X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=d54c7ebd91fbcc5379974d7556bf14a86fff2f8a;hp=df74d580ec2b954cd346b310438a976b9819bbca;hb=dac1bcab9007e0fe4c73fda4d6e5ac5b9add435c;hpb=5ed0a60203c1c93c5630894b4eca1f801241fe27

diff --git a/src/search.cpp b/src/search.cpp
index df74d580..d54c7ebd 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1643,7 +1643,7 @@ namespace {
     StateInfo st;
     Move ttMove, move;
     Value staticValue, bestValue, value, futilityBase, futilityValue;
-    bool isCheck, enoughMaterial, moveIsCheck;
+    bool isCheck, enoughMaterial, moveIsCheck, evasionPrunable;
     const TTEntry* tte = NULL;
     int moveCount = 0;
     bool pvNode = (beta - alpha != 1);
@@ -1744,8 +1744,15 @@ namespace {
           }
       }
 
-      // Don't search captures and checks with negative SEE values
-      if (   !isCheck
+      // Detect blocking evasions that are candidate to be pruned
+      evasionPrunable =   isCheck
+                       && bestValue != -VALUE_INFINITE
+                       && !pos.move_is_capture(move)
+                       && pos.type_of_piece_on(move_from(move)) != KING
+                       && !pos.can_castle(pos.side_to_move());
+
+      // Don't search moves with negative SEE values
+      if (   (!isCheck || evasionPrunable)
           &&  move != ttMove
           && !move_is_promotion(move)
           &&  pos.see_sign(move) < 0)
@@ -1813,7 +1820,7 @@ namespace {
     assert(threadID >= 0 && threadID < ActiveThreads);
     assert(ActiveThreads > 1);
 
-    Position pos = Position(sp->pos);
+    Position pos(*sp->pos);
     CheckInfo ci(pos);
     SearchStack* ss = sp->sstack[threadID];
     Value value = -VALUE_INFINITE;
@@ -1955,7 +1962,7 @@ namespace {
     assert(threadID >= 0 && threadID < ActiveThreads);
     assert(ActiveThreads > 1);
 
-    Position pos = Position(sp->pos);
+    Position pos(*sp->pos);
     CheckInfo ci(pos);
     SearchStack* ss = sp->sstack[threadID];
     Value value = -VALUE_INFINITE;
@@ -2950,7 +2957,6 @@ namespace {
     assert(ActiveThreads > 1);
 
     SplitPoint* splitPoint;
-    int i;
 
     lock_grab(&MPLock);
 
@@ -2967,7 +2973,7 @@ namespace {
     splitPoint = SplitPointStack[master] + Threads[master].activeSplitPoints;
     Threads[master].activeSplitPoints++;
 
-    // Initialize the split point object and copy current position
+    // Initialize the split point object
     splitPoint->parent = Threads[master].splitPoint;
     splitPoint->finished = false;
     splitPoint->ply = ply;
@@ -2981,37 +2987,40 @@ namespace {
     splitPoint->mp = mp;
     splitPoint->moves = *moves;
     splitPoint->cpus = 1;
-    splitPoint->pos.copy(p);
+    splitPoint->pos = &p;
     splitPoint->parentSstack = sstck;
-    for (i = 0; i < ActiveThreads; i++)
+    for (int i = 0; i < ActiveThreads; i++)
         splitPoint->slaves[i] = 0;
 
-    // Copy the current search stack to the master thread
-    memcpy(splitPoint->sstack[master], sstck, (ply+1) * sizeof(SearchStack));
+    Threads[master].idle = false;
+    Threads[master].stop = false;
     Threads[master].splitPoint = splitPoint;
 
-    // Make copies of the current position and search stack for each thread
-    for (i = 0; i < ActiveThreads && splitPoint->cpus < MaxThreadsPerSplitPoint; i++)
+    // Allocate available threads setting idle flag to false
+    for (int i = 0; i < ActiveThreads && splitPoint->cpus < MaxThreadsPerSplitPoint; i++)
         if (thread_is_available(i, master))
         {
-            memcpy(splitPoint->sstack[i], sstck, (ply+1) * sizeof(SearchStack));
+            Threads[i].idle = false;
+            Threads[i].stop = false;
             Threads[i].splitPoint = splitPoint;
             splitPoint->slaves[i] = 1;
             splitPoint->cpus++;
         }
 
+    assert(splitPoint->cpus > 1);
+
+    // We can release the lock because master and slave threads are already booked
+    lock_release(&MPLock);
+
     // Tell the threads that they have work to do. This will make them leave
-    // their idle loop.
-    for (i = 0; i < ActiveThreads; i++)
+    // their idle loop. But before copy search stack tail for each thread.
+    for (int i = 0; i < ActiveThreads; i++)
         if (i == master || splitPoint->slaves[i])
         {
-            Threads[i].workIsWaiting = true;
-            Threads[i].idle = false;
-            Threads[i].stop = false;
+            memcpy(splitPoint->sstack[i] + ply - 1, sstck + ply - 1, 3 * sizeof(SearchStack));
+            Threads[i].workIsWaiting = true; // This makes the slave to exit from idle_loop()
         }
 
-    lock_release(&MPLock);
-
     // Everything is set up. The master thread enters the idle loop, from
     // which it will instantly launch a search, because its workIsWaiting
     // slot is 'true'.  We send the split point as a second parameter to the