X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.h;h=8b70f79787619ca4c1b6326f55cfa456a2dcf04f;hp=98b054d397207525a45978e6bae6a15055e29181;hb=ddcbacd04d1c860e808202ce8c1206c8acdca627;hpb=09bef14c76e119103cc1a9404cbde7e249205deb diff --git a/src/tt.h b/src/tt.h index 98b054d3..8b70f797 100644 --- a/src/tt.h +++ b/src/tt.h @@ -41,7 +41,7 @@ struct TTEntry { Value value() const { return (Value)value16; } Value eval() const { return (Value)eval16; } Depth depth() const { return (Depth)depth8 + DEPTH_OFFSET; } - bool is_pv() const { return (bool)(genBound8 & 0x4); } + bool is_pv() const { return (bool)(genBound8 & 0x4); } Bound bound() const { return (Bound)(genBound8 & 0x3); } void save(Key k, Value v, bool pv, Bound b, Depth d, Move m, Value ev); @@ -57,24 +57,22 @@ 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 -/// 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. +/// A TranspositionTable is an array of Cluster, of size clusterCount. Each +/// cluster consists of ClusterSize number of TTEntry. Each non-empty TTEntry +/// contains information on exactly one position. The size of a Cluster should +/// divide the size of a cache line for best performance, +/// as the cacheline is prefetched when possible. class TranspositionTable { - static constexpr int CacheLineSize = 64; static constexpr int ClusterSize = 3; struct Cluster { TTEntry entry[ClusterSize]; - char padding[2]; // Align to a divisor of the cache line size + char padding[2]; // Pad to 32 bytes }; - static_assert(CacheLineSize % sizeof(Cluster) == 0, "Cluster size incorrect"); + static_assert(sizeof(Cluster) == 32, "Unexpected Cluster size"); public: ~TranspositionTable() { free(mem); }