1 files changed, 21 insertions, 27 deletions

diff --git a/src/searchsup.c b/src/searchsup.c
index 0cf52bf..c7ac842 100644
--- a/src/searchsup.c
+++ b/src/searchsup.c
@@ -187,35 +187,28 @@ ThreadUnderTerminatingSplit(IN SEARCHER_THREAD_CONTEXT *ctx)
 }
 
 
-FLAG
-WeShouldDoHistoryPruning(IN SCORE iRoughEval,
-                         IN SCORE iAlpha,
-                         IN SCORE iBeta,
-                         IN SEARCHER_THREAD_CONTEXT *ctx,
-                         IN ULONG uRemainingDepth,
-                         IN ULONG uLegalMoves,
-                         IN MOVE mv,
-                         IN ULONG uMoveNum,
-                         IN INT iExtend)
+INT
+GetLMRReduction(IN SCORE iRoughEval,
+               IN SCORE iAlpha,
+               IN SCORE iBeta,
+               IN SEARCHER_THREAD_CONTEXT *ctx,
+               IN ULONG uRemainingDepth,
+               IN ULONG uLegalMoves,
+               IN MOVE mv,
+               IN ULONG uMoveNum,
+               IN INT iExtend)
 /**
 
 Routine description:
 
-    Decide whether or not to do history pruning at this node for the
-    given move.  Note: this function is called after the move has
-    been played on the board.
-
-Parameters:
-
-    SEARCHER_THREAD_CONTEXT *ctx,
-    ULONG uRemainingDepth,
-    ULONG uLegalMoves,
-    MOVE mv,
-    INT iExtend
+    True pre-LMR/pre-counter-move baseline: original binary history
+    pruning (fixed -ONE_PLY), no graded table, no PV-parent guard, no
+    counter-move exemption. Kept under the GetLMRReduction name so
+    search.c/split.c's call sites need no changes.
 
 Return value:
 
-    FLAG
+    INT : 0 if no reduction, else -ONE_PLY.
 
 **/
 {
@@ -226,7 +219,6 @@ Return value:
         (iBeta == (iAlpha + 1)) &&
         (uLegalMoves > 5) &&
         (0 == iExtend) &&
-//        (iRoughEval + ComputeMoveScore(ctx, mv, uMoveNum - 1) + 200 < iAlpha) &&
         (!IS_ESCAPING_CHECK(mv)) &&
         (!IS_CAPTURE_OR_PROMOTION(mv)) &&
         (!IS_CHECKING_MOVE(mv)) &&
@@ -238,9 +230,9 @@ Return value:
         (GetMoveFailHighPercentage(mv) <= 10))
     {
         ASSERT(!InCheck(&ctx->sPosition, ctx->sPosition.uToMove));
-        return(TRUE);
+        return(-ONE_PLY);
     }
-    return(FALSE);
+    return(0);
 }
 
 
@@ -1027,7 +1019,7 @@ WeShouldTryNullmovePruning(SEARCHER_THREAD_CONTEXT *ctx,
             ASSERT(u <= 6);
             if ((iRoughEval + _iDistAlphaSkipNull[u] <= iAlpha) ||
                 ((iRoughEval + _iDistAlphaSkipNull[u] / 2 <= iAlpha) &&
-                 (ValueOfMaterialInTroubleAfterNull(pos, pos->uToMove))))
+                 (ValueOfMaterialInTroubleAfterNull(ctx, pos->uToMove))))
             {
                 return FALSE;
             }
@@ -1125,7 +1117,9 @@ TryNullmovePruning(SEARCHER_THREAD_CONTEXT *ctx,
         {
             ASSERT(GET_COLOR(mv.pCaptured) == FLIP(pos->uToMove));
             ASSERT(mv.pCaptured == pos->rgSquare[mv.cTo].pPiece);
-            StoreEnprisePiece(pos, mv.cTo);
+            // Victim belongs to FLIP(pos->uToMove) here, i.e. the
+            // mover at ctx->uPly - 1 (see RecordEnprisePieceAtPly).
+            RecordEnprisePieceAtPly(ctx, ctx->uPly - 1, mv.cTo);
             mvRef = ctx->mvNullmoveRefutations[ctx->uPly - 2];
             if ((mvRef.uMove) &&
                 (mvRef.pCaptured == mv.pCaptured) &&