define pos_blockers2str(p, str, len)  bb_sq2str(p->blockers, str, len)
+
 //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(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 void pos_print(pos_t *pos);
-extern void pos_pieces_print(pos_t *pos);
+void pos_set_checkers_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 void raw_board_print(const pos_t *pos);
+bool pos_ok(const pos_t *pos, const bool strict);

-//extern pos_t *pos_startpos(pos_t *pos);
+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);
+
+void pos_print_pieces(const pos_t *pos);

-//void pos_check(position *pos);

 #endif  /* POSITION_H */
--- a/src/search.c
+++ b/src/search.c
@@ -1,6 +1,6 @@
-/* search.c - search good moves.
+/* search.c - perft + search.
 *
- * 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 +11,111 @@
 *
 */

+#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"
+
+/**
+ * perft() - Perform perft on position
+ * @pos:   &position to search
+ * @depth: Wanted depth.
+ * @ply:   perft depth level.
+ *
+ * Run perft on a position. This function displays the available moves at @depth
+ * level for each possible first move, and the total of moves.
+ *
+ * This version uses the algorithm:
+ *    if last depth
+ *      return 1;
+ *    gen pseudo-legal moves
+ *    loop for each legal move
+ *      do-move
+ *      perft (depth -1)
+ *      undo-move
+ *
+ * @return: total moves found at @depth level.
+ */
+u64 perft(pos_t *pos, int depth, int ply)
+{
+    int subnodes, movetmp = 0;
+    u64 nodes = 0;
+    movelist_t pseudo;
+    move_t move;
+    state_t state;
+
+    if (depth == 0)
+        return 1;
+    pseudo.nmoves = 0;
+    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("Total: %lu\n", nodes);
+    return nodes;
+}
+
+/**
+ * perft_new_pinners() - Perform perft on position
+ * @pos:   &position to search
+ * @depth: Wanted depth.
+ * @ply:   perft depth level.
+ *
+ * Run perft on a position. This function displays the available moves at @depth
+ * level for each possible first move, and the total of moves.
+ *
+ * @return: total moves found at @depth level.
+ */
+u64 perft_new_pinners(pos_t *pos, int depth, int ply)
+{
+    int subnodes, movetmp = 0;
+    u64 nodes = 0;
+    movelist_t pseudo;
+    move_t move;
+    state_t state;
+
+    if (depth == 0)
+        return 1;
+    pseudo.nmoves = 0;
+    pos_set_checkers_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_new_pinners(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("Total: %lu\n", nodes);
+    return nodes;
+}

 /**
 * negamax() - search position negamax.
@@ -31,32 +128,34 @@
 *
 * @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 +173,76 @@ 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 +16,11 @@

 #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);
+u64 perft_new_pinners(pos_t *pos, int depth, int ply);

 #endif  /* SEARCH_H */
--- a/test/attack-test.c
+++ b/test/attack-test.c
@@ -0,0 +1,65 @@
+/* attack-test.c - basic square attack 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-gen.h"
+#include "attack.h"
+
+#include "common-test.h"
+
+int main(int __unused ac, __unused char**av)
+{
+    int i = 0;
+    char *fen;
+    pos_t *pos;//, *fishpos = pos_new();
+    bitboard_t checkers, pinners, blockers;
+
+    setlinebuf(stdout);                           /* line-buffered stdout */
+
+    bitboard_init();
+    hyperbola_init();
+
+    while ((fen = next_fen(ATTACK))) {
+        //printf(">>>>> %s\n", test[i]);
+        printf("original fen %d: [%p][%s]\n", i, fen, fen);
+        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_print(pos);
+
+        checkers = pos->checkers;
+        pinners = pos->pinners;
+        blockers = pos->blockers;
+
+        pos_set_checkers_pinners_blockers(pos);
+
+        printf("******* %s\n", cur_comment());
+        bb_print_multi("checkers", 2, checkers, pos->checkers);
+        bb_print_multi("pinners", 2, pinners, pos->pinners);
+        bb_print_multi("blockers", 2, blockers, pos->blockers);
+
+        pos_del(pos);
+        i++;
+    }
+    return 0;
+}
--- a/test/bitboard-test.c
+++ b/test/bitboard-test.c
@@ -1,13 +1,24 @@
-//#include "debug.h"
-//#include "pool.h"
+/* bitboard-test.c - basic bitboard/hyperbola 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 <string.h>

