create (unused) thread.[ch] files.

I am still unsure if I will go for thread or process...

Makefile

@@ -39,9 +39,7 @@ OBJ       := $(addprefix $(OBJDIR)/,$(SRC_FN:.c=.o))
 TSTSRC    := $(wildcard $(TSTDIR)/*.c)
 
 LIB       := br_$(shell uname -m)                           # library name
-LIB       := $(strip $(LIB))
+LIBS      := $(strip -l$(LIB))
-LIBFILE   := ${BRLIBDIR}/lib$(strip ${LIB}).a
-LIBS      := $(addprefix -l,$(strip $(LIB)))
 
 DEP_FN    := $(SRC_FN)
 DEP       := $(addprefix $(DEPDIR)/,$(DEP_FN:.c=.d))
@@ -104,7 +102,7 @@ endif
 # if no version, use last commit and date.
 # else, if last commit != last tag commit, add commit and date to version number
 ifeq ($(VERSION),)
-  VERSION := $(build)-git.$(COMMIT)-$(DATE)
+  VERSION := $(build)-$(COMMIT)-$(DATE)
 else ifneq ($(COMMIT), $(TAG_COMMIT))
   VERSION := $(VERSION)-next-$(build)-$(COMMIT)-$(DATE)
 endif
@@ -126,14 +124,13 @@ else # ifeq ($(build),dev)
         #        fen.c
         #CPPFLAGS  += -DDEBUG_FEN                           # FEN decoding
         #        hash / TT
-        #CPPFLAGS  += -DZOBRIST_VERIFY                      # incr. zobrist check
+        #CPPFLAGS  += -DZOBRIST_VERIFY                      # double chk zobrist
         #CPPFLAGS  += -DPERFT_MOVE_HISTORY                  # perft, keep prev moves
         #        attack.c
         #CPPFLAGS  += -DDEBUG_ATTACK_ATTACKERS              # sq_attackers
         #CPPFLAGS  += -DDEBUG_ATTACK_PINNERS                # sq_pinners details
         #        eval.c eval-simple.c
-        CPPFLAGS  += -DDEBUG_EVAL                          # eval
+        CPPFLAGS  += -DDEBUG_EVAL                           # eval
-        CPPFLAGS  += -DPHASE_VERIFY                        # incr. phase check
 
         #        old unused flags
         #CPPFLAGS  += -DDEBUG_POS                           # position.c
@@ -347,7 +344,6 @@ brlib:
 	$(info calling with build=$(build))
 	$(MAKE) -e -C $(BRLIB) lib-static
 unexport build
-
 ##################################### brchess binaries
 .PHONY: targets cleanbin cleanbindir
 
@@ -359,9 +355,9 @@ cleanbin:
 cleanbindir:
 	$(call rmdir,$(BINDIR),binaries)
 
-$(TARGET): $(LIBFILE) $(OBJ) | $(BINDIR) libs
+$(TARGET): libs $(OBJ) | $(BINDIR)
 	@echo linking $@.
-	$(CC) $(ALL_LDFLAGS) $(OBJ) -o $@
+	$(CC) $(LDFLAGS) $(OBJ) $(LIBS) -o $@
 
 ##################################### pre-processed (.i) and assembler (.s) output
 .PHONY: cleanasmcpp
@@ -419,7 +415,7 @@ TEST          += movedo-test perft-test tt-test
 PIECE_OBJS    := piece.o
 FEN_OBJS      := $(PIECE_OBJS) fen.o position.o bitboard.o board.o \
 	hq.o attack.o hash.o init.o util.o alloc.o move.o \
-	eval.o eval-defs.o eval-simple.o hist.o
+	eval.o eval-defs.o eval-simple.o
 BB_OBJS       := $(FEN_OBJS)
 MOVEGEN_OBJS  := $(BB_OBJS) move-gen.o
 ATTACK_OBJS   := $(MOVEGEN_OBJS)
@@ -494,7 +490,6 @@ wtf:
 	@#echo LIBSRC=$(LIBSRC)
 
 zob:
-	echo $(LIBFILE)
 	@#$(CC) $(LDFLAGS) $(CPPFLAGS) $(CFLAGS) $< $(LIBS) src/util.c -o util
 
