create (unused) thread.[ch] files.

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

Makefile

@@ -420,7 +420,7 @@ BB_OBJS       := $(FEN_OBJS)
 MOVEGEN_OBJS  := $(BB_OBJS) move-gen.o
 ATTACK_OBJS   := $(MOVEGEN_OBJS)
 MOVEDO_OBJS   := $(ATTACK_OBJS) move-do.o
-PERFT_OBJS    := $(MOVEDO_OBJS) search.o
+PERFT_OBJS    := $(MOVEDO_OBJS) perft.o
 TT_OBJS       := $(MOVEDO_OBJS)
 
 TEST          := $(addprefix $(BINDIR)/,$(TEST))

src/perft.c

@@ -0,0 +1,131 @@
+/* perft.c - perft functions.
+ *
+ * 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 "perft.h"
+#include "move-gen.h"
+#include "move-do.h"
+
+/**
+ * perft() - Perform perft on position
+ * @pos:    &position to search
+ * @depth:  Wanted depth.
+ * @ply:    current perft depth level (root = 1)
+ * @divide: 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 divide)
+{
+    u64 subnodes = 0, 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) {
+            subnodes = 1;
+        } else {
+            move_do(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 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);
+        }
+        nodes += subnodes;
+        if (ply == 1 && divide) {
+            char movestr[8];
+            printf("%s: %lu\n", move_to_str(movestr, *move, 0), subnodes);
+        }
+    }
+
+    return nodes;
+}
+
+/**
+ * perft_alt() - Perform perft on position, experimental version.
+ * @pos:    &position to search
+ * @depth:  Wanted depth.
+ * @ply:    current perft depth level (root = 1)
+ * @divide: 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 divide)
+{
+    u64 subnodes = 0, 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) {
+            subnodes = 1;
+        } 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, divide);
+            }
+            move_undo_alt(pos, *move, &state);
+        }
+        nodes += subnodes;
+        if (ply == 1 && divide) {
+            char movestr[8];
+            printf("%s: %lu\n", move_to_str(movestr, *move, 0), subnodes);
+        }
+    }
+
+    return nodes;
+}

src/perft.h

@@ -0,0 +1,22 @@
+/* perft.h.h - perft.
+ *
+ * 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 PERFT_H
+#define PERFT_H
+
+#include "position.h"
+
+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/search.c

@@ -1,4 +1,4 @@
-/* search.c - perft + search.
+/* search.c - search for perfect move.
  *
  * Copyright (C) 2023-2024 Bruno Raoult ("br")
  * Licensed under the GNU General Public License v3.0 or later.
@@ -21,117 +21,6 @@
 #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)
- * @divide: 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 divide)
-{
-    u64 subnodes = 0, 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) {
-            subnodes = 1;
-        } else {
-            move_do(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 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);
-        }
-        nodes += subnodes;
-        if (ply == 1 && divide) {
-            char movestr[8];
-            printf("%s: %lu\n", move_to_str(movestr, *move, 0), subnodes);
-        }
-    }
-
-    return nodes;
-}
-
-/**
- * perft_alt() - Perform perft on position, experimental version.
- * @pos:    &position to search
- * @depth:  Wanted depth.
- * @ply:    current perft depth level (root = 1)
- * @divide: 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 divide)
-{
-    u64 subnodes = 0, 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) {
-            subnodes = 1;
-        } 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, divide);
-            }
-            move_undo_alt(pos, *move, &state);
-        }
-        nodes += subnodes;
-        if (ply == 1 && divide) {
-            char movestr[8];
-            printf("%s: %lu\n", move_to_str(movestr, *move, 0), subnodes);
-        }
-    }
-
-    return nodes;
-}
-
 /**
  * negamax() - search position negamax.
  * @pos: &position to search

src/search.h

@@ -19,7 +19,4 @@
 //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/thread.c

@@ -0,0 +1,69 @@
+/* thread.c - thread 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 <stdio.h>
+
+#include <brlib.h>
+#include <pthread.h>
+#include <poll.h>
+#include <sys/socket.h>
+
+#include "thread.h"
+
+/* Still have to decide: thread or process ?
+ *
+ */
+thread_pool_t threadpool;
+
+/**
+ * thrd_create - initialize thrd.
+ */
+int thrd_create(__unused int num)
+{
+    int fd[2];
+    /* shall we make a communication channel via a pipe or socket ? */
+    int __unused ret = socketpair(AF_LOCAL, SOCK_SEQPACKET, PF_LOCAL, fd);
+    return 1;
+}
+
+/**
+ * thread_init - initialize thread pool.
+ */
+int thread_init(int nb)
+{
+    nb = clamp(nb, MIN_THRDS, MAX_THRDS);
+
+    /* stop unwanted threads, always keep 1 */
+    for (int i = nb + 1; i < threadpool.nb; ++i) {
+        printf("stopping thread %d - status = \n", i);
+        threadpool.thread[i].cmd = THRD_DO_QUIT;
+    }
+    for (int i = threadpool.nb; i < nb; ++i) {
+        printf("creating thread %d - status = \n", i);
+        thrd_create(i);
+
+    }
+
+    return nb;
+}
+
+/*
+  communication:
+  main thread -> thread
+           commands via memory
+  thread -> main thread
+           status via memory
+           output via pipe/socket
+  thread output will be output/filtered by main thread
+
+ */

src/thread.h

@@ -0,0 +1,55 @@
+/* thread.h - thread management.
+ *
+ * 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 THREAD_H
+#define THREAD_H
+
+#include <pthread.h>
+
+#include <brlib.h>
+
+#include "position.h"
+
+#define MIN_THRDS 1
+#define MAX_THRDS 16
+
+typedef enum {
+    THRD_DEAD,
+    THRD_IDLE,
+    THRD_WORKING,
+} thread_status_t;
+
+typedef enum {
+    /* main thread to subs */
+    THRD_DO_SEARCH,
+    THRD_DO_STOP,
+    THRD_DO_QUIT,
+} thread_cmd_t;
+
+typedef struct {
+    int id;
+    thread_status_t status;
+    thread_cmd_t cmd;
+    int fd[2];
+    pos_t pos;
+} thread_t;
+
+typedef struct {
+    int nb;
+    thread_t thread[MAX_THRDS + 1];
+} thread_pool_t;
+
+int thrd_create(__unused int num);
+int thread_init(int nb);
+
+#endif  /* THREAD_H */

src/uci.c

@@ -26,6 +26,7 @@
 #include "move-gen.h"
 #include "move-do.h"
 #include "search.h"
+#include "perft.h"
 #include "eval-defs.h"
 #include "uci.h"
 

test/perft-test.c

@@ -25,7 +25,7 @@
 #include "move.h"
 #include "move-do.h"
 #include "move-gen.h"
-#include "search.h"
+#include "perft.h"
 
 #include "common-test.h"