-#include "../src/position.h"
-#include "../src/piece.h"
-#include "../src/bitboard.h"
-#include "../src/hyperbola-quintessence.h"
+#include "bug.h"
+
+#include "chessdefs.h"
+#include "bitboard.h"
+#include "hyperbola-quintessence.h"

 int main(int __unused ac, __unused char**av)
 {
@@ -19,20 +30,40 @@ int main(int __unused ac, __unused char**av)
                "sliding", "diagonal", "antidiagonal", "file", "rank", "knight",
                "king"
                );
-        bitboard_print_multi(str, 7,
-                             bb_file[i] | bb_rank[i] |
-                             bb_diagonal[i] | bb_antidiagonal[i],
-                             bb_diagonal[i], bb_antidiagonal[i],
-                             bb_file[i], bb_rank[i],
+        bb_print_multi(str, 7,
+                             bb_sqfile[i] | bb_sqrank[i] |
+                             bb_sqdiag[i] | bb_sqanti[i],
+                             bb_sqdiag[i], bb_sqanti[i],
+                             bb_sqfile[i], bb_sqrank[i],
                             bb_knight[i], bb_king[i]);
    }
-    /*
-     * for (square_t sq = 0; sq < 64; ++sq) {
-     *     sprintf(str, "%2d %#lx %#lx knight", sq, bb_sq[sq], bb_knight[sq]);
-     *     bitboard_print(str, bb_knight[sq]);
-     *     sprintf(str, "%2d %#lx %#lx knight", sq, bb_sq[sq], bb_king[sq]);
-     *     bitboard_print(str, bb_king[sq]);
-     * }
-     */
+    sprintf(str, "between: %-22s%-22s%-22s%-22s%-22s%-22s",
+            "a1-a8", "a1-h8", "a1-h1", "a2-a7", "a2-g7", "a2-g2");
+    bb_print_multi(str, 6,
+                         bb_between[A1][A8], bb_between[A1][H8],
+                         bb_between[A1][H1], bb_between[A2][A7],
+                         bb_between[A2][G7], bb_between[A2][G2]);
+    sprintf(str, "between: %-22s%-22s%-22s%-22s%-22s%-22s%-22s%-22s",
+            "c3-c6", "c3-f6", "c3-f3", "c3-e1", "c3-c1", "c3-a1", "c3-a3", "c3-a5");
+    bb_print_multi(str, 8,
+                   bb_between[C3][C6], bb_between[C3][F6],
+                   bb_between[C3][F3], bb_between[C3][E1],
+                   bb_between[C3][C1], bb_between[C3][A1],
+                   bb_between[C3][A3], bb_between[C3][A5]);
+    sprintf(str, "between: %-22s%-22s%-22s%-22s%-22s%-22s%-22s%-22s",
+            "c4-c6", "c4-f6", "c4-f3", "c4-e1", "c4-c1", "c4-a1", "c4-a3", "c4-a5");
+    bb_print_multi(str, 8,
+                   bb_between[C4][C6], bb_between[C4][F6],
+                   bb_between[C4][F3], bb_between[C4][E1],
+                   bb_between[C4][C1], bb_between[C4][A1],
+                   bb_between[C4][A3], bb_between[C4][A5]);
+    sprintf(str, "Pwn att: %-22s%-22s%-22s%-22s%-22s%-22s%-22s%-22s",
+            "White a2", "Black a2", "White h7", "Black h7",
+            "White c3", "Black c3", "White e5", "Black e5");
+    bb_print_multi(str, 8,
+                   bb_pawn_attacks[WHITE][A2], bb_pawn_attacks[BLACK][A2],
+                   bb_pawn_attacks[WHITE][H7], bb_pawn_attacks[BLACK][H7],
+                   bb_pawn_attacks[WHITE][C3], bb_pawn_attacks[BLACK][C3],
+                   bb_pawn_attacks[WHITE][E5], bb_pawn_attacks[BLACK][E5]);
    return 0;
 }
--- a/test/common-test.h
+++ b/test/common-test.h
@@ -0,0 +1,434 @@
+/* common-test.h - common static vars/funcs 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 "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 MOVEDO     16
+#define PERFT      32
+
+struct fentest {
+    int line;
+    uint modules;
+    char *comment;
+    char *fen;
+} fentest[] = {
+    /*
+    { __LINE__.
+      ATTACK,
+      "checkers: ",
+      ""
+    },
+     */
+
+/* ***************** TEMP TESTS ABOVE ************************** */
+
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
+      "illegal white e.p.",
+      "3k4/8/5K2/3pP3/8/2b5/8/8 w - d6 0 1",
+    },
+    { __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",
+    },
+
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
+      "legal white e.p.",
+      "1K1k4/8/8/3pP3/8/6b1/8/8 w - d6 0 1",
+    },
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
+      "legal black e.p.",
+      "8/8/6B1/8/3Pp3/8/8/1k1K4 b - d3 0 1",
+    },
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
+      "illegal e.p.",