 ##################################### End of multi-targets

src/brchess.c

@@ -37,10 +37,10 @@ int main(int ac, char **av)
     pos_t *pos;
     int opt;
 
-    printf("brchess " VERSION "\n");
     init_all();
     pos = pos_new();
-    printf("Engine ready.\n");
+    hist_link(pos);
+    printf("\nWelcome to brchess " VERSION "\nEngine ready.\n");
 
     // size_t len = 0;
     // char *str = NULL;

src/chessdefs.h

@@ -85,9 +85,9 @@ typedef struct __movelist_s movelist_t;
 
 /* basic types
  */
+
 typedef u64 bitboard_t;
 typedef s16 eval_t;
-typedef s8 phase_t;
 
 /* forward enum definition is impossible in C11.
  * To simplify cross-dependancies, all important enum are moved here.

src/eval-defs.c

@@ -22,10 +22,6 @@
 //#include "eval-simple.h"
 //#include "eval.h"
 
-phase_t piece_phase[PIECE_TYPE_NB] = {
-    0, P_PHASE, N_PHASE, B_PHASE, R_PHASE, Q_PHASE, 0
-};
-
 /* eval parameters definition. */
 static const struct ev_params ev_param_def [EV_PARAMS_NB] = {
     /*                type      setable def   min    max  name */

src/eval-defs.h

@@ -14,6 +14,7 @@
 #ifndef EVAL_DEFS_H
 #define EVAL_DEFS_H
 
+
 #include "chessdefs.h"
 #include "piece.h"
 #include "eval.h"
@@ -25,6 +26,7 @@ enum {
     ENDGAME,
     PHASE_NB
 };
+typedef s16 phase_t;
 
 /* pieces weight in phase calculation.
  */
@@ -36,24 +38,18 @@ enum {
     Q_PHASE = 4,
     ALL_PHASE = P_PHASE*16 + N_PHASE*4 + B_PHASE*4 + R_PHASE*4 + Q_PHASE*2
 };
-extern phase_t piece_phase[PIECE_TYPE_NB];
-
-static inline phase_t pt_phase(piece_type_t pt)
-{
-    return piece_phase[pt];
-}
 
 /* max pieces eval is 9*QUEEN_VALUE + 2*ROOK_VALUE + 2*BISHOP_VALUE
  * + 2*KNIGHT_VALUE which is (for a pawn valued at 100) well less than 15,000.
  */
 #define EVAL_MAX     (SHRT_MAX)                   /* 32767 */
 #define EVAL_MIN     (-EVAL_MAX)
-#define EVAL_DRAW    0
+
 #define EVAL_INV     EVAL_MIN
 
 #define EVAL_MATE    30000
 
-/* engine parameters */
+/* eval parameters */
 enum {
     WT_MAT,
     WT_PST,

src/eval.c

@@ -19,50 +19,6 @@
 #include "position.h"
 #include "eval.h"
 #include "eval-simple.h"
-#include "hist.h"
-
-/**
- * calc_phase - calculate position phase
- * @pos: &position
- *
- * This function should be calculated when a new position is setup, or as
- * a verification of an incremental one.
- * Note: phase is *not* clamped, to avoid update errors.
- *
- * @return: phase value
- */
-phase_t calc_phase(pos_t *pos)
-{
-    int phase = ALL_PHASE;
-    for (piece_type_t pt = PAWN; pt < KING; ++pt)
-        phase -= piece_phase[pt] * popcount64(pos->bb[WHITE][pt] | pos->bb[BLACK][pt]);
-#   ifdef DEBUG_PHASE
-    printf("calc phase:%d\n", phase);
-#   endif
-    return phase;
-}
-
-/**
- * phase_verify() - verify position phase.
- * @pos: &position
- *
- * Verify that position phase is correct (a full recalculation is performed).
- * This function is inactive if PHASE_VERIFY is not set.
- *
- * @return: True if phase key is OK, no return otherwise.
- */
-#ifdef PHASE_VERIFY
-bool phase_verify(pos_t *pos)
-{
-    phase_t verif = calc_phase(pos);
-    if (pos->phase != verif) {
-        warn(true, "warn phase=%d verif=%d\n", pos->phase, verif);
-        hist_print(pos);
-        bug_on(pos->phase != verif);
-    }
-    return true;
-}
-#endif
 
