From 5a02743c0c9563f41a8c3821a7bbce4fc3b0b839 Mon Sep 17 00:00:00 2001
From: Aargh Rai <aargh.rai+git@gmail.com>
Date: Thu, 27 Aug 2026 17:41:07 +0530
Subject: bug fixes

---
 include/engine/search.h  |  9 +++++++++
 include/engine/threads.h | 17 ++++++++++++++---
 2 files changed, 23 insertions(+), 3 deletions(-)

(limited to 'include/engine')

diff --git a/include/engine/search.h b/include/engine/search.h
index 94b5da5..506a4bc 100644
--- a/include/engine/search.h
+++ b/include/engine/search.h
@@ -33,4 +33,13 @@ search_result_t search(
   search_ctx_t *ctx
 );
 
+// Reconstruct the principal variation by following TT best-move entries.
+// Writes at most `max_len` moves into `pv_out`; returns the number written.
+int reconstruct_pv(
+  position_t position,
+  ttable_t tt,
+  move_t *pv_out,
+  int max_len
+);
+
 #endif // SEARCH_H
diff --git a/include/engine/threads.h b/include/engine/threads.h
index 1e63a5d..a511998 100644
--- a/include/engine/threads.h
+++ b/include/engine/threads.h
@@ -11,12 +11,17 @@
 
 enum { SPLITPOINT_STATE_FREE, SPLITPOINT_STATE_ACTIVE };
 enum { NODE_PV, NODE_CUT, NODE_ALL };
+
+// §2.1 thrashing guard: refuse HELP when nodes_searched < THRESHOLD at a
+// split point.  Prevents the end-of-iteration "N idle procs split 1 proc".
+enum { SPLITPOINT_THRASH_THRESHOLD = 256 };
 typedef struct split_point {
   atomic_int state;
   atomic_int next_move_idx;
   atomic_int alpha, beta;
   atomic_int best_score;
   atomic_int workers;
+  atomic_int nodes_searched; // §2.1 thrashing guard: refuse HELP when < threshold
   move_t best_move;
 
   struct split_point *parent;
@@ -60,12 +65,12 @@ struct root_thread_args {
   split_point_t *split_points; // shared DTS pool (§2.4)
   size_t sp_pool_capacity;
 
-  // the root stops its workers when the search completes
-  atomic_int *workers_stop;
+  // the root stops its workers when the search completes.
+  struct threads *handler;
   int workers_count;
 };
 
-typedef union {
+typedef union thread_args {
   struct child_thread_args child_thread_args;
   struct root_thread_args root_thread_args;
 } thread_args_t;
@@ -101,6 +106,10 @@ bool split_point_claim_move(split_point_t *split_point, move_t *move);
 bool split_point_merge(split_point_t *split_point);
 void split_point_share(split_point_t *split_point, i32 score, move_t move);
 
+// §2.1 thrashing guard: true if this split point has been searched enough
+// to be worth publishing for HELP.
+bool split_point_worth_sharing(split_point_t *split_point);
+
 // HELP (§2.3): scan the pool for a published split point with work left
 split_point_t *threads_find_work(struct threads *handler);
 split_point_t *__pool_find_work(split_point_t *pool, size_t capacity);
@@ -111,6 +120,8 @@ void threads_reserve(struct threads *handler, size_t capacity);
 void threads_go(struct threads *handler);
 bool threads_go_loop(struct threads *handler);
 bool threads_all_done(struct threads *handler);
+void threads_stop_all(struct threads *handler);
+void threads_join(struct threads *handler);
 void threads_cleanup(struct threads *handler);
 
 void *child_thread(void *args);
-- 
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