+      "1nbqkbn1/ppp1pppp/8/r1rpP1K1/8/8/PPPP1PPP/RNBQ1BNR w - d6 0 1",
+    },
+    { __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,
+      "only 3 K moves (but impossible situation)",
+      "1k6/8/8/8/8/8/8/r2K3r w - - 0 1"
+    },
+    { __LINE__, ATTACK,
+      "checkers: a8 h8",
+      "R2k3R/8/8/8/8/8/8/1K6 b - - 0 1"
+    },
+    { __LINE__, ATTACK,
+      "checkers: b3 g3",
+      "1k6/8/8/8/8/1r1K2r1/8/8 w - - 0 1"
+    },
+
+    { __LINE__, ATTACK,
+      "checkers: b6 g6",
+      "8/8/1R1k2R1/8/8/8/8/1K6 b - - 0 1"
+    },
+
+    { __LINE__, ATTACK,
+      "checkers: g2 g7",
+      "8/k5r1/8/8/6K1/8/6r1/8 w - - 0 1"
+    },
+    { __LINE__, ATTACK,
+      "checkers: g2 g7",
+      "8/6R1/8/6k1/8/8/K5R1/8 b - - 0 1"
+    },
+    { __LINE__, ATTACK,
+      "checkers: d5 e3, pinners: none (2 pieces between attacker & K)",
+      "3k4/8/8/3r3b/b7/1N2nn2/2n1B3/rNBK1Rbr w - - 0 1"
+    },
+
+    { __LINE__, ATTACK,
+      "checkers: d4 e6 pinners: h4 a5 a8 h8",
+      "Rn1k1r1R/4b3/1n2N3/B7/3R3B/8/8/3K4 b - - 0 1"
+    },
+    { __LINE__, ATTACK,
+      "checkers: d5 e3, pinners: a1 h1 a4 h5",
+      "3k4/8/8/3r3b/b7/1N2n3/4B3/rN1K1R1r w - - 0 1"
+    },
+
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
+      "only pawn captures",
+      "4k3/8/2p1p3/2PpP3/8/pp4pp/PP4PP/4K3 w - d6 0 1"
+    },
+
+    { __LINE__, FEN | ATTACK,
+      "checker: h4",
+      "4k3/8/8/8/7b/8/8/4K3 w - - 0 1"
+    },
+// First game moves
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "startpos",
+      "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
+    },
+    //{ __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"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "1.Nh3",
+      "rnbqkbnr/pppppppp/8/8/8/7N/PPPPPPPP/RNBQKB1R b KQkq - 1 1"
+    },
+    { __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
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "no Q castling",
+      "r3k2r/8/3B4/8/8/3b4/8/R3K2R w KQkq - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "no castling, 2 mates in 1",
+      "r3k2r/8/3BB3/8/8/3bb3/8/R3K2R w KQkq - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "r2bkb1r/8/8/8/8/3bb3/8/R2BKB1R w KQkq - 0 1"
+    },
+    //
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "4 castle possible, only K+R",
+      "r3k2r/8/8/8/8/8/8/R3K2R w KQkq - 0 1"
+    },
+    //
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "only kings on A1/A8, white to play",
+      "k7/8/8/8/8/8/8/K7 w - - 0 1"
+    },
+    //
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "only one move possible (Pf2xBg3)",
+      "k7/8/8/1p1p4/pPpPp3/P1PpPpb1/NBNP1P2/KBB1B3 w - - 0 1"
+    },
+    //
+    { __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"
+    },
+    //
+    { __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"
+    },
+    // white castled, and can e.p. on c6 black can castle
+    // 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
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "rnbqk2r/pp1pbpp1/7p/2pPp3/4n3/3B1N2/PPP2PPP/RNBQ1RK1 w kq c6 0 7"
+    },
+
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "4k3/4p3/8/b7/1BR1p2p/1Q3P2/5N2/4K3 w - - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "r1bq1rk1/pppp1ppp/2n2n2/4p3/2B1P3/3PPN2/PPP3PP/RN1QK2R b KQ - 1 7"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "6k1/6pp/R2p4/p1p5/8/1P1r3P/6P1/6K1 b - - 3 3"
+    },
+
+    // some of tests below are from:
+    // - Rodent IV
+    // - https://www.chessprogramming.net/perfect-perft/
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "8/2p5/3p4/Kp5r/1R3p1k/8/4P1P1/8 w - - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "4rrk1/pp1n3p/3q2pQ/2p1pb2/2PP4/2P3N1/P2B2PP/4RRK1 b - - 7 19"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "rq3rk1/ppp2ppp/1bnpb3/3N2B1/3NP3/7P/PPPQ1PP1/2KR3R w - - 7 14"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "r1bq1r1k/1pp1n1pp/1p1p4/4p2Q/4Pp2/1BNP4/PPP2PPP/3R1RK1 w - - 2 14"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "r3r1k1/2p2ppp/p1p1bn2/8/1q2P3/2NPQN2/PPP3PP/R4RK1 b - - 2 15"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "1rbqk1nr/p3ppbp/2np2p1/2p5/1p2PP2/3PB1P1/PPPQ2BP/R2NK1NR b KQk - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "r1bqk2r/pp1p1ppp/2n1pn2/2p5/1bPP4/2NBP3/PP2NPPP/R1BQK2R b KQkq - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "rnb1kb1r/ppp2ppp/1q2p3/4P3/2P1Q3/5N2/PP1P1PPP/R1B1KB1R b KQkq - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "r1b2rk1/pp2nppp/1b2p3/3p4/3N1P2/2P2NP1/PP3PBP/R3R1K1 b - - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "n1q1r1k1/3b3n/p2p1bp1/P1pPp2p/2P1P3/2NBB2P/3Q1PK1/1R4N1 b - - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "r1bq1r1k/b1p1npp1/p2p3p/1p6/3PP3/1B2NN2/PP3PPP/R2Q1RK1 w - - 1 16"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "3r1rk1/p5pp/bpp1pp2/8/q1PP1P2/b3P3/P2NQRPP/1R2B1K1 b - - 6 22"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "r1q2rk1/2p1bppp/2Pp4/p6b/Q1PNp3/4B3/PP1R1PPP/2K4R w - - 2 18"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "4k2r/1pb2ppp/1p2p3/1R1p4/3P4/2r1PN2/P4PPP/1R4K1 b - - 3 22"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "3q2k1/pb3p1p/4pbp1/2r5/PpN2N2/1P2P2P/5PP1/Q2R2K1 b - - 4 26"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "2r5/8/1n6/1P1p1pkp/p2P4/R1P1PKP1/8/1R6 w - - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "r2q1rk1/1b1nbppp/4p3/3pP3/p1pP4/PpP2N1P/1P3PP1/R1BQRNK1 b - - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "6k1/5pp1/7p/p1p2n1P/P4N2/6P1/1P3P1K/8 w - - 0 35"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "r4rk1/1pp1q1pp/p2p4/3Pn3/1PP1Pp2/P7/3QB1PP/2R2RK1 b - - 0 1"
+    },
+
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "r3k2r/Pppp1ppp/1b3nbN/nP6/BBP1P3/q4N2/Pp1P2PP/R2Q1RK1 w kq - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "",
+      "1k6/1b6/8/8/7R/8/8/4K2R b K - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "Illegal ep move #1",
+      "3k4/3p4/8/K1P4r/8/8/8/8 b - - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "Illegal ep move #2",
+      "8/8/4k3/8/2p5/8/B2P2K1/8 w - - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "EP Capture Checks Opponent",
+      "8/8/1k6/2b5/2pP4/8/5K2/8 b - d3 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "Short Castling Gives Check",
+      "5k2/8/8/8/8/8/8/4K2R w K - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "Long Castling Gives Check",
+      "3k4/8/8/8/8/8/8/R3K3 w Q - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "Castle Rights",
+      "r3k2r/1b4bq/8/8/8/8/7B/R3K2R w KQkq - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "Castling Prevented",
+      "r3k2r/8/3Q4/8/8/5q2/8/R3K2R b KQkq - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "Promote out of Check",
+      "2K2r2/4P3/8/8/8/8/8/3k4 w - - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "Discovered Check",
+      "8/8/1P2K3/8/2n5/1q6/8/5k2 b - - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "Promote to give check",
+      "4k3/1P6/8/8/8/8/K7/8 w - - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "Under Promote to give check",
+      "8/P1k5/K7/8/8/8/8/8 w - - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "Self Stalemate",
+      "K1k5/8/P7/8/8/8/8/8 w - - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "Stalemate & Checkmate",
+      "8/k1P5/8/1K6/8/8/8/8 w - - 0 1"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "Stalemate & Checkmate",
+      "8/8/2k5/5q2/5n2/8/5K2/8 b - - 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"
+    },
+    { __LINE__, FEN,
+      "illegal, SF crash",
+      "4k3/8/8/8/7b/8/8/4K3 b - - 0 1"
+    },
+    { __LINE__, FEN,
+      "illegal, SF crash",
+      "2r1k3/3B4/8/8/8/8/8/4K3 w - - 0 1"
+    },
+    { __LINE__, FEN,
+      "illegal, SF crash",
+      "2r1k3/3P4/8/8/8/8/8/4K3 w - - 0 1"
+    },
+    { __LINE__, 0, NULL, NULL }
+};
+
+static int cur = -1;
+
+static char *next_fen(uint module)
+{
+    cur++;
+    while (fentest[cur].fen && !(fentest[cur].modules & module))
+        cur++;
+    return fentest[cur].fen;
+}
+
+static __unused char* cur_comment()
+{
+    return fentest[cur].comment;
+}
+
+static __unused int cur_line()
+{
+    return fentest[cur].line;
+}
--- a/test/fen-test.c
+++ b/test/fen-test.c
@@ -1,30 +1,51 @@
-#include "debug.h"
-#include "pool.h"
+/* fen-test.c - basic fen 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 "../src/position.h"
-#include "../src/fen.h"
+#include <stdio.h>

