MovePicker: rