add git-split.sh

perft: normal "get_next_legal()" before movegen
perft2: is_in_check() after movegen

.dir-locals.el

@@ -1,3 +1,3 @@
 ((nil . ((compile-command . (concat "make -C "
                                        (vc-root-dir)
-                                       " -k -j2 testing")))))
+                                       " -k -j4 testing")))))

.gitignore

@@ -4,6 +4,7 @@ vgcore.*
 *.i
 *.old
 *.save
+perf.data
 /GPATH
 /GRTAGS
 /GTAGS

Makefile

@@ -1,6 +1,6 @@
 # Makefile - brchess Makefile, **GNU make only**
 #
-# Copyright (C) 2021-2023 Bruno Raoult ("br")
+# Copyright (C) 2021-2024 Bruno Raoult ("br")
 # Licensed under the GNU General Public License v3.0 or later.
 # Some rights reserved. See COPYING.
 #
@@ -12,8 +12,8 @@
 
 SHELL     := /bin/bash
 CC        := gcc
+#CC        := gcc-13
 #CC        := clang
-LD        := ld
 BEAR      := bear
 TOUCH     := touch
 RM        := rm
@@ -21,7 +21,7 @@ RMDIR     := rmdir
 MAKE      := make
 
 SRCDIR    := ./src
-INCDIR    := ./src					    # used by ./test sources
+INCDIR    := ./src                                          # used by ./test sources
 OBJDIR    := ./obj
 BINDIR    := ./bin
 DEPDIR    := ./dep
@@ -34,13 +34,13 @@ BRLIBDIR  := $(BRLIB)/lib
 CCLSROOT  := .ccls-root
 CCLSFILE  := compile_commands.json
 
-SRC       := $(wildcard $(SRCDIR)/*.c)			    # project sources
-SRC_FN    := $(notdir $(SRC))				    # source basename
+SRC       := $(wildcard $(SRCDIR)/*.c)                      # project sources
+SRC_FN    := $(notdir $(SRC))                               # source basename
 OBJ       := $(addprefix $(OBJDIR)/,$(SRC_FN:.c=.o))
 
 TSTSRC    := $(wildcard $(TSTDIR)/*.c)
 
-LIB       := br_$(shell uname -m)			    # library name
+LIB       := br_$(shell uname -m)                           # library name
 LIBS      := $(strip -l$(LIB) -lreadline)
 
 DEP_FN    := $(SRC_FN)
@@ -55,54 +55,75 @@ CPPFILES  := $(SRC:.c=.i) $(TSTSRC:.c=.i)
 ##################################### pre-processor flags
 CPPFLAGS  := -I$(BRINCDIR) -I$(INCDIR)
 
-CPPFLAGS  += -DNDEBUG                                       # assert
-
-CPPFLAGS  += -DBUG_ON                                       # brlib bug.h
+CPPFLAGS  += -DNDEBUG                                       # assert (unused)
 CPPFLAGS  += -DWARN_ON                                      # brlib bug.h
+CPPFLAGS  += -DBUG_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_POS                                    # position.c
 #CPPFLAGS  += -DDEBUG_MOVE                                   # move generation
 
 # fen.c
 #CPPFLAGS  += -DDEBUG_FEN                                    # FEN decoding
 
+# hash / TT
+#CPPFLAGS  += -DZOBRIST_VERIFY                                # double chk zobrist
+#CPPFLAGS  += -DPERFT_MOVE_HISTORY			      # perft, keep prev moves
+
 # attack.c
-#CPPFLAGS  += -DDEBUG_ATTACK_ATTACKERS1			     # sq_attackers details
-CPPFLAGS  += -DDEBUG_ATTACK_ATTACKERS			    # sq_attackers
-CPPFLAGS  += -DDEBUG_ATTACK_PINNERS			    # sq_pinners 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
+CPPFLAGS  += -DDIAGRAM_SYM                                  # UTF8 symbols in diagrams
 
 # remove extraneous spaces (due to spaces before comments)
 CPPFLAGS  := $(strip $(CPPFLAGS))
 
 ##################################### compiler flags
 CFLAGS    := -std=gnu11
-#CFLAGS    += -flto
-CFLAGS    += -O1
-CFLAGS    += -g
+
+### dev OR release
+
+# dev
+CFLAGS    += -g                                             # symbols (gdb, perf, etc.)
+CFLAGS    += -ginline-points                                # inlined funcs debug info
+#CFLAGS    += -Og
+# for gprof
+#CFLAGS += -pg
+# Next one may be useful for valgrind (when invalid instructions)
+#CFLAGS += -mno-tbm
+
+# release
+CFLAGS    += -O3
+
+CFLAGS    += -march=native
+CFLAGS    += -flto
+CFLAGS    += -funroll-loops
 CFLAGS    += -Wall
 CFLAGS    += -Wextra
-CFLAGS    += -march=native
+CFLAGS    += -Wshadow
 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 := -Og
+#DEV_CFLAGS += -g
+
+# release CFLAGS - unused - TODO
+#REL_CFLAGS := -Ofast
+
 ##################################### linker flags
-LDFLAGS   := -L$(BRLIBDIR)
-#LDFLAGS   += -flto
+LDFLAGS   := --static
+LDFLAGS   += -L$(BRLIBDIR)
+LDFLAGS   += -flto
 
 LDFLAGS   := $(strip $(LDFLAGS))
 
@@ -114,6 +135,38 @@ DEPFLAGS   = -MMD -MP -MF $(DEPDIR)/$*.d
 ALL_CFLAGS  = $(DEPFLAGS) $(CPPFLAGS) $(CFLAGS)
 ALL_LDFLAGS = $(LDFLAGS) $(LIBS)
 
+##################################### Multi-targets
+# We can have an issue with Make's "-j" option, in some situations,
+# for example "make -j2 clean testing".
+# See https://stackoverflow.com/a/8496333/3079831
+
+# Check if job server supported:
+ifeq ($(filter jobserver, $(.FEATURES)),)
+# Job server not supported: sub-makes will only start one job unless
+# you specify a higher number here.  Here we use a MS Windows environment
+# variable specifying number of processors.
+JOBSARG := -j $(NUMBER_OF_PROCESSORS)
+else
+# Job server is supported; let GNU Make work as normal.
+JOBSARG :=
+endif
+
+# .FEATURES only works in GNU Make 3.81+.
+# If GNU make is older, assume job server support.
+ifneq ($(firstword $(sort 3.81 $(MAKE_VERSION))),3.81)
+# If you are using GNU Make < 3.81 that does not support job servers, you
+# might want to specify -jN parameter here instead.
+JOBSARG :=
+endif
+
+ifneq ($(words $(MAKECMDGOALS)),1)
+.NOTPARALLEL:
+# The "all" target is required in the list,
+# in case user invokes make with no targets.
+$(sort all $(MAKECMDGOALS)):
+	@$(MAKE) $(JOBSARG) -f $(firstword $(MAKEFILE_LIST)) $@
+else
+
 ##################################### General targets
 .PHONY: all compile clean cleanall
 
@@ -243,11 +296,11 @@ cleanasmcpp:
 	@$(call rmfiles,$(ASMFILES) $(CPPFILES),asm and pre-processed)
 
 %.i: %.c
-	@echo generating $@ (cpp processed).
+	@echo "generating $@ (cpp processed)."
 	@$(CC) -E $(CPPFLAGS) $(CFLAGS) $< -o $@
 
 %.s: %.c
-	@echo generating $@ (asm).
+	@echo "generating $@ (asm)."
 	@$(CC) -S -fverbose-asm $(CPPFLAGS) $(CFLAGS) $< -o $@
 
 ##################################### LSP (ccls)
@@ -286,19 +339,18 @@ memcheck: targets
 ##################################### test binaries
 .PHONY: testing test
 
-TEST          := piece-test fen-test bitboard-test movegen-test attack-test movedo-test
+TEST          := piece-test fen-test bitboard-test movegen-test attack-test
+TEST          += movedo-test perft-test tt-test
 
 PIECE_OBJS    := piece.o
-FEN_OBJS      := fen.o position.o piece.o bitboard.o board.o hyperbola-quintessence.o \
-	attack.o
-BB_OBJS       := fen.o position.o piece.o bitboard.o board.o hyperbola-quintessence.o \
-	attack.o
-MOVEGEN_OBJS  := fen.o position.o piece.o bitboard.o board.o hyperbola-quintessence.o \
-	attack.o move.o move-gen.o
-ATTACK_OBJS   := fen.o position.o piece.o bitboard.o board.o hyperbola-quintessence.o \
-	 attack.o move.o move-gen.o
-MOVEDO_OBJS   := fen.o position.o piece.o bitboard.o board.o hyperbola-quintessence.o \
-	 attack.o move.o move-gen.o move-do.o
+FEN_OBJS      := $(PIECE_OBJS) fen.o position.o bitboard.o board.o \
+	hyperbola-quintessence.o attack.o hash.o init.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 misc.o
+PERFT_OBJS    := $(MOVEDO_OBJS) search.o
+TT_OBJS       := $(MOVEDO_OBJS)
 
 TEST          := $(addprefix $(BINDIR)/,$(TEST))
 
@@ -308,6 +360,8 @@ 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))
+TT_OBJS       := $(addprefix $(OBJDIR)/,$(TT_OBJS))
 
 test:
 	echo TEST=$(TEST)
@@ -339,6 +393,14 @@ 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 $@
+
+bin/tt-test: test/tt-test.c test/common-test.h $(TT_OBJS)
+	@echo compiling $@ test executable.
+	@$(CC) $(ALL_CFLAGS) $< $(TT_OBJS) $(ALL_LDFLAGS) -o $@
+
 ##################################### Makefile debug
 .PHONY: showflags wft
 
@@ -361,3 +423,6 @@ wtf:
 
 zob:
 	$(CC) $(LDFLAGS) $(CPPFLAGS) $(CFLAGS) $< $(LIBS) src/util.c -o util
+
+##################################### End of multi-targets
+endif

scripts/fetch-all.sh

@@ -0,0 +1,44 @@
+#!/usr/bin/env bash
+#
+# Fetch all branches from remotes, and track missing ones.
+#
+# The value of variable ORIGIN is used for repository origin. If
+# not set, the default is "origin".
+
+default_origin=origin
+
+origin=${ORIGIN:-$default_origin}
+
+declare -a local_b
+declare -A alocal_b
+
+# fetch all remotes
+git fetch --all --tags
+
+# get local branches, and build reverse associative array
+readarray -t local_b < <(git for-each-ref --format='%(refname:short)' refs/heads/)
+for ref in "${local_b[@]}"; do
+    alocal_b[$ref]=1
+done
+
+# get "origin" branches
+readarray -t orig_b  < <(git for-each-ref --format='%(refname:short)' \
+                             refs/remotes/"$origin"/)
+
+# find-out missing local branches and track them.
+# bugs:
+#  - We only check local branch existence, not tracking information correctness.
+#  - What about sub-branches ? Like remote/a and remote/a/b not being tracked ?
+for remote_b in "${orig_b[@]}"; do
+    short=${remote_b#"$origin"/};
+    # OR (??): short=${remote_b##*/}
+
+    if ! [[ -v alocal_b[$short] ]]; then
+        printf "local branch %s set to track %s.\n" "$short" "$remote_b"
+        git branch --track "$short" "$remote_b"
+    else
+        printf "skipping %s.\n" "$remote_b"
+    fi
+done
+
+git pull -a

scripts/git-split.sh

@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+#
+# Copy a git file, keeping history.
+# Source: https://stackoverflow.com/a/53849613/3079831
+
+if (( $# != 2 )) ; then
+  echo "Usage: git-split.sh original copy"
+  exit 1
+fi
+
+from="$1"
+to="$2"
+
+git mv "$from" "$to"
+git commit -n -m "Split history $from to $to - rename file to target-name"
+REV=$(git rev-parse HEAD)
+git reset --hard HEAD^
+git mv "$from" temp
+git commit -n -m "Split history $from to $to - rename source-file to temp"
+git merge "$REV"
+git commit -a -n -m "Split history $from to $to - resolve conflict and keep both files"
+git mv temp "$from"
+git commit -n -m "Split history $from to $to - restore name of source-file"
+
+exit 0

src/attack.c

@@ -21,7 +21,73 @@
 #include "attack.h"
 
 
-// #define DEBUG_ATTACK_ATTACKERS1
+/**
+ * sq_is_attacked() - find if a square is attacked
+ * @pos: position
+ * @occ: occupation mask used
+ * @sq:  square to test
+ * @c:   attacker color
+ *
+ * Find if a @c piece attacks @sq.
+ *
+ * Algorithm:  We perform a reverse attack, and check if any given
+ * piece type on @sq can attack a @c piece of same type.
+ *
+ * For example, if @c is white, we test for all T in P,N,B,R,Q,K if
+ * T on @sq could attack a white T piece.
+ *
+ * @Return: true if @sq is attacked by a @c piece, false otherwise.
+ */
+bool sq_is_attacked(const pos_t *pos, const bitboard_t occ, const square_t sq, const color_t c)
+{
+    color_t opp = OPPONENT(c);
+
+    /*
+     * return (hyperbola_bishop_moves(occ, sq) & (pos->bb[c][BISHOP] | pos->bb[c][QUEEN])
+     *      || hyperbola_rook_moves(occ, sq) & (pos->bb[c][ROOK] | pos->bb[c][QUEEN])
+     *      || bb_pawn_attacks[opp][sq] & pos->bb[c][PAWN]
+     *      || bb_knight_moves(pos->bb[c][KNIGHT], sq)
+     *      || bb_king_moves(pos->bb[c][KING], sq)
+     *  )
+     */
+
+    /* 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;
+
+    /* knight */
+    if (bb_knight_moves(pos->bb[c][KNIGHT], sq))
+        return true;
+
+    /* pawn */
+    if (bb_pawn_attacks[opp][sq] & pos->bb[c][PAWN])
+        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
@@ -43,35 +109,29 @@
 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 sqbb = BIT(sq);
     bitboard_t to;
     color_t opp = OPPONENT(c);
 
     /* pawn */
     to =  pos->bb[c][PAWN];
-    tmp = pawn_shift_upleft(sqbb, opp) & to;
+    tmp = bb_pawns_attacks(sqbb, sq_up(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);
+#   ifdef DEBUG_ATTACK_ATTACKERS
+    bb_print("att pawn", tmp);
 #   endif
 
     /* knight & king */
     to = pos->bb[c][KNIGHT];
     tmp = bb_knight_moves(to, sq);
     attackers |= tmp;
-#   ifdef DEBUG_ATTACK_ATTACKERS1
+#   ifdef DEBUG_ATTACK_ATTACKERS
     bb_print("att knight", tmp);
 #   endif
     to = pos->bb[c][KING];
     tmp = bb_king_moves(to, sq);
     attackers |= tmp;
-#   ifdef DEBUG_ATTACK_ATTACKERS1
+#   ifdef DEBUG_ATTACK_ATTACKERS
     bb_print("att king", tmp);
 #   endif
 
@@ -79,7 +139,7 @@ bitboard_t sq_attackers(const pos_t *pos, const bitboard_t occ, const square_t s
     to = pos->bb[c][BISHOP] | pos->bb[c][QUEEN];
     tmp = hyperbola_bishop_moves(occ, sq) & to;
     attackers |= tmp;
-#   ifdef DEBUG_ATTACK_ATTACKERS1
+#   ifdef DEBUG_ATTACK_ATTACKERS
     bb_print("att bishop/queen", tmp);
 #   endif
 
@@ -87,10 +147,9 @@ bitboard_t sq_attackers(const pos_t *pos, const bitboard_t occ, const square_t s
     to = pos->bb[c][ROOK] | pos->bb[c][QUEEN];
     tmp = hyperbola_rook_moves(occ, sq) & to;
     attackers |= tmp;
-#   ifdef DEBUG_ATTACK_ATTACKERS1
+#   ifdef DEBUG_ATTACK_ATTACKERS
     bb_print("att rook/queen", tmp);
     bb_print("ATTACKERS", attackers);
-    printf("attackers=%lx\n", attackers);
 #   endif
 
     return attackers;
@@ -121,7 +180,7 @@ bitboard_t sq_pinners(const pos_t *pos, const square_t sq, const color_t color)
         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);
+            pinners |= BIT(maybe_pinner);
     }
 
     /* same for rook type */
@@ -130,7 +189,7 @@ bitboard_t sq_pinners(const pos_t *pos, const square_t sq, const color_t color)
     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);
+            pinners |= BIT(maybe_pinner);
     }
 #   ifdef DEBUG_ATTACK_ATTACKERS1
     char str[32];

src/attack.h

@@ -17,6 +17,9 @@
 #include "chessdefs.h"
 #include "bitboard.h"
 
+bool sq_is_attacked(const pos_t *pos, const bitboard_t occ, const square_t sq, const color_t c);
+bool is_in_check(const pos_t *pos, const color_t color);
+
 bitboard_t sq_attackers(const pos_t *pos, const bitboard_t occ, const square_t sq, const color_t c);
 bitboard_t sq_attackers_all(const pos_t *pos, const square_t sq);
 bitboard_t sq_pinners(const pos_t *pos, const square_t sq, const color_t c);

src/bitboard.c

@@ -27,7 +27,7 @@ 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];
+bitboard_t bb_knight[64], bb_king[64], bb_pawn_attacks[2][64];
 
 /*  vectors are clockwise from N */
 static int knight_vector[] = {
@@ -53,8 +53,8 @@ static int king_vector[8] = {
 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);
+    const bitboard_t a2a7 = U64(0x0001010101010100);
+    const bitboard_t b7h1 = U64(0x0002040810204080);
     bitboard_t btwn_bits, ray_bits;
     u32 rank_diff, file_diff, anti_diff, diag_diff;
 
@@ -105,9 +105,11 @@ void bitboard_init(void)
     } ;
     bitboard_t tmpbb[64][4] = { 0 };
 
-    /* 1) square to bitboard, and in-between-sq2-excluded */
+    /* 1) square to bitboard
+     *    in-between, sq2 excluded
+     */
     for (square_t sq1 = A1; sq1 <= H8; ++sq1) {
-        bb_sq[sq1] = mask(sq1);
+        bb_sq[sq1] = BIT(sq1);
         for (square_t sq2 = A1; sq2 <= H8; ++sq2)
             bb_between_excl[sq1][sq2] = bitboard_between_excl(sq1, sq2);
     }
@@ -119,15 +121,15 @@ void bitboard_init(void)
         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));
+            tmpbb[sq][vec] |= BIT(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);
+                    tmpbb[sq][vec] |= BIT(dest);
+                    mask_between |= BIT(dest);
                     bb_between[sq][dest] = mask_between;
                     f2 += df, r2 += dr;
                 }
@@ -151,18 +153,18 @@ void bitboard_init(void)
                     bb_line[sq1][sq2] = bb_sqdiag[sq1];
                 else if (bb_sqanti[sq1] == bb_sqanti[sq2])
                     bb_line[sq1][sq2] = bb_sqanti[sq1];
-
-                //if (bb_line[sq1][sq2]) {
-                //    printf("bb_line[%d][%d] = %16lx\n", sq1, sq2, bb_line[sq1][sq2]);
-                //}
             }
         }
     }
 
-    /* 3) knight and king moves */
+    /* 3) pawn, knight and king attacks
+     */
     for (square_t sq = A1; sq <= H8; ++sq) {
-        //rank_t r1 = sq_rank(sq);
-        //file_t f1 = sq_file(sq);
+         if (sq <= H7)
+             bb_pawn_attacks[WHITE][sq] = bb_pawns_attacks(BIT(sq), sq_up(WHITE));
+         if (sq >= A2)
+             bb_pawn_attacks[BLACK][sq] = bb_pawns_attacks(BIT(sq), sq_up(BLACK));
+
         for (int vec = 0; vec < 8; ++vec) {
             int dst = sq + knight_vector[vec];
             if (sq_ok(dst)) {
@@ -190,8 +192,6 @@ void bitboard_init(void)
  */
 bitboard_t bb_knight_moves(bitboard_t notmine, square_t sq)
 {
-    //bitboard_print("bb_knight_move mask", bb_knight[sq]);
-    //bitboard_print("bb_knight_move  res", bb_knight[sq] & notmine);
     return bb_knight[sq] & notmine;
 }
 
