Simplify a condition in gives_check()

[stockfish] / src / position.cpp

diff --git a/src/position.cpp b/src/position.cpp
index 52e6dd0fc5b520d1696b2987ff907e512b009526..2f3c62f552ac8fec90ef1e1bb3fa1d8f7600702e 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -21,7 +21,6 @@
 #include <cassert>
 #include <cstring>
 #include <iomanip>
-#include <iostream>
 #include <sstream>
 
 #include "bitcount.h"
@@ -34,8 +33,6 @@
 #include "tt.h"
 
 using std::string;
-using std::cout;
-using std::endl;
 
 static const string PieceToChar(" PNBRQK  pnbrqk");
 
@@ -455,23 +452,6 @@ Bitboard Position::attackers_to(Square s, Bitboard occ) const {
 }
 
 
-/// Position::attacks_from() computes a bitboard of all attacks of a given piece
-/// put in a given square. Slider attacks use occ bitboard as occupancy.
-
-Bitboard Position::attacks_from(Piece p, Square s, Bitboard occ) {
-
-  assert(is_ok(s));
-
-  switch (type_of(p))
-  {
-  case BISHOP: return attacks_bb<BISHOP>(s, occ);
-  case ROOK  : return attacks_bb<ROOK>(s, occ);
-  case QUEEN : return attacks_bb<BISHOP>(s, occ) | attacks_bb<ROOK>(s, occ);
-  default    : return StepAttacksBB[p][s];
-  }
-}
-
-
 /// Position::legal() tests whether a pseudo-legal move is legal
 
 bool Position::legal(Move m, Bitboard pinned) const {
@@ -515,7 +495,7 @@ bool Position::legal(Move m, Bitboard pinned) const {
   // is moving along the ray towards or away from the king.
   return   !pinned
         || !(pinned & from)
-        ||  squares_aligned(from, to_sq(m), king_square(us));
+        ||  aligned(from, to_sq(m), king_square(us));
 }
 
 
@@ -653,14 +633,11 @@ bool Position::gives_check(Move m, const CheckInfo& ci) const {
   if (ci.checkSq[pt] & to)
       return true;
 
-  // Discovery check ?
-  if (unlikely(ci.dcCandidates) && (ci.dcCandidates & from))
-  {
-      // For pawn and king moves we need to verify also direction
-      if (   (pt != PAWN && pt != KING)
-          || !squares_aligned(from, to, king_square(~sideToMove)))
-          return true;
-  }
+  // Discovered check ?
+  if (   unlikely(ci.dcCandidates)
+      && (ci.dcCandidates & from)
+      && !aligned(from, to, king_square(~sideToMove)))
+      return true;
 
   // Can we skip the ugly special cases ?
   if (type_of(m) == NORMAL)
@@ -672,7 +649,7 @@ bool Position::gives_check(Move m, const CheckInfo& ci) const {
   switch (type_of(m))
   {
   case PROMOTION:
-      return attacks_from(Piece(promotion_type(m)), to, pieces() ^ from) & ksq;
+      return attacks_bb(Piece(promotion_type(m)), to, pieces() ^ from) & ksq;
 
   // En passant capture with check ? We have already handled the case
   // of direct checks and ordinary discovered check, the only case we