1 files changed, 58 insertions, 0 deletions
diff --git a/src/lmr_testing/generate_counter_move_block.c b/src/lmr_testing/generate_counter_move_block.c
new file mode 100644
index 0000000..f58efda
--- /dev/null
+++ b/src/lmr_testing/generate_counter_move_block.c
@@ -0,0 +1,58 @@
+// generate.c changes to restore counter-move scoring. Three pieces, in
+// the same function (the one with PRECOMP_KILLERS sKillers[...] and the
+// "Pre-populate killer/bonuses" comment -- search for that to find it).
+
+// LOCATION 1: local var decls at top of the function -- add mvLast and
+// pi, bump sKillers to 6:
+//
+//   PLY_INFO *pi = &ctx->sPlyInfo[ctx->uPly];      // ADD
+//   ULONG uPly = ctx->uPly;
+//   POSITION *pos = &ctx->sPosition;
+//   ULONG u;
+//   MOVE mv;
+//   MOVE mvLast = (pi-1)->mv;                        // ADD
+//   SCORE s;
+//   MOVE_STACK_MOVE_VALUE_FLAGS mvf;
+//   ULONG uHashMoveLoc = (ULONG)-1;
+//   ULONG uColor = pos->uToMove;
+//   PRECOMP_KILLERS sKillers[6];                     // was [4]
+//   COOR cEnprise = FindEnprisePiece(ctx, uColor);
+
+// LOCATION 2: right after the killer sKillers[0..3] population block
+// (after the SORT_THESE_FIRST |= lines for sKillers[0..3]), insert:
+
+    //
+    // Pre-populate counter-move bonuses -- keyed by whatever move the
+    // opponent just played to reach this node, not by ply.  A/B test:
+    // applied as a small *additive* nudge (like history counters),
+    // not a hard priority-tier flag -- the ~56% measured hit rate
+    // isn't confident enough to justify unconditionally outranking
+    // ordinary PSQT-scored quiet moves.  Bonus scales with the ply
+    // depth the entry was recorded at (deeper = more confident),
+    // capped at the same 400/200 ceiling the flat version used.
+    //
+    sKillers[4].mv.uMove = sKillers[5].mv.uMove = 0;
+    if (mvLast.uMove != 0)
+    {
+        u = MOVE_TO_INDEX(mvLast);
+        sKillers[4].mv = ctx->mvCounter[u][0];
+        sKillers[4].uBonus = 400;
+        sKillers[5].mv = ctx->mvCounter[u][1];
+        sKillers[5].uBonus = 200;
+    }
+
+// LOCATION 3: in the quiet-move scoring branch (the `else` branch that
+// computes `s = g_iPSQT[...]` and applies killer bonuses via `s |= ...`),
+// right after the GOOD_MOVE/cEnprise line and before `ASSERT(s >= 0);`,
+// add (note: additive `+=`, not `|=` -- this was the measured-best
+// config vs. a hard flag):
+
+                s += (IS_SAME_MOVE(sKillers[4].mv, mv) * sKillers[4].uBonus);
+                s += (IS_SAME_MOVE(sKillers[5].mv, mv) * sKillers[5].uBonus);
+
+// This same three-part change applies in BOTH scoring functions in
+// generate.c that have this sKillers array (there are two -- one for
+// the normal move-scoring path, one for escaping-check; check whether
+// the second one had the counter-move block too before assuming it's
+// identical -- verify via `grep -n PRECOMP_KILLERS generate.c` and
+// diff both call sites against this file's saved state if unsure).