@@ -281,7 +281,7 @@ char *bb_rank_sprint(char *str, const uchar bb8)
 {
     file_t f;
     for (f = FILE_A; f <= FILE_H; ++f) {
-        *(str + f) = bb8 & mask(f) ? '1': '.';
+        *(str + f) = bb8 & BIT(f) ? '1': '.';
     }
     *(str + f) = 0;
     //printf(" 0 1 2 3 4 5 6 7\n");

src/bitboard.h

@@ -14,8 +14,8 @@
 #ifndef _BITBOARD_H
 #define _BITBOARD_H
 
-#include "brlib.h"
-#include "bitops.h"
+#include <brlib.h>
+#include <bitops.h>
 
 #include "chessdefs.h"
 #include "board.h"
@@ -39,9 +39,8 @@ 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];
 
-/* knight and king moves */
-extern bitboard_t bb_knight[64], bb_king[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
  *
@@ -183,13 +182,77 @@ static __always_inline bitboard_t bb_file(int 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;
+}
+
+/**
+ * bb_pawns_attacks() - shift up pawns on both diagonals (attacks)
+ * @bb:      pawns bitboard
+ * @push:    shift value for pawn up
+ *
+ * Get the possible attacks for all @bb pawns.
+ *
+ * @return: squares attacked by @bbpawns
+ */
+static __always_inline bitboard_t bb_pawns_attacks(const bitboard_t bb, int push)
+{
+    return bb_shift(bb & ~FILE_Abb, push - 1) | bb_shift(bb & ~FILE_Hbb, push + 1);
+}
+
 #define bb_rank(r)        ((u64) RANK_1bb << ((r) * 8))
-#define BB_FILE(f)        ((u64) FILE_Abb << (f))
+#define bb_file(f)        ((u64) FILE_Abb << (f))
 
 #define bb_rel_rank(r, c) bb_rank(sq_rel_rank(r, c))
-
-//#define BB_REL_RANK(r, c) (RANK_1bb << (SQ_REL_RANK(r, c) * 8))
-//#define BB_REL_FILE(f, c) (FILE_Abb << (SQ_REL_RANK((f), (c))))
+#define bb_rel_file(f, c) bb_file(sq_rel_rank(f, c)) /* likely useless */
 
 /**
  * bb_sq_aligned() - check if two squares are aligned (same file or rank).
@@ -210,7 +273,7 @@ static __always_inline bool bb_sq_aligned(square_t sq1, square_t sq2)
  */
 static __always_inline bool bb_sq_aligned3(square_t sq1, square_t sq2, square_t sq3)
 {
-    return bb_line[sq1][sq2] & mask(sq3);
+    return bb_line[sq1][sq2] & BIT(sq3);
 }
 
 /**
@@ -219,68 +282,22 @@ static __always_inline bool bb_sq_aligned3(square_t sq1, square_t sq2, square_t
  * @sq1: square 1
  * @sq2: square 2
  *
- * @return: bitboard of @betw if between @sq1 and @sq2.
+ * @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);
+    return bb_between_excl[sq1][sq2] & BIT(sq);
 }
 
-/* TODO: when OK, replace with macros */
-static __always_inline bitboard_t shift_n(const bitboard_t bb)
-{
-    return bb << NORTH;
-}
-static __always_inline bitboard_t shift_ne(const bitboard_t bb)
-{
-    return (bb & ~FILE_Hbb) << NORTH_EAST;
-}
-static __always_inline bitboard_t shift_e(const bitboard_t bb)
-{
-    return (bb & ~FILE_Hbb) << EAST;
-}
-static __always_inline bitboard_t shift_se(const bitboard_t bb)
-{
-    return (bb & ~FILE_Hbb) >> -SOUTH_EAST;
-}
-static __always_inline bitboard_t shift_s(const bitboard_t bb)
-{
-    return bb >> -SOUTH;
-}
-static __always_inline bitboard_t shift_sw(const bitboard_t bb)
-{
-    return (bb & ~FILE_Abb) >> -SOUTH_WEST;
-}
-static __always_inline bitboard_t shift_w(const bitboard_t bb)
-{
-    return (bb & ~FILE_Abb) >> -WEST;
-}
-static __always_inline bitboard_t shift_nw(const bitboard_t bb)
-{
-    return (bb & ~FILE_Abb) << NORTH_WEST;
-}
+bitboard_t bitboard_between_excl(square_t sq1, square_t sq2);
+void bitboard_init(void);
 
-#define pawn_up_value(c)          ((c) == WHITE ? 8: -8)
-/* 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))
-/* 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 bb_knight_moves(bitboard_t notmine, square_t sq);
+bitboard_t bb_king_moves(bitboard_t notmine, square_t sq);
 
-extern bitboard_t bitboard_between_excl(square_t sq1, square_t sq2);
-extern void bitboard_init(void);
-
-extern bitboard_t bb_knight_moves(bitboard_t occ, square_t sq);
-extern bitboard_t bb_king_moves(bitboard_t occ, square_t sq);
-
-extern void bb_print(const char *title, const bitboard_t bitboard);
-extern void bb_print_multi(const char *title, const int n, ...);
-extern char *bb_rank_sprint(char *str, const uchar bb8);
-extern char *bb_sq2str(const bitboard_t bb, char *str, int len);
+void bb_print(const char *title, const bitboard_t bitboard);
+void bb_print_multi(const char *title, const int n, ...);
+char *bb_rank_sprint(char *str, const uchar bb8);
+char *bb_sq2str(const bitboard_t bb, char *str, int len);
 
 #endif  /* _BITBOARD_H */

src/board.c

@@ -14,7 +14,8 @@
 #include <stdio.h>
 #include <ctype.h>
 
-#include "brlib.h"
+#include <brlib.h>
+
 #include "board.h"
 #include "bitboard.h"
 
@@ -93,7 +94,7 @@ void board_print_mask(const piece_t *board, const bitboard_t mask)
         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;
+            bitboard_t set = BIT(sq) & mask;
             printf("%s", set? REVERSE : " ");
 #           ifdef DIAGRAM_SYM
             printf("%s", pc? piece_to_sym(pc): " ");

src/chessdefs.h

@@ -16,11 +16,12 @@
 
 #include "brlib.h"                                /* brlib types */
 
-#define ONE                1ull
-#define C64(const_u64)     const_u64##ULL
-#define mask(i)            ( (u64) (ONE << (i)) )
+#define ONE                1ul
+#define U64(const_u64)     const_u64##UL
+#define BIT(i)             ( (u64) (ONE << (i)) )
 
 #define BOARDSIZE          (8*8)
+#define GAMESIZE           1024                   /* max game size (512 moves) */
 
 /**
  * sq_rel - get relative square
@@ -45,21 +46,24 @@
  * @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
  */
 typedef enum {
-    CASTLE_WK = (1 << 0),                         /* 0x01 00000001 */
-    CASTLE_WQ = (1 << 1),                         /* 0x02 00000010 */
-    CASTLE_BK = (1 << 2),                         /* 0x04 00000100 */
-    CASTLE_BQ = (1 << 3),                         /* 0x08 00001000 */
+    CASTLE_NONE = 0,
+    CASTLE_WK   = (1 << 0),                       /* 0001 */
+    CASTLE_WQ   = (1 << 1),                       /* 0010 */
+    CASTLE_BK   = (1 << 2),                       /* 0100 */
+    CASTLE_BQ   = (1 << 3),                       /* 1000 */
 
-    CASTLE_W  = (CASTLE_WK | CASTLE_WQ),          /* 00000011 W castle mask */
-    CASTLE_B  = (CASTLE_BK | CASTLE_BQ),          /* 00001100 B castle mask */
+    CASTLE_W    = (CASTLE_WK | CASTLE_WQ),        /* 0011 =  3 = W castle mask */
+    CASTLE_B    = (CASTLE_BK | CASTLE_BQ),        /* 1100 = 12 = B castle mask */
+    CASTLE_ALL  = (CASTLE_W | CASTLE_B),          /* 1111 = 15 */
 
     CASTLE_K  = (1 << 0),                         /* generic K/Q, bits 0 and 1 */
     CASTLE_Q  = (1 << 1),
-    CASTLE_KQ = (CASTLE_K |CASTLE_Q)
+    CASTLE_KQ = (CASTLE_K |CASTLE_Q),
 } castle_rights_t;
 
 /* determine is oo or ooo is possible with castle flags f and color c
@@ -134,5 +138,49 @@ typedef enum {
     NORTH_WEST = (NORTH + WEST),
 } dir_t;
 
+/* define diff for relative squares */
+#define sq_up(c)          ((c) == WHITE ? NORTH: SOUTH)
+/* Attention here: We mix "up" (color dependent) and W/E, color independant.
+ */
+#define sq_upwest(up)     ((up) - 1)
+#define sq_upeast(up)     ((up) + 1)
+
+#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);
+
+#define RAND_SEED_DEFAULT U64(0xb0d1ccea)
+
+void rand_init(u64 seed);
+u64 rand64(void);
+
+void init_all(void);
 
 #endif  /* _CHESSDEFS_H */

src/eval.h

@@ -1,6 +1,6 @@
 /* eval.h - static position evaluation.
  *
- * 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.
  *

src/fen.c

@@ -61,46 +61,50 @@ 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
+ * fen_ok() - test (and try to fix) fen-generated position.
+ * @pos:    &position
+ * @fixit:  action flag
  *
- * Test and fix the following:
+ * Test and possibly fix the following:
  * - inconsistent castle flags (if K & R are not in correct position)
- * - inconsistent en-passant square (turn, bad pawn position)
+ * - inconsistent en-passant square (turn, bad pawns positions)
  *
- * pos_check() is also called, leading to fatal errors if something is wrong.
+ * if @fixit is true, any error above will be fixed, and pos_ok() will
+ 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)
+int fen_ok(pos_t *pos, bool fixit)
 {
     char *colstr[2] = { "white", "black"};
-    int error = 0, warning = 0;
+    int warning = 0;
+    color_t us = pos->turn, them = OPPONENT(us);
+    int up = sq_up(us);                           /* pawn up */
+    square_t ep = pos->en_passant;
 
     /* 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
+    if (ep != SQUARE_NONE) {
+        rank_t eprank = sq_rank(ep);
+        rank_t rank6 = sq_rel_rank(RANK_6, us);
+        piece_t pawn = MAKE_PIECE(PAWN, them);
+        bitboard_t att = bb_pawn_attacks[them][ep] & pos->bb[us][PAWN];
+
+        if (eprank != rank6 ||
+            pos->board[ep - up] != pawn ||
+            pos->board[ep] != EMPTY ||
+            pos->board[ep + up] != EMPTY ||
+            att == 0ull) {
+
             warning++;
-            pos->en_passant = SQUARE_NONE;
+            if (fixit) {
+                warn(true, "pos warn: wrong en-passant settings (fixed).\n");
+                pos->en_passant = SQUARE_NONE;
+            }
         }
     }
 
     for (int color = WHITE; color <= BLACK; ++color) {
-        rank_t rank1 = color == WHITE? RANK_1: RANK_8;
+        rank_t rank1 = sq_rel_rank(RANK_1, color);
 
         /* castling */
         /* where K and R should be for valid castle flag */
@@ -109,34 +113,28 @@ static int fen_check(pos_t *pos)
         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];
+        bitboard_t kingbb = pos->bb[color][KING];
+        bitboard_t rookbb = 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++;
+        if (pos->castle & castle_k && !(k & kingbb && r_k & rookbb)) {
+            warning++;
+            if (fixit) {
+                warn(true, "fen warn: wrong %s short castling (fixed)\n",
+                     colstr[color]);
                 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++;
+        if (pos->castle & castle_q && !(k & kingbb && r_q & rookbb)) {
+            warning++;
+            if (fixit) {
+                warn(true, "fen warn: wrong %s long castling (fixed)\n",
+                     colstr[color]);
                 pos->castle &= ~castle_q;
             }
         }
     }
-    if (!(error = pos_check(pos, 0))) {
-        /* TODO: Should it really be here ? */
-        pos->checkers = pos_checkers(pos, pos->turn);
-        pos->pinners = pos_king_pinners(pos, pos->turn);
-        pos->blockers = pos_king_blockers(pos, pos->turn, pos->pinners);
-    }
-    return error ? -1: warning;
+    return warning;
 }
 
 /**
@@ -168,7 +166,7 @@ pos_t *fen2pos(pos_t *pos, const char *fen)
     char *p;
     short rank, file, tmp;
     piece_t piece;
-    int consumed, err_line = 0, err_pos, err_char;
+    int consumed, err_line = 0, err_pos = 0, err_char = 0;
     pos_t tmppos;
 
     pos_clear(&tmppos);
@@ -190,6 +188,8 @@ pos_t *fen2pos(pos_t *pos, const char *fen)
                   piece, PIECE(piece), COLOR(piece));
 #           endif
             pos_set_sq(&tmppos, sq_make(file, rank), piece);
+            if (PIECE(piece) == KING)
+                tmppos.king[COLOR(piece)] = sq_make(file, rank);
             file++;
         } else {                                  /* error */
             err_line = __LINE__, err_char = *cur, err_pos = cur - fen;
@@ -254,13 +254,15 @@ end:
              err_line, err_pos, err_char, err_char)) {
         return NULL;
     }
-    if (fen_check(&tmppos) < 0)
-        return NULL;
+
+    fen_ok(&tmppos, true);                        /* fix e.p & castling flags */
+    if (!pos_ok(&tmppos, false))
+        return NULL;                              /* invalid position: ignored */
+
+    tmppos.key = zobrist_calc(&tmppos);
     if (!pos)
-        pos = pos_dup(&tmppos);
-    //puts("prout 1");
-    //pos_print_raw(&tmppos, 1);
-    //puts("prout 2");
+        pos = pos_new();
+    pos_copy(&tmppos, pos);
 #   ifdef DEBUG_FEN
     pos_print_raw(&tmppos, 1);
 #   endif
@@ -330,7 +332,7 @@ char *pos2fen(const pos_t *pos, char *fen)
         fen[cur++] = '-';
     } else {
         for (int i = 0; i < 4; ++i)
-            if (pos->castle & mask(i))
+            if (pos->castle & BIT(i))
                 fen[cur++] = castle_str[i];
     }
     fen[cur++] = ' ';
@@ -340,8 +342,8 @@ char *pos2fen(const pos_t *pos, char *fen)
     if (pos->en_passant == SQUARE_NONE) {
         fen[cur++] = '-';
     } else {
-        fen[cur++] = FILE2C(sq_file(pos->en_passant));
-        fen[cur++] = RANK2C(sq_rank(pos->en_passant));
+        strcpy(fen+cur, sq_to_string(pos->en_passant));
+        cur += 2;
     }
     fen[cur++] = ' ';
 

src/fen.h

@@ -20,6 +20,7 @@
 
 extern const char *startfen;                      /* startup position */
 
+extern int fen_ok(pos_t *pos, bool fixit);
 extern pos_t *startpos(pos_t *pos);
 extern pos_t *fen2pos(pos_t *pos, const char *fen);
 extern char *pos2fen(const pos_t *pos, char *fen);

