Split search() in independent sections

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 775ad3effeddd7275f3f1769fa3bf350d8dcb412..ebd004d39c541d5632163ffe8817f113a6891f74 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1267,29 +1267,30 @@ namespace {
     if (depth < OnePly)
         return qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID);
 
-    // Initialize, and make an early exit in case of an aborted search,
-    // an instant draw, maximum ply reached, etc.
+    // Step 1. Initialize node and poll
+    // Polling can abort search.
     init_node(ss, ply, threadID);
 
-    // After init_node() that calls poll()
+    // Step 2. Check for aborted search and immediate draw
     if (AbortSearch || TM.thread_should_stop(threadID))
         return Value(0);
 
     if (pos.is_draw() || ply >= PLY_MAX - 1)
         return VALUE_DRAW;
 
-    // Mate distance pruning
+    // Step 3. Mate distance pruning
     if (value_mated_in(ply) >= beta)
         return beta;
 
     if (value_mate_in(ply + 1) < beta)
         return beta - 1;
 
+    // Step 4. Transposition table lookup
+
     // We don't want the score of a partial search to overwrite a previous full search
     // TT value, so we use a different position key in case of an excluded move exsists.
     Key posKey = excludedMove ? pos.get_exclusion_key() : pos.get_key();
 
-    // Transposition table lookup
     tte = TT.retrieve(posKey);
     ttMove = (tte ? tte->move() : MOVE_NONE);
 
@@ -1299,9 +1300,9 @@ namespace {
         return value_from_tt(tte->value(), ply);
     }
 
+    // Step 5. Evaluate the position statically
     isCheck = pos.is_check();
 
-    // Evaluate the position statically
     if (!isCheck)
     {
         if (tte && (tte->type() & VALUE_TYPE_EVAL))
@@ -1835,7 +1836,7 @@ namespace {
           if (ss[sp->ply].reduction)
           {
               value = -search(pos, ss, -(sp->beta-1), newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID);
-              doFullDepthSearch = (value >= sp->beta);
+              doFullDepthSearch = (value >= sp->beta && !TM.thread_should_stop(threadID));
           }
       }
 
@@ -1932,7 +1933,7 @@ namespace {
           {
               Value localAlpha = sp->alpha;
               value = -search(pos, ss, -localAlpha, newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID);
-              doFullDepthSearch = (value > localAlpha);
+              doFullDepthSearch = (value > localAlpha && !TM.thread_should_stop(threadID));
           }
       }
 
@@ -1942,16 +1943,14 @@ namespace {
           ss[sp->ply].reduction = Depth(0);
           value = -search(pos, ss, -localAlpha, newDepth, sp->ply+1, true, threadID);
 
-          if (value > localAlpha && value < sp->beta)
+          if (value > localAlpha && value < sp->beta && !TM.thread_should_stop(threadID))
           {
               // If another thread has failed high then sp->alpha has been increased
               // to be higher or equal then beta, if so, avoid to start a PV search.
               localAlpha = sp->alpha;
               if (localAlpha < sp->beta)
                   value = -search_pv(pos, ss, -sp->beta, -localAlpha, newDepth, sp->ply+1, threadID);
-              else
-                  assert(TM.thread_should_stop(threadID));
-        }
+          }
       }
       pos.undo_move(move);
 
@@ -2594,6 +2593,7 @@ namespace {
         // instead of wasting CPU time polling for work.
         while (AllThreadsShouldSleep || threadID >= ActiveThreads)
         {
+            assert(!waitSp);
             assert(threadID != 0);
             threads[threadID].state = THREAD_SLEEPING;
 
@@ -2960,12 +2960,9 @@ namespace {
     // This makes the threads to go to sleep
     AllThreadsShouldSleep = true;
 
-    // Wait for the threads to be all sleeping and reset flags
-    // to a known state.
+    // Reset flags to a known state.
     for (int i = 1; i < ActiveThreads; i++)
     {
-        while (threads[i].state != THREAD_SLEEPING);
-
         // This flag can be in a random state
         threads[i].printCurrentLineRequest = false;
     }