-int main(int ac, char**av)
+#include "chessdefs.h"
+#include "bitboard.h"
+#include "position.h"
+#include "fen.h"
+
+#include "common-test.h"
+
+int main(__unused int ac, __unused char**av)
 {
    pos_t *pos;
-
    const char *fen;
    char revfen[128];
-    int comp;

-    //debug_init(5, stderr, true);
-    //pos_pool_init();
-    pos = pos_new();
-    if (ac == 1) {
-        fen = startfen;
-        startpos(pos);
-    } else {
-        fen = av[1];
-        fen2pos(pos, fen);
+    setlinebuf(stdout);                           /* line-buffered stdout */
+
+    bitboard_init();
+
+    while ((fen = next_fen(FEN))) {
+        printf("***** [%s] ", fen);
+        fflush(stdout);
+        if (!(pos = fen2pos(NULL, fen))) {
+            printf("**INVALID\n");
+        } else {
+            //pos_print(pos);
+            pos2fen(pos, revfen);
+            if (!strcmp(fen, revfen)) {
+                printf("OK\n");
+            } else {
+                //printf("fen = [%s]\nrev = [%s]", fen, revfen);
+                printf("-> [%s] **FIXED\n",revfen);
+                pos_print_raw(pos, 1);
+            }
+            pos_del(pos);
+        }
    }
-    pos_print(pos);
-    pos2fen(pos, revfen);
-    //printf("reverse fen=[%s]\n", pos2fen(pos, NULL));
-    comp = strcmp(fen, revfen);
-    printf("compare=%d - %s\n", comp, comp? "NOK": "OK");
 }
--- 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
@@ -0,0 +1,288 @@
+/* movegen-test.c - basic movegen 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 "move-gen.h"
+#include "position.h"
+
+#include "common-test.h"
+
+#define RD 0
+#define WR 1
+
+/**
+ * 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 void send_stockfish_fen(FILE *desc, pos_t *pos, movelist_t *movelist, char *fen)
+{
+    char *buf = NULL;
+    int count, __unused 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 1\n", fen);
+    //fflush(desc);
+    while ((buflen = getline(&buf, &alloc, stdin)) > 0) {
+        buf[--buflen] = 0;
+        if (buflen == 0)
+            continue;
+        if (sscanf(buf, "Nodes searched: %d", &fishcount) == 1) {
+            break;
+        }
+        //printf("%d: %s\n", line++, buf);
+        if (sscanf(buf, "%*4s: %d", &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: %d", &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);
+}
+
+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;
+    FILE *outfd;
+    char *fen;
+    pos_t *pos, *fishpos = pos_new();
+    movelist_t pseudo, legal, fishmoves;
+    //bitboard_t wrong = 0x5088000040, tmp, loop;
+    //bit_for_each64(loop, tmp, )
+    //printf("fishpos 1=%p\n", fishpos);
+
+    setlinebuf(stdout);                           /* line-buffered stdout */
+
+    bitboard_init();
+    hyperbola_init();
+    outfd = open_stockfish();
+
+    while ((fen = next_fen(MOVEGEN))) {
+        //printf(">>>>> %s\n", test[i]);
+        //printf("fishpos 2=%p\n", fishpos);
+        //printf("original fen %d: [%p][%s]\n", i, fen, fen);
+        if (!(pos = fen2pos(NULL, fen))) {
+            printf("wrong fen %d: [%s]\n", i, fen);
+            continue;
+        }
+        /* print movelists */
+        send_stockfish_fen(outfd, fishpos, &fishmoves, fen);
+
+        pos_set_checkers_pinners_blockers(pos);
+        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);
+        //printf("Mu ");
+        //moves_print(pos, 0);
+        //fflush(stdout);
+