 /**
  * calc_phase - calculate position phase
@@ -74,7 +30,7 @@ bool phase_verify(pos_t *pos)
  *
  * @return:
  */
-__unused static phase_t calc_phase2(pos_t *pos)
+s16 calc_phase(pos_t *pos)
 {
     int phase = ALL_PHASE;
     phase -= P_PHASE * popcount64(pos->bb[WHITE][PAWN]   | pos->bb[BLACK][PAWN]);
@@ -85,7 +41,7 @@ __unused static phase_t calc_phase2(pos_t *pos)
 
     phase = max(phase, 0);
 #   ifdef DEBUG_EVAL
-    printf("calc phase:%d verif=%d\n", phase, calc_phase(pos));
+    printf("calc phase:%d\n", phase);
 #   endif
     return phase;
 }

src/eval.h

@@ -19,12 +19,7 @@
 #include "chessdefs.h"
 #include "eval-defs.h"
 
-phase_t calc_phase(pos_t *pos);
+s16 calc_phase(pos_t *pos);
-#ifdef PHASE_VERIFY
-bool phase_verify(pos_t *pos);
-#else
-#define phase_verify(p) true
-#endif
 
 eval_t eval_mobility(pos_t *pos, bool color);
 eval_t eval_square_control(pos_t *pos, bool color);

src/fen.c

@@ -230,12 +230,12 @@ pos_t *fen2pos(pos_t *pos, const char *fen)
 
     /* 5) half moves since last capture or pawn move (50 moves rule)
      */
-    tmppos.ply50 = 0;
+    tmppos.clock_50 = 0;
     tmppos.plycount = 1;
     if (sscanf(cur, "%hd%n", &tmp, &consumed) != 1)
         goto end;                                 /* early end, ignore w/o err */
 
-    tmppos.ply50 = tmp;
+    tmppos.clock_50 = tmp;
     cur += consumed;
     SKIP_BLANK(cur);
 
@@ -350,7 +350,7 @@ char *pos2fen(const pos_t *pos, char *fen)
     /* 5) moves since last capture or pawn move (50 moves rule)
      * 6) current full move number, starting with 1
      */
-    sprintf(fen+cur, "%d %d", pos->ply50,
+    sprintf(fen+cur, "%d %d", pos->clock_50,
             1 + (pos->plycount - (pos->turn == BLACK)) / 2);
     return fen;
 }

src/hash.c

@@ -97,11 +97,12 @@ hkey_t zobrist_calc(pos_t *pos)
  * @pos: &position
  *
  * Verify that position Zobrist key matches a full Zobrist calculation.
- * This function is inactive if ZOBRIST_VERIFY is not set.
+ * This function cannot be called if ZOBRIST_VERIFY is not set.
  *
- * @return: True if Zobrist key is OK, no return otherwise.
+ * @return: True if Zobrist key is OK.
  */
 #ifdef ZOBRIST_VERIFY
+
 bool zobrist_verify(pos_t *pos)
 {
     hkey_t diff, key = zobrist_calc(pos);

src/hist.c

@@ -37,16 +37,6 @@ void hist_init(void)
     hist.state[0].prev = &hist.state[0];
 }
 