src/hash.c

@@ -0,0 +1,423 @@
+/* hash.c - hash management.
+ *
+ * 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 <string.h>
+#include <assert.h>
+
+#include <brlib.h>
+#include <bitops.h>
+
+#include "chessdefs.h"
+#include "util.h"
+#include "position.h"
+#include "piece.h"
+#include "hash.h"
+
+u64 zobrist_pieces[16][64];
+u64 zobrist_castling[4 * 4 + 1];
+u64 zobrist_turn;                                 /* for black, XOR each ply */
+u64 zobrist_ep[9];                                /* 0-7: ep file, 8: SQUARE_NONE */
+
+hasht_t hash_tt;                                  /* main transposition table */
+
+/**
+ * zobrist_init() - initialize zobrist tables.
+ *
+ * Initialize all zobrist random bitmasks. Must be called before any other
+ * zobrist function, and can be called once only (further calls will be ignored).
+ */
+void zobrist_init(void)
+{
+    static bool called = false;
+    if (!called) {
+        called = true;
+        for (color_t c = WHITE; c <= BLACK; ++c) {
+            for (piece_type_t p = PAWN; p <= KING; ++p)
+                for (square_t sq = A1; sq <= H8; ++sq)
+                    zobrist_pieces[MAKE_PIECE(p, c)][sq] = rand64();
+        }
+        for (castle_rights_t c = CASTLE_NONE; c <= CASTLE_ALL; ++c)
+            zobrist_castling[c] = rand64();
+        for (file_t f = FILE_A; f <= FILE_H; ++f)
+            zobrist_ep[f] = rand64();
+        zobrist_ep[8] = 0;                        /* see EP_ZOBRIST_IDX macro */
+        zobrist_turn = rand64();
+    }
+}
+
+/**
+ * zobrist_calc() - calculate a position zobrist hash.
+ * @pos: &position
+ *
+ * Normally, Zobrist keys are incrementally calculated when doing or
+ * undoing a move.
+ * This function should normally only be called:
+ * - When starting a new position
+ * - To verify incremental Zobrist calculation is correct
+ *
+ * @return: @pos Zobrist key
+ */
+hkey_t zobrist_calc(pos_t *pos)
+{
+    hkey_t key = 0;
+
+    if (pos->turn == BLACK)
+        key ^= zobrist_turn;
+
+    for (color_t c = WHITE; c <= BLACK; ++c) {
+        for (piece_type_t pt = PAWN; pt <= KING; ++pt) {
+            piece_t piece = MAKE_PIECE(pt, c);
+            bitboard_t bb = pos->bb[c][pt];
+            while (bb) {
+                square_t sq = bb_next(&bb);
+                key ^= zobrist_pieces[piece][sq];
+            }
+        }
+    }
+    key ^= zobrist_castling[pos->castle];
+    key ^= zobrist_ep[EP_ZOBRIST_IDX(pos->en_passant)];
+
+    return key;
+}
+
+/**
+ * zobrist_verify() - verify current position Zobrist key.
+ * @pos: &position
+ *
+ * Verify that position Zobrist key matches a full Zobrist calculation.
+ * This function cannot be called if ZOBRIST_VERIFY is not set.
+ *
+ * @return: True if Zobrist key is OK.
+ */
+#ifdef ZOBRIST_VERIFY
+
+#pragma push_macro("BUG_ON")                      /* force BUG_ON and WARN_ON */
+#pragma push_macro("WARN_ON")
+#undef BUG_ON
+#define BUG_ON
+#undef WARN_ON
+#define WARN_ON
+
+bool zobrist_verify(pos_t *pos)
+{
+    hkey_t diff, key = zobrist_calc(pos);
+    if (pos->key == key)
+        return true;
+
+    printf("key verify: cur=%#lx != %#lx\n", pos->key, key);
+
+    /* try to find-out the key in different zobrist tables */
+    diff = pos->key ^ key;
+
+    for (color_t c = WHITE; c <= BLACK; ++c) {
+        for (piece_type_t p = PAWN; p <= KING; ++p)
+            for (square_t sq = A1; sq <= H8; ++sq)
+                if (diff == zobrist_pieces[MAKE_PIECE(p, c)][sq]) {
+                    warn(true, "zobrist difference is piece:[%s][%s]\n",
+                         piece_to_fen(MAKE_PIECE(p, c)), sq_to_string(sq));
+                    goto end;
+                }
+    }
+    for (castle_rights_t c = CASTLE_NONE; c <= CASTLE_ALL; ++c) {
+        if (diff == zobrist_castling[c]) {
+            warn(true, "zobrist difference is castling:[%d]\n", c);
+            goto end;
+        }
+    }
+
+    for (file_t f = FILE_A; f <= FILE_H; ++f) {
+        if (diff == zobrist_ep[f]) {
+            warn(true, "zobrist difference is ep:[%d]\n", f);
+            goto end;
+        }
+    }
+    if (diff == zobrist_turn) {
+        warn(true, "zobrist difference is turn\n");
+        goto end;
+    }
+    warn(true, "zobrist diff %lx is unknown\n", diff);
+end:
+    bug_on(false);
+    /* not reached */
+    return true;
+}
+#pragma pop_macro("WARN_ON")
+#pragma pop_macro("BUG_ON")
+
+#endif
+
+/**
+ * tt_create() - create transposition table
+ * @sizemb: s32 size of hash table in Mb
+ *
+ * Create a hash table of max @sizemb (or HASH_SIZE_MBif @sizemb <= 0) Mb size.
+ * This function must be called at startup.
+ *
+ * The number of bucket_t entries fitting in @sizemb is calculated, and rounded
+ * (down) to a power of 2.
+ * This means the actual size could be lower than @sizemb (nearly halved in
+ * worst case).
+ *
+ * If transposition hashtable already exists and new size would not change,
+ * the old one is cleared.
+ * If transposition hashtable already exists and new size is different,
+ * the old one is destroyed first (old data is not preserved).
+ *
+ * TODO:
+ * - Rebuild old hashtable data ?
+ *
+ * @return: hash table size in Mb. If memory allocation fails, the function does
+ * not return.
+ */
+int tt_create(s32 sizemb)
+{
+    size_t bytes, target_nbuckets;
+    u32 nbits;
+
+    static_assert(sizeof(hentry_t) == 16, "fatal: hentry_t size != 16");
+
+    //printf("mb = %'7u ", sizemb);
+    /* adjust tt size */
+    if (sizemb <= 0)
+        sizemb = HASH_SIZE_DEFAULT;
+    sizemb = clamp(sizemb, HASH_SIZE_MIN, HASH_SIZE_MAX);
+    //printf("-> %'6d ", sizemb);
+
+    bytes = sizemb * 1024ull * 1024ull;           /* bytes wanted */
+    target_nbuckets = bytes / sizeof(bucket_t);   /* target buckets */
+
+    nbits = msb64(target_nbuckets);               /* adjust to power of 2 */
+
+    if (hash_tt.nbits != nbits) {
+        if (hash_tt.nbits)
+            tt_delete();
+
+        hash_tt.nbits    = nbits;
+
+        hash_tt.nbuckets = BIT(hash_tt.nbits);
+        hash_tt.nkeys    = hash_tt.nbuckets * ENTRIES_PER_BUCKET;
+
+        hash_tt.bytes    = hash_tt.nbuckets * sizeof(bucket_t);
+        hash_tt.mb       = hash_tt.bytes / 1024 / 1024;
+
+        hash_tt.mask     = -1ull >> (64 - nbits);
+
+        hash_tt.keys     = safe_malloc(hash_tt.bytes);
+
+        //printf("bits=%2d size=%'15lu/%'6d Mb/%'14lu buckets ",
+        //       hash_tt.nbits, hash_tt.bytes, hash_tt.mb, hash_tt.nbuckets);
+        //printf("mask=%9x\n", hash_tt.mask);
+    }
+    //else {
+    //    printf("unchanged (cleared)\n");
+    //}
+    /* attention - may fail ! */
+    tt_clear();
+
+    return hash_tt.nbits;
+}
+
+/**
+ * tt_clear() - clear transposition table
+ *
+ * Reset hashtable entries (if available) and statistic information.
+ */
+void tt_clear()
+{
+    if (hash_tt.keys)
+        memset(hash_tt.keys, 0, hash_tt.bytes);
+
+    hash_tt.used_keys = 0;
+    hash_tt.collisions = 0;
+    hash_tt.hits = 0;
+    hash_tt.misses = 0;
+}
+
+/**
+ * tt_delete() - delete transposition table
+ *
+ * free hashtable data.
+ */
+void tt_delete()
+{
+    if (hash_tt.keys) {
+        safe_free(hash_tt.keys);
+        hash_tt.keys = NULL;
+    }
+    tt_clear();
+}
+
+/**
+ * tt_probe() - probe tt for an entry
+ *
+ *
+ */
+hentry_t *tt_probe(hkey_t key)
+{
+    bucket_t *bucket;
+    hentry_t *entry;
+    int i;
+
+    bug_on(!hash_tt.keys);
+    bucket = hash_tt.keys + (key & hash_tt.mask);
+
+    /* find key in buckets */
+    for (i = 0; i < ENTRIES_PER_BUCKET; ++i) {
+        entry = bucket->entry + i;
+        if (key == entry->key)
+            break;
+    }
+    if (i < ENTRIES_PER_BUCKET)
+        return entry;
+    return NULL;
+}
+
+/**
+ * tt_probe_perft() - probe tt for an entry (perft version)
+ * @key:   Zobrist (hkey_t) key
+ * @depth: depth from search root
+ *
+ * Search transposition for @key entry with @depth depth.
+ *
+ * @return: @hentry_t address is found, TT_MISS otherwise.
+ */
+hentry_t *tt_probe_perft(const hkey_t key, const u16 depth)
+{
+    bucket_t *bucket;
+    hentry_t *entry;
+    int i;
+
+    bug_on(!hash_tt.keys);
+    bucket = hash_tt.keys + (key & hash_tt.mask);
+
+    /* find key in buckets */
+    for (i = 0; i < ENTRIES_PER_BUCKET; ++i) {
+        entry = bucket->entry + i;
+        if (key == entry->key && HASH_PERFT_DEPTH(entry->data) == depth) {
+            hash_tt.hits++;
+            /*
+             * printf("tt hit: key=%lx depth=%d bucket=%lu entry=%d!\n",
+             *        key, depth, bucket - hash_tt.keys, i);
+             */
+            return entry;
+        }
+    }
+    /*
+     * printf("tt miss: key=%lx depth=%d ucket=%lu\n",
+     *        key, depth, bucket - hash_tt.keys);
+     */
+    hash_tt.misses++;
+    return TT_MISS;
+}
+
+/**
+ * tt_store_perft() - store a transposition table entry (perft version)
+ * @key:   Zobrist (hkey_t) key
+ * @depth: depth from search root
+ * @nodes: value to store
+ *
+ */
+hentry_t *tt_store_perft(const hkey_t key, const u16 depth, const u64 nodes)
+{
+    bucket_t *bucket;
+    hentry_t *entry;
+    int replace = -1;
+    uint mindepth = 1024;
+    u64 data = HASH_PERFT(depth, nodes);
+
+    //printf("tt_store: key=%lx data=%lx depth=%d=%d nodes=%lu=%lu\n",
+    //       key, data, depth, HASH_PERFT_DEPTH(data), nodes, HASH_PERFT_VAL(data));
+    /*
+     * printf("tt_store: key=%lx depth=%d nodes=%lu ",
+     *        key, depth, nodes);
+     */
+    bug_on(!hash_tt.keys);
+    bucket = hash_tt.keys + (key & hash_tt.mask);
+
+    /* find key in buckets */
+    for (int i = 0; i < ENTRIES_PER_BUCKET; ++i) {
+        entry = bucket->entry + i;
+        //if (!entry->key) {
+        //    replace = i;
+            //hash_tt.used_keys++;
+        //    break;
+        //}
+        if (key == entry->key) {
+            if (depth == HASH_PERFT_DEPTH(entry->data)) {
+                printf("tt_store: dup key=%lx depth=%d, this should not happen!\n",
+                       key, depth);
+                return NULL;
+            }
+        }
+        /* always keep higher nodes */
+        if (HASH_PERFT_DEPTH(entry->data) < mindepth) {
+            mindepth = HASH_PERFT_DEPTH(entry->data);
+            replace = i;
+        }
+    }
+
+    if (replace >= 0) {
+        entry = bucket->entry + replace;
+
+        hash_tt.used_keys  += entry->key == 0;
+        hash_tt.collisions += entry->key && (key != entry->key);
+        /*
+         * if (HASH_PERFT_VAL(entry->data)) {
+         *     printf("REPL entry=%lu[%d] key=%lx->%lx val=%lu->%lu\n",
+         *            bucket - hash_tt.keys, replace,
+         *            entry->key, key,
+         *            HASH_PERFT_VAL(entry->data), nodes);
+         * } else {
+         *     printf("NEW entry=%lu[%d] key=%lx val=%lu\n",
+         *            bucket - hash_tt.keys, replace,
+         *            entry->key, nodes);
+         * }
+         */
+        entry->key = key;
+        entry->data = data;
+        return entry;
+    } else {
+        //printf("TT full, skip\n");
+    }
+    return NULL;
+}
+
+/**
+ * tt_info() - print hash-table information.
+ */
+void tt_info()
+{
+    if (hash_tt.keys) {
+        printf("TT: Mb:%d buckets:%'lu (bits:%u mask:%#x) entries:%'lu\n",
+               hash_tt.mb, hash_tt.nbuckets, hash_tt.nbits,
+               hash_tt.mask, hash_tt.nkeys);
+    } else {
+        printf("TT: not set.\n");
+    }
+}
+
+/**
+ * tt_stats() - print hash-table usage.
+ */
+void tt_stats()
+{
+    if (hash_tt.keys) {
+        float percent = 100.0 * hash_tt.used_keys / hash_tt.nkeys;
+        printf("hash: used:%'lu/%'lu (%.2f%%) hit:%'lu miss:%'lu coll:%'lu\n",
+               hash_tt.used_keys, hash_tt.nkeys, percent,
+               hash_tt.hits, hash_tt.misses,
+               hash_tt.collisions);
+    } else {
+        printf("hash: not set.\n");
+    }
+}

src/hash.h

@@ -0,0 +1,138 @@
+/* hash.h - hash management.
+ *
+ * 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 HASH_H
+#define HASH_H
+
+#include <bug.h>
+
+#include "chessdefs.h"
+
+#define ENTRIES_PER_BUCKET   4                    /* buckets per hash table entry */
+
+#define HASH_SIZE_DEFAULT   32                    /* default: 32Mb */
+#define HASH_SIZE_MIN        4
+#define HASH_SIZE_MAX    32768                    /* 32Gb */
+
+#define TT_MISS   NULL
+#define TT_DUP    (void *) U64(0x01)
+#define TT_OK(p)  ((p) > (void *)U64(0xF))
+
+typedef u64 hkey_t;                               /* cannot use typedef for key_t */
+
+/**
+ * hentry_t: hashtable bucket.
+ *
+ * Size should be exactly 16 bytes. If impossible to fit necessary data in
+ * 16 bytes in future, it should be updated to be exactly 32 bytes.
+ */
+typedef struct {
+    hkey_t key;                                   /* zobrist */
+    union {
+        u64 data;
+        struct {
+            u16 depth;                            /* ply in search */
+            s16 eval;
+            u16 move;
+            u8 flags;                             /* maybe for locking, etc... */
+            u8 filler;
+        };
+    };
+} hentry_t;
+
+/* hentry perft data:
+ * 0-47:  perft value
+ * 48-63: depth
+ */
+#define HASH_PERFT_MASK        U64(0xffffffffffff)
+#define HASH_PERFT(depth, val) ((((u64) depth) << 48) | ((val) & HASH_PERFT_MASK))
+#define HASH_PERFT_VAL(data)   ((data) & HASH_PERFT_MASK)
+#define HASH_PERFT_DEPTH(data) ((u16)((data) >> 48))
+
+
+typedef struct {
+    hentry_t entry[ENTRIES_PER_BUCKET];
+} bucket_t;
+
+typedef struct {
+    bucket_t *keys;                               /* &hashtable entries */
+
+    /* memory size in bytes/mb */
+    size_t bytes;
+    u32  mb;
+
+    /* size in buckets/keys */
+    size_t nbuckets;
+    size_t nkeys;                                 /* nbuckets * NBUCKETS */
+
+    /* internal representation */
+    u32  nbits;                                   /* #buckets in bits, power of 2 */
+    u32  mask;                                    /* nbuckets - 1, key mask */
+
+    /* stats - unsure about usage */
+    //size_t used_buckets;
+    size_t used_keys;
+    u64 collisions;
+    u64 hits;
+    u64 misses;
+} hasht_t;
+
+/* hack:
+ *  ep zobrist key index is 0-7 for each en-passant file, 8 for SQUARE_NONE.
+ * To transform :
+ *   - ep == 64 (SQUARE_NONE) to id = 8
+ *   - ep == 0~63 to idx = sq_file(ep), i.e. (ep & 7)
+ * we use the formula:
+ * idx = ( ( ep & SQUARE_NONE ) >> 3 ) | sq_file(ep);
+ */
+#define EP_ZOBRIST_IDX(ep) ( ( ( ep & SQUARE_NONE ) >> 3 ) | sq_file(ep) )
+
+extern hkey_t zobrist_pieces[16][64];
+extern hkey_t zobrist_castling[4 * 4 + 1];
+extern hkey_t zobrist_turn;                        /* for black, XOR each ply */
+extern hkey_t zobrist_ep[9];                       /* 0-7: ep file, 8: SQUARE_NONE */
+
+extern hasht_t hash_tt;                           /* main transposition table */
+
+void zobrist_init(void);
+hkey_t zobrist_calc(pos_t *pos);
+
+#ifdef ZOBRIST_VERIFY
+bool zobrist_verify(pos_t *pos);
+#else
+#define zobrist_verify(p) true
+#endif
+
+/**
+ * tt_prefetch() - prefetch hash table entry
+ * @hash: u64 key
+ *
+ * Prefetch memory for @key.
+ */
+static inline void tt_prefetch(hkey_t key)
+{
+    bug_on(!hash_tt.keys);
+    __builtin_prefetch(hash_tt.keys + (key & hash_tt.mask));
+}
+
+int tt_create(int Mb);
+void tt_clear(void);
+void tt_delete(void);
+
+hentry_t *tt_probe(hkey_t key);
+hentry_t *tt_probe_perft(const hkey_t key, const u16 depth);
+hentry_t *tt_store_perft(const hkey_t key, const u16 depth, const u64 nodes);
+void tt_info(void);
+void tt_stats(void);
+
+#endif  /* HASH_H */

src/hyperbola-quintessence.c

@@ -129,8 +129,8 @@ bitboard_t hyperbola_moves(const bitboard_t pieces, const square_t sq,
     bitboard_t r = bswap64(o);
     square_t  r_sq = FLIP_V(sq);
 
-    return (         (o - 2 * mask(sq)   )
-            ^ bswap64(r - 2 * mask(r_sq)))
+    return (         (o - 2 * BIT(sq)   )
+            ^ bswap64(r - 2 * BIT(r_sq)))
         & mask;
 }
 

src/hyperbola-quintessence.h

@@ -17,17 +17,17 @@
 #include "board.h"
 #include "bitboard.h"
 
-extern void hyperbola_init(void);
+void hyperbola_init(void);
 
-extern bitboard_t hyperbola_rank_moves(const bitboard_t occ, const square_t sq);
-extern bitboard_t hyperbola_moves(const bitboard_t pieces, const square_t sq,
-                                  const bitboard_t mask);
-extern bitboard_t hyperbola_file_moves(const bitboard_t occ, const square_t sq);
-extern bitboard_t hyperbola_diag_moves(const bitboard_t occ, const square_t sq);
-extern bitboard_t hyperbola_anti_moves(const bitboard_t occ, const square_t sq);
+bitboard_t hyperbola_rank_moves(const bitboard_t occ, const square_t sq);
+bitboard_t hyperbola_moves(const bitboard_t pieces, const square_t sq,
+                           const bitboard_t mask);
+bitboard_t hyperbola_file_moves(const bitboard_t occ, const square_t sq);
+bitboard_t hyperbola_diag_moves(const bitboard_t occ, const square_t sq);
+bitboard_t hyperbola_anti_moves(const bitboard_t occ, const square_t sq);
 
-extern bitboard_t hyperbola_bishop_moves(const bitboard_t occ, const square_t sq);
-extern bitboard_t hyperbola_rook_moves(const bitboard_t occ, const square_t sq);
-extern bitboard_t hyperbola_queen_moves(const bitboard_t occ, const square_t sq);
+bitboard_t hyperbola_bishop_moves(const bitboard_t occ, const square_t sq);
+bitboard_t hyperbola_rook_moves(const bitboard_t occ, const square_t sq);
+bitboard_t hyperbola_queen_moves(const bitboard_t occ, const square_t sq);
 
 #endif  /* _HYPERBOLA_QUINTESSENCE_H */

src/init.c

@@ -0,0 +1,42 @@
+/* init.c - initialize all.
+ *
+ * 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 <locale.h>
+
+#include "chessdefs.h"
+
+#include "bitboard.h"
+#include "hyperbola-quintessence.h"
+
+#include "hash.h"
+
+void init_all(void)
+{
+    /* for printf() numeric thousands separator */
+    setlocale(LC_NUMERIC, "");
+    /* line-buffered stdout */
+    setlinebuf(stdout);
+
+    /* pseudo random generator seed */
+    rand_init(RAND_SEED_DEFAULT);
+
+    /* bitboards & hq */
+    bitboard_init();
+    hyperbola_init();
+
+    /* zobrist tables & default tt hashtable */
+    zobrist_init();
+    tt_create(HASH_SIZE_DEFAULT);
+
+}

src/misc.c

@@ -0,0 +1,152 @@
+/* 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 <stdlib.h>
+
+#include <bug.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;
+}
+
+static u64 rand_seed = 1ull;
+
+/**
+ * rand_init() - initialize random generator seed.
+ * @seed: u64, the random generator seed.
+ *
+ * No change is made is performed if If @seed is zero. By default, @seed is
+ * 1.
+ * This seed is used by rand64().
+ */
+void rand_init(u64 seed)
+{
+    if (seed)
+        rand_seed = seed;
+}
+
+/**
+ * rand64() - get a random number, xorshift method.
+ *
+ * Source:
+ *   https://en.wikipedia.org/wiki/Xorshift#xorshift*
+ * We do not want true random numbers, like those offered by getrandom(2), as we
+ * need to be able to get predictable results.
+ * Note: For predictable results in MT, we should use separate seeds.
+ *
+ * @return: a 64 bits random number.
+ */
+u64 rand64(void)
+{
+    bug_on(rand_seed == 0ull);
+
+    rand_seed ^= rand_seed >> 12;
+    rand_seed ^= rand_seed << 25;
+    rand_seed ^= rand_seed >> 27;
+    return rand_seed * 0x2545f4914f6cdd1dull;
+}

src/move-do.c

@@ -17,10 +17,13 @@
 
 #include "brlib.h"
 #include "likely.h"
+#include "bug.h"
 
 #include "chessdefs.h"
 #include "move.h"
 #include "position.h"
+#include "move-do.h"
+#include "hash.h"
 
 /**
  * move_do() - do move.
@@ -37,32 +40,49 @@
  *   - castling
  *   - en-passant
  * - captured piece (excl. en-passant)
+ * - tt hash values are updated for:
+ *   - side-to-move
+ *   - en-passant
+ *   - castling rights.
  *
- * @return: pos.
+ * @return: updated pos.
  */
-pos_t *move_do(pos_t *pos, move_t move, state_t *state)
+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);
     piece_t new_piece = piece;
+    int up = sq_up(us);
+    hkey_t key = pos->key;
+
+    *state = pos->state;                          /* save irreversible changes */
+
+    /* update key: switch turn, reset castling and ep */
+    key ^= zobrist_turn;
+    key ^= zobrist_castling[pos->castle];
+    key ^= zobrist_ep[EP_ZOBRIST_IDX(pos->en_passant)];
 
