X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=21b669c42ef53b1ae987caf5f85253d7da853666;hp=cfa737dbd6773bf72cd460a19eb71f9b143232e1;hb=82ad9ce9cfb0eff33f1d781f329f7c5dc0b277eb;hpb=95ba7f78d5e025499ec8124e37e9f3b769660e4a;ds=sidebyside

diff --git a/src/search.cpp b/src/search.cpp
index cfa737db..21b669c4 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -84,11 +84,10 @@ namespace {
     return d > 17 ? 0 : 29 * d * d + 138 * d - 134;
   }
 
-  // Add a small random component to draw evaluations to keep search dynamic
-  // and to avoid 3fold-blindness.
+  // Add a small random component to draw evaluations to avoid 3fold-blindness
   Value value_draw(Depth depth, Thread* thisThread) {
     return depth < 4 ? VALUE_DRAW
-                     : VALUE_DRAW + Value(2 * (thisThread->nodes.load(std::memory_order_relaxed) % 2) - 1);
+                     : VALUE_DRAW + Value(2 * (thisThread->nodes & 1) - 1);
   }
 
   // Skill structure is used to implement strength limit
@@ -162,12 +161,12 @@ void Search::clear() {
   Time.availableNodes = 0;
   TT.clear();
   Threads.clear();
-  Tablebases::init(Options["SyzygyPath"]); // Free up mapped files
+  Tablebases::init(Options["SyzygyPath"]); // Free mapped files
 }
 
 
-/// MainThread::search() is called by the main thread when the program receives
-/// the UCI 'go' command. It searches from the root position and outputs the "bestmove".
+/// MainThread::search() is started when the program receives the UCI 'go'
+/// command. It searches from the root position and outputs the "bestmove".
 
 void MainThread::search() {
 
@@ -221,8 +220,9 @@ void MainThread::search() {
   if (Limits.npmsec)
       Time.availableNodes += Limits.inc[us] - Threads.nodes_searched();
 
-  // Check if there are threads with a better score than main thread
   Thread* bestThread = this;
+
+  // Check if there are threads with a better score than main thread
   if (    Options["MultiPV"] == 1
       && !Limits.depth
       && !Skill(Options["Skill Level"]).enabled()
@@ -273,9 +273,9 @@ void MainThread::search() {
 
 void Thread::search() {
 
-  // To allow access to (ss-5) up to (ss+2), the stack must be oversized.
+  // To allow access to (ss-7) up to (ss+2), the stack must be oversized.
   // The former is needed to allow update_continuation_histories(ss-1, ...),
-  // which accesses its argument at ss-4, also near the root.
+  // which accesses its argument at ss-6, also near the root.
   // The latter is needed for statScores and killer initialization.
   Stack stack[MAX_PLY+10], *ss = stack+7;
   Move  pv[MAX_PLY+1];
@@ -317,7 +317,7 @@ void Thread::search() {
           : Options["Analysis Contempt"] == "Black" && us == WHITE ? -ct
           : ct;
 
-  // In evaluate.cpp the evaluation is from the white point of view
+  // Evaluation score is from the white point of view
   contempt = (us == WHITE ?  make_score(ct, ct / 2)
                           : -make_score(ct, ct / 2));
 
@@ -832,8 +832,7 @@ namespace {
     }
 
     // Step 11. Internal iterative deepening (~2 Elo)
-    if (    depth >= 8 * ONE_PLY
-        && !ttMove)
+    if (depth >= 8 * ONE_PLY && !ttMove)
     {
         search<NT>(pos, ss, alpha, beta, depth - 7 * ONE_PLY, cutNode);
 
@@ -847,6 +846,7 @@ moves_loop: // When in check, search starts from here
     const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory,
                                           nullptr, (ss-4)->continuationHistory,
                                           nullptr, (ss-6)->continuationHistory };
+
     Move countermove = thisThread->counterMoves[pos.piece_on(prevSq)][prevSq];
 
     MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory,
@@ -854,8 +854,8 @@ moves_loop: // When in check, search starts from here
                                       contHist,
                                       countermove,
                                       ss->killers);
-    value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
 
+    value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
     moveCountPruning = false;
     ttCapture = ttMove && pos.capture_or_promotion(ttMove);
 
@@ -946,7 +946,7 @@ moves_loop: // When in check, search starts from here
           && bestValue > VALUE_MATED_IN_MAX_PLY)
       {
           // Skip quiet moves if movecount exceeds our FutilityMoveCount threshold
-          moveCountPruning = moveCount >= futility_move_count(improving,depth / ONE_PLY);
+          moveCountPruning = moveCount >= futility_move_count(improving, depth / ONE_PLY);
 
           if (   !captureOrPromotion
               && !givesCheck