Retire operator|(File f, Rank r)

[stockfish] / src / bitbase.cpp

diff --git a/src/bitbase.cpp b/src/bitbase.cpp
index e4428d2d4aad5e7afb97e715a7b6570710d243a7..b73b72c4c17506f2e2dc7da58ada30a7caa93ccb 100644 (file)
--- a/src/bitbase.cpp
+++ b/src/bitbase.cpp
@@ -1,7 +1,7 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
+  Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, 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
@@ -25,15 +25,15 @@
 
 namespace {
 
-  // The possible pawns squares are 24, the first 4 files and ranks from 2 to 7
-  const unsigned IndexMax = 2*24*64*64; // stm * psq * wksq * bksq = 196608
+  // There are 24 possible pawn squares: the first 4 files and ranks from 2 to 7
+  const unsigned MAX_INDEX = 2*24*64*64; // stm * psq * wksq * bksq = 196608
 
   // Each uint32_t stores results of 32 positions, one per bit
-  uint32_t KPKBitbase[IndexMax / 32];
+  uint32_t KPKBitbase[MAX_INDEX / 32];
 
   // A KPK bitbase index is an integer in [0, IndexMax] range
   //
-  // Information is mapped in a way that minimizes number of iterations:
+  // Information is mapped in a way that minimizes the number of iterations:
   //
   // bit  0- 5: white king square (from SQ_A1 to SQ_H8)
   // bit  6-11: black king square (from SQ_A1 to SQ_H8)
@@ -84,20 +84,20 @@ void Bitbases::init_kpk() {
 
   unsigned idx, repeat = 1;
   std::vector<KPKPosition> db;
-  db.reserve(IndexMax);
+  db.reserve(MAX_INDEX);
 
   // Initialize db with known win / draw positions
-  for (idx = 0; idx < IndexMax; idx++)
+  for (idx = 0; idx < MAX_INDEX; ++idx)
       db.push_back(KPKPosition(idx));
 
-  // Iterate through the positions until no more of the unknown positions can be
+  // Iterate through the positions until none of the unknown positions can be
   // changed to either wins or draws (15 cycles needed).
   while (repeat)
-      for (repeat = idx = 0; idx < IndexMax; idx++)
+      for (repeat = idx = 0; idx < MAX_INDEX; ++idx)
           repeat |= (db[idx] == UNKNOWN && db[idx].classify(db) != UNKNOWN);
 
   // Map 32 results into one KPKBitbase[] entry
-  for (idx = 0; idx < IndexMax; idx++)
+  for (idx = 0; idx < MAX_INDEX; ++idx)
       if (db[idx] == WIN)
           KPKBitbase[idx / 32] |= 1 << (idx & 0x1F);
 }
@@ -110,7 +110,7 @@ namespace {
     wksq = Square((idx >>  0) & 0x3F);
     bksq = Square((idx >>  6) & 0x3F);
     us   = Color ((idx >> 12) & 0x01);
-    psq  = File  ((idx >> 13) & 0x03) | Rank(RANK_7 - (idx >> 15));
+    psq  = make_square(File((idx >> 13) & 0x03), Rank(RANK_7 - (idx >> 15)));
     result  = UNKNOWN;
 
     // Check if two pieces are on the same square or if a king can be captured
@@ -120,14 +120,14 @@ namespace {
 
     else if (us == WHITE)
     {
-        // Immediate win if pawn can be promoted without getting captured
+        // Immediate win if a pawn can be promoted without getting captured
         if (   rank_of(psq) == RANK_7
             && wksq != psq + DELTA_N
             && (   square_distance(bksq, psq + DELTA_N) > 1
                 ||(StepAttacksBB[KING][wksq] & (psq + DELTA_N))))
             result = WIN;
     }
-    // Immediate draw if is stalemate or king captures undefended pawn
+    // Immediate draw if it is a stalemate or a king captures undefended pawn
     else if (  !(StepAttacksBB[KING][bksq] & ~(StepAttacksBB[KING][wksq] | StepAttacksBB[PAWN][psq]))
              || (StepAttacksBB[KING][bksq] & psq & ~StepAttacksBB[KING][wksq]))
         result = DRAW;
@@ -138,13 +138,13 @@ namespace {
 
     // White to Move: If one move leads to a position classified as WIN, the result
     // of the current position is WIN. If all moves lead to positions classified
-    // as DRAW, the current position is classified DRAW otherwise the current
+    // as DRAW, the current position is classified as DRAW, otherwise the current
     // position is classified as UNKNOWN.
     //
     // Black to Move: If one move leads to a position classified as DRAW, the result
     // of the current position is DRAW. If all moves lead to positions classified
-    // as WIN, the position is classified WIN otherwise the current position is
-    // classified UNKNOWN.
+    // as WIN, the position is classified as WIN, otherwise the current position is
+    // classified as UNKNOWN.
 
     const Color Them = (Us == WHITE ? BLACK : WHITE);