     ++pos->clock_50;
     ++pos->plycount;
     pos->en_passant = SQUARE_NONE;
     pos->turn = them;
+    pos->captured = captured;
 
-    if (is_promotion(move))
+    bug_on(COLOR(piece) != us);
+
+    if (is_promotion(move)) {
+        bug_on(sq_rank(to) != sq_rel_rank(RANK_8, us));
         new_piece = MAKE_PIECE(move_promoted(move), us);
+    }
 
-    if (is_capture(move)) {
+    if (captured != EMPTY) {
         pos->clock_50 = 0;
-        pos->captured = pos->board[to];           /* save capture info */
+        //pos->captured = pos->board[to];           /* save capture info */
+        bug_on(pos->board[to] == EMPTY || COLOR(pos->captured) != them);
+        key ^= zobrist_pieces[captured][to];
         pos_clr_sq(pos, to);                      /* clear square */
     } else if (is_castle(move)) {                 /* handle rook move */
         square_t rookfrom, rookto;
@@ -73,22 +93,34 @@ pos_t *move_do(pos_t *pos, move_t move, state_t *state)
             rookfrom = sq_rel(A1, us);
             rookto = sq_rel(D1, us);
         }
+        key ^= zobrist_pieces[pos->board[rookfrom]][rookto] ^
+            zobrist_pieces[pos->board[rookfrom]][rookfrom];
         pos_set_sq(pos, rookto, pos->board[rookfrom]);
         pos_clr_sq(pos, rookfrom);
         pos->castle = clr_castle(pos->castle, us);
-    } else if (PIECE(piece) == PAWN) {            /* pawn non capture or e.p. */
+    } else if (ptype == PAWN) {                   /* pawn non capture or e.p. */
         pos->clock_50 = 0;
-        if (is_dpush(move))                       /* if pawn double push, set e.p. */
-            pos->en_passant = pawn_push_up(from, us);
-        else if (is_enpassant(move)) {            /* clear grabbed pawn */
-            square_t grabbed = pawn_push_up(to, them);
+        if (from + up + up == to) {               /* if pawn double push, set e.p. */
+            square_t ep = from + up;
+            if (bb_pawn_attacks[us][ep] & pos->bb[them][PAWN]) {
+                pos->en_passant = ep;
+                key ^= zobrist_ep[EP_ZOBRIST_IDX(pos->en_passant)];
+            }
+        } else if (is_enpassant(move)) {          /* clear grabbed pawn */
+            square_t grabbed = to - up;
+            piece_t pc = pos->board[grabbed];
+            key ^= zobrist_pieces[pc][grabbed];
             pos_clr_sq(pos, grabbed);
         }
     }
 
-    pos_clr_sq(pos, from);                        /* always clear "from" and set "to" */
+    key ^= zobrist_pieces[piece][from] ^ zobrist_pieces[new_piece][to];
+    pos_clr_sq(pos, from);                        /* 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"
@@ -96,7 +128,8 @@ pos_t *move_do(pos_t *pos, move_t move, state_t *state)
      */
     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);
+        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)
@@ -104,14 +137,22 @@ pos_t *move_do(pos_t *pos, move_t move, state_t *state)
         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 (can_castle(pos->castle, them)) {
+        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);
     }
 
+    /* update castling rights key */
+    key ^= zobrist_castling[pos->castle];
+
+    pos->key = key;
+
+    zobrist_verify(pos);
+
     return pos;
 }
 
@@ -134,23 +175,21 @@ pos_t *move_do(pos_t *pos, move_t move, state_t *state)
  */
 pos_t *move_undo(pos_t *pos, const move_t move, const state_t *state)
 {
-//#   ifdef DEBUG_MOVE
-    //log(1, "new move: ");
-    //move_print(0, move, M_PR_NL | M_PR_LONG);
-//#   endif
     color_t them = pos->turn, us = OPPONENT(them);
     square_t from = move_from(move), to = move_to(move);
     piece_t piece = pos->board[to];
-
-    pos->state = *state;                          /* restore irreversible changes */
+    int up = sq_up(them);
 
     if (is_promotion(move))
         piece = MAKE_PIECE(PAWN, us);
 
-    pos_clr_sq(pos, to);                          /* always clear "to" and set "from" */
-    pos_set_sq(pos, from, piece);
+    pos_clr_sq(pos, to);                          /* always clear "to" ... */
+    pos_set_sq(pos, from, piece);                 /* ... and set "from" */
 
-    if (is_capture(move)) {
+    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;
@@ -164,9 +203,162 @@ pos_t *move_undo(pos_t *pos, const move_t move, const state_t *state)
         pos_set_sq(pos, rookto, pos->board[rookfrom]);
         pos_clr_sq(pos, rookfrom);
     } else if (is_enpassant(move)) {              /* restore grabbed pawn */
-        square_t grabbed = pawn_push_up(to, them);
+        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;
+}
+
+/**
+ * move_{do,undo}_alt - alternative move_do/move_undo (to experiment)
+ */
+pos_t *move_do_alt(pos_t *pos, const move_t move, state_t *state)
+{
+    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);
+    piece_t new_piece = piece;
+    int up = sq_up(us);
+    hkey_t key = pos->key;
+
+    *state = pos->state;                          /* save irreversible changes */
+
+    /* update key: switch turn, reset castling and ep */
+    key ^= zobrist_turn;
+    key ^= zobrist_castling[pos->castle];
+    key ^= zobrist_ep[EP_ZOBRIST_IDX(pos->en_passant)];
+
+    ++pos->clock_50;
+    ++pos->plycount;
+    pos->en_passant = SQUARE_NONE;
+    pos->turn = them;
+    pos->captured = captured;
+
+    bug_on(COLOR(piece) != 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);
+        key ^= zobrist_pieces[captured][to];
+        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);
+        }
+        key ^= zobrist_pieces[pos->board[rookfrom]][rookto] ^
+            zobrist_pieces[pos->board[rookfrom]][rookfrom];
+        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 (from + up + up == to) {               /* if pawn double push, set e.p. */
+            square_t ep = from + up;
+            if (bb_pawn_attacks[us][ep] & pos->bb[them][PAWN]) {
+                pos->en_passant = ep;
+                key ^= zobrist_ep[EP_ZOBRIST_IDX(pos->en_passant)];
+            }
+        } else if (is_enpassant(move)) {          /* clear grabbed pawn */
+            square_t grabbed = to - up;
+            piece_t pc = pos->board[grabbed];
+            key ^= zobrist_pieces[pc][grabbed];
+            pos_clr_sq(pos, grabbed);
+        }
+    }
+
+    key ^= zobrist_pieces[piece][from] ^ zobrist_pieces[new_piece][to];
+    pos_clr_sq(pos, from);                        /* 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)) {
+        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);
+    }
+
+    /* update castling rights key */
+    key ^= zobrist_castling[pos->castle];
+
+    pos->key = key;
+
+    zobrist_verify(pos);
+
+    return pos;
+}
+
+pos_t *move_undo_alt(pos_t *pos, const move_t move, const state_t *state)
+{
+    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;
 }

src/move-do.h

@@ -1,6 +1,6 @@
 /* move-do.h - move do/undo.
  *
- * Copyright (C) 2021 Bruno Raoult ("br")
+ * Copyright (C) 2021-2024 Bruno Raoult ("br")
  * Licensed under the GNU General Public License v3.0 or later.
  * Some rights reserved. See COPYING.
  *
@@ -14,7 +14,13 @@
 #ifndef MOVE_DO_H
 #define MOVE_DO_H
 
-//extern pos_t *move_do(pos_t *pos, move_t *move);
-//extern void move_undo(pos_t *pos, move_t *move);
+#include "position.h"
+
+pos_t *move_do(pos_t *pos, const move_t move, state_t *state);
+pos_t *move_undo(pos_t *pos, const move_t move, const state_t *state);
+
+/* new version testing */
+pos_t *move_do_alt(pos_t *pos, const move_t move, state_t *state);
+pos_t *move_undo_alt(pos_t *pos, const move_t move, const state_t *state);
 
 #endif  /* MOVE_DO_H */

src/move-gen.c

@@ -36,66 +36,75 @@
  */
 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), king = pos->king[us], sq;
-    piece_type_t piece = PIECE(pos->board[from]);
-    bitboard_t kingbb = pos->bb[us][KING], tmp;
+    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 = BIT(from) & pos->blockers;
+    u64 checkers = pos->checkers;
 
-    /* (1) - King
-     * For castling, we already tested intermediate squares attacks
-     * in pseudo move generation, so we only care destination square here.
-     * Attention: We need to exclude king from occupation bitboard !
+    /* (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 (piece == KING) {
-        bitboard_t occ = pos_occ(pos) ^ kingbb;
-        return !sq_attackers(pos, occ, to, them);
+    if (unlikely(from == king)) {
+        if (unlikely(is_castle(move))) {
+            square_t dir = to > from? 1: -1;
+            if (sq_is_attacked(pos, occ, from + dir, them))
+                return false;
+        }
+        return !sq_is_attacked(pos, occ ^ kingbb, to, them);
     }
 
     /* (2) - King is in check
-     * Double-check is already handled, as only K moves were generated.
-     * Here, allowed moves are only on King-attacker line, including
-     * attacker.We can move a piece on
-     * in pseudo move generation, so we only care destination square here.
+     * 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 (pos->checkers) {
-        if (popcount64(pos->checkers) == 1) {     /* one checker */
-            square_t checker = ctz64(pos->checkers);
-            bitboard_t between = bb_between[king][checker];
-            return mask(to) & between;
+    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 false;                             /* double check */
+        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 & pos->bb[us][ALL_PIECES]) {
-        bitboard_t line = bb_line[from][king];
-        return line & mask(to);                   /* to is not on pin line */
+    if (BIT(from) & pos->blockers) {
+        return bb_line[from][king] & BIT(to);    /* is to on pinner line ? */
     }
 
     /* (4) - En-passant
-     * We only care the situation where our King and enemy R/Q are on
-     * 5th relative rank. To do so, we create an occupation bb without
-     * the 2 pawns.
+     * 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)) {
-         /* from rank bitboard */
-        bitboard_t rank5 = bb_sqrank[from];
-        /* enemy rooks/queens on from rank */
-        bitboard_t rooks = (pos->bb[them][ROOK] | pos->bb[them][QUEEN]) & rank5;
+    if (unlikely(is_enpassant(move))) {
+        bitboard_t rank5 = bb_rel_rank(RANK_5, us);
 
-        if ((kingbb & rank5) && rooks) { /* K and enemy R/Q on rank */
-            /* captured pawn square (beside from square) */
-            square_t captured = sq_make(sq_file(pos->en_passant), sq_rank(from));
-            /* occupation bitboard without the two "disappearing" pawns */
-            bitboard_t occ = pos_occ(pos) ^ mask(from) ^ mask(captured);
+        if (unlikely((pos->bb[us][KING] & rank5))) {
+            bitboard_t exclude = BIT(pos->en_passant - sq_up(us)) | BIT(from);
+            bitboard_t rooks = (pos->bb[them][ROOK] | pos->bb[them][QUEEN]) & rank5;
 
-            bit_for_each64(sq, tmp, rooks)        /* check all rooks/queens */
-                if (hyperbola_rank_moves(occ, sq) & kingbb)
-                    return false;
+            if (hyperbola_rank_moves(occ ^ exclude, king) & rooks)
+                return false;
         }
-        return true;
     }
     return true;
 }
@@ -103,18 +112,19 @@ bool pseudo_is_legal(const pos_t *pos, const move_t move)
 /**
  * pos_next_legal() - get next legal move in position.
  * @pos:  position
- * @start:  &int, starting position in move list
+ * @movelist: &pseudo-legal movelist
+ * @start:  &int, starting position in @movelist
  *
  * Get next valid move in @pos move list, from move @start, or MOVE_NONE.
  * @start is set to next non-checked move in pseudo-legal list.
  * Position pseudo-legal moves must be already calculated before calling this function.
  *
- * @return: move, or -1 if no move.
+ * @return: move, or MOVE_NONE if no move.
  */
-move_t pos_next_legal(const pos_t *pos, int *start)
+move_t pos_next_legal(const pos_t *pos, movelist_t *movelist, int *start)
 {
-    const int nmoves = pos->moves.nmoves;
-    const move_t *moves = pos->moves.move;
+    const int nmoves = movelist->nmoves;
+    const move_t *moves = movelist->move;
     move_t move;
 
     while (*start < nmoves) {
@@ -125,39 +135,89 @@ move_t pos_next_legal(const pos_t *pos, int *start)
 }
 
 /**
- * pos_all_legal() - get the list of legal moves from pseudo-legal.
+ * pos_legal_dup() - get legal moves from pseudo-legal ones in new list.
  * @pos:  position
- * @dest: destination &movelist_t
+ * @pseudo: &movelist_t pseudo-legal moves list
+ * @legal: &movelist_t legal moves
  *
  * The pseudo-legal moves must be already calculated before calling this function.
- * No check is done on @dest limits.
+ * No check is done on @legal limits.
+ * This function is similar to pos_legal(), but creates a new list for legal moves.
+ * It should only be used for debug purpose, when we want to keep a copy of
+ * pseudo-legal moves.
  *
- * @Return: @dest
+ * @return: @legal
  */
-movelist_t *pos_all_legal(const pos_t *pos, movelist_t *dest)
+movelist_t *pos_legal_dup(const pos_t *pos, movelist_t *pseudo, movelist_t *legal)
 {
-    int tmp = dest->nmoves = 0;
+    int tmp = legal->nmoves = 0;
     move_t move;
-    //int tmp = 0;
 
-    while ((move = pos_next_legal(pos, &tmp)) != MOVE_NONE)
-        dest->move[dest->nmoves++] = move;
-    return dest;
+    while ((move = pos_next_legal(pos, pseudo, &tmp)) != MOVE_NONE)
+        legal->move[legal->nmoves++] = move;
+    return legal;
 }
 
 /**
- * pos_gen_pseudomoves() - generate position pseudo-legal moves
+ * pos_legal() - get legal moves from pseudo-legal ones in new list.
+ * @pos:  position
+ * @list: &movelist_t pseudo-legal moves list
+ *
+ * The pseudo-legal moves must be already calculated before calling this function.
+ * @list is replaced by legal moves.
+ *
+ * @return: @list
+ */
+movelist_t *pos_legal(const pos_t *pos, movelist_t *list)
+{
+    move_t *cur = list->move, *last = list->move + list->nmoves;
+
+    while (cur < last) {
+        if (pseudo_is_legal(pos, *cur))
+            cur++;
+        else {
+            *cur = *--last;
+        }
+    }
+    list->nmoves = last - list->move;
+    return list;
+}
+
+/**
+ * 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.
- * The @pos->moves table is filled with the moves.
+ * @movelist is filled with the moves.
  *
  * Only a few validity checks are done here (i.e. moves are not generated):
  *  - castling, if king is in check
  *  - castling, if king passes an enemy-controlled square (not final square).
  * When immediately known, a few move flags are also applied in these cases:
  *  - castling: M_CASTLE_{K,Q}
- *  - pawn capture (excl. en-passant): M_CAPTURE
+ *  - capture (excl. en-passant): M_CAPTURE
  *  - en-passant: M_EN_PASSANT
  *  - pawn double push: M_DPUSH
  *  - promotion: M_PROMOTION
@@ -167,179 +227,258 @@ movelist_t *pos_all_legal(const pos_t *pos, movelist_t *dest)
  *
  * @Return: The total number of moves.
  */
-int pos_gen_pseudomoves(pos_t *pos)
+
+/**
+ * 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);
+ *
+ * }
+ */
+
+/**
+ * moves_gen_flags() - generate all moves from square to bitboard (with flags).
+ * @moves: &move_t array where to store moves
+ * @from: square_t piece position
+ * @to_bb: destination bitboard
+ * @flags: flags to apply
+ *
+ * Generate (at address @moves) moves from square @from to each square in @to_bb,
+ * with flags @flags.
+ *
+ * @Return: New @moves.
+ */
+static inline __unused move_t *moves_gen_flags(move_t *moves, square_t from, bitboard_t to_bb,
+    __unused move_flags_t flags)
+{
+    square_t to;
+    while(to_bb) {
+        to = bb_next(&to_bb);
+        *moves++ = move_make_flags(from, to, flags);
+    }
+    return moves;
+}
+
+/**
+ * move_gen_promotions() - generate all promotions for given pawn and dest.
+ * @moves: &move_t array where to store moves
+ * @from: pawn position
+ * @to: promotion square
+ *
+ * Generate  (at address @moves) all promotion (Q/R/B/N) moves on @to for
+ * pawn @from.
+ *
+ * @Return: New @moves.
+ */
+static inline move_t *move_gen_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;
+}
+
+/**
+ * moves_gen() - generate all moves from square to bitboard.
+ * @moves: &move_t array where to store moves
+ * @from: square_t piece position
+ * @to_bb: destination bitboard
+ *
+ * Generate (at address @moves) moves from square @from to each square in @to_bb.
+ *
+ * @Return: New @moves.
+ */
+static inline move_t *moves_gen(move_t *moves, square_t from, bitboard_t to_bb)
+{
+    square_t to;
+    // bb_print(sq_to_string(from), to_bb);
+    while(to_bb) {
+        to = bb_next(&to_bb);
+        *moves++ = move_make(from, to);
+    }
+    return moves;
+}
+
+/**
+ * pos_gen_pseudo() - 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: movelist
+ */
+movelist_t *pos_gen_pseudo(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 not_my_pieces = ~my_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 movebits, from_pawns;
-    bitboard_t tmp1, tmp2;
+    bitboard_t from_bb, to_bb;
+    bitboard_t tmp_bb;
+    move_t *moves            = movelist->move;
+    square_t from, to;
+    square_t king = pos->king[us];
 
-    move_t *moves            = pos->moves.move;
-    int nmoves               = pos->moves.nmoves;
-    int from, to;
+    /* king - MUST BE FIRST */
+    to_bb = bb_king_moves(dest_squares, king);
+    moves = moves_gen(moves, king, to_bb);
 
-    bug_on(nmoves != 0);
+    if (bb_multiple(pos->checkers))               /* double check, we stop here */
+        goto finish;
 
