phase A

8 files changed, 122 insertions, 30 deletions

diff --git a/PLAN.md b/PLAN.md
index 2b3a05d..7581307 100644
--- a/PLAN.md
+++ b/PLAN.md
@@ -293,15 +293,15 @@ These are concrete, ordered steps. Each should be a single commit/patch and
 build (`just test`) green before the next.
 
 ### Phase A — Data-structure fixes
-- [ ] **A1.** In `include/engine/threads.h`, rename the duplicate
+- [x] **A1.** In `include/engine/threads.h`, rename the duplicate
       `move_t best_score` on `split_point_t` → `move_t best_move`.
-- [ ] **A2.** Finish `struct child_thread_args`: add
+- [x] **A2.** Finish `struct child_thread_args`: add
       `engine_message_handler_t *message;` field; remove or complete the
       dangling `int sp_stack;`.
-- [ ] **A3.** In `src/main.c`, add `ttable_init(&ipc_state.threads.ttable,
+- [x] **A3.** In `src/main.c`, add `ttable_init(&ipc_state.threads.ttable,
       <log2 of Hash option>)` before `threads_link` (use the `hash` spin option,
       default 256 → pick a sensible log2, e.g. 18 for ~256 MiB buckets, clamped).
-- [ ] **A4.** In `src/engine/threads.c`, make `__threads_args_init` copy
+- [x] **A4.** In `src/engine/threads.c`, make `__threads_args_init` copy
       `handler->ttable` and `handler->go_args` into each `thread_args_t`
       (currently `go_args`/`ttable` are set on `handler` but never propagated to
       per-thread args). Build + existing tests still pass.
diff --git a/build.c b/build.c
index d7914d1..5b73d58 100644
--- a/build.c
+++ b/build.c
@@ -8,7 +8,7 @@
 
 #define GLOBAL_INCLUDE "-Iinclude/"
 
-#define CC "gcc", "-fsanitize=address", "-g", GLOBAL_INCLUDE
+#define CC "gcc", "-fsanitize=address", "-g", "-pthread", GLOBAL_INCLUDE
 
 #define ENGINE_O "output/engine.o"
 #define UCI_O "output/uci.o"
diff --git a/include/engine/threads.h b/include/engine/threads.h
index b5f2163..da221a8 100644
--- a/include/engine/threads.h
+++ b/include/engine/threads.h
@@ -17,7 +17,7 @@ typedef struct split_point {
   atomic_int alpha, beta;
   atomic_int best_score;
   atomic_int workers;
-  move_t best_score;
+  move_t best_move;
 
   struct split_point *parent;
   int ply;
@@ -37,9 +37,10 @@ struct child_thread_args {
   int id;
   go_args_t *go_args;
 
-  position_t position;
+  position_t *position;
+  ttable_t *ttable;
   int sp_stack;
-  int 
+  engine_message_handler_t *message;
 };
 struct root_thread_args {
   // signal sent by threads manager
@@ -52,6 +53,7 @@ struct root_thread_args {
   position_t *position;
   go_args_t *go_args;
   engine_message_handler_t *message;
+  ttable_t *ttable;
 };
 
 typedef union {
diff --git a/src/engine/thread.c b/src/engine/thread.c
index 25e583e..912b70f 100644
--- a/src/engine/thread.c
+++ b/src/engine/thread.c
@@ -1,6 +1,20 @@
+#define ENGINE_THREADS_INTERNAL
 #include "engine/threads.h"
 #include <stdio.h>
 
+void threads_go(struct threads *handler) {
+  int running_count = handler->running_count;
+  for (int i = 0; i < running_count; i++) {
+    __threads_args_init(handler->args + i, handler, i);
+    pthread_create(
+      handler->threads + i,
+      NULL,
+      i == 0 ? root_thread : child_thread,
+      handler->args + i
+    );
+  }
+}
+
 void *child_thread(void *_args) {
   struct child_thread_args *args = (struct child_thread_args*)_args;
   args->stop = 0;
diff --git a/src/engine/threads.c b/src/engine/threads.c
index 541efb1..5bf630a 100644
--- a/src/engine/threads.c
+++ b/src/engine/threads.c
@@ -41,28 +41,18 @@ void threads_reserve(struct threads *handler, size_t capacity) {
   handler->capacity = capacity;
 }
 