+        /* sort and print movelists */
+        move_sort_by_sq(&fishmoves);
+        move_sort_by_sq(&legal);
+        // printf("\nFs ");
+        // moves_print(fishpos, 0);
+        // fflush(stdout);
+        // printf("Ms ");
+        // moves_print(pos, 0);
+        // fflush(stdout);
+
+        /* compare movelists */
+        if (!movelists_equal(&fishmoves, &legal)) {
+            pos_print(pos);
+            printf("F: ");
+            moves_print(&fishmoves, 0);
+            printf("M: ");
+            moves_print(&legal, 0);
+        } else {
+            printf("[%s]: OK (%d Moves)\n", fen, legal.nmoves);
+            //moves_print(&fishpos->moves, 0);
+        }
+        //compare_moves(&fishpos->moves, &legal);
+            //} else {
+            //printf("fen %d: [%s] - OK (%d moves)\n", i, fen, legal.nmoves);
+            //}
+        //pos_print_board_raw(pos, 1);
+        //printf("%s\n", pos2fen(pos, str));
+        //get_stockfish_moves(test[i]);
+        //exit(0);
+        pos_del(pos);
+        i++;
+    }
+    fclose(outfd);
+    return 0;
+}
--- a/test/perft-test.c
+++ b/test/perft-test.c
@@ -0,0 +1,310 @@
+/* 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;
+    s64 ms1 = 0, ms1_total = 0;
+    s64 ms2 = 0, ms2_total = 0;
+
+    int depth = 6, run = 3;
+
+    if (ac > 1)
+        depth = atoi(av[1]);
+    if (ac > 2)
+        run =  atoi(av[2]) & 3;
+    printf("depth = %d run=%d\n", depth, run);
+
+    if (!run)
+        exit(0);
+    setlocale(LC_NUMERIC, "");
+    setlinebuf(stdout);                           /* line-buffered stdout */
+    outfd = open_stockfish();
+
+    bitboard_init();
+    hyperbola_init();
+
+    CLOCK_DEFINE(clock, CLOCK_PROCESS);
+    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);
+        savepos = pos_dup(pos);
+
+        if (run & 1) {
+            clock_start(&clock);
+            my_count = perft(pos, depth, 1);
+            ms1 = clock_elapsed_ms(&clock);
+            ms1_total += ms1;
+
+            if (sf_count == my_count) {
+                printf("pt1 OK : line=%3d perft=%'lu %'ldms lps=%'lu \"%s\"\n",
+                       test_line, my_count, ms1,
+                       ms1? my_count*1000l/ms1: 0,
+                       fen);
+            } else  {
+                printf("pt1 ERR: line=%3d sf=%'lu me=%'lu \"%s\"\n",
+                       test_line, sf_count, my_count, fen);
+            }
+        }
+
+        if (run & 2) {
+            clock_start(&clock);
+            my_count = perft_new_pinners(pos, depth, 1);
+            ms2 = clock_elapsed_ms(&clock);
+            ms2_total += ms2;
+
+            if (sf_count == my_count) {
+                printf("pt2 OK : line=%3d perft=%'lu %'ldms lps=%'lu \"%s\"\n",
+                       test_line, my_count, ms2,
+                       ms2? my_count*1000l/ms2: 0,
+                       fen);
+            } else  {
+                printf("pt2 ERR: line=%3d sf=%'lu me=%'lu \"%s\"\n",
+                       test_line, sf_count, my_count, fen);
+            }
+        }
+        printf("\n");
+        pos_del(savepos);
+        pos_del(pos);
+        i++;
+        /* to run first test only */
+        // exit(0);
+    }
+    if (run & 1)
+        printf("total perft  %'ldms\n", ms1_total);
+    if (run & 2)
+        printf("total perft2 %'ldms\n", ms2_total);
+    return 0;
+}
--- a/test/piece-test.c
+++ b/test/piece-test.c
@@ -1,55 +1,20 @@
 #include <stdio.h>

