Big assorted spelling fixes

No functional change.

Readme.md

@@ -8,7 +8,7 @@ documentation for your GUI of choice for information about how to use
 Stockfish with it.
 
 This version of Stockfish supports up to 64 CPUs. The engine defaults
-to one search thread it is therefore recommended to inspect the value of
+to one search thread, so it is therefore recommended to inspect the value of
 the *Threads* UCI parameter, and to make sure it equals the number of CPU
 cores on your computer.
 
@@ -46,7 +46,7 @@ Stockfish has support for 32 or 64-bit CPUs, the hardware POPCNT
 instruction, big-endian machines such as Power PC, and other platforms.
 
 In general it is recommended to run `make help` to see a list of make
-targets with corresponding descriptions. When not using Makefile to
+targets with corresponding descriptions. When not using the Makefile to
 compile (for instance with Microsoft MSVC) you need to manually
 set/unset some switches in the compiler command line; see file *types.h*
 for a quick reference.

src/benchmark.cpp

@@ -66,7 +66,7 @@ static const char* Defaults[] = {
 
 
 /// benchmark() runs a simple benchmark by letting Stockfish analyze a set
-/// of positions for a given limit each. There are five parameters; the
+/// of positions for a given limit each. There are five parameters, the
 /// transposition table size, the number of search threads that should
 /// be used, the limit value spent for each position (optional, default is
 /// depth 12), an optional file name where to look for positions in fen
@@ -150,7 +150,7 @@ void benchmark(const Position& current, istream& is) {
       }
   }
 
-  elapsed = Time::now() - elapsed + 1; // Assure positive to avoid a 'divide by zero'
+  elapsed = Time::now() - elapsed + 1; // Ensure positivity to avoid a 'divide by zero'
 
   cerr << "\n==========================="
        << "\nTotal time (ms) : " << elapsed

src/bitboard.cpp

@@ -80,8 +80,8 @@ namespace {
   }
 }
 
-/// lsb()/msb() finds the least/most significant bit in a nonzero bitboard.
-/// pop_lsb() finds and clears the least significant bit in a nonzero bitboard.
+/// lsb()/msb() finds the least/most significant bit in a non-zero bitboard.
+/// pop_lsb() finds and clears the least significant bit in a non-zero bitboard.
 
 #ifndef USE_BSFQ
 

src/bitboard.h

@@ -265,8 +265,8 @@ inline Bitboard attacks_bb(Piece p, Square s, Bitboard occ) {
   }
 }
 
-/// lsb()/msb() finds the least/most significant bit in a nonzero bitboard.
-/// pop_lsb() finds and clears the least significant bit in a nonzero bitboard.
+/// lsb()/msb() finds the least/most significant bit in a non-zero bitboard.
+/// pop_lsb() finds and clears the least significant bit in a non-zero bitboard.
 
 #ifdef USE_BSFQ
 

src/bitcount.h

@@ -32,14 +32,14 @@ enum BitCountType {
   CNT_HW_POPCNT
 };
 
-/// Determine at compile time the best popcount<> specialization according if
-/// platform is 32 or 64 bits, to the maximum number of nonzero bits to count
-/// and if hardware popcnt instruction is available.
+/// Determine at compile time the best popcount<> specialization according to
+/// whether the platform is 32 or 64 bits, to the maximum number of non-zero
+/// bits to count and if the hardware popcnt instruction is available.
 const BitCountType Full  = HasPopCnt ? CNT_HW_POPCNT : Is64Bit ? CNT_64 : CNT_32;
 const BitCountType Max15 = HasPopCnt ? CNT_HW_POPCNT : Is64Bit ? CNT_64_MAX15 : CNT_32_MAX15;
 
 
-/// popcount() counts the number of nonzero bits in a bitboard
+/// popcount() counts the number of non-zero bits in a bitboard
 template<BitCountType> inline int popcount(Bitboard);
 
 template<>

src/book.cpp

@@ -354,7 +354,7 @@ PolyglotBook::~PolyglotBook() { if (is_open()) close(); }
 
 
 /// operator>>() reads sizeof(T) chars from the file's binary byte stream and
-/// converts them in a number of type T. A Polyglot book stores numbers in
+/// converts them into a number of type T. A Polyglot book stores numbers in
 /// big-endian format.
 