-void threads_go(struct threads *handler) {
-  int running_count = handler->running_count;
-  for (int i = 0; i < running_count; i++) {
-    __threads_args_init(handler->args + i, handler, i);
-    pthread_create(
-      handler->threads + i,
-      NULL,
-      i == 0 ? root_thread : child_thread,
-      handler->args + i
-    );
-  }
-}
-
 bool threads_go_loop(struct threads *handler) {
   // idk maybe do something while waiting for calculations to flow in
+  return false;
 }
 
 bool threads_all_done(struct threads *handler) {
   int running_count = handler->running_count;
   assert(running_count > 0);
   for (int i = 0; i < running_count; i++) {
-    if (atomic_load(&handler->args[i].finished) == 1) continue;
+    // `finished` is part of the common initial sequence of both union
+    // members (stop, finished), so reading it via either member is well-defined.
+    if (atomic_load(&handler->args[i].root_thread_args.finished) == 1) continue;
     return false;
   }
   return true;
@@ -83,21 +73,93 @@ void __threads_args_init(
   int i
 ) {
   if (i > 0) {
-    struct child_thread_args *args = _args;
+    struct child_thread_args *args = (struct child_thread_args*)_args;
     atomic_init(&args->stop, 0);
     atomic_init(&args->finished, 0);
     args->id = i;
     args->position = handler->position;
     args->go_args = handler->go_args;
+    args->ttable = &handler->ttable;
+    args->sp_stack = 0;
     args->message = handler->engine_messages->data[i];
     return;
   }
 
-  struct root_thread_args *args = _args;
+  struct root_thread_args *args = (struct root_thread_args*)_args;
   atomic_init(&args->stop, 0);
   atomic_init(&args->finished, 0);
   args->id = i;
   args->position = handler->position;
   args->go_args = handler->go_args;
   args->message = handler->engine_messages->data[i];
+  args->ttable = &handler->ttable;
+}
+
+#ifdef TEST_MOD
+bool test_threads_args_init_root_propagates() {
+  engine_message_handler_t dummy[2];
+  engine_message_handler_t *dummy_ptrs[2] = { &dummy[0], &dummy[1] };
+  engine_messages_t messages = {
+    .data = dummy_ptrs,
+    .count = 2,
+    .capacity = 2,
+  };
+
+  go_args_t go_args = {0};
+  position_t pos = {0};
+
+  struct threads handler = {0};
+  handler.engine_messages = &messages;
+  handler.go_args = &go_args;
+  handler.position = &pos;
+  ttable_init(&handler.ttable, 2);
+
+  thread_args_t args;
+  __threads_args_init(&args, &handler, 0);
+
+  bool ok = true;
+  ok &= args.root_thread_args.id == 0;
+  ok &= atomic_load(&args.root_thread_args.stop) == 0;
+  ok &= atomic_load(&args.root_thread_args.finished) == 0;
+  ok &= args.root_thread_args.ttable == &handler.ttable;
+  ok &= args.root_thread_args.go_args == &go_args;
+  ok &= args.root_thread_args.position == &pos;
+  ok &= args.root_thread_args.message == &dummy[0];
+
+  ttable_deinit(handler.ttable);
+  return ok;
+}
+
+bool test_threads_args_init_child_propagates() {
+  engine_message_handler_t dummy[2];
+  engine_message_handler_t *dummy_ptrs[2] = { &dummy[0], &dummy[1] };
+  engine_messages_t messages = {
+    .data = dummy_ptrs,
+    .count = 2,
+    .capacity = 2,
+  };
+
+  go_args_t go_args = {0};
+  position_t pos = {0};
+
+  struct threads handler = {0};
+  handler.engine_messages = &messages;
+  handler.go_args = &go_args;
+  handler.position = &pos;
+  ttable_init(&handler.ttable, 2);
+
+  thread_args_t args;
+  __threads_args_init(&args, &handler, 1);
+
+  bool ok = true;
+  ok &= args.child_thread_args.id == 1;
+  ok &= args.child_thread_args.ttable == &handler.ttable;
+  ok &= args.child_thread_args.go_args == &go_args;
+  ok &= args.child_thread_args.position == &pos;
+  ok &= args.child_thread_args.message == &dummy[1];
+  ok &= args.child_thread_args.sp_stack == 0;
+
+  ttable_deinit(handler.ttable);
+  return ok;
 }
+#endif
diff --git a/src/main.c b/src/main.c
index 5ece480..61a3850 100644
--- a/src/main.c
+++ b/src/main.c
@@ -30,6 +30,14 @@ int main(int argc, char** argv) {
   threads_init(&engine_threads, ipc_state.uci_state.threads);
   threads_link(&engine_threads, &ipc_state);
 
