After a "stop" do not read new input until search finishes

[stockfish] / src / thread.cpp

diff --git a/src/thread.cpp b/src/thread.cpp
index 57faa6e90bb39b53ccff0a3cf3f5c6e84ef6f225..536f22c1194cf6912eb578f550cf1d298d21d959 100644 (file)
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -418,11 +418,28 @@ void Thread::main_loop() {
       if (do_terminate)
           return;
 
-      think(); // Search entry point
+      Search::think();
   }
 }
 
 
+// ThreadsManager::wait_end_of_search() blocks UI thread until main thread has
+// returned to sleep in main_loop(). It is needed becuase xboard sends immediately
+// new position to search after a "stop" due to ponder miss.
+
+void ThreadsManager::wait_end_of_search() {
+
+  Thread& main = threads[0];
+
+  lock_grab(&main.sleepLock);
+
+  while (!main.do_sleep)
+      cond_wait(&sleepCond, &main.sleepLock);
+
+  lock_release(&main.sleepLock);
+}
+
+
 // ThreadsManager::start_thinking() is used by UI thread to wake up the main
 // thread parked in main_loop() and starting a new search. If asyncMode is true
 // then function returns immediately, otherwise caller is blocked waiting for
@@ -432,11 +449,13 @@ void ThreadsManager::start_thinking(bool asyncMode) {
 
   Thread& main = threads[0];
 
+  // Wait main thread has finished before to launch a new search
+  wait_end_of_search();
+
   lock_grab(&main.sleepLock);
 
-  // Wait main thread has finished before to launch a new search
-  while (!main.do_sleep)
-      cond_wait(&sleepCond, &main.sleepLock);
+  // Reset signals before to start the search
+  memset((void*)&Search::Signals, 0, sizeof(Search::Signals));
 
   main.do_sleep = false;
   cond_signal(&main.sleepCond); // Wake up main thread
@@ -446,3 +465,25 @@ void ThreadsManager::start_thinking(bool asyncMode) {
 
   lock_release(&main.sleepLock);
 }
+
+
+// ThreadsManager::wait_for_stop_or_ponderhit() is called when the maximum depth
+// is reached while the program is pondering. The point is to work around a wrinkle
+// in the UCI protocol: When pondering, the engine is not allowed to give a
+// "bestmove" before the GUI sends it a "stop" or "ponderhit" command.
+// We simply wait here until one of these commands (that raise StopRequest) is
+// sent, and return, after which the bestmove and pondermove will be printed.
+
+void ThreadsManager::wait_for_stop_or_ponderhit() {
+
+  Search::Signals.stopOnPonderhit = true;
+
+  Thread& main = threads[0];
+
+  lock_grab(&main.sleepLock);
+
+  while (!Search::Signals.stop)
+      cond_wait(&main.sleepCond, &main.sleepLock);
+
+  lock_release(&main.sleepLock);
+}