From 4784ff2b3be97a0364b77a677e21a644403f7b3a Mon Sep 17 00:00:00 2001
From: Guenther Demetz <guenther.demetz@wuerth-phoenix.com>
Date: Mon, 3 Nov 2025 08:55:26 +0100
Subject: [PATCH] Unify do_move & do_null_move workload

While being there also remove and unused assignment.

Tested for non-regression at STC:
https://tests.stockfishchess.org/tests/view/69060d81ea4b268f1fac1f36
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 94496 W: 24570 L: 24421 D: 45505
Ptnml(0-2): 264, 10145, 26275, 10306, 258

closes https://github.com/official-stockfish/Stockfish/pull/6383

no functional change
---
 src/search.cpp | 17 ++++++++---------
 src/search.h   |  2 +-
 2 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/src/search.cpp b/src/search.cpp
index 43d96bf24..d28ac5f27 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -544,7 +544,12 @@ void Search::Worker::do_move(
     }
 }
 
-void Search::Worker::do_null_move(Position& pos, StateInfo& st) { pos.do_null_move(st, tt); }
+void Search::Worker::do_null_move(Position& pos, StateInfo& st, Stack* const ss) {
+    pos.do_null_move(st, tt);
+    ss->currentMove                   = Move::null();
+    ss->continuationHistory           = &continuationHistory[0][0][NO_PIECE][0];
+    ss->continuationCorrectionHistory = &continuationCorrectionHistory[NO_PIECE][0];
+}
 
 void Search::Worker::undo_move(Position& pos, const Move move) {
     pos.undo_move(move);
@@ -868,12 +873,7 @@ Value Search::Worker::search(
 
         // Null move dynamic reduction based on depth
         Depth R = 6 + depth / 3 + improving;
-
-        ss->currentMove                   = Move::null();
-        ss->continuationHistory           = &continuationHistory[0][0][NO_PIECE][0];
-        ss->continuationCorrectionHistory = &continuationCorrectionHistory[NO_PIECE][0];
-
-        do_null_move(pos, st);
+        do_null_move(pos, st, ss);
 
         Value nullValue = -search<NonPV>(pos, ss + 1, -beta, -beta + 1, depth - R, false);
 
@@ -1580,8 +1580,7 @@ Value Search::Worker::qsearch(Position& pos, Stack* ss, Value alpha, Value beta)
         futilityBase = ss->staticEval + 352;
     }
 
-    const PieceToHistory* contHist[] = {(ss - 1)->continuationHistory,
-                                        (ss - 2)->continuationHistory};
+    const PieceToHistory* contHist[] = {(ss - 1)->continuationHistory};
 
     Square prevSq = ((ss - 1)->currentMove).is_ok() ? ((ss - 1)->currentMove).to_sq() : SQ_NONE;
 
diff --git a/src/search.h b/src/search.h
index 4c4357d3e..f3d99d415 100644
--- a/src/search.h
+++ b/src/search.h
@@ -299,7 +299,7 @@ class Worker {
     void do_move(Position& pos, const Move move, StateInfo& st, Stack* const ss);
     void
     do_move(Position& pos, const Move move, StateInfo& st, const bool givesCheck, Stack* const ss);
-    void do_null_move(Position& pos, StateInfo& st);
+    void do_null_move(Position& pos, StateInfo& st, Stack* const ss);
     void undo_move(Position& pos, const Move move);
     void undo_null_move(Position& pos);