+  // initialise the transposition table from the UCI "Hash" option (in MiB).
+  // pick the smallest power of two (>= 2^4) that fills at least that much memory.
+  size_t hash_mb = (size_t)ipc_state.uci_state.hash;
+  u64 buckets = (hash_mb * 1024 * 1024) / sizeof(tbucket_t);
+  int hash_log2 = 4;
+  while ((1ULL << (hash_log2 + 1)) <= buckets && hash_log2 < 30) hash_log2++;
+  ttable_init(&engine_threads.ttable, hash_log2);
+
   engine_messages_init(&ipc_state.engine_messages);
   goto skip_refresh;
 waiting_for_go:
diff --git a/src/uci/command.c b/src/uci/command.c
index 327e0e2..17a0c9a 100644
--- a/src/uci/command.c
+++ b/src/uci/command.c
@@ -6,7 +6,7 @@
 void uci_cmd_init(uci_cmd_t *cmd) {
   cmd->empty = true;
   cmd->args_capacity = 32;
-  cmd->args = calloc(sizeof(char) * MAX_TOKEN_SIZE, output.args_capacity);
+  cmd->args = calloc(sizeof(char) * MAX_TOKEN_SIZE, cmd->args_capacity);
 }
 
 bool is_valid_cmd(const char *token) {
@@ -91,7 +91,8 @@ void uci_cmd_deinit(uci_cmd_t cmd) {
 #include <string.h>
 
 bool test_uci_cmd_t() {
-  uci_cmd_t cmd = uci_cmd_init();
+  uci_cmd_t cmd;
+  uci_cmd_init(&cmd);
   uci_cmd_set_root(&cmd, "root");
   uci_cmd_append_arg(&cmd, "arg1");
   uci_cmd_append_arg(&cmd, "arg2");
diff --git a/tests/generated.c b/tests/generated.c
index a605554..8a9014f 100644
--- a/tests/generated.c
+++ b/tests/generated.c
@@ -1,11 +1,12 @@
 #include "../src/fen.c"
 #include "../src/engine/ttable.c"
+#include "../src/engine/threads.c"
 #include "../src/engine/moves.c"
 #include "../src/engine/moves/king.c"
 #include "../src/uci/command.c"
 
-int total_test_count = 17;
-bool (*tests[17])(void) = {
+int total_test_count = 19;
+bool (*tests[19])(void) = {
   test_fen_no_passant,
   test_fen_passant,
   test_starting_position,
@@ -16,6 +17,8 @@ bool (*tests[17])(void) = {
   test_bucket_collision,
   test_ttable_replace_shallowest,
   test_ttable_many_entries,
+  test_threads_args_init_root_propagates,
+  test_threads_args_init_child_propagates,
   test_perft_starting_position,
   test_perft_kiwipete_position,
   test_perft_position3,
@@ -25,8 +28,8 @@ bool (*tests[17])(void) = {
   test_invalid_cmd_uci_cmd_t,
 };
 
-int max_test_name_size = 25;
-char test_names[17][100] = {
+int max_test_name_size = 34;
+char test_names[19][100] = {
   "fen_no_passant",
   "fen_passant",
   "starting_position",
@@ -37,6 +40,8 @@ char test_names[17][100] = {
   "bucket_collision",
   "ttable_replace_shallowest",
   "ttable_many_entries",
+  "threads_args_init_root_propagates",
+  "threads_args_init_child_propagates",
   "perft_starting_position",
   "perft_kiwipete_position",
   "perft_position3",