X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.h;h=84a4b9faec4701fb4b69b9c246cd01bf0952f267;hp=dd667841419f26b0b0c82b3638049f86afba2565;hb=ed72a1e9ba37a9fa2674da8f46bb0597a1721c2d;hpb=01fab4d432b50f95f9def1b757d854fd0c385224

diff --git a/src/tt.h b/src/tt.h
index dd667841..84a4b9fa 100644
--- a/src/tt.h
+++ b/src/tt.h
@@ -50,7 +50,7 @@ struct TTEntry {
     // Don't overwrite more valuable entries
     if (  (k >> 48) != key16
         || d > depth8 - 2
-     /* || g != (genBound8 & 0xFC) // Any matching keys are already refreshed by probe() */
+     /* || g != (genBound8 & 0xFC) // Matching non-zero keys are already refreshed by probe() */
         || b == BOUND_EXACT)
     {
         key16     = (uint16_t)(k >> 48);
@@ -76,8 +76,9 @@ private:
 /// A TranspositionTable consists of a power of 2 number of clusters and each
 /// cluster consists of ClusterSize number of TTEntry. Each non-empty entry
 /// contains information of exactly one position. The size of a cluster should
-/// not be bigger than a cache line size. In case it is less, it should be padded
-/// to guarantee always aligned accesses.
+/// divide the size of a cache line size, to ensure that clusters never cross
+/// cache lines. This ensures best cache performance, as the cacheline is
+/// prefetched, as soon as possible.
 
 class TranspositionTable {
 
@@ -86,10 +87,10 @@ class TranspositionTable {
 
   struct Cluster {
     TTEntry entry[ClusterSize];
-    char padding[2]; // Align to the cache line size
+    char padding[2]; // Align to a divisor of the cache line size
   };
 
-  static_assert(sizeof(Cluster) == CacheLineSize / 2, "Cluster size incorrect");
+  static_assert(CacheLineSize % sizeof(Cluster) == 0, "Cluster size incorrect");
 
 public:
  ~TranspositionTable() { free(mem); }