King-safety recalibration, lazy-eval material floor, eval hot-path trimming

Recalibrate iKingSwingP90 against the bitboard-rewritten
CountKingSafetyDefects (~1.28B samples via new CALIBRATE_POSITIONAL/
CALIBRATE_BASE_MARGIN/CALIBRATE_MARGIN_SAFETY diagnostic build flags,
board_representation/EVAL.md section 9). Add LAZY_EVAL_MIN_MATERIAL:
measured the regular lazy exit's real swing exceeding its own assumed
margin 20.6% of the time in near-bare-king endgames (vs <=0.36%
elsewhere) -- skip lazy eval entirely below that material floor.
Double the stale search.c/searchsup.c CountKingSafetyDefects extension
thresholds as a stopgap pending their own recalibration.

Eval hot-path trimming (measured via EVAL_TIME, ~1759 -> ~1386 avg
cycles/eval on a representative middlegame position):
  - Pull _GetFileStormDefects out of EstimatePositionalScore's hot path
    (cost more than the "cheap cached lookup" it was assumed to be,
    running on ~90% of all Eval() calls).
  - Add pos->bbOccupiedSide[2], incrementally maintained alongside
    bbOccupied, so _BuildFriendlySideBB is a field read instead of a
    6-term OR.
  - Switch CoorFromBitBoardRank8ToRank1/Rank1ToRank8 to the existing
    static-inline FastFirstBit/FastLastBit (same bsf/bsr instruction,
    no call/ret overhead).
  - Defer EvalPasserRaces' uRacerDist/fDontCountMeOut past its
    no-passer early return.
  - Remove the mailbox-era "max mobility in a row" term from
    _EvalBishop/_EvalRook (no bitboard-mobility equivalent need for it).
  - Simplify _EvalBishopPairs and rook file-openness/passer bonuses to
    flat DNA-tunable constants instead of distance/pawn-count-scaled
    tables, rook file-openness now a branchless bitboard-indexed lookup.
  - Remove pos->cPiece (write-only, no reader anywhere).
  - Collapse WHITE/BLACK mirror-branches (castle-rights block,
    rook-trapped-in-corner) to color-indexed constants.
  - Close the PAWN_BIT..KING_BIT gap (bits 7-3 -> bits 4-0), removing
    the bvPattern >>= 3 before its KING_COUNTER_BY_ATTACK_PATTERN
    lookup. This also fixes a real bug introduced earlier this session
    when _WhoControlsSquareFast was converted to read these constants
    directly: g_SwapTable is only [32][32], but the old bit values
    (up to 0xF8) indexed far out of bounds on any attacked square --
    data.c's InitializeSwapTable was always built assuming the bits
    0-4 range this change now actually produces.

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01XxmVi2sTMwpPp4i6WYFjan

1 files changed, 74 insertions, 0 deletions

diff --git a/src/command.c b/src/command.c
index a51bb33..cf8f939 100755
--- a/src/command.c
+++ b/src/command.c
@@ -753,6 +753,74 @@ Return value:
 }
 
 
+COMMAND(CalibrateCommand)
+/**
+
+Routine description:
+
+    This function implements the 'calibrate' engine command, only
+    available in a CALIBRATE_POSITIONAL build (board_representation/
+    EVAL.md section 9's king-safety recalibration).
+
+    Usage:
+
+        calibrate dump
+
+        Prints a fresh iKingSwingP90[]-shaped table (p90 of the real
+        KING_SAFETY_BY_COUNTER magnitude observed at each cheap
+        defect-index bucket) built from every full-eval sample seen so
+        far this run. Run a representative workload first (the curated
+        suites or an ecm.ep_ slice, at real search depth via `sd`/
+        `script`) so the histogram reflects positions the search tree
+        actually evaluates, not just root positions.
+
+Parameters:
+
+    The COMMAND macro hides four arguments from the input parser:
+
+        CHAR *szInput : the full line of input
+        ULONG argc    : number of argument chunks
+        CHAR *argv[]  : array of ptrs to each argument chunk
+        POSITION *pos : a POSITION pointer to operate on
+
+Return value:
+
+    void
+
+**/
+{
+    if (argc >= 2 && !STRCMPI(argv[1], "basemargin"))
+    {
+#ifdef CALIBRATE_BASE_MARGIN
+        DumpBaseMarginCalibration();
+#else
+        Trace("This binary was not built with CALIBRATE_BASE_MARGIN.\n");
+#endif
+        return;
+    }
+    if (argc >= 2 && !STRCMPI(argv[1], "marginsafety"))
+    {
+#ifdef CALIBRATE_MARGIN_SAFETY
+        DumpMarginSafetyCalibration();
+#else
+        Trace("This binary was not built with CALIBRATE_MARGIN_SAFETY.\n");
+#endif
+        return;
+    }
+#ifdef CALIBRATE_POSITIONAL
+    if ((argc < 2) || STRCMPI(argv[1], "dump"))
+    {
+        Trace("Usage: calibrate dump | calibrate basemargin | "
+              "calibrate marginsafety\n");
+        return;
+    }
+    DumpPositionalCalibration();
+#else
+    Trace("This binary was not built with CALIBRATE_POSITIONAL.\n");
+#endif
+}
+
+
 COMMAND(ExitCommand)
 /**
 
@@ -2352,6 +2420,12 @@ COMMAND_PARSER_ENTRY g_ParserTable[] =
       FALSE,
       FALSE,
       "Offer the engine a draw" },
+    { "calibrate",
+      CalibrateCommand,
+      FALSE,
+      FALSE,
+      FALSE,
+      "Dump the CALIBRATE_POSITIONAL king-safety histogram (calibrate dump)" },
     { "edit",
       EditCommand,
       FALSE,