From 99cd7e7f5ed180e8a65578719f80a22016602ba9 Mon Sep 17 00:00:00 2001
From: SzilBalazs <szilprogramming@gmail.com>
Date: Fri, 28 Jul 2023 21:23:28 +0200
Subject: [PATCH] Added prefetch method to improve transposition table
 performance

Bench: 3364651
---
 src/search/search_thread.h | 2 ++
 src/search/tt.h            | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/src/search/search_thread.h b/src/search/search_thread.h
index a13a75b..4da63fe 100644
--- a/src/search/search_thread.h
+++ b/src/search/search_thread.h
@@ -301,6 +301,8 @@ namespace search {
                 board.make_move(move, &nnue);
                 Score score;
 
+                shared.tt.prefetch(board.get_hash());
+
                 if (!in_check && depth >= 3 && made_moves >= 4 && !move.is_promo() && move.is_quiet()) {
                     Depth R = lmr_reductions[depth][made_moves];
 
diff --git a/src/search/tt.h b/src/search/tt.h
index ba39b90..9016b77 100644
--- a/src/search/tt.h
+++ b/src/search/tt.h
@@ -90,6 +90,10 @@ namespace search {
             }
         }
 
+        void prefetch(U64 hash) {
+            __builtin_prefetch(get_entry(hash), 0);
+        }
+
         core::Move get_hash_move(U64 hash) {
             TTEntry *entry = get_entry(hash);
             if (entry->hash == hash)