 template<typename T> PolyglotBook& PolyglotBook::operator>>(T& n) {
@@ -382,14 +382,15 @@ bool PolyglotBook::open(const char* fName) {
   ifstream::open(fName, ifstream::in | ifstream::binary);
 
   fileName = is_open() ? fName : "";
-  ifstream::clear(); // Reset any error flag to allow retry ifstream::open()
+  ifstream::clear(); // Reset any error flag to allow a retry ifstream::open()
   return !fileName.empty();
 }
 
 
 /// probe() tries to find a book move for the given position. If no move is
-/// found returns MOVE_NONE. If pickBest is true returns always the highest
-/// rated move, otherwise randomly chooses one, based on the move score.
+/// found, it returns MOVE_NONE. If pickBest is true, then it always returns
+/// the highest-rated move, otherwise it randomly chooses one based on the
+/// move score.
 
 Move PolyglotBook::probe(const Position& pos, const string& fName, bool pickBest) {
 
@@ -426,10 +427,10 @@ Move PolyglotBook::probe(const Position& pos, const string& fName, bool pickBest
   // bit  6-11: origin square (from 0 to 63)
   // bit 12-14: promotion piece (from KNIGHT == 1 to QUEEN == 4)
   //
-  // Castling moves follow "king captures rook" representation. So in case book
-  // move is a promotion we have to convert to our representation, in all the
-  // other cases we can directly compare with a Move after having masked out
-  // the special Move's flags (bit 14-15) that are not supported by PolyGlot.
+  // Castling moves follow the "king captures rook" representation. If a book
+  // move is a promotion, we have to convert it to our representation and in
+  // all other cases, we can directly compare with a Move after having masked
+  // out the special Move flags (bit 14-15) that are not supported by PolyGlot.
   int pt = (move >> 12) & 7;
   if (pt)
       move = make<PROMOTION>(from_sq(move), to_sq(move), PieceType(pt + 1));

src/endgame.cpp

@@ -145,7 +145,7 @@ void Endgames::add(const string& code) {
 
 
 /// Mate with KX vs K. This function is used to evaluate positions with
-/// King and plenty of material vs a lone king. It simply gives the
+/// king and plenty of material vs a lone king. It simply gives the
 /// attacking side a bonus for driving the defending king towards the edge
 /// of the board, and for keeping the distance between the two kings small.
 template<>
@@ -187,9 +187,9 @@ Value Endgame<KBNK>::operator()(const Position& pos) const {
   Square loserKSq = pos.king_square(weakSide);
   Square bishopSq = pos.list<BISHOP>(strongSide)[0];
 
-  // kbnk_mate_table() tries to drive toward corners A1 or H8,
-  // if we have a bishop that cannot reach the above squares we
-  // flip the kings so to drive enemy toward corners A8 or H1.
+  // kbnk_mate_table() tries to drive toward corners A1 or H8, if we have a
+  // bishop that cannot reach the above squares we flip the kings in order
+  // to drive the enemy toward corners A8 or H1.
   if (opposite_colors(bishopSq, SQ_A1))
   {
       winnerKSq = ~winnerKSq;
@@ -301,9 +301,10 @@ Value Endgame<KRKN>::operator()(const Position& pos) const {
 }
 
 
-/// KQ vs KP.  In general, a win for the stronger side, however, there are a few
-/// important exceptions.  Pawn on 7th rank, A,C,F or H file, with king next can
-/// be a draw, so we scale down to distance between kings only.
+/// KQ vs KP. In general, this is a win for the stronger side, but there are a
+/// few important exceptions. A pawn on 7th rank and on the A,C,F or H files
+/// with a king positioned next to it can be a draw, so in that case, we only
+/// use the distance between the kings.
 template<>
 Value Endgame<KQKP>::operator()(const Position& pos) const {
 
@@ -405,20 +406,20 @@ ScaleFactor Endgame<KBPsK>::operator()(const Position& pos) const {
           return SCALE_FACTOR_DRAW;
   }
 
-  // All pawns on same B or G file? Then potential draw
+  // If all the pawns are on the same B or G file, then it's potentially a draw
   if (    (pawnFile == FILE_B || pawnFile == FILE_G)
       && !(pos.pieces(PAWN) & ~file_bb(pawnFile))
       && pos.non_pawn_material(weakSide) == 0
       && pos.count<PAWN>(weakSide) >= 1)
   {
-      // Get weakSide pawn that is closest to home rank
+      // Get weakSide pawn that is closest to the home rank
       Square weakPawnSq = backmost_sq(weakSide, pos.pieces(weakSide, PAWN));
 
       Square strongKingSq = pos.king_square(strongSide);
       Square weakKingSq = pos.king_square(weakSide);
       Square bishopSq = pos.list<BISHOP>(strongSide)[0];
 
-      // Potential for a draw if our pawn is blocked on the 7th rank
+      // There's potential for a draw if our pawn is blocked on the 7th rank
       // the bishop cannot attack it or they only have one pawn left
       if (   relative_rank(strongSide, weakPawnSq) == RANK_7
           && (pos.pieces(strongSide, PAWN) & (weakPawnSq + pawn_push(weakSide)))
@@ -427,7 +428,7 @@ ScaleFactor Endgame<KBPsK>::operator()(const Position& pos) const {
           int strongKingDist = square_distance(weakPawnSq, strongKingSq);
           int weakKingDist = square_distance(weakPawnSq, weakKingSq);
 
-          // Draw if the weak king is on it's back two ranks, within 2
+          // It's a draw if the weak king is on its back two ranks, within 2
           // squares of the blocking pawn and the strong king is not
           // closer. (I think this rule only fails in practically
           // unreachable positions such as 5k1K/6p1/6P1/8/8/3B4/8/8 w
@@ -473,7 +474,7 @@ ScaleFactor Endgame<KQKRPs>::operator()(const Position& pos) const {
 /// probably be a good idea to add more knowledge in the future.
 ///
 /// It would also be nice to rewrite the actual code for this function,
-/// which is mostly copied from Glaurung 1.x, and not very pretty.
+/// which is mostly copied from Glaurung 1.x, and isn't very pretty.
 template<>
 ScaleFactor Endgame<KRPKR>::operator()(const Position& pos) const {
 
@@ -760,8 +761,8 @@ ScaleFactor Endgame<KBPPKB>::operator()(const Position& pos) const {
   switch (file_distance(psq1, psq2))
   {
   case 0:
-    // Both pawns are on the same file. Easy draw if defender firmly controls
-    // some square in the frontmost pawn's path.
+    // Both pawns are on the same file. It's an easy draw if the defender firmly
+    // controls some square in the frontmost pawn's path.
     if (   file_of(ksq) == file_of(blockSq1)
         && relative_rank(strongSide, ksq) >= relative_rank(strongSide, blockSq1)
         && opposite_colors(ksq, wbsq))
@@ -770,9 +771,9 @@ ScaleFactor Endgame<KBPPKB>::operator()(const Position& pos) const {
         return SCALE_FACTOR_NONE;
 
   case 1:
-    // Pawns on adjacent files. Draw if defender firmly controls the square
-    // in front of the frontmost pawn's path, and the square diagonally behind
-    // this square on the file of the other pawn.
+    // Pawns on adjacent files. It's a draw if the defender firmly controls the
+    // square in front of the frontmost pawn's path, and the square diagonally
+    // behind this square on the file of the other pawn.
     if (   ksq == blockSq1
         && opposite_colors(ksq, wbsq)
         && (   bbsq == blockSq2

src/endgame.h

@@ -64,9 +64,9 @@ enum EndgameType {
 };
 
 
-/// Endgame functions can be of two types according if return a Value or a
-/// ScaleFactor. Type eg_fun<int>::type equals to either ScaleFactor or Value
-/// depending if the template parameter is 0 or 1.
+/// Endgame functions can be of two types depending on whether they return a
+/// Value or a ScaleFactor. Type eg_fun<int>::type returns either ScaleFactor
+/// or Value depending on whether the template parameter is 0 or 1.
 
 template<int> struct eg_fun { typedef Value type; };
 template<> struct eg_fun<1> { typedef ScaleFactor type; };
@@ -95,9 +95,9 @@ struct Endgame : public EndgameBase<T> {
 };
 
 
-/// Endgames class stores in two std::map the pointers to endgame evaluation
-/// and scaling base objects. Then we use polymorphism to invoke the actual
-/// endgame function calling its operator() that is virtual.
+/// The Endgames class stores the pointers to endgame evaluation and scaling
+/// base objects in two std::map typedefs. We then use polymorphism to invoke
+/// the actual endgame function by calling its virtual operator().
 
 class Endgames {