-    /* king - MUST BE FIRST (we stop if doubler check) */
-    from = pos->king[us];
-    movebits = bb_king_moves(not_my_pieces, from);
-    bit_for_each64(to, tmp1, movebits & empty) {
-        moves[nmoves++] = move_make(from, to);
-    }
-    bit_for_each64(to, tmp1, movebits & enemy_pieces) {
-        moves[nmoves++] = move_make_capture(from, to);
-    }
-
-    if (popcount64(pos->checkers) > 1)            /* double check, we stop here */
-        return (pos->moves.nmoves = nmoves);
-
-    /* sliding pieces */
-    bit_for_each64(from, tmp1, pos->bb[us][BISHOP] | pos->bb[us][QUEEN]) {
-        movebits = hyperbola_bishop_moves(occ, from) & not_my_pieces;
-        bit_for_each64(to, tmp2, movebits & empty) {
-            moves[nmoves++] = move_make(from, to);
-        }
-        bit_for_each64(to, tmp2, movebits & enemy_pieces) {
-            moves[nmoves++] = move_make_capture(from, to);
-        }
-    }
-    bit_for_each64(from, tmp1, pos->bb[us][ROOK] | pos->bb[us][QUEEN]) {
-        // printf("rook=%d/%s\n", from, sq_to_string(from));
-        movebits = hyperbola_rook_moves(occ, from) & not_my_pieces;
-        bit_for_each64(to, tmp2, movebits & empty) {
-            moves[nmoves++] = move_make(from, to);
-        }
-        bit_for_each64(to, tmp2, movebits & enemy_pieces) {
-            moves[nmoves++] = move_make_capture(from, to);
-        }
-    }
-
-    /* knight */
-    bit_for_each64(from, tmp1, pos->bb[us][KNIGHT]) {
-        movebits = bb_knight_moves(not_my_pieces, from);
-        bit_for_each64(to, tmp2, movebits & empty) {
-            moves[nmoves++] = move_make(from, to);
-        }
-        bit_for_each64(to, tmp2, movebits & enemy_pieces) {
-            moves[nmoves++] = move_make_capture(from, to);
-        }
-    }
-
-    /* pawn: relative rank and files */
-    bitboard_t rel_rank7 = bb_rel_rank(RANK_7, us);
-    bitboard_t rel_rank3 = bb_rel_rank(RANK_3, us);
-
-    /* pawn: ranks 2-6 push 1 and 2 squares */
-    movebits = pawn_shift_up(pos->bb[us][PAWN] & ~rel_rank7, us) & empty;
-    bit_for_each64(to, tmp1, movebits) {
-        from = pawn_push_up(to, them);              /* reverse push */
-        //printf("push %d->%d %s->%s", from, to, sq_to_string(from), sq_to_string(to));
-        moves[nmoves++] = move_make(from, to);
-    }
-    /* possible second push */
-    movebits = pawn_shift_up(movebits & rel_rank3, us) & empty;
-    bit_for_each64(to, tmp1, movebits) {
-        from = pawn_push_up(pawn_push_up(to, them), them);
-        moves[nmoves++] = move_make_flags(from, to, M_DPUSH);
-    }
-
-    /* pawn: ranks 2-6 captures left */
-    from_pawns = pos->bb[us][PAWN] & ~rel_rank7; // & ~rel_filea;
-    movebits = pawn_shift_upleft(from_pawns, us) & enemy_pieces;
-    bit_for_each64(to, tmp1, movebits) {
-        from = pawn_push_upleft(to, them);         /* reverse capture */
-        moves[nmoves++] = move_make_capture(from, to);
-    }
-    /* pawn: ranks 2-6 captures right */
-    from_pawns = pos->bb[us][PAWN] & ~rel_rank7; // & ~rel_fileh;
-    movebits = pawn_shift_upright(from_pawns, us) & enemy_pieces;
-    bit_for_each64(to, tmp1, movebits) {
-        from = pawn_push_upright(to, them);
-        moves[nmoves++] = move_make_capture(from, to);
-    }
-
-    /* pawn: en-passant */
-    if ((to = pos->en_passant) != SQUARE_NONE) {
-        movebits = mask(to);
-        from_pawns = pos->bb[us][PAWN]
-            & (pawn_shift_upleft(movebits, them) | pawn_shift_upright(movebits, them));
-        bit_for_each64(from, tmp1, from_pawns) {
-            moves[nmoves++] = move_make_enpassant(from, to);
-        }
-    }
-
-    /* pawn: rank 7 push */
-    movebits = pawn_shift_up(pos->bb[us][PAWN] & rel_rank7, us) & empty;
-    bit_for_each64(to, tmp1, movebits) {
-        from = pawn_push_up(to, them);              /* reverse push */
-        moves[nmoves++] = move_make_promote(from, to, QUEEN);
-        moves[nmoves++] = move_make_promote(from, to, ROOK);
-        moves[nmoves++] = move_make_promote(from, to, BISHOP);
-        moves[nmoves++] = move_make_promote(from, to, KNIGHT);
-    }
-    /* pawn promotion: rank 7 captures left */
-    from_pawns = pos->bb[us][PAWN] & rel_rank7; // & ~rel_filea;
-    movebits = pawn_shift_upleft(from_pawns, us) & enemy_pieces;
-    bit_for_each64(to, tmp1, movebits) {
-        from = pawn_push_upleft(to, them);         /* reverse capture */
-        moves[nmoves++] = move_make_promote_capture(from, to, QUEEN);
-        moves[nmoves++] = move_make_promote_capture(from, to, ROOK);
-        moves[nmoves++] = move_make_promote_capture(from, to, BISHOP);
-        moves[nmoves++] = move_make_promote_capture(from, to, KNIGHT);
-    }
-    /* pawn: rank 7 captures right */
-    from_pawns = pos->bb[us][PAWN] & rel_rank7; // & ~rel_fileh;
-    movebits = pawn_shift_upright(from_pawns, us) & enemy_pieces;
-    bit_for_each64(to, tmp1, movebits) {
-        from = pawn_push_upright(to, them);         /* reverse capture */
-        moves[nmoves++] = move_make_promote_capture(from, to, QUEEN);
-        moves[nmoves++] = move_make_promote_capture(from, to, ROOK);
-        moves[nmoves++] = move_make_promote_capture(from, to, BISHOP);
-        moves[nmoves++] = move_make_promote_capture(from, to, KNIGHT);
-    }
-
-    /* castle - Attention ! Castling flags are assumed correct
-     */
-    if (!pos->checkers) {
+    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);
-        from = pos->king[us];
-        square_t from_square[2] = { E1, E8 };     /* verify king is on E1/E8 */
-        bug_on(can_castle(pos->castle, us) && from != from_square[us]);
         /* 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) &&
-                !sq_attackers(pos, occ, from+1, them)) { /* f1/f8 */
-                moves[nmoves++] = move_make_flags(from, from + 2, M_CASTLE_K);
+            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) &&
-                !sq_attackers(pos, occ, from-1, them)) { /* d1/d8 */
-                moves[nmoves++] = move_make_flags(from, from - 2, M_CASTLE_Q);
+            if (!(occ & occmask)) { // &&
+                *moves++ = move_make_flags(king, king - 2, M_CASTLE_Q);
             }
         }
     }
-    /* TODO
-     * DONE. pawn ranks 2-6 advance (1 push, + 2 squares for rank 2)
-     * DONE. pawns rank 7 advance + promotions
-     * DONE. pawns ranks 2-6 captures, left and right
-     * DONE. pawns en-passant (with capture)
-     * DONE. pawns rank 7 capture + promotion
-     * DONE. castle
-     *
-     * add function per piece, and type, for easier debug
-     *
+
+    /* 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;
+        moves = moves_gen(moves, from, to_bb);
+    }
+    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;
+        moves = moves_gen(moves, from, to_bb);
+    }
+
+    /* knight */
+    from_bb = pos->bb[us][KNIGHT];
+    while (from_bb) {
+        from = bb_next(&from_bb);
+        to_bb = bb_knight_moves(dest_squares, from);
+        moves = moves_gen(moves, from, to_bb);
+    }
+
+    /* 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_gen_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(from, to);
+    }
+
+    /* pawn: captures */
+    tmp_bb = bb_pawns_attacks(pos->bb[us][PAWN], shift) & enemy_pieces;
+    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_gen_promotions(moves, from, to);
+        }
+    }
+
+    /* pawn: en-passant
+     * TODO: special case when in-check here ?
      */
-    return (pos->moves.nmoves = nmoves);
+    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);
+        }
+    }
+
+    /* TODO: add function per piece, and type, for easier debug
+     */
+finish:
+    movelist->nmoves = moves - movelist->move;
+    return movelist;
+    //return movelist->nmoves = moves - movelist->move;
 }

src/move-gen.h

@@ -22,8 +22,10 @@
 #include "move.h"
 
 bool pseudo_is_legal(const pos_t *pos, const move_t move);
-move_t pos_next_legal(const pos_t *pos, int *start);
-movelist_t *pos_all_legal(const pos_t *pos, movelist_t *dest);
-int pos_gen_pseudomoves(pos_t *pos);
+move_t pos_next_legal(const pos_t *pos, movelist_t *movelist, int *start);
+movelist_t *pos_legal_dup(const pos_t *pos, movelist_t *pseudo, movelist_t *legal);
+movelist_t *pos_legal(const pos_t *pos, movelist_t *list);
+
+movelist_t *pos_gen_pseudo(pos_t *pos, movelist_t *movelist);
 
 #endif  /* MOVEGEN_H */

src/move.c

@@ -1,6 +1,6 @@
 /* move.c - 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.
  *
@@ -89,7 +89,7 @@
  */
 
 /**
- * move_str() - get a move string
+ * move_to_str() - get a move string
  * @dst: destination memory
  * @move: move
  * @flags: moves selection and display options.
@@ -102,7 +102,7 @@
  * M_PR_NL:    print a newline after move
  * M_PR_EVAL:  print move eval
  */
-char *move_str(char *dst, const move_t move, __unused const int flags)
+char *move_to_str(char *dst, const move_t move, __unused const int flags)
 {
     square_t from = move_from(move);
     square_t to   = move_to(move);
@@ -116,7 +116,6 @@ char *move_str(char *dst, const move_t move, __unused const int flags)
     return dst;
 }
 
-
 /**
  * moves_print() - print movelist moves.
  * @moves: &movelist_t moves list
@@ -135,7 +134,7 @@ void moves_print(movelist_t *moves, __unused int flags)
     char str[16];
     //printf("%2d:", moves->nmoves);
     for (int m = 0; m < moves->nmoves; ++m)
-        printf("%s ", move_str(str, moves->move[m], flags));
+        printf("%s ", move_to_str(str, moves->move[m], flags));
     printf("\n");
 }
 

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.
  *
@@ -35,37 +35,37 @@
 typedef s32 move_t;
 
 /* special move_t values */
-#define MOVE_NONE (-1)
-#define MOVE_NULL (0)                             /* hack: from = to = A1 */
+#define MOVE_NONE ((move_t) -1)
+#define MOVE_NULL ((move_t) 0)                    /* hack: from = to = A1 */
 
 enum {
     M_OFF_FROM     = 0,
     M_OFF_TO       = 6,
     M_OFF_PROMOTED = 12,
-    M_OFF_CAPTURED = 15,
-    M_OFF_FLAGS    = 18
+//    M_OFF_CAPTURED = 15,
+    M_OFF_FLAGS    = 15
 };
 
 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 */
+    M_PROMOTION = 070000,
+//    M_CAPTURE   = BIT(M_OFF_FLAGS + 0),
+    M_ENPASSANT = BIT(M_OFF_FLAGS + 0),
+    M_CASTLE_K  = BIT(M_OFF_FLAGS + 1),           /* maybe only one ? */
+    M_CASTLE_Q  = BIT(M_OFF_FLAGS + 2),           /* maybe only one ? */
+    M_CHECK     = BIT(M_OFF_FLAGS + 3),           /* maybe unknown/useless ? */
+//    M_DPUSH     = BIT(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_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 is_dpush(m)     ((m) & M_DPUSH)
 
 #define MOVES_MAX   256
 
@@ -89,10 +89,12 @@ 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 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)
 {
@@ -101,13 +103,16 @@ static inline move_t move_make(square_t from, square_t to)
 
 static inline move_t move_make_flags(square_t from, square_t to, move_flags_t flags)
 {
-    return move_set_flags(move_make(from, to), flags);
+    return (to << M_OFF_TO) | from | flags;
+    //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_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)
 {
@@ -117,19 +122,23 @@ static inline move_t move_make_enpassant(square_t from, square_t to)
 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);
+    return move_make(from, to) | (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_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);
-}
+/*
+ * static inline move_t move_set_captured(move_t move, piece_type_t captured)
+ * {
+ *     return move | (captured << M_OFF_CAPTURED);
+ * }
+ */
 
 /* moves_print flags
  */
@@ -143,7 +152,7 @@ static inline move_t move_set_captured(move_t move, piece_type_t captured)
 #define M_PR_LONG      0x80
 
 //int move_print(int movenum, move_t *move, move_flags_t flags);
-char *move_str(char *dst, const move_t move, __unused const int flags);
+char *move_to_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);
 

src/perft.c

@@ -0,0 +1,368 @@
+/* search.c - perft + search.
+ *
+ * Copyright (C) 2023-2024 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 <brlib.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:    current perft depth level (root = 1)
+ * @output: output total for 1st level moves.
+ *
+ * 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 legal moves
+ *    loop for 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, bool output)
+{
+    u64 subnodes, nodes = 0;
+    movelist_t movelist;
+    move_t *move, *last;
+    state_t state;
+#   ifdef PERFT_MOVE_HISTORY
+    static movelist_t stack;
+    if (ply == 1)
+        stack.nmoves = 0;
+#   endif
+
+    pos_set_checkers_pinners_blockers(pos);
+
+    pos_legal(pos, pos_gen_pseudo(pos, &movelist));
+    last = movelist.move + movelist.nmoves;
+    for (move = movelist.move; move < last; ++move) {
+        if (depth == 1) {
+            nodes++;
+        } else {
+            move_do(pos, *move, &state);
+#           ifdef PERFT_MOVE_HISTORY
+            stack.move[stack.nmoves++] = *move;
+#           endif
+            if (depth == 2) {
+                movelist_t movelist2;
+                pos_set_checkers_pinners_blockers(pos);
+                subnodes = pos_legal(pos, pos_gen_pseudo(pos, &movelist2))->nmoves;
+            } else if (ply >= 4) {
+                hentry_t *entry = tt_probe_perft(pos->key, depth);
+                if (entry != TT_MISS) {
+                    subnodes = HASH_PERFT_VAL(entry->data);
+                } else {
+                    subnodes = perft(pos, depth - 1, ply + 1, output);
+                    tt_store_perft(pos->key, depth, subnodes);
+                }
+            } else {
+                subnodes = perft(pos, depth - 1, ply + 1, output);
+            }
+            if (output && ply == 1) {
+                char movestr[8];
+                printf("%s: %lu\n", move_to_str(movestr, *move, 0), subnodes);
+            }
+            nodes += subnodes;
+            move_undo(pos, *move, &state);
+#           ifdef PERFT_MOVE_HISTORY
+            stack.nmoves--;
+#           endif
+        }
+    }
+
+    if (output && ply == 1)
+        printf("Total: %lu\n", nodes);
+    return nodes;
+}
+
+/**
+ * perft_alt() - Perform perft on position, experimental version.
+ * @pos:    &position to search
+ * @depth:  Wanted depth.
+ * @ply:    current perft depth level (root = 1)
+ * @output: output total for 1st level moves.
+ *
+ * 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_alt(pos_t *pos, int depth, int ply, bool output)
+{
+    u64 subnodes, nodes = 0;
+    movelist_t movelist;
+    move_t *move, *last;
+    state_t state;
+
+    pos_set_checkers_pinners_blockers(pos);
+
+    pos_legal(pos, pos_gen_pseudo(pos, &movelist));
+    last = movelist.move + movelist.nmoves;
+    for (move = movelist.move; move < last; ++move) {
+        if (depth == 1) {
+            nodes++;
+        } else {
+            move_do_alt(pos, *move, &state);
+            if (depth == 2) {
+                movelist_t movelist2;
+                pos_set_checkers_pinners_blockers(pos);
+                subnodes = pos_legal(pos, pos_gen_pseudo(pos, &movelist2))->nmoves;
+            } else {
+                subnodes = perft_alt(pos, depth - 1, ply + 1, output);
+            }
+            if (output && ply == 1) {
+                char movestr[8];
+                printf("%s: %lu\n", move_to_str(movestr, *move, 0), subnodes);
+            }
+            nodes += subnodes;
+            move_undo_alt(pos, *move, &state);
+        }
+    }
+
+    if (output && ply == 1)
+        printf("Total: %lu\n", nodes);
+    return nodes;
+}
+
+/**
+ * negamax() - search position negamax.
+ * @pos: &position to search
+ * @depth: Wanted depth.
+ * @color: 1 for white, -1 for black.
+ *
+ * Calculate the negamax value of @pos. This is an extensive search, with
+ * absolutely no cutoff.
+ *
+ * @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;
+ * }
+ */
+
+
+/**
+ * pvs() - Principal Variation Search.
+ * @pos: &position to search
+ * @depth: wanted depth.
+ * @alpha: alpha value.
+ * @beta: beta value.
+ * @color: 1 for white, -1 for black.
+ *
+ * Calculate the PVS value of @pos.
+ * See https://en.wikipedia.org/wiki/Principal_variation_search
+ *
+ * Moves list should be first generated and evaluated/sorted.
+ *
+ * @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;
+ * }
+ */
+
+/*
+ * int negascout (pos_t *pos, int depth, int alpha, int beta )
+ * {                     /\* compute minimax value of position p *\/
+ *     move_t *move;
+ *     pos_t *newpos;
+ *     eval_t best = EVAL_MIN, score;
+ *
+ *     int a, b, t, i;
+ *
+ *     if (depth == 0) {
+ *         //return quiesce(p, alpha, beta);           /\* leaf node *\/
+ *         moves_gen_all_nomoves(pos);
+ *         score = eval(pos) * color;
+ *         return score;
+ *     }
+ *     moves_gen_all(pos);
+ *     a = alpha;
+ *     b = beta;
+ *     list_for_each_entry(move, &pos->moves[pos->turn], list) {
+ *         log(1, "%.*s", 5 - depth, "                ");
+ *         newpos = move_do(pos, move);
+ * //    for ( i = 1; i <= w; i++ ) {
+ *         t = -negascout (newpos, depth - 1, -b, -alpha);
+ *         if ( (t > a) && (t < beta) && (i > 1) )
+ *             t = -NegaScout ( p_i, -beta, -alpha ); /\* re-search *\/
+ *         alpha = max( alpha, t );
+ *         if ( alpha >= beta )
+ *             return alpha;                            /\* cut-off *\/
+ *         b = alpha + 1;                  /\* set new null window *\/
+ *     }
+ *     return alpha;
+ * }
+ */
+
+/*
+ * int quiesce(pos_t *pos, int alpha, int beta)
+ * {
+ *     int stand_pat = eval(pos);
+ *
+ *     if( stand_pat >= beta )
+ *         return beta;
+ *     if( alpha < stand_pat )
+ *         alpha = stand_pat;
+ *
+ *     /\*
+ *      * until( every_capture_has_been_examined )  {
+ *      *     MakeCapture();
+ *      *     score = -Quiesce( -beta, -alpha );
+ *      *     TakeBackMove();
+ *      *
+ *      *     if( score >= beta )
+ *      *         return beta;
+ *      *     if( score > alpha )
+ *      *        alpha = score;
+ *      * }
+ *      *\/
+ *     return alpha;
+ * }
+ */
+
+/**
+ * ab_negamax() - search position negamax with alpha-beta cutoff.
+ * @pos: &position to search
+ * @depth: Wanted depth.
+ * @color: 1 for white, -1 for black.
+ *
+ * Calculate the negamax value of @pos, with alpha-beta pruning.
+ *
+ * @return: The @pos negamax evaluation.
+ */
+/*int ab_negamax(pos_t *pos, int alpha, int beta, int depth)
+  {
+  move_t *move;
+  pos_t *newpos;
+  eval_t best = EVAL_MIN, score;
+
+  if(depth == 0) {
+  //return quiesce( alpha, beta );
+  moves_gen_all_nomoves(pos);
+  score = eval(pos) * color;
+  return score;
+  }
+  for ( all moves)  {
+  score = -alphaBeta( -beta, -alpha, depthleft - 1 );
+  if( score >= beta )
+  return beta;   //  fail hard beta-cutoff
+  if( score > alpha )
+  alpha = score; // alpha acts like max in MiniMax
+  }
+  return alpha;
+  }
+*/

src/perft.h

@@ -0,0 +1,25 @@
+/* search.h - search for perfect move.
+ *
+ * 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 SEARCH_H
+#define SEARCH_H
+
+#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);
+
+u64 perft(pos_t *pos, int depth, int ply, bool output);
+u64 perft_alt(pos_t *pos, int depth, int ply, bool output);
+
+#endif  /* SEARCH_H */

src/piece.c

@@ -78,8 +78,12 @@ char *piece_to_name(piece_t p)
 
 piece_type_t piece_t_from_char(char c)
 {
-    char *p = strchr(pieces_str, c);
-    return p? (p - pieces_str) % 6 + 1: NO_PIECE_TYPE;
+    char *p;
+    piece_type_t pt = NO_PIECE_TYPE;
+    if (c && (p = strchr(pieces_str, c))) {
+        pt = (p - pieces_str) % 6 + 1;
+    }
+    return pt;
 }
 