-/**
- * hist_next() - get next history slot.
- *
- * return: @state_t next history slot.
- */
-state_t *hist_next(void)
-{
-    return hist.state + hist.nstates++;
-}
-
 /**
  * hist_push() - add a state to hist list
  * @st:   &state_t to add
@@ -144,10 +134,9 @@ void hist_static_print(void)
 
     printf("UCI state history: ");
     while (true) {
-        printf("%s(#%lx r=%d) ",
+        printf("%s(#%lx) ",
                move_to_str(movestr, st->move, 0),
-               hash_short(st->key),
+               hash_short(st->key));
-               st->repcount);
         if (st == HIST_START)
             break;
         st = hist_prev(st);
@@ -165,10 +154,9 @@ void hist_print(pos_t *pos)
     state_t *st = &pos->state;
     printf("position states history: ");
     while (true) {
-        printf("%s(#%lx r=%d) ",
+        printf("%s(#%lx) ",
                move_to_str(movestr, st->move, 0),
-               hash_short(st->key),
+               hash_short(st->key));
-               st->repcount);
         if (st == HIST_START)
             break;
         st = hist_prev(st);

src/hist.h

@@ -48,7 +48,6 @@ extern hist_t hist;
 #define HIST_START  (hist.state)
 
 void hist_init(void);
-state_t *hist_next(void);
 void hist_push(state_t *st); //, move_t *move);
 void hist_link(pos_t *pos);
 state_t *hist_pop(void);

src/move-do.c

@@ -24,7 +24,6 @@
 #include "position.h"
 #include "move-do.h"
 #include "hash.h"
-#include "hist.h"
 
 /**
  * move_do() - do move.
@@ -60,16 +59,14 @@ pos_t *move_do(pos_t *pos, const move_t move, state_t *state)
     hkey_t key = pos->key;
 
     *state = pos->state;                          /* save irreversible changes */
-    pos->prev = state;
 
     /* 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->ply50;
+    ++pos->clock_50;
     ++pos->plycount;
-    ++pos->plyroot;
     pos->en_passant = SQUARE_NONE;
     pos->turn = them;
     pos->captured = captured;
@@ -79,21 +76,16 @@ pos_t *move_do(pos_t *pos, const move_t move, state_t *state)
 
     if (is_promotion(move)) {
         bug_on(sq_rank(to) != sq_rel_rank(RANK_8, us));
-        piece_t promoted = move_promoted(move);
+        new_piece = MAKE_PIECE(move_promoted(move), us);
-        new_piece = MAKE_PIECE(promoted, us);
-        pos->phase += pt_phase(PAWN) - pt_phase(promoted);
     }
 
     if (captured != EMPTY) {
-        pos->ply50 = 0;
+        pos->clock_50 = 0;
-        pos->phase += pt_phase(PIECE(captured));
+        bug_on(pos->board[to] == EMPTY || COLOR(pos->captured) != them);
-
-        bug_on(COLOR(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 (to > from) {
             rookfrom = sq_rel(H1, us);
             rookto = sq_rel(F1, us);
@@ -107,10 +99,9 @@ pos_t *move_do(pos_t *pos, const move_t move, state_t *state)
         pos_clr_sq(pos, rookfrom);
         pos->castle = clr_castle(pos->castle, us);
     } else if (ptype == PAWN) {                   /* pawn non capture or e.p. */
-        pos->ply50 = 0;
+        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)];
@@ -118,8 +109,6 @@ pos_t *move_do(pos_t *pos, const move_t move, state_t *state)
         } else if (is_enpassant(move)) {          /* clear grabbed pawn */
             square_t grabbed = to - up;
             piece_t pc = pos->board[grabbed];
-
-            pos->phase += pt_phase(PAWN);
             key ^= zobrist_pieces[pc][grabbed];
             pos_clr_sq(pos, grabbed);
         }
@@ -162,13 +151,7 @@ pos_t *move_do(pos_t *pos, const move_t move, state_t *state)
 
     pos->key = key;
 
-    pos->repcount = pos_repcount(pos);
-
-    /* consistency checks.
-     * Checks done only if compiled with '-DZOBRIST_VERIFY' or '-DPHASE_VERIFY'
-     */
     zobrist_verify(pos);
-    phase_verify(pos);
 
     return pos;
 }
@@ -226,8 +209,6 @@ pos_t *move_undo(pos_t *pos, const move_t move, const state_t *state)
 
     pos->state = *state;                          /* restore irreversible changes */
     pos->turn = us;
-    --pos->plycount;
-    --pos->plyroot;
     return pos;
 }
 
@@ -246,16 +227,14 @@ pos_t *move_do_alt(pos_t *pos, const move_t move, state_t *state)
     hkey_t key = pos->key;
 
