1 files changed, 8 insertions, 2 deletions
diff --git a/src/bitboard.c b/src/bitboard.c
index ad45ea6..2832fdb 100755
--- a/src/bitboard.c
+++ b/src/bitboard.c
@@ -344,7 +344,11 @@ Return value:
 **/
 {
     COOR c = ILLEGAL_COOR;
-    ULONG uFirstBit = FirstBit(*pbb);
+    // FastFirstBit (chess.h): same bsf instruction as the extern
+    // FirstBit, but static inline -- no call/ret/arg-marshal overhead.
+    // Measured directly: ~7 cycles/call via the extern vs ~1-3 for the
+    // bare instruction (board_representation/EVAL.md section 9).
+    ULONG uFirstBit = FastFirstBit(*pbb);
 
     ASSERT(uFirstBit == SlowFirstBit(*pbb));
     if (0 != uFirstBit)
@@ -381,7 +385,9 @@ Return value:
 **/
 {
     COOR c;
-    ULONG uLastBit = LastBit(*pbb);
+    // FastLastBit (chess.h): same bsr instruction as the extern
+    // LastBit, but static inline -- no call/ret/arg-marshal overhead.
+    ULONG uLastBit = FastLastBit(*pbb);
     ASSERT(SlowLastBit(*pbb) == uLastBit);
     
     c = ILLEGAL_COOR;