Fix pawn double-step move validation

fairy-stockfish · Aug 20, 2019 · 05d1624 · 05d1624
1 parent aab6f77
commit 05d1624
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Showing 2 changed files with 3 additions and 3 deletions.
diff --git a/src/movegen.cpp b/src/movegen.cpp
@@ -134,7 +134,7 @@ namespace {
             if (dcCandidateQuiets)
             {
                 Bitboard dc1 = shift<Up>(dcCandidateQuiets) & emptySquares & ~file_bb(ksq);
-                Bitboard dc2 = shift<Up>(dc1 & TRank3BB) & emptySquares;
+                Bitboard dc2 = pos.double_step_enabled() ? shift<Up>(dc1 & TRank3BB) & emptySquares : Bitboard(0);
 
                 b1 |= dc1;
                 b2 |= dc2;

diff --git a/src/position.cpp b/src/position.cpp
@@ -920,8 +920,8 @@ bool Position::pseudo_legal(const Move m) const {
       if (   !(attacks_from<PAWN>(us, from) & pieces(~us) & to) // Not a capture
           && !((from + pawn_push(us) == to) && empty(to))       // Not a single push
           && !(   (from + 2 * pawn_push(us) == to)              // Not a double push
-               && (rank_of(from) == relative_rank(us, double_step_rank())
-                   || (first_rank_double_steps() && rank_of(from) == relative_rank(us, RANK_1)))
+               && (rank_of(from) == relative_rank(us, double_step_rank(), max_rank())
+                   || (first_rank_double_steps() && rank_of(from) == relative_rank(us, RANK_1, max_rank())))
                && empty(to)
                && empty(to - pawn_push(us))
                && double_step_enabled()))