 //piece_type_t piece_from_promotion(char c, color_t color)

src/position.c

@@ -18,12 +18,13 @@
 #include <ctype.h>
 #include <assert.h>
 
-#include "brlib.h"
-#include "bitops.h"
+#include <brlib.h>
+#include <bitops.h>
 
 #include "chessdefs.h"
 #include "position.h"
 #include "bitboard.h"
+#include "hyperbola-quintessence.h"
 #include "fen.h"
 #include "piece.h"
 #include "util.h"
@@ -61,9 +62,25 @@ pos_t *pos_dup(const pos_t *pos)
     return newpos;
 }
 
+/**
+ * pos_copy() - copy a position into another one.
+ * @from: &position to duplicate.
+ * @to: &destination position.
+ *
+ * Return a copy of @from into @to.
+ *
+ * @Return: @to.
+ */
+pos_t *pos_copy(const pos_t *from, pos_t *to)
+{
+    *to = *from;
+    return to;
+}
+
 /**
  * pos_del() - delete a position.
  * @pos: &position.
+ *
  */
 void pos_del(pos_t *pos)
 {
@@ -85,6 +102,7 @@ pos_t *pos_clear(pos_t *pos)
     pos->turn = WHITE;
 
     /* move_do/undo position state */
+    pos->key = 0;
     pos->en_passant = SQUARE_NONE;
     pos->castle = 0;
     pos->clock_50 = 0;
@@ -105,8 +123,8 @@ pos_t *pos_clear(pos_t *pos)
     pos->pinners = 0;
     pos->blockers = 0;
 
-    //pos->moves.curmove = 0;
-    pos->moves.nmoves = 0;
+    pos->repeat.moves = 0;
+
     return pos;
 }
 
@@ -114,54 +132,45 @@ pos_t *pos_clear(pos_t *pos)
  * pos_cmp() - compare two positions..
  * @pos1, @pos2: The two &position.
  *
+ * Used only for move_{do,undo} test/debug.
+ *
  * @return: true if equal, false otherwise.
  */
 bool pos_cmp(const pos_t *pos1, const pos_t *pos2)
 {
 #define _cmpf(a) (pos1->a != pos2->a)
     bool ret = false;
-    if (warn_on(_cmpf(node_count)))
-        goto end;
-    if (warn_on(_cmpf(turn)))
+
+    if (_cmpf(node_count) || _cmpf(turn))
         goto end;
 
     /* move_do/undo position state */
-    if (warn_on(_cmpf(en_passant)))
+    if (_cmpf(key) || _cmpf(en_passant) || _cmpf(castle) ||
+        _cmpf(clock_50) || _cmpf(plycount) || _cmpf(captured))
         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)))
+
+    if (_cmpf(checkers) || _cmpf(pinners) || _cmpf(blockers))
         goto end;
 
     for (square_t sq = A1; sq <= H8; ++sq)
-        if (warn_on(_cmpf(board[sq])))
+        if (_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])))
+        for (piece_type_t piece = ALL_PIECES; piece <= KING; ++piece)
+            if (_cmpf(bb[color][piece]))
                 goto end;
-        //pos->controlled[color] = 0;
-        if (warn_on(_cmpf(king[color])))
+        if (_cmpf(king[color]))
             goto end;
     }
 
-    if (warn_on(_cmpf(checkers)))
-        goto end;
-    if (warn_on(_cmpf(pinners)))
-        goto end;
-    if (warn_on(_cmpf(blockers)))
+    if (_cmpf(checkers) ||_cmpf(pinners) || _cmpf(blockers))
         goto end;
 
-    if (warn_on(_cmpf(moves.nmoves)))
+    if (_cmpf(repeat.moves) ||
+        memcmp(pos1->repeat.key, pos2->repeat.key,
+               pos1->repeat.moves * sizeof pos1->repeat.key))
         goto end;
-    for (int i = 0; i < pos1->moves.nmoves; ++i)
-        if (warn_on(_cmpf(moves.move[i])))
-            goto end;
 
     ret = true;
 end:
@@ -177,7 +186,7 @@ end:
  * Get a bitboard of all checkers on @color king.
  * Just a wrapper over @sq_attackers().
  *
- * @return: a bitboard of attackers.
+ * @return: a bitboard of checkers.
  */
 bitboard_t pos_checkers(const pos_t *pos, const color_t color)
 {
@@ -185,6 +194,102 @@ bitboard_t pos_checkers(const pos_t *pos, const color_t color)
     return sq_attackers(pos, occ, pos->king[color], OPPONENT(color));
 }
 
+/**
+ * pos_set_checkers_pinners_blockers() - calculate checkers, pinners and blockers.
+ * @pos:   &position
+ *
+ * Set position checkers, pinners and blockers on player-to-play king.
+ * It should be slightly 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 |= BIT(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 |= BIT(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
@@ -217,19 +322,18 @@ bitboard_t pos_king_blockers(const pos_t *pos, const color_t color, const bitboa
     square_t pinner, king = pos->king[color];
 
     bit_for_each64(pinner, tmp, pinners) {
-        bitboard_t blocker = bb_between_excl[pinner][king] & occ;
-        warn_on(popcount64(blocker) != 1);
-        if (popcount64(blocker) != 1) {
-            printf("n blockers = %d\n", popcount64(blocker));
-            bb_print("blockers", blocker);
-        }
-        blockers |= blocker;
+        //warn_on(popcount64(blocker) != 1);
+        //if (popcount64(blocker) != 1) {
+        //    printf("n blockers = %d\n", popcount64(blocker));
+        //    bb_print("blockers", blocker);
+        //}
+        blockers |= bb_between_excl[pinner][king] & occ;
     }
     return blockers;
 }
 
 /**
- * pos_check() - extensive position consistency check.
+ * pos_ok() - extensive position consistency check.
  * @pos:    &position
  * @strict: if true, call bug_on() on any error.
  *
@@ -239,11 +343,11 @@ bitboard_t pos_king_blockers(const pos_t *pos, const color_t color, const bitboa
  * - 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
+ * - TODO: - castling / e.p. flags
  *
  * In case of errors, and @strict is true, @bug_on() is called, and program will
  * be terminated.
@@ -251,19 +355,25 @@ bitboard_t pos_king_blockers(const pos_t *pos, const color_t color, const bitboa
  * (eg after fen parsing), and with @strict == true otherwise (as we have some data
  * corruption).
  *
- * TODO: add more checks:
- * - kings attacking each other
- *
- * @Return: Number of detected error (only if @strict is false).
+ * @return: (if @strict is false) return true if check is ok, false otherwise.
  */
-int pos_check(const pos_t *pos, const bool strict)
+bool pos_ok(pos_t *pos, const bool strict)
 {
     int n, count = 0, bbcount = 0, error = 0;
-    bitboard_t tmp;
+    color_t us = pos->turn, them = OPPONENT(us);
+
+    /* force BUG_ON and WARN_ON */
+#   pragma push_macro("BUG_ON")
+#   pragma push_macro("WARN_ON")
+#   undef BUG_ON
+#   define BUG_ON
+#   undef WARN_ON
+#   define WARN_ON
+#   include <bug.h>
 
     /* pawns on 1st ot 8th rank */
-    tmp = (pos->bb[WHITE][PAWN] | pos->bb[BLACK][PAWN]) & (RANK_1bb | RANK_8bb);
-    error += warn_on(tmp);
+    error += warn_on((pos->bb[WHITE][PAWN] | pos->bb[BLACK][PAWN]) &
+                     (RANK_1bb | RANK_8bb));
 
     for (color_t color = WHITE; color <= BLACK; ++color) {
         /* pawn count */
@@ -286,21 +396,28 @@ int pos_check(const pos_t *pos, const bool strict)
             continue;
         color_t c = COLOR(piece);
         piece_type_t p = PIECE(piece);
-        match = pos->bb[c][p] & mask(sq);
+        match = pos->bb[c][p] & BIT(sq);
         error += warn_on(!match);
         count++;
     }
-    /* occupied occupation is different from bitboards */
+    /* occupied board is different from bitboards */
     error += warn_on(count != bbcount);
     /* is opponent already in check ? */
-    error += warn_on(pos_checkers(pos, OPPONENT(pos->turn)));
+    error += warn_on(pos_checkers(pos, them));
     /* is color to play in check more than twice ? */
-    error += warn_on(popcount64(pos_checkers(pos, OPPONENT(pos->turn))) > 2);
+    error += warn_on(popcount64(pos_checkers(pos, us)) > 2);
     /* kings distance is less than 2 */
     error += warn_on(sq_dist(pos->king[WHITE], pos->king[BLACK]) < 2);
+    /* e.p. and castling rights check */
+    error += fen_ok(pos, false);
 
-    bug_on(strict && error);
-    return error;
+    if (strict) {
+        bug_on(error);
+        /* not reached */
+    }
+    return error? false: true;
+#   pragma pop_macro("WARN_ON")
+#   pragma pop_macro("BUG_ON")
 }
 
 /**
@@ -312,9 +429,10 @@ void pos_print(const pos_t *pos)
     char str[128];
 
     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("key:%lx ", pos->key);
+    printf("fen: %s\n", pos2fen(pos, str));
+    printf("checkers:%s ", pos_checkers2str(pos, str, sizeof(str)));
+    printf("pinners: %s ", pos_pinners2str(pos, str, sizeof(str)));
     printf("blockers: %s\n", pos_blockers2str(pos, str, sizeof(str)));
 }
 
@@ -332,7 +450,7 @@ void pos_print_mask(const pos_t *pos, const bitboard_t mask)
 }
 
 /**
- * pos_print_board_raw - print simple position board (octal/FEN symbol values)
+ * pos_print_raw - print simple position board (octal/FEN symbol values)
  * @bb: the bitboard
  * @type: int, 0 for octal, 1 for fen symbol
  */

src/position.h

@@ -16,43 +16,55 @@
 
 #include <stdint.h>
 
-#include "brlib.h"
-#include "bitops.h"
-#include "struct-group.h"
+#include <brlib.h>
+#include <bitops.h>
+#include <struct-group.h>
+#include <bug.h>
 
 #include "chessdefs.h"
+#include "hash.h"
 #include "bitboard.h"
 #include "piece.h"
 #include "move.h"
 #include "board.h"
 
+#define REPEAT_SIZE 1024
+
+typedef struct {
+    hkey_t key[REPEAT_SIZE];
+    int moves;
+} repeat_t;
+
 typedef struct __pos_s {
     u64 node_count;                               /* evaluated nodes */
     int turn;                                     /* WHITE or BLACK */
 
-    /* data which cannot be recovered by move_undo
-     * following data can be accessed either directly, either via "movesave"
+    /* data which cannot be recovered by move_undo (like castle_rights, ...).
+     *
+     * Attention: checkers/pinners/blockers are not included here, and
+     * are not available in move_undo or any following legality check.
+     *
+     * Following data can be accessed either directly, either via "state"
      * 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,
+                        hkey_t key;
                         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 */
+                        int clock_50;
+                        int plycount;             /* plies so far, start from 1 */
+                        piece_t captured;         /* only used in move_undo */
         );
-
-    piece_t board[BOARDSIZE];
-
-    bitboard_t bb[2][PIECE_TYPE_MAX];             /* bb[0][PAWN], bb[1][ALL_PIECES] */
-    //bitboard_t controlled[2];                     /* unsure */
-    square_t king[2];                             /* dup with bb, faster retrieval */
     bitboard_t checkers;                          /* opponent checkers */
     bitboard_t pinners;                           /* opponent pinners */
     bitboard_t blockers;                          /* pieces blocking pin */
-    movelist_t moves;
+
+    piece_t board[BOARDSIZE];
+    bitboard_t bb[2][PIECE_TYPE_MAX];             /* bb[0][PAWN], bb[1][ALL_PIECES] */
+    square_t king[2];                             /* dup with bb, faster retrieval */
+    repeat_t repeat;                              /* for repetition detection */
 } pos_t;
 
 typedef struct state_s state_t;
@@ -71,11 +83,16 @@ static __always_inline void pos_set_sq(pos_t *pos, square_t square, piece_t piec
 {
     color_t color = COLOR(piece);
     piece_type_t type = PIECE(piece);
+
+    bug_on(pos->board[square] != EMPTY);
+
     pos->board[square] = piece;
-    pos->bb[color][type] |= mask(square);
-    pos->bb[color][ALL_PIECES] |= mask(square);
-    if (type == KING)
-        pos->king[color] = square;
+    pos->bb[color][type] |= BIT(square);
+    pos->bb[color][ALL_PIECES] |= BIT(square);
+    //if (type == KING)
+    //    pos->king[color] = square;
+
+    //pos->key ^= zobrist_pieces[piece][square];
 }
 
 /**
@@ -90,11 +107,16 @@ 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);
+
+    bug_on(pos->board[square] == EMPTY);
+
+    //pos->key ^= zobrist_pieces[piece][square];
+
     pos->board[square] = EMPTY;
-    pos->bb[color][type] &= ~mask(square);
-    pos->bb[color][ALL_PIECES] &= ~mask(square);
-    if (type == KING)
-        pos->king[color] = SQUARE_NONE;
+    pos->bb[color][type] &= ~BIT(square);
+    pos->bb[color][ALL_PIECES] &= ~BIT(square);
+    //if (type == KING)
+    //    pos->king[color] = SQUARE_NONE;
 }
 
 /**
@@ -155,18 +177,18 @@ static __always_inline int pos_between_count(const pos_t *pos,
 
 pos_t *pos_new();
 pos_t *pos_dup(const pos_t *pos);
+pos_t *pos_copy(const pos_t *from, pos_t *to);
 void pos_del(pos_t *pos);
 pos_t *pos_clear(pos_t *pos);
 bool pos_cmp(const pos_t *pos1, const pos_t *pos2);
 
+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 );
-//bitboard_t set_king_pinners_blockers(pos_t *pos);
-//char *pos_checkers2str(const pos_t *pos, char *str);
-//char *pos_pinners2str(const pos_t *pos, char *str);
 
-int pos_check(const pos_t *pos, const bool strict);
+bool pos_ok(pos_t *pos, const bool strict);
 
 void pos_print(const pos_t *pos);
 void pos_print_mask(const pos_t *pos, const bitboard_t mask);

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 +11,141 @@
  *
  */
 
+#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:    current perft depth level (root = 1)
+ * @output: output total for 1st level moves.
+ *
+ * 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 legal moves
+ *    loop for 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, bool output)
+{
+    u64 subnodes, nodes = 0;
+    movelist_t movelist;
+    move_t *move, *last;
+    state_t state;
+#   ifdef PERFT_MOVE_HISTORY
+    static movelist_t stack;
+    if (ply == 1)
+        stack.nmoves = 0;
+#   endif
+
+    pos_set_checkers_pinners_blockers(pos);
+
+    pos_legal(pos, pos_gen_pseudo(pos, &movelist));
+    last = movelist.move + movelist.nmoves;
+    for (move = movelist.move; move < last; ++move) {
+        if (depth == 1) {
+            nodes++;
+        } else {
+            move_do(pos, *move, &state);
+#           ifdef PERFT_MOVE_HISTORY
+            stack.move[stack.nmoves++] = *move;
+#           endif
+            if (depth == 2) {
+                movelist_t movelist2;
+                pos_set_checkers_pinners_blockers(pos);
+                subnodes = pos_legal(pos, pos_gen_pseudo(pos, &movelist2))->nmoves;
+            } else if (ply >= 4) {
+                hentry_t *entry = tt_probe_perft(pos->key, depth);
+                if (entry != TT_MISS) {
+                    subnodes = HASH_PERFT_VAL(entry->data);
+                } else {
+                    subnodes = perft(pos, depth - 1, ply + 1, output);
+                    tt_store_perft(pos->key, depth, subnodes);
+                }
+            } else {
+                subnodes = perft(pos, depth - 1, ply + 1, output);
+            }
+            if (output && ply == 1) {
+                char movestr[8];
+                printf("%s: %lu\n", move_to_str(movestr, *move, 0), subnodes);
+            }
+            nodes += subnodes;
+            move_undo(pos, *move, &state);
+#           ifdef PERFT_MOVE_HISTORY
+            stack.nmoves--;
+#           endif
+        }
+    }
+
+    if (output && ply == 1)
+        printf("Total: %lu\n", nodes);
+    return nodes;
+}
+
+/**
+ * perft_alt() - Perform perft on position, experimental version.
+ * @pos:    &position to search
+ * @depth:  Wanted depth.
+ * @ply:    current perft depth level (root = 1)
+ * @output: output total for 1st level moves.
+ *
+ * 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_alt(pos_t *pos, int depth, int ply, bool output)
+{
+    u64 subnodes, nodes = 0;
+    movelist_t movelist;
+    move_t *move, *last;
+    state_t state;
+
+    pos_set_checkers_pinners_blockers(pos);
+
+    pos_legal(pos, pos_gen_pseudo(pos, &movelist));
+    last = movelist.move + movelist.nmoves;
+    for (move = movelist.move; move < last; ++move) {
+        if (depth == 1) {
+            nodes++;
+        } else {
+            move_do_alt(pos, *move, &state);
+            if (depth == 2) {
+                movelist_t movelist2;
+                pos_set_checkers_pinners_blockers(pos);
+                subnodes = pos_legal(pos, pos_gen_pseudo(pos, &movelist2))->nmoves;
+            } else {
+                subnodes = perft_alt(pos, depth - 1, ply + 1, output);
+            }
+            if (output && ply == 1) {
+                char movestr[8];
+                printf("%s: %lu\n", move_to_str(movestr, *move, 0), subnodes);
+            }
+            nodes += subnodes;
+            move_undo_alt(pos, *move, &state);
+        }
+    }
+
+    if (output && ply == 1)
+        printf("Total: %lu\n", nodes);
+    return nodes;
+}
 
 /**
  * negamax() - search position negamax.
@@ -31,32 +158,34 @@
  *
  * @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 +203,76 @@ 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 )
@@ -214,24 +345,24 @@ eval_t pvs(pos_t *pos, int depth, int alpha, int beta, int color)
  * @return: The @pos negamax evaluation.
  */
 /*int ab_negamax(pos_t *pos, int alpha, int beta, int depth)
-{
-    move_t *move;
-    pos_t *newpos;
-    eval_t best = EVAL_MIN, score;
+  {
+  move_t *move;
+  pos_t *newpos;
+  eval_t best = EVAL_MIN, score;
 
-    if(depth == 0) {
-       //return quiesce( alpha, beta );
-        moves_gen_all_nomoves(pos);
-       score = eval(pos) * color;
-       return score;
-    }
-   for ( all moves)  {
-      score = -alphaBeta( -beta, -alpha, depthleft - 1 );
-      if( score >= beta )
-         return beta;   //  fail hard beta-cutoff
-      if( score > alpha )
-         alpha = score; // alpha acts like max in MiniMax
-   }
-   return alpha;
-}
+  if(depth == 0) {
+  //return quiesce( alpha, beta );
+  moves_gen_all_nomoves(pos);
+  score = eval(pos) * color;
+  return score;
+  }
+  for ( all moves)  {
+  score = -alphaBeta( -beta, -alpha, depthleft - 1 );
+  if( score >= beta )
+  return beta;   //  fail hard beta-cutoff
+  if( score > alpha )
+  alpha = score; // alpha acts like max in MiniMax
+  }
+  return alpha;
+  }
 */

src/search.h

@@ -1,6 +1,6 @@
 /* search.h - search for perfect move.
  *
- * Copyright (C) 2021 Bruno Raoult ("br")
+ * Copyright (C) 2021-2024 Bruno Raoult ("br")
  * Licensed under the GNU General Public License v3.0 or later.
  * Some rights reserved. See COPYING.
  *
@@ -16,7 +16,10 @@
 