     *state = pos->state;                          /* save irreversible changes */
-    pos->prev = state;
 
     /* 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->ply50;
+    ++pos->clock_50;
     ++pos->plycount;
-    ++pos->plyroot;
     pos->en_passant = SQUARE_NONE;
     pos->turn = them;
     pos->captured = captured;
@@ -269,7 +248,8 @@ pos_t *move_do_alt(pos_t *pos, const move_t move, state_t *state)
     }
 
     if (captured != EMPTY) {
-        pos->ply50 = 0;
+        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 */
@@ -288,7 +268,7 @@ pos_t *move_do_alt(pos_t *pos, const move_t move, state_t *state)
         pos_clr_sq(pos, rookfrom);
         pos->castle = clr_castle(pos->castle, us);
     } else if (ptype == PAWN) {                   /* pawn non capture or e.p. */
-        pos->ply50 = 0;
+        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]) {
@@ -340,7 +320,6 @@ pos_t *move_do_alt(pos_t *pos, const move_t move, state_t *state)
 
     pos->key = key;
 
-    pos->repcount = pos_repcount(pos);
     zobrist_verify(pos);
 
     return pos;
@@ -382,7 +361,5 @@ pos_t *move_undo_alt(pos_t *pos, const move_t move, const state_t *state)
 
     pos->state = *state;                          /* restore irreversible changes */
     pos->turn = us;
-    --pos->plycount;
-    --pos->plyroot;
     return pos;
 }

src/move-gen.c

@@ -480,18 +480,3 @@ finish:
     return movelist;
     //return movelist->nmoves = moves - movelist->move;
 }
-
-/**
- * pos_gen_legal() - generate position legal moves
- * @pos: position
- * @movelist: &movelist_t array to store moves
- *
- * Generate all @pos legal moves for player-to-move.
- * @movelist is filled with the moves.
- *
- * @Return: movelist
- */
-movelist_t *pos_gen_legal(pos_t *pos, movelist_t *movelist)
-{
-    return pos_legal(pos, pos_gen_pseudo(pos, movelist));
-}

src/move-gen.h

@@ -27,6 +27,5 @@ movelist_t *pos_legal_dup(const pos_t *pos, movelist_t *pseudo, movelist_t *lega
 movelist_t *pos_legal(const pos_t *pos, movelist_t *list);
 
 movelist_t *pos_gen_pseudo(pos_t *pos, movelist_t *movelist);
-movelist_t *pos_gen_legal(pos_t *pos, movelist_t *movelist);
 
 #endif  /* MOVEGEN_H */

src/perft.c

@@ -19,84 +19,6 @@
 #include "move-gen.h"
 #include "move-do.h"
 