-#include "debug.h"
+#include "brlib.h"

-#include "../src/fen.h"
-#include "../src/position.h"
-#include "../src/bitboard.h"
+#include "piece.h"

-int main(int ac, char**av)
+int main(__unused int ac, __unused char**av)
 {
-    pos_t *pos;
-    printf("zobi\n");fflush(stdout);
-    debug_init(6, stderr, true);
-    log_f(5, "kfsjdhg\n");
-    pos_pool_init();
-    pos = pos_get();
-    piece_pool_init();

-    if (ac == 1) {
-    printf("zoba\n");fflush(stdout);
-        pos_startpos(pos);
-    } else {
-        fen2pos(pos, av[1]);
+    piece_t p;
+    char *test="PNBRQKpnbrqk";
+
+    for (u64 i = 0; i < sizeof(test); ++i) {
+        char c1 = test[i], *c2;
+        p = piece_from_fen(c1);
+        c2 = piece_to_fen(p);
+        printf("c1=%c c2=%c\n", c1, *c2);
    }
-    pos_print(pos);
-    pos_pieces_print(pos);
-
-    printf("0x1c = 11100 = C1-E1:\n");
-    bitboard_print(0x1c);
-
-    printf("0x70 = 111 = A1-C1\n");
-    bitboard_print(0x70);
-
-    printf("0x0e = 1110 = B1-D1\n");
-    bitboard_print(0x0e);
-
-    printf("0x60 = 1100000 = F1-G1\n");
-    bitboard_print(0x60);
-
-    printf("A1:\n");
-    bitboard_print(A1);
-
-    printf("1:\n");
-    bitboard_print(1L);
-    printf("H1:\n");
-    bitboard_print(H1);
-    printf("C1:\n");
-    bitboard_print(C1);
-    printf("D1:\n");
-    bitboard_print(D1);
-    printf("C1|D1:\n");
-    bitboard_print(C1|D1);
-    printf("H8:\n");
-    bitboard_print(H8);
+    return 0;
 }
--- a/util.c
+++ b/util.c
Author	SHA1	Message	Date
Bruno Raoult	926dfa0765	untabify Makefile, cosmetic change in pos_set_checkers_pinners_blockers()	2024-04-10 17:12:20 +02:00
Bruno Raoult	374116b1e7	simplify pos_set_checkers_pinners_blockers() (cont'd)	2024-04-10 15:59:24 +02:00
Bruno Raoult	9b5c2253b1	Makefile: add -ginline-points	2024-04-10 13:02:23 +02:00
Bruno Raoult	e301e6c726	bug fix in perft() - stupid initialization !	2024-04-10 12:57:39 +02:00
Bruno Raoult	e78eae21e6	cleanup move_do()	2024-04-10 12:57:08 +02:00
Bruno Raoult	711306c92a	simplify/improve pos_set_checkers_pinners_blockers()	2024-04-10 12:54:47 +02:00
Bruno Raoult	660722fadc	cleanup	2024-04-10 12:53:31 +02:00
Bruno Raoult	e8240c6cab	move_make_promotions(), clean move_do(), pos_gen_pseudomoves()	2024-04-09 08:15:43 +02:00
Bruno Raoult	eb590f1438	bug fix, wrong perft recursion !	2024-04-09 08:11:31 +02:00
Bruno Raoult	f2ce20a504	add bb_pawn_attacks[][], bb_shift()	2024-04-09 08:10:53 +02:00
Bruno Raoult	027aa2c132	bb: bb_{first_bb,next,multiple{}, chessdefs: relative sq diffs	2024-04-04 10:03:43 +02:00
Bruno Raoult	30af886594	comment	2024-04-02 21:18:01 +02:00
Bruno Raoult	afecbeb955	movegen-test: add set_checkers_pinners_blockers call	2024-04-02 20:40:44 +02:00
Bruno Raoult	05748e19ab	Makefile: build static	2024-04-02 20:38:50 +02:00
Bruno Raoult	4816b4a53a	experiment: add pos_set_checkers_pinners_blockers()	2024-03-30 18:45:13 +01:00
Bruno Raoult	96744cea20	perft-test: option to run perft/perft2/both	2024-03-29 10:00:01 +01:00
Bruno Raoult	24207583d1	perft2: is_in_check() before recursion	2024-03-29 09:59:14 +01:00
Bruno Raoult	92d6909546	update (C) notice	2024-03-28 10:37:52 +01:00
Bruno Raoult	85ae4a2230	better comments on perft() and perft2()	2024-03-28 09:41:39 +01:00
Bruno Raoult	ad8a9609ce	misc.c: add a few basic clock functions	2024-03-28 08:33:27 +01:00
Bruno Raoult	ad704c216b	Merge branch 'perft': perft() and perft2() - see comments. perft: normal "get_next_legal()" before movegen perft2: is_in_check() after movegen	2024-03-27 18:09:25 +01:00
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
Bruno Raoult	9d40a53aea	simplify pos_next_legal()	2024-03-16 12:14:59 +01:00
Bruno Raoult	260d8d34bd	move.h: simplify flags. movegen.c: add pos_next_legal()	2024-03-16 10:06:55 +01:00
Bruno Raoult	037d49e4ca	move-do: copy from pre-bitboard version	2024-03-15 10:53:26 +01:00