 #include "position.h"
 
-eval_t negamax(pos_t *pos, int depth, int color);
-eval_t pvs(pos_t *pos, int depth, int alpha, int beta, int color);
+//eval_t negamax(pos_t *pos, int depth, int color);
+//eval_t pvs(pos_t *pos, int depth, int alpha, int beta, int color);
+
+u64 perft(pos_t *pos, int depth, int ply, bool output);
+u64 perft_alt(pos_t *pos, int depth, int ply, bool output);
 
 #endif  /* SEARCH_H */

src/util.h

@@ -17,13 +17,19 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-#include "bug.h"
+#include <bug.h>
 
 #include "chessdefs.h"
 
 #undef safe_malloc
 #undef safe_free
 
+/* force BUG_ON, to get a program abort for failed malloc/free
+ */
+#pragma push_macro("BUG_ON")
+#undef BUG_ON
+#define BUG_ON
+
 #define safe_malloc(size) ({                   \
             void *_ret = malloc(size);         \
             bug_on(_ret == NULL);              \
@@ -35,4 +41,8 @@
         free(ptr);                             \
     } while (0)
 
+/* restore BUG_ON
+ */
+#pragma pop_macro("BUG_ON")
+
 #endif  /* UTIL_H */

test/attack-test.c

@@ -28,6 +28,7 @@ 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 */
 
@@ -41,8 +42,22 @@ int main(int __unused ac, __unused char**av)
             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++;
     }

test/bitboard-test.c

@@ -46,16 +46,24 @@ int main(int __unused ac, __unused char**av)
     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]);
+                   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]);
+                   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;
 }

test/common-test.h

@@ -20,160 +20,211 @@
 #define MOVEGEN     4
 #define ATTACK      8
 #define MOVEDO     16
+#define PERFT      32
 
 struct fentest {
+    int line;
     uint modules;
     char *comment;
     char *fen;
 } fentest[] = {
-    /*
-    { ATTACK,
-      "checkers: ",
-      ""
-    },
-     */
-    /* tests rank movegen bug - FIXED
-     */
-    //"4k3/pppppppp/8/8/8/8/PPPPPPPP/2BRK3 w - - 0 1",
-    //"4k3/pppppppp/8/8/8/8/PPPPPPPP/1B1R1K2 w - - 0 1",
-    { MOVEGEN,
-      "illegal white e.p.",
-      "3k4/8/8/2qpPK2/8/8/8/8 w - d6 0 1",
-    },
-    { MOVEGEN,
-      "illegal black e.p.",
-      "8/8/8/8/2QPpk2/8/8/3K4 b - d3 0 1",
-    },
+    /************************************************************
+     * TEMP TESTS BELOW - only run them (till sentinel below)   *
+     ************************************************************/
 
-    { MOVEGEN,
+    /*
+     * { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+     *   "startpos + 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4",
+     *   "r1bqkbnr/1ppp1ppp/p1n5/4p3/B3P3/5N2/PPPP1PPP/RNBQK2R b KQkq - 1 4"
+     * },
+     * { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+     *   "",
+     *   "r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 1"
+     * },
+     */
+
+    /******************************************************************
+     * DO NOT DELETE NEXT LINE - sentinel entry for temp tests above. *
+     *                           ignored if first array entry.        *
+     ******************************************************************/
+    { __LINE__, 0, NULL, NULL },
+
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
       "illegal white e.p.",
       "3k4/8/5K2/3pP3/8/2b5/8/8 w - d6 0 1",
     },
-    { MOVEGEN,
+    { __LINE__, PERFT,
+      "only K, pawn push and ep moves",
+      "3k4/8/8/3pPK2/8/8/8/8 w - d6 0 1"
+    },
+
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
+      "illegal white e.p.",
+      "3k4/8/8/2qpPK2/8/8/8/8 w - d6 0 1",
+    },
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
+      "illegal black e.p.",
+      "8/8/8/8/2QPpk2/8/8/3K4 b - d3 0 1",
+    },
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
       "illegal black e.p.",
       "8/8/2B5/8/3Pp3/5k2/8/3K4 b - d3 0 1",
     },
 
-    { MOVEGEN,
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
       "legal white e.p.",
       "1K1k4/8/8/3pP3/8/6b1/8/8 w - d6 0 1",
     },
-    { MOVEGEN,
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
       "legal black e.p.",
       "8/8/6B1/8/3Pp3/8/8/1k1K4 b - d3 0 1",
     },
-
-    { MOVEGEN,
-      "white mate.",
-      "1nbqkbn1/ppp1pppp/8/r1rpP1K1/8/8/PPPP1PPP/RNBQ1BNR w - d6 0 1",
-    },
-    { MOVEGEN,
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
       "illegal e.p.",
       "1nbqkbn1/ppp1pppp/8/r1rpP1K1/8/8/PPPP1PPP/RNBQ1BNR w - d6 0 1",
     },
-    { ATTACK,
-      "checkers: a1 h1",
-      "1k6/8/8/8/8/8/8/r2K3r w - - 1 1"
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
+      "illegal e.p. bug perft at depth 4",
+      "1nbqkbn1/ppp2ppp/4p3/r1rpP3/6K1/P7/1PPP1PPP/RNBQ1BNR b - - 1 2"
     },
-    { ATTACK,
+    /*
+     * { __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 - - 1 1"
+      "R2k3R/8/8/8/8/8/8/1K6 b - - 0 1"
     },
-    { ATTACK,
+    { __LINE__, ATTACK,
       "checkers: b3 g3",
-      "1k6/8/8/8/8/1r1K2r1/8/8 w - - 1 1"
+      "1k6/8/8/8/8/1r1K2r1/8/8 w - - 0 1"
     },
 
-    { ATTACK,
+    { __LINE__, ATTACK,
       "checkers: b6 g6",
-      "8/8/1R1k2R1/8/8/8/8/1K6 b - - 1 1"
+      "8/8/1R1k2R1/8/8/8/8/1K6 b - - 0 1"
     },
 
-    { ATTACK,
+    { __LINE__, ATTACK,
       "checkers: g2 g7",
-      "8/k5r1/8/8/6K1/8/6r1/8 w - - 1 1"
+      "8/k5r1/8/8/6K1/8/6r1/8 w - - 0 1"
     },
-    { ATTACK,
+    { __LINE__, ATTACK,
       "checkers: g2 g7",
-      "8/6R1/8/6k1/8/8/K5R1/8 b - - 1 1"
+      "8/6R1/8/6k1/8/8/K5R1/8 b - - 0 1"
     },
-    { ATTACK,
+    { __LINE__, ATTACK,
       "checkers: d5 e3, pinners: none (2 pieces between attacker & K)",
-      "3k4/8/8/3r3b/b7/1N2nn2/2n1B3/rNBK1Rbr w - - 1 1"
+      "3k4/8/8/3r3b/b7/1N2nn2/2n1B3/rNBK1Rbr w - - 0 1"
     },
 
-    { ATTACK,
+    { __LINE__, ATTACK,
       "checkers: d4 e6 pinners: h4 a5 a8 h8",
-      "Rn1k1r1R/4b3/1n2N3/B7/3R3B/8/8/3K4 b - - 1 1"
+      "Rn1k1r1R/4b3/1n2N3/B7/3R3B/8/8/3K4 b - - 0 1"
     },
-    { ATTACK,
+    { __LINE__, ATTACK,
       "checkers: d5 e3, pinners: a1 h1 a4 h5",
-      "3k4/8/8/3r3b/b7/1N2n3/4B3/rN1K1R1r w - - 1 0"
+      "3k4/8/8/3r3b/b7/1N2n3/4B3/rN1K1R1r w - - 0 1"
     },
 
-    { MOVEGEN,
+    { __LINE__, MOVEGEN | MOVEDO | PERFT,
       "only pawn captures",
       "4k3/8/2p1p3/2PpP3/8/pp4pp/PP4PP/4K3 w - d6 0 1"
     },
 
-    { FEN | ATTACK,
+    { __LINE__, FEN | ATTACK,
       "checker: h4",
       "4k3/8/8/8/7b/8/8/4K3 w - - 0 1"
     },
-// First game moves
-    { FEN | MOVEGEN,
-      "initial pos",
+    /*
+     * { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+     *   "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"
+     * },
+     */
+    // First game moves
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "startpos",
       "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
     },
-    { FEN | MOVEGEN,
-      "1.e4",
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "startpos + 1.e4",
       "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq - 0 1"
     },
-    { FEN | MOVEGEN,
-      "1.Nh3",
-      "rnbqkbnr/pppppppp/8/8/8/7N/PPPPPPPP/RNBQKB1R b KQkq - 1 1"
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "startpos + 1.e4 e5 2.Nf3",
+      "rnbqkbnr/pppp1ppp/8/4p3/4P3/5N2/PPPP1PPP/RNBQKB1R b KQkq - 1 2"
     },
-    { FEN | MOVEGEN,
-      "1.e4 e5 2.Nf3 Nc6",
-      "r1bqkbnr/pp1ppppp/2n5/2p5/4P3/5N2/PPPP1PPP/RNBQKB1R w KQkq - 0 1"
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "startpos + 1.e4 e5 2.Nf3 Nc6",
+      "r1bqkbnr/pppp1ppp/2n5/4p3/4P3/5N2/PPPP1PPP/RNBQKB1R w KQkq - 2 3"
+    },
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "startpos + 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4",
+      "r1bqkbnr/1ppp1ppp/p1n5/4p3/B3P3/5N2/PPPP1PPP/RNBQK2R b KQkq - 1 4"
     },
-
     // castling test
     // both can castle queen only
-    { FEN | MOVEGEN,
-      "",
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "no Q castling",
       "r3k2r/8/3B4/8/8/3b4/8/R3K2R w KQkq - 0 1"
     },
-    { FEN | MOVEGEN,
-      "",
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
+      "no castling, 2 mates in 1",
       "r3k2r/8/3BB3/8/8/3bb3/8/R3K2R w KQkq - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "r2bkb1r/8/8/8/8/3bb3/8/R2BKB1R w KQkq - 0 1"
     },
     //
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "4 castle possible, only K+R",
       "r3k2r/8/8/8/8/8/8/R3K2R w KQkq - 0 1"
     },
     //
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "only kings on A1/A8, white to play",
       "k7/8/8/8/8/8/8/K7 w - - 0 1"
     },
     //
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "only one move possible (Pf2xBg3)",
       "k7/8/8/1p1p4/pPpPp3/P1PpPpb1/NBNP1P2/KBB1B3 w - - 0 1"
     },
     //
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "only 2 moves possible (Ph5xg6 e.p., Ph5-h6)",
       "k7/8/8/1p1p2pP/pPpPp3/P1PpPp2/NBNP1P2/KBB1B3 w - g6 0 1"
     },
     //
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "2 Kings, W/B/ pawns on 7th for promotion",
       "k4n2/4P3/8/8/8/8/4p3/K4N2 w - - 0 1"
     },
@@ -181,20 +232,20 @@ struct fentest {
     // white is a pawn down
     // white has 36 moves: P=11 + 1 e.p. N=6+3 B=5+5 R=1 Q=3 K=1 + 1 e.p.
     // black has 33 moves: P=11 N=2+7 B=5 R=3 Q=3 K=1 + castle
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "rnbqk2r/pp1pbpp1/7p/2pPp3/4n3/3B1N2/PPP2PPP/RNBQ1RK1 w kq c6 0 7"
     },
 
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "4k3/4p3/8/b7/1BR1p2p/1Q3P2/5N2/4K3 w - - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "r1bq1rk1/pppp1ppp/2n2n2/4p3/2B1P3/3PPN2/PPP3PP/RN1QK2R b KQ - 1 7"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "6k1/6pp/R2p4/p1p5/8/1P1r3P/6P1/6K1 b - - 3 3"
     },
@@ -202,197 +253,210 @@ struct fentest {
     // some of tests below are from:
     // - Rodent IV
     // - https://www.chessprogramming.net/perfect-perft/
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "8/2p5/3p4/Kp5r/1R3p1k/8/4P1P1/8 w - - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "4rrk1/pp1n3p/3q2pQ/2p1pb2/2PP4/2P3N1/P2B2PP/4RRK1 b - - 7 19"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "rq3rk1/ppp2ppp/1bnpb3/3N2B1/3NP3/7P/PPPQ1PP1/2KR3R w - - 7 14"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "r1bq1r1k/1pp1n1pp/1p1p4/4p2Q/4Pp2/1BNP4/PPP2PPP/3R1RK1 w - - 2 14"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "r3r1k1/2p2ppp/p1p1bn2/8/1q2P3/2NPQN2/PPP3PP/R4RK1 b - - 2 15"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "1rbqk1nr/p3ppbp/2np2p1/2p5/1p2PP2/3PB1P1/PPPQ2BP/R2NK1NR b KQk - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "r1bqk2r/pp1p1ppp/2n1pn2/2p5/1bPP4/2NBP3/PP2NPPP/R1BQK2R b KQkq - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "rnb1kb1r/ppp2ppp/1q2p3/4P3/2P1Q3/5N2/PP1P1PPP/R1B1KB1R b KQkq - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "r1b2rk1/pp2nppp/1b2p3/3p4/3N1P2/2P2NP1/PP3PBP/R3R1K1 b - - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "n1q1r1k1/3b3n/p2p1bp1/P1pPp2p/2P1P3/2NBB2P/3Q1PK1/1R4N1 b - - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "r1bq1r1k/b1p1npp1/p2p3p/1p6/3PP3/1B2NN2/PP3PPP/R2Q1RK1 w - - 1 16"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "3r1rk1/p5pp/bpp1pp2/8/q1PP1P2/b3P3/P2NQRPP/1R2B1K1 b - - 6 22"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "r1q2rk1/2p1bppp/2Pp4/p6b/Q1PNp3/4B3/PP1R1PPP/2K4R w - - 2 18"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "4k2r/1pb2ppp/1p2p3/1R1p4/3P4/2r1PN2/P4PPP/1R4K1 b - - 3 22"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "3q2k1/pb3p1p/4pbp1/2r5/PpN2N2/1P2P2P/5PP1/Q2R2K1 b - - 4 26"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "2r5/8/1n6/1P1p1pkp/p2P4/R1P1PKP1/8/1R6 w - - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "r2q1rk1/1b1nbppp/4p3/3pP3/p1pP4/PpP2N1P/1P3PP1/R1BQRNK1 b - - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "6k1/5pp1/7p/p1p2n1P/P4N2/6P1/1P3P1K/8 w - - 0 35"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "r4rk1/1pp1q1pp/p2p4/3Pn3/1PP1Pp2/P7/3QB1PP/2R2RK1 b - - 0 1"
     },
 
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "r3k2r/Pppp1ppp/1b3nbN/nP6/BBP1P3/q4N2/Pp1P2PP/R2Q1RK1 w kq - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "",
       "1k6/1b6/8/8/7R/8/8/4K2R b K - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "Illegal ep move #1",
       "3k4/3p4/8/K1P4r/8/8/8/8 b - - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "Illegal ep move #2",
       "8/8/4k3/8/2p5/8/B2P2K1/8 w - - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "EP Capture Checks Opponent",
       "8/8/1k6/2b5/2pP4/8/5K2/8 b - d3 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "Short Castling Gives Check",
       "5k2/8/8/8/8/8/8/4K2R w K - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "Long Castling Gives Check",
       "3k4/8/8/8/8/8/8/R3K3 w Q - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "Castle Rights",
       "r3k2r/1b4bq/8/8/8/8/7B/R3K2R w KQkq - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "Castling Prevented",
       "r3k2r/8/3Q4/8/8/5q2/8/R3K2R b KQkq - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "Promote out of Check",
       "2K2r2/4P3/8/8/8/8/8/3k4 w - - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "Discovered Check",
       "8/8/1P2K3/8/2n5/1q6/8/5k2 b - - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "Promote to give check",
       "4k3/1P6/8/8/8/8/K7/8 w - - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "Under Promote to give check",
       "8/P1k5/K7/8/8/8/8/8 w - - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "Self Stalemate",
       "K1k5/8/P7/8/8/8/8/8 w - - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "Stalemate & Checkmate",
       "8/k1P5/8/1K6/8/8/8/8 w - - 0 1"
     },
-    { FEN | MOVEGEN,
+    { __LINE__, FEN | MOVEGEN | MOVEDO | PERFT,
       "Stalemate & Checkmate",
       "8/8/2k5/5q2/5n2/8/5K2/8 b - - 0 1"
     },
-
-    { FEN,
-      "illegal EP and castle flags, fix-able by fen parser, SF crash",
-      "4k3/8/8/8/7B/8/8/4K3 w KQkq e6 0 1"
-    },
-    { FEN,
-      "illegal, SF crash",
-      "4k3/8/8/8/7b/8/8/4K3 b - - 0 1"
-    },
-    { FEN,
-      "illegal, SF crash",
-      "2r1k3/3B4/8/8/8/8/8/4K3 w - - 0 1"
-    },
-    { FEN,
-      "illegal, SF crash",
-      "2r1k3/3P4/8/8/8/8/8/4K3 w - - 0 1"
-    },
-    { MOVEDO,
+    { __LINE__, MOVEDO | PERFT,
       "simple movedo/undo: only 2 W knights",
       "8/1k6/8/8/8/8/6K1/1NN5 w - - 0 1"
     },
-    { MOVEDO,
-      "simple movedo/undo: only 2 W knights",
-      "8/1k6/8/8/8/8/6K1/1NN5 w - - 0 1"
-    },
-    { MOVEDO,
+    { __LINE__, MOVEDO | PERFT,
       "simple movedo/undo: only 2 W knights",
       "5n2/1k6/8/8/5K2/8/P7/1N6 w - - 0 1"
     },
-    { 0, NULL, NULL }
+    { __LINE__, FEN,
+      "legal EP",
+      "4k3/8/8/3pP3/8/8/8/4K3 w - d6 0 1"
+    },
+    { __LINE__, FEN,
+      "illegal EP, fix-able by fen parser",
+      "4k3/8/8/3p1P2/8/8/8/4K3 w - d6 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 = 0;
+static int fentest_cur = -1;
 
 static char *next_fen(uint module)
 {
-    while (fentest[cur].fen && !(fentest[cur].modules & module))
-        cur++;
-    return fentest[cur].fen ? fentest[cur++].fen: NULL;
+    fentest_cur++;
+
+    /* skip first entry if NULL - for special testing, see  */
+    if (fentest_cur == 0 && fentest[fentest_cur].fen == NULL)
+        fentest_cur++;
+    while (fentest[fentest_cur].fen && !(fentest[fentest_cur].modules & module))
+        fentest_cur++;
+    return fentest[fentest_cur].fen;
 }
 
 static __unused char* cur_comment()
 {
-    return fentest[cur].comment;
+    return fentest[fentest_cur].comment;
+}
+
+static __unused int cur_line()
+{
+    return fentest[fentest_cur].line;
 }

test/fen-test.c

@@ -31,8 +31,7 @@ int main(__unused int ac, __unused char**av)
     bitboard_init();
 
     while ((fen = next_fen(FEN))) {
-        printf("***** [%s] ", fen);
-        fflush(stdout);
+        printf("line %3d: [%s] ", cur_line(), fen);
         if (!(pos = fen2pos(NULL, fen))) {
             printf("**INVALID\n");
         } else {

test/movedo-test.c

@@ -26,52 +26,62 @@
 
 int main(int __unused ac, __unused char**av)
 {
-    int i = 1;
+    int i = 0, test_line;
     char *fen, movebuf[8];;
     pos_t *pos, *savepos;
-    move_t move;
+    movelist_t movelist;
+    move_t *move, *last;
 
