From: snicolet <cassio@free.fr>
Date: Wed, 26 Apr 2017 00:57:30 +0000 (-0700)
Subject: Avoid misuse of StepAttacksBB for pawns
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=49a9d4cf99e56d071af3060b3f306b9daa0a62a6

Avoid misuse of StepAttacksBB for pawns

Make it explicit that first index of StepAttacksBB is a piece, not a piece type.

No functional change

Closes #1083
---

diff --git a/src/bitbase.cpp b/src/bitbase.cpp
index 1a6e8076..0e4521c1 100644
--- a/src/bitbase.cpp
+++ b/src/bitbase.cpp
@@ -117,7 +117,7 @@ namespace {
     if (   distance(ksq[WHITE], ksq[BLACK]) <= 1
         || ksq[WHITE] == psq
         || ksq[BLACK] == psq
-        || (us == WHITE && (StepAttacksBB[PAWN][psq] & ksq[BLACK])))
+        || (us == WHITE && (StepAttacksBB[W_PAWN][psq] & ksq[BLACK])))
         result = INVALID;
 
     // Immediate win if a pawn can be promoted without getting captured
@@ -130,7 +130,7 @@ namespace {
 
     // Immediate draw if it is a stalemate or a king captures undefended pawn
     else if (   us == BLACK
-             && (  !(StepAttacksBB[KING][ksq[us]] & ~(StepAttacksBB[KING][ksq[~us]] | StepAttacksBB[PAWN][psq]))
+             && (  !(StepAttacksBB[KING][ksq[us]] & ~(StepAttacksBB[KING][ksq[~us]] | StepAttacksBB[W_PAWN][psq]))
                  || (StepAttacksBB[KING][ksq[us]] & psq & ~StepAttacksBB[KING][ksq[~us]])))
         result = DRAW;
 
diff --git a/src/position.h b/src/position.h
index e571048a..5a07193b 100644
--- a/src/position.h
+++ b/src/position.h
@@ -273,6 +273,7 @@ inline Square Position::castling_rook_square(CastlingRight cr) const {
 
 template<PieceType Pt>
 inline Bitboard Position::attacks_from(Square s) const {
+  assert(Pt != PAWN);
   return  Pt == BISHOP || Pt == ROOK ? attacks_bb<Pt>(s, byTypeBB[ALL_PIECES])
         : Pt == QUEEN  ? attacks_from<ROOK>(s) | attacks_from<BISHOP>(s)
         : StepAttacksBB[Pt][s];