Retire the misdesigned StepAttacks[] array.

[stockfish] / src / bitbase.cpp

diff --git a/src/bitbase.cpp b/src/bitbase.cpp
index 25570e12a4b54a63f57e194e585caeca02f58368..d206210414846e3c3392ac655318080397c8b4a4 100644 (file)
--- a/src/bitbase.cpp
+++ b/src/bitbase.cpp
@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -117,21 +117,21 @@ namespace {
     if (   distance(ksq[WHITE], ksq[BLACK]) <= 1
         || ksq[WHITE] == psq
         || ksq[BLACK] == psq
-        || (us == WHITE && (StepAttacksBB[PAWN][psq] & ksq[BLACK])))
+        || (us == WHITE && (PawnAttacks[WHITE][psq] & ksq[BLACK])))
         result = INVALID;
 
     // Immediate win if a pawn can be promoted without getting captured
     else if (   us == WHITE
              && rank_of(psq) == RANK_7
-             && ksq[us] != psq + DELTA_N
-             && (    distance(ksq[~us], psq + DELTA_N) > 1
-                 || (StepAttacksBB[KING][ksq[us]] & (psq + DELTA_N))))
+             && ksq[us] != psq + NORTH
+             && (    distance(ksq[~us], psq + NORTH) > 1
+                 || (PseudoAttacks[KING][ksq[us]] & (psq + NORTH))))
         result = WIN;
 
     // 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]] & psq & ~StepAttacksBB[KING][ksq[~us]])))
+             && (  !(PseudoAttacks[KING][ksq[us]] & ~(PseudoAttacks[KING][ksq[~us]] | PawnAttacks[~us][psq]))
+                 || (PseudoAttacks[KING][ksq[us]] & psq & ~PseudoAttacks[KING][ksq[~us]])))
         result = DRAW;
 
     // Position will be classified later
@@ -157,7 +157,7 @@ namespace {
     const Result Bad  = (Us == WHITE ? DRAW  : WIN);
 
     Result r = INVALID;
-    Bitboard b = StepAttacksBB[KING][ksq[Us]];
+    Bitboard b = PseudoAttacks[KING][ksq[Us]];
 
     while (b)
         r |= Us == WHITE ? db[index(Them, ksq[Them]  , pop_lsb(&b), psq)]
@@ -166,12 +166,12 @@ namespace {
     if (Us == WHITE)
     {
         if (rank_of(psq) < RANK_7)      // Single push
-            r |= db[index(Them, ksq[Them], ksq[Us], psq + DELTA_N)];
+            r |= db[index(Them, ksq[Them], ksq[Us], psq + NORTH)];
 
         if (   rank_of(psq) == RANK_2   // Double push
-            && psq + DELTA_N != ksq[Us]
-            && psq + DELTA_N != ksq[Them])
-            r |= db[index(Them, ksq[Them], ksq[Us], psq + DELTA_N + DELTA_N)];
+            && psq + NORTH != ksq[Us]
+            && psq + NORTH != ksq[Them])
+            r |= db[index(Them, ksq[Them], ksq[Us], psq + NORTH + NORTH)];
     }
 
     return result = r & Good  ? Good  : r & UNKNOWN ? UNKNOWN : Bad;