Bruno Raoult	4eb620a873	add occ param in sq_attackers()	2024-03-15 09:14:10 +01:00
Bruno Raoult	92dcb1e778	fix king move in pos_is_legal()	2024-03-15 09:12:42 +01:00
Bruno Raoult	c8aea61529	pos_checkers(): add occ parameter	2024-03-15 09:11:28 +01:00
Bruno Raoult	b3f0dd0534	add move_str()	2024-03-15 09:10:32 +01:00
Bruno Raoult	0f06ccb8db	simplify piece_details structure/functions (need to rewrite)	2024-03-15 09:08:49 +01:00
Bruno Raoult	3e477f7442	movegen-test: add SF/uci promotion parsing	2024-03-15 09:07:02 +01:00
Bruno Raoult	aba0113344	add piece-test	2024-03-15 09:04:44 +01:00
Bruno Raoult	cc7d91ebfb	default compile-command: make testing	2024-03-15 09:03:30 +01:00
Bruno Raoult	17d1dc52f9	movegen: pseudo_is_legal() and pos_legalmoves()	2024-03-12 10:45:20 +01:00
Bruno Raoult	cc3754ae00	add position blockers	2024-03-12 10:44:25 +01:00
Bruno Raoult	08082faed3	moves_print() and move_sort_by_sq(): use movelist_t instead of pos_t	2024-03-12 10:42:24 +01:00
Bruno Raoult	6ee4cd1642	cleanup	2024-03-11 16:12:45 +01:00
Bruno Raoult	b7fdcca66d	pos_check(): add adjacent kings test	2024-03-11 16:11:51 +01:00
Bruno Raoult	890cb05296	add move_make_promote_capture and move_make_capture	2024-03-11 16:10:16 +01:00
Bruno Raoult	301ca24783	add funcs comments and const parameters	2024-03-11 16:07:12 +01:00
Bruno Raoult	d81dca6e23	add sq_line array, bb_sq_aligned3, renamed sq_manh to sq_taxi	2024-03-11 16:04:45 +01:00
Bruno Raoult	87e7695873	new pos/bb funcs, legal(), better castling gen, etc. [see commit details] - new sq_pinners - new pseudo_is_legal() (unfinished) - improve castling pseudo move gen - more position and lower level bitboard helper funcs: - pos_{_occ,between_occ,between_count,pinners} - bb_{rank,file,rel_rank,_sq_aligned,_sq_between) - rename some bitboard globals - replace bb ranks/files enums with defines (issue with clang) -> Need to find a way to use enum safely - tests: - add common-test.h - new attack-test.c	2024-03-10 10:58:14 +01:00
Bruno Raoult	b351d198b8	sq_attackers() + others (see dedails). Ready for move do/undo ? - add many "const" in func parameters - attack.c: sq_attackers() - move print_board_raw from position.c to to board.c - move some fen_check() tests to pos_check() - add REL_RANK() macro. TODO: add one more for bitboards - fen.c: more tests for FEN validity - position.c: add pos_checkers() and pos_check() - tests: add common-test.h (for shared FEN positions access)	2024-03-04 21:34:29 +01:00
Bruno Raoult	a499893f32	add board_print, board_print_mask	2024-03-02 07:10:23 +01:00
Bruno Raoult	dc6ceb3407	Makefile cleanup	2024-02-29 10:05:44 +01:00
Bruno Raoult	beaa7bfcbc	movegen: start to fix early bugs (wrong masks, etc...)	2024-02-29 09:33:18 +01:00
Bruno Raoult	be32bae86a	strengthen FEN parsing	2024-02-29 09:31:40 +01:00
Bruno Raoult	8f0840fc2f	add functions documentation - should be done earlier !!	2024-02-29 09:31:00 +01:00
Bruno Raoult	6d412e7fce	add move.c from pre-bitboard version	2024-02-29 09:27:29 +01:00
Bruno Raoult	7859228f89	movegen-test: add fen test array	2024-02-29 09:19:24 +01:00
Bruno Raoult	a8e3ec70f8	add square attackers fct	2024-02-29 09:18:19 +01:00
Bruno Raoult	f1a081a7b6	add pawn movegen (untested)	2024-02-26 19:15:42 +01:00
Bruno Raoult	ca4e274957	add in-between masks (with/without dest square. TODO: keep only one !)	2024-02-26 19:14:20 +01:00
Bruno Raoult	e50d9a73e6	Makefile: cleanup	2024-02-26 19:11:46 +01:00
Bruno Raoult	ccc0dfd2f6	temp commit for machine transfer	2024-02-22 09:37:02 +01:00
Bruno Raoult	fa5c9bb8ab	bitboard8_sprint -> bitboard_rank_sprint (temp, need BB+rank as input)	2024-02-22 09:29:10 +01:00
Bruno Raoult	d00eab54e7	board.h: fix sq_make/sq_file	2024-02-22 09:13:12 +01:00
Bruno Raoult	9c02a02c1e	fen: add fen_test()	2024-02-22 09:11:25 +01:00
Bruno Raoult	4d8f69e8c9	position: raw_board_print in octal, fix mask in pos_set_sq/pos_clr_sq	2024-02-22 08:35:26 +01:00