-/**
- * do_perft() - perft engine
- * @pos:    &position to search
- * @depth:  Wanted depth.
- *
- * Run perft on a position.
- *
- * This version uses the algorithm:
- *    gen legal moves
- *    if last depth
- *      return number of legal move
- *    loop for legal move
- *      do-move
- *      if depth == 2
- *
- *      do_perft (depth -1)
- *      undo-move
- *
- * @return: total moves found at @depth level.
- */
-static u64 do_perft(pos_t *pos, int depth)
-{
-    u64 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));
-
-    //if (depth == 1)
-    //    return movelist.nmoves;
-
-    last = movelist.move + movelist.nmoves;
-    switch (depth) {
-        case 1:
-            /* This case could be removed if 'case 2' is handled in perft()
-             */
-            return movelist.nmoves;
-            break;
-        case 2:
-            /* For depth 2, we directly calculate the possible legal moves
-             * after each possible moves.
-             */
-            for (move = movelist.move; move < last; ++move) {
-                move_do(pos, *move, &state);
-                movelist_t movelist2;
-                pos_set_checkers_pinners_blockers(pos);
-                nodes += pos_legal(pos, pos_gen_pseudo(pos, &movelist2))->nmoves;
-                move_undo(pos, *move, &state);
-            }
-            break;
-        default:
-            /* Default: Search in TT for same key+depth. Use it if found, create
-             * it otherwise.
-             */
-            for (move = movelist.move; move < last; ++move) {
-                move_do(pos, *move, &state);
-                hentry_t *entry = tt_probe_perft(pos->key, depth);
-                if (entry != TT_MISS) {
-                    nodes += HASH_PERFT_VAL(entry->data);
-                } else {
-                    u64 subnodes = do_perft(pos, depth - 1);
-                    tt_store_perft(pos->key, depth, subnodes);
-                    nodes += subnodes;
-                }
-                move_undo(pos, *move, &state);
-            }
-            //} else {
-            //subnodes = do_perft(pos, depth - 1);
-    }
-        //move_undo(pos, *move, &state);
-        //nodes += subnodes;
-    //}
-
-    return nodes;
-}
-
 /**
  * perft() - Perform perft on position
  * @pos:    &position to search
@@ -118,7 +40,7 @@ static u64 do_perft(pos_t *pos, int depth)
  *
  * @return: total moves found at @depth level.
  */
-u64 perft(pos_t *pos, int depth, bool divide)
+u64 perft(pos_t *pos, int depth, int ply, bool divide)
 {
     u64 subnodes = 0, nodes = 0;
     movelist_t movelist;
@@ -134,15 +56,30 @@ u64 perft(pos_t *pos, int depth, bool divide)
             subnodes = 1;
         } else {
             move_do(pos, *move, &state);
-            subnodes = do_perft(pos, depth - 1);
+            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 >= 3) {
+                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, divide);
+                    tt_store_perft(pos->key, depth, subnodes);
+                }
+            } else {
+                subnodes = perft(pos, depth - 1, ply + 1, divide);
+            }
             move_undo(pos, *move, &state);
         }
-        if (divide) {
+        nodes += subnodes;
+        if (ply == 1 && divide) {
             char movestr[8];
             printf("%s: %lu\n", move_to_str(movestr, *move, 0), subnodes);
         }
-        nodes += subnodes;
     }
+
     return nodes;
 }
 

src/perft.h

@@ -16,7 +16,7 @@
 
 #include "position.h"
 
-u64 perft(pos_t *pos, int depth,/* int ply,*/ bool divide);
+u64 perft(pos_t *pos, int depth, int ply, bool output);
 u64 perft_alt(pos_t *pos, int depth, int ply, bool output);
 
 #endif  /* PERFT_H */

src/position.c

@@ -108,7 +108,6 @@ pos_t *pos_clear(pos_t *pos)
 
     pos->king[WHITE] = SQUARE_NONE;
     pos->king[BLACK] = SQUARE_NONE;
-    pos->prev = HIST_START;
 
     return pos;
 }
@@ -131,7 +130,7 @@ bool pos_cmp(const pos_t *pos1, const pos_t *pos2)
 
     /* move_do/undo position state */
     if (_cmpf(key) || _cmpf(en_passant) || _cmpf(castle) ||
-        _cmpf(ply50) || _cmpf(plycount) || _cmpf(captured))
+        _cmpf(clock_50) || _cmpf(plycount) || _cmpf(captured))
         goto end;
 
     if (_cmpf(checkers) || _cmpf(pinners) || _cmpf(blockers))
@@ -181,36 +180,6 @@ bitboard_t pos_checkers(const pos_t *pos, const color_t color)
     return sq_attackers(pos, occ, pos->king[color], OPPONENT(color));
 }
 
-/**
- * pos_repcount() - return position repetition count.
- * @pos: &position to search
- *
- * Attention: positions before (and including) root position repcount are
- * already decreased by one. See do_moves() in uci.c.
- *
- * @return: The number of repetitions in history, zero otherwise.
- */
-u8 pos_repcount(pos_t *pos)
-{
-    int c50 = pos->ply50;
-    state_t *st = &pos->state;
-    hkey_t key = pos->key;
-
-    st = hist_prev4(st);
-    //printf("is rep: START=%p ", HIST_START);
-    //printf("state=%p diff=%zd c50=%d k1=%#lx k2=%#lx\n",
-    //       st, st - HIST_START, c50, hash_short(pos->key), hash_short(st->key));
-
-    /* attention, what about root position ? Isn't it dangerous to compare with
-     * its key ? like: st->prev != HIST_START
-     */
-    for (; c50 >= 0 && st != HIST_START; st = hist_prev2(st), c50 -= 2) {
-        if (key == st->key)
-            return st->repcount + 1;
-    }
-    return false;
-}
-
 /**
  * pos_set_checkers_pinners_blockers() - calculate checkers, pinners and blockers.
  * @pos:   &position