-    setlinebuf(stdout);                           /* line-buffered stdout */
+    init_all();
 
-    bitboard_init();
-    hyperbola_init();
-
-    while ((fen = next_fen(MOVEGEN | MOVEDO))) {
+    while ((fen = next_fen(MOVEDO))) {
+        test_line = cur_line();
         if (!(pos = fen2pos(NULL, fen))) {
             printf("wrong fen %d: [%s]\n", i, fen);
             continue;
         }
-        pos_gen_pseudomoves(pos);
-        savepos = pos_dup(pos);
-        if (pos_cmp(pos, savepos) != true) {
-            printf("*** positions differ 1\n");
-            exit(0);
-        }
-        int tmp = 0, j = 1;
-        while ((move = pos_next_legal(pos, &tmp)) != MOVE_NONE) {
-            state_t state;
 
-            pos_print(pos);
-            printf("i=%d j=%d  turn=%d move=[%s]\n", i, j, pos->turn,
-                   move_str(movebuf, move, 0));
+        movelist.nmoves = 0;
+        pos_set_checkers_pinners_blockers(pos);
+        pos_legal(pos, pos_gen_pseudo(pos, &movelist));
+        last = movelist.move + movelist.nmoves;
+        savepos = pos_dup(pos);
+
+        state_t state = pos->state;
+        int j = 0;
+        for (move = movelist.move; move < last; ++move) {
+            //pos_print(pos);
+            //printf("i=%d j=%d  turn=%d move=[%s]\n", i, j, pos->turn,
+            //       move_str(movebuf, move, 0));
             //move_p
-            move_do(pos, move, &state);
-            pos_print(pos);
-            fflush(stdout);
-            pos_check(pos, true);
-            printf("%d/%d move_do check ok\n", i, j);
-            move_undo(pos, move, &state);
-            if (pos_cmp(pos, savepos) != true) {
-                printf("*** positions differ 2\n");
+            move_do(pos, *move, &state);
+            //pos_print(pos);
+            //fflush(stdout);
+            if (!pos_ok(pos, false)) {
+                printf("*** fen %d [%s] move %d [%s] invalid position after move_do\n",
+                       test_line, fen, j, move_to_str(movebuf, *move, 0));
                 exit(0);
             }
-            fflush(stdout);
-            pos_check(pos, true);
-            printf("%d/%d move_undo check ok\n", i, j);
 
-            if (j++ == 1000)
+            //printf("%d/%d move_do check ok\n", i, j);
+            move_undo(pos, *move, &state);
+            pos->state = state;
+            if (!pos_ok(pos, false)) {
+                printf("*** fen %d [%s] move %d [%s] invalid position after move_undo\n",
+                       test_line, fen, j, movebuf);
                 exit(0);
+            }
+            if (pos_cmp(pos, savepos) != true) {
+                printf("*** fen %d [%s] move %d [%s] position differ after move_{do,undo}\n",
+                       test_line, fen, 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++;

test/movegen-test.c

@@ -76,7 +76,7 @@ static FILE *open_stockfish()
     return out_desc;
 }
 
-static void send_stockfish_fen(FILE *desc, pos_t *pos, char *fen)
+static void send_stockfish_fen(FILE *desc, pos_t *pos, movelist_t *movelist, char *fen)
 {
     char *buf = NULL;
     int count, __unused mycount = 0, fishcount;
@@ -85,8 +85,9 @@ static void send_stockfish_fen(FILE *desc, pos_t *pos, char *fen)
 
     pos_clear(pos);
 
-    move_t *moves = pos->moves.move;
-    int nmoves = pos->moves.nmoves;
+    move_t *moves = movelist->move;
+    int *nmoves = &movelist->nmoves;
+    *nmoves = 0;
     //char nodescount[] = "Nodes searched";
     //printf("nmoves = %d\n", nmoves);
     fflush(stdout);
@@ -109,7 +110,7 @@ static void send_stockfish_fen(FILE *desc, pos_t *pos, char *fen)
             //       buf[0], buf[1], buf[2], buf[3],
             //       sq_to_string(from), sq_to_string(to),
             //       count);
-            moves[nmoves++] = move_make(from, to);
+            moves[(*nmoves)++] = move_make(from, to);
 
         } else if (sscanf(buf, "%*5s: %d", &count) == 1) {
             square_t from = sq_from_string(buf);
@@ -120,10 +121,10 @@ static void send_stockfish_fen(FILE *desc, pos_t *pos, char *fen)
             //       buf[0], buf[1], buf[2], buf[3],
             //       sq_to_string(from), sq_to_string(to),
             //       count);
-            moves[nmoves++] = move_make_promote(from, to, promoted);
+            moves[(*nmoves)++] = move_make_promote(from, to, promoted);
         }
     }
-    pos->moves.nmoves = nmoves;
+    //pos->moves.nmoves = nmoves;
     // printf("fishcount=%d mycount=%d\n", fishcount, mycount);
     free(buf);
 }
@@ -215,7 +216,7 @@ int main(int __unused ac, __unused char**av)
     FILE *outfd;
     char *fen;
     pos_t *pos, *fishpos = pos_new();
-    movelist_t legal;
+    movelist_t pseudo, fishmoves;
     //bitboard_t wrong = 0x5088000040, tmp, loop;
     //bit_for_each64(loop, tmp, )
     //printf("fishpos 1=%p\n", fishpos);
@@ -235,9 +236,14 @@ int main(int __unused ac, __unused char**av)
             continue;
         }
         /* print movelists */
-        send_stockfish_fen(outfd, fishpos, fen);
-        pos_gen_pseudomoves(pos);
-        pos_all_legal(pos, &legal);
+        send_stockfish_fen(outfd, fishpos, &fishmoves, fen);
+
+        pos_set_checkers_pinners_blockers(pos);
+        pos_gen_pseudo(pos, &pseudo);
+        //moves_print(&pseudo, 0);
+        pos_legal(pos, &pseudo);
+
+        //moves_print(&legal, 0);
         //printf("Fu ");
         //moves_print(fishpos, 0);
         //fflush(stdout);
@@ -246,8 +252,8 @@ int main(int __unused ac, __unused char**av)
         //fflush(stdout);
 
         /* sort and print movelists */
-        move_sort_by_sq(&fishpos->moves);
-        move_sort_by_sq(&legal);
+        move_sort_by_sq(&fishmoves);
+        move_sort_by_sq(&pseudo);
         // printf("\nFs ");
         // moves_print(fishpos, 0);
         // fflush(stdout);
@@ -256,14 +262,14 @@ int main(int __unused ac, __unused char**av)
         // fflush(stdout);
 
         /* compare movelists */
-        if (!movelists_equal(&fishpos->moves, &legal)) {
+        if (!movelists_equal(&fishmoves, &pseudo)) {
             pos_print(pos);
             printf("F: ");
-            moves_print(&fishpos->moves, 0);
+            moves_print(&fishmoves, 0);
             printf("M: ");
-            moves_print(&legal, 0);
+            moves_print(&pseudo, 0);
         } else {
-            printf("[%s]: OK (%d Moves)\n", fen, legal.nmoves);
+            printf("[%s]: OK (%d Moves)\n", fen, pseudo.nmoves);
             //moves_print(&fishpos->moves, 0);
         }
         //compare_moves(&fishpos->moves, &legal);

test/perft-test.c

@@ -0,0 +1,463 @@
+/* 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 <limits.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;
+    char *buf = NULL;
+    size_t alloc = 0;
+    ssize_t buflen;
+
+    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);
+
+    fprintf(out_desc, "uci\n");
+    while (true) {
+        if ((buflen = getline(&buf, &alloc, stdin)) < 0) {
+            perror("getline");
+            exit(1);
+        }
+        if (!strncmp(buf, "uciok", 5))
+            break;
+    }
+    free(buf);
+    return out_desc;
+}
+
+static void stockfish_fen(FILE *desc, char *fen)
+{
+    char *buf = NULL;
+    size_t alloc = 0;
+    ssize_t buflen;
+
+    fprintf(desc, "ucinewgame\nisready\n");
+    while ((buflen = getline(&buf, &alloc, stdin)) > 0) {
+        if (!strncmp(buf, "readyok", 7))
+            break;
+    }
+    fprintf(desc, "position fen %s\n", fen);
+    free(buf);
+}
+
+static u64 stockfish_perft(FILE *desc, pos_t *pos, movelist_t *movelist,
+                               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);
+    fprintf(desc, "go perft %d\n", depth);
+
+    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);
+}
+
+static int usage(char *prg)
+{
+    fprintf(stderr, "Usage: %s [-cms][-d depth] [-p version] [-t size:\n", prg);
+    fprintf(stderr, "\t-c:         do *not* print FEN comments\n");
+    fprintf(stderr, "\t-d depth:   perft depth (default: 6)");
+    fprintf(stderr, "\t-m:         print moves details\n");
+    fprintf(stderr, "\t-s:         use Stockfish to validate perft result\n");
+    fprintf(stderr, "\t-t size:    Transposition Table size (Mb). Default: 32\n");
+    fprintf(stderr,
+            "\t-p flavor:  perft flavor, 1:perft, 2:perft_alt 3:both, default:1\n");
+    return 1;
+}
+
+int main(int ac, char**av)
+{
+    int curtest = 0;
+    u64 sf_count = 0, my_count;
+    bool comment = true, sf_run = false, moves_output = false;
+    char *fen;
+    pos_t *pos = NULL, *fenpos;
+    pos_t *fishpos = pos_new();
+    movelist_t fishmoves;
+    FILE *outfd = NULL;
+    s64 ms, lps;
+    int opt, depth = 6, run = 3, tt = 32, newtt = 32;
+    struct {
+        s64 count, ms;
+        s64 minlps, maxlps;
+        int skipped;
+    } res[3] = {
+        { .minlps=LONG_MAX },
+        { .minlps=LONG_MAX },
+        { .minlps=LONG_MAX },
+    };
+
+    while ((opt = getopt(ac, av, "cd:mp:st:")) != -1) {
+        switch (opt) {
+            case 'c':
+                comment = false;
+                break;
+            case 'd':
+                depth = atoi(optarg);
+                if (depth <= 0)
+                    depth = 6;
+                break;
+            case 'm':
+                moves_output = false;
+                break;
+            case 'p':
+                run = atoi(optarg);
+                break;
+            case 's':
+                sf_run = true;
+                break;
+            case 't':
+                newtt = atoi(optarg);
+                break;
+            default:
+                    return usage(*av);
+        }
+    }
+
+    if (!run) {
+        printf("Nothing to do, exiting\n");
+        exit(0);
+    }
+
+    init_all();
+    if (newtt != 32 && newtt > 1) {
+        printf("changing TT size from %d to %d\n", tt, newtt);
+        tt_create(newtt);
+        tt = newtt;
+    }
+    printf("%s: depth:%d tt_size:%d run:%x SF:%s\n",
+           *av,
+           depth, newtt, run,
+           sf_run? "yes": "no");
+
+    tt_info();
+    printf("\n");
+
+    printf("move_t size:%lu\n", sizeof(move_t));
+
+    if (sf_run)
+        outfd = open_stockfish();
+
+    CLOCK_DEFINE(clock, CLOCK_MONOTONIC);
+    while ((fen = next_fen(PERFT | MOVEDO))) {
+        if (!(fenpos = fen2pos(pos, fen))) {
+            printf("wrong fen line:%d fen:%s\n\n", cur_line(), fen);
+            continue;
+        }
+        curtest++;
+        printf("test:%d line:%d", curtest, cur_line());
+        if (comment)
+            printf(" comment:%s\n",
+                   *cur_comment()? cur_comment(): "no test desc");
+        printf("\t%s\n", fen);
+
+        tt_clear();
+
+        pos = fenpos;
+        if (sf_run) {
+            stockfish_fen(outfd, fen);
+            clock_start(&clock);
+            sf_count = stockfish_perft(outfd, fishpos, &fishmoves, depth);
+            ms = clock_elapsed_ms(&clock);
+            if (!ms) {
+                res[2].skipped++;
+                lps = 0;
+            } else {
+                lps = sf_count * 1000l / ms;
+                res[2].ms += ms;
+                res[2].count += sf_count;
+                if (lps > res[2].maxlps)
+                    res[2].maxlps = lps;
+                if (lps < res[2].minlps)
+                    res[2].minlps = lps;
+            }
+            printf("Stockfish : perft:%'lu ms:%'ld lps:%'lu\n",
+                   sf_count, ms, lps);
+        }
+
+        if (run & 1) {
+            clock_start(&clock);
+            my_count = perft(pos, depth, 1, moves_output);
+            ms = clock_elapsed_ms(&clock);
+            if (!ms) {
+                res[0].skipped++;
+                lps = 0;
+            } else {
+                lps = my_count * 1000l / ms;
+                res[0].ms += ms;
+                res[0].count += my_count;
+                if (lps > res[0].maxlps)
+                    res[0].maxlps = lps;
+                if (lps < res[0].minlps)
+                    res[0].minlps = lps;
+            }
+
+            if (!sf_run || sf_count == my_count) {
+                printf("perft     : perft:%'lu ms:%'ld lps:%'lu ",
+                       my_count, ms, lps);
+                tt_stats();
+            } else  {
+                printf("perft     : perft:%'lu ***ERROR***\n", my_count);
+            }
+        }
+
+        if (run & 2) {
+            clock_start(&clock);
+            my_count = perft_alt(pos, depth, 1, moves_output);
+            ms = clock_elapsed_ms(&clock);
+            if (!ms) {
+                res[1].skipped++;
+                lps = 0;
+            } else {
+                lps = my_count * 1000l / ms;
+                res[1].ms += ms;
+                res[1].count += my_count;
+                if (lps > res[1].maxlps)
+                    res[1].maxlps = lps;
+                if (lps < res[1].minlps)
+                    res[1].minlps = lps;
+            }
+
+            if (!sf_run || sf_count == my_count) {
+                printf("perft_alt : perft:%'lu ms:%'ld lps:%'lu\n",
+                       my_count, ms, lps);
+            } else  {
+                printf("perft_alt : perft:%'lu ***ERROR***\n", my_count);
+            }
+        }
+        printf("\n");
+    }
+    pos_del(pos);
+    if (sf_run) {
+        if (!res[2].ms)
+            res[2].ms = 1;
+        printf("total Stockfish : perft:%'lums ms:%'lums lps:%'lu min:%'lu max:%'lu "
+               "(skipped %d/%d)\n",
+               res[2].count, res[2].ms,
+               res[2].count * 1000l / res[2].ms,
+               res[2].minlps, res[2].maxlps,
+               res[0].skipped, curtest);
+    }
+    if (run & 1) {
+        if (!res[0].ms)
+            res[0].ms = 1;
+        printf("total perft     : perft:%'lums ms:%'lums lps:%'lu min:%'lu max:%'lu "
+               "(skipped %d/%d)\n",
+               res[0].count, res[0].ms,
+               res[0].count * 1000l / res[0].ms,
+               res[0].minlps, res[0].maxlps,
+               res[0].skipped, curtest);
+    }
+    if (run & 2) {
+        if (!res[1].ms)
+            res[1].ms = 1;
+        printf("total perft_alt : perft:%'lums ms:%'lums lps:%'lu min:%'lu max:%'lu "
+               "(skipped %d/%d)\n",
+               res[1].count, res[1].ms,
+               res[1].count * 1000l / res[1].ms,
+               res[1].minlps, res[1].maxlps,
+               res[0].skipped, curtest);
+    }
+    return 0;
+}

test/tt-test.c

@@ -0,0 +1,159 @@
+/* tt-test.c - transposition table 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 <ctype.h>
+#include <unistd.h>
+#include <time.h>
+#include <locale.h>
+#include <limits.h>
+
+#include <brlib.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"
+
+static move_t move_in_movelist(movelist_t *ml, square_t from, square_t to, piece_type_t pt)
+{
+    const int nmoves = ml->nmoves;
+    const move_t *moves = ml->move;
+    int movenum = 0;
+    move_t move;
+    for (movenum = 0; movenum < nmoves; ++movenum) {
+        move = moves[movenum];
+        printf("compare %s%s to %s%s pt=%d ",
+               sq_to_string(from), sq_to_string(to),
+               sq_to_string(move_from(move)),
+               sq_to_string(move_to(move)),
+               pt
+            );
+        if (move_from(move) == from && move_to(move) == to) {
+            printf("HIT!\n");
+            if (pt != NO_PIECE_TYPE && move_promoted(move) != pt)
+                continue;
+            printf("move_in_movelist(%s%s) found from=%s to=%s\n",
+                   sq_to_string(from), sq_to_string(to),
+                   sq_to_string(move_from(move)),
+                   sq_to_string(move_to(move)));
+            return move;
+        } else
+            puts("");
+    }
+    return MOVE_NONE;
+}
+
+static move_t move_from_str(pos_t *pos, const char *move)
+{
+    movelist_t movelist;
+    square_t from = sq_from_string(move);
+    square_t to = sq_from_string(move + 2);
+    piece_type_t promoted = piece_t_from_char(*(move + 4));
+    printf("from=%o to=%o promoted=%d\n", from, to, promoted);
+
+    pos_set_checkers_pinners_blockers(pos);
+    pos_legal(pos, pos_gen_pseudo(pos, &movelist));
+    return  move_in_movelist(&movelist, from, to, promoted);
+}
+
+static void pr_entry(hentry_t *entry)
+{
+    if (!entry)
+        printf("entry: NULL\n");
+    else {
+        printf("entry: key=%lx depth=%d n=%lu\n",
+               entry->key, HASH_PERFT_DEPTH(entry->data),
+               HASH_PERFT_VAL(entry->data));
+    }
+}
+
+int main()
+{
+    pos_t *pos = NULL;
+    char *token, *str, buf[128];
+    hentry_t *entry;
+    move_t move;
+    state_t state;
+    //movelist_t movelist;
+
+    const char *moves_array[] = {
+        "e2e4 e7e5 g1f3 b8c6",
+        "e2e4 b8c6 g1f3 e7e5"
+    };
+
+    init_all();
+
+    for (uint i = 0; i < ARRAY_SIZE(moves_array); ++i) {
+        int depth = 0;
+        str = strdup(moves_array[i]);
+        printf("%2d: ", i + 1);
+
+        pos = startpos(pos);
+        entry = tt_store_perft(pos->key, 0, 123 + depth);
+        pr_entry(entry);
+        token = strtok(str, " \t");
+        while (token) {
+            depth++;
+            printf("%s ", token);
+
+            //pos_set_checkers_pinners_blockers(pos);
+            //pos_legal(pos, pos_gen_pseudo(pos, &movelist));
+            move = move_from_str(pos, token);
+            printf("move: %s\n", move_to_str(buf, move, 0));
+            move_do(pos, move, &state);
+            if ((entry = tt_probe_perft(pos->key, depth))) {
+                printf("tt hit: depth=%d val=%lu",
+                       HASH_PERFT_DEPTH(entry->data),
+                       HASH_PERFT_VAL(entry->data));
+            } else {
+                tt_store_perft(pos->key, i + 1, depth);
+                printf("tt store: depth=%d val=%lu", depth, (u64)i * 123);
+            };
+
+            token = strtok(NULL, " \t");
+        }
+        printf("\n");
+        free(str);
+    }
+    return 0;
+}
+
+/* ccls bug report: https://github.com/emacs-lsp/emacs-ccls/issues/126
+ */
+/*
+ * int called(int), caller();
+ *
+ * /\**
+ *  * called() - test ccls.
+ *  * @x: int, the test value
+ *  *
+ *  * @called() description.
+ *  *
+ *  * @return: int, a very interesting value.
+ *  *\/
+ * int called(int x) { return x; }
+ *
+ * int caller()
+ * {
+ *     int i = 0;
+ *     called(int x)
+ *     return i;
+ * }
+ */