From 855bee20409c9647fe72e694beb29ed0957fad71 Mon Sep 17 00:00:00 2001
From: syzygy1 <3028851+syzygy1@users.noreply.github.com>
Date: Wed, 1 Jul 2020 23:01:01 +0200
Subject: [PATCH] Bugfix See
 https://github.com/syzygy1/Cfish/commit/bcfb5f50bb05df8121f683a3ec746bb51b0180c3

---
 src/ntsearch.c |  8 ++++----
 src/search.c   | 13 ++++++-------
 2 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/src/ntsearch.c b/src/ntsearch.c
index ea2c2f12..75a87301 100644
--- a/src/ntsearch.c
+++ b/src/ntsearch.c
@@ -57,8 +57,8 @@ Value search_NonPV(Pos *pos, Stack *ss, Value alpha, Depth depth, int cutNode)
   Move ttMove, move, excludedMove, bestMove;
   Depth extension, newDepth;
   Value bestValue, value, ttValue, eval, maxValue;
-  int ttHit, ttPv, inCheck, givesCheck, improving, didLMR;
-  bool doFullDepthSearch, moveCountPruning;
+  int ttHit, ttPv, inCheck, givesCheck, didLMR;
+  bool improving, doFullDepthSearch, moveCountPruning;
   bool ttCapture, captureOrPromotion, singularLMR;
   Piece movedPiece;
   int moveCount, captureCount, quietCount;
@@ -228,7 +228,7 @@ Value search_NonPV(Pos *pos, Stack *ss, Value alpha, Depth depth, int cutNode)
   // Step 6. Static evaluation of the position
   if (inCheck) {
     ss->staticEval = eval = VALUE_NONE;
-    improving = 0;
+    improving = false;
     goto moves_loop; // Skip early pruning when in check
   } else if (ttHit) {
     // Never assume anything about values stored in TT
@@ -458,7 +458,7 @@ Value search_NonPV(Pos *pos, Stack *ss, Value alpha, Depth depth, int cutNode)
         && bestValue > VALUE_MATED_IN_MAX_PLY)
     {
       // Skip quiet moves if movecount exceeds our FutilityMoveCount threshold
-      moveCountPruning = moveCount >= FutilityMoveCounts[improving][depth];
+      moveCountPruning = moveCount >= futility_move_count(improving, depth);
 
       if (   !captureOrPromotion
           && !givesCheck)
diff --git a/src/search.c b/src/search.c
index 5995cc15..e7d599d9 100644
--- a/src/search.c
+++ b/src/search.c
@@ -63,8 +63,7 @@ INLINE int futility_margin(Depth d, int improving) {
   return 217 * (d - improving);
 }
 
-// Futility and reductions lookup tables, initialized at startup
-static int FutilityMoveCounts[2][16]; // [improving][depth]
+// Reductions lookup table, initialized at startup
 static int Reductions[MAX_MOVES]; // [depth or moveNumber]
 
 INLINE Depth reduction(int i, Depth d, int mn)
@@ -73,6 +72,11 @@ INLINE Depth reduction(int i, Depth d, int mn)
   return ((r + 511) / 1024 + (!i && r > 1007));
 }
 
+INLINE int futility_move_count(bool improving, Depth depth)
+{
+  return improving ? 5 + depth  * depth - 1 : (5 + depth * depth) / 2 - 1;
+}
+
 // History and stats update bonus, based on depth
 static Value stat_bonus(Depth depth)
 {
@@ -130,11 +134,6 @@ void search_init(void)
 {
   for (int i = 1; i < MAX_MOVES; i++)
     Reductions[i] = (24.8 + log(Threads.numThreads)) * log(i);
-
-  for (int d = 0; d < 16; ++d) {
-    FutilityMoveCounts[0][d] = (5 + d * d) / 2 - 1;
-    FutilityMoveCounts[1][d] = 5 + d * d - 1;
-  }
 }