src/position.h

@@ -27,7 +27,6 @@
 #include "piece.h"
 #include "move.h"
 #include "board.h"
-#include "eval-defs.h"
 
 typedef struct __pos_s {
     u64 node_count;                               /* evaluated nodes */
@@ -51,14 +50,14 @@ typedef struct __pos_s {
 
                         /* 16 bits */
                         move_t move;
+                        u16 plycount;             /* plies so far, start from 1 */
+                        s16 phase;
 
                         /* 8 bits */
                         square_t en_passant;
                         castle_rights_t castle;
                         piece_t captured;         /* only used in move_undo */
-                        phase_t phase;
+                        u8 clock_50;
-                        u8 ply50;
-                        u8 repcount;              /* repetition count */
         );
     eval_t eval;
     bitboard_t checkers;                          /* opponent checkers */
@@ -67,8 +66,6 @@ typedef struct __pos_s {
     piece_t board[BOARDSIZE];
     bitboard_t bb[2][PT_NB];                      /* bb[0][PAWN], bb[1][ALL_PIECES] */
     square_t king[2];                             /* dup with bb, faster retrieval */
-    u16 plycount;                                 /* plies in game, start from 1 */
-    u8 plyroot;                                   /* plies since search root. root=0 */
 } pos_t;
 
 typedef struct state_s state_t;
@@ -186,7 +183,6 @@ void pos_del(pos_t *pos);
 pos_t *pos_clear(pos_t *pos);
 bool pos_cmp(const pos_t *pos1, const pos_t *pos2);
 
-u8 pos_repcount(pos_t *pos);
 void pos_set_checkers_pinners_blockers(pos_t *pos);
 void pos_set_pinners_blockers(pos_t *pos);
 bitboard_t pos_checkers(const pos_t *pos, const color_t color);

src/search.c

@@ -20,21 +20,6 @@
 #include "move-do.h"
 #include "search.h"
 #include "attack.h"
-#include "hist.h"
-
-/**
- * is_draw() - check if position is draw by 50 or repetition rule.
- * @pos: &position to search
- *
- * Note that states before (and including) root position state have
- * their repcount decreased by one.
- *
- * @return: The @pos negamax evaluation.
- */
-bool is_draw(pos_t *pos)
-{
-    return (pos->ply50 > 100 || pos->repcount);
-}
 
 /**
  * negamax() - search position negamax.
@@ -47,36 +32,34 @@ bool is_draw(pos_t *pos)
  *
  * @return: The @pos negamax evaluation.
  */
-eval_t negamax(pos_t *pos, int depth, int color)
+/*
-{
+ * eval_t negamax(pos_t *pos, int depth, int color)
-    move_t *move, *last;
+ * {
-    state_t state;
+ *     move_t *move;
-    eval_t best = EVAL_MIN, score;
+ *     pos_t *newpos;
-    movelist_t movelist;
+ *     eval_t best = EVAL_MIN, score;
-
+ *
-    pos->node_count++;
+ *     pos->node_count++;
-    if (depth == 0) {
+ *     if (depth == 0) {
-        score = eval(pos) * color;
+ *         moves_gen_all_nomoves(pos);
-        return score;
+ *         score = eval(pos) * color;
-    }
+ *         return score;
-    pos_set_checkers_pinners_blockers(pos);
+ *     }
-    pos_gen_legal(pos, &movelist);
+ *     moves_gen_all(pos);
-    last = movelist.move + movelist.nmoves;
+ *     list_for_each_entry(move, &pos->moves[pos->turn], list) {
-    //moves_gen_all(pos);
+ *         newpos = move_do(pos, move);
-    for (move = movelist.move; move < last; ++move) {
+ *         score = -negamax(newpos, depth - 1, -color);
-        //list_for_each_entry(move, &pos->moves[pos->turn], list) {
+ *         pos->node_count += newpos->node_count;
-        move_do(pos, *move, &state);
+ *         move->negamax = score;
-        score = -negamax(pos, depth - 1, -color);
+ *         if (score > best) {
-        pos->node_count += pos->node_count;
+ *             best = score;
-        //move->negamax = score;
+ *             pos->bestmove = move;
-        if (score > best) {
+ *         }
-            best = score;
+ *         move_undo(newpos, move);
-            pos->eval = best;
+ *     }
-        }
+ *     return best;
-        move_undo(pos, *move, &state);
+ * }
-    }
+ */
-    return best;
-}
 
 
 /**

src/search.h

@@ -16,7 +16,6 @@
 
 #include "position.h"
 
-bool is_draw(pos_t *pos);
 //eval_t negamax(pos_t *pos, int depth, int color);
 //eval_t pvs(pos_t *pos, int depth, int alpha, int beta, int color);
 

src/thread.c

@@ -25,7 +25,6 @@
  */
 thread_pool_t threadpool;
 
-
 /**
  * thrd_create - initialize thrd.
  */

src/uci.c

@@ -370,7 +370,7 @@ int do_position(pos_t *pos, char *arg)
     }
     /* link last position t history */
     //hist_pop();
-    //hist_link(pos);
+    hist_link(pos);
     return 1;
 }
 
@@ -378,8 +378,8 @@ int do_moves(__unused pos_t *pos, char *arg)
 {
     char *saveptr = NULL, *token, check[8];
     move_t move;
+    state_t state;
     movelist_t movelist;
-
     saveptr = NULL;
     token = strtok_r(arg, " ", &saveptr);
     while (token) {
@@ -395,26 +395,13 @@ int do_moves(__unused pos_t *pos, char *arg)
             return 1;
         }
         //printf("move: %s\n", move_to_str(check, move, 0));
-        //hist_push(&pos->state);                   /* push previous state */
+        hist_push(&pos->state);                   /* push previous state */
-        move_do(pos, move, hist_next());
+        move_do(pos, move, &state);
-        printf("repet=%d\n", pos->repcount);
+        pos_print(pos);
-        //if (is_repetition(pos))
-        //    printf("rep detected\n");
-        //else if(is_draw(pos))
-        //    printf("draw detected\n");
         hist_static_print();
         token = strtok_r(NULL, " ", &saveptr);
     }
-    /* reset position root, and decrease history moves repcounts.
+    //hist_static_print();
-     * TODO: Maybe use "ucinewgame" to decide when to perform this decrease ?
-     */
-    pos->plyroot = 0;
-    for (state_t *st = &pos->state; st != HIST_START; st = hist_prev(st)) {
-        //printf("adjust rep=%d->\n");
-        st->repcount = max(0, st->repcount - 1);
-    }
-    pos_print(pos);
-    hist_print(pos);
     return 1;
 }
 
@@ -442,7 +429,7 @@ int do_perft(__unused pos_t *pos, __unused char *arg)
     printf("perft: divide=%d alt=%d depth=%d\n", divide, alt, depth);
     if (depth > 0) {
         if (!alt)
-            perft(pos, depth, divide);
+            perft(pos, depth, 1, divide);
         else
             perft_alt(pos, depth, 1, divide);
     }
@@ -451,7 +438,7 @@ int do_perft(__unused pos_t *pos, __unused char *arg)
 
 int do_hist(__unused pos_t *pos, __unused char *arg)
 {
-    hist_print(pos);
+    hist_static_print();
     return 0;
 }
 

test/perft-test.c

@@ -364,7 +364,7 @@ int main(int ac, char**av)
 
         if (run & 1) {
             clock_start(&clock);
-            my_count = perft(pos, depth, divide);
+            my_count = perft(pos, depth, 1, divide);
             ms = clock_elapsed_ms(&clock);
             if (!ms) {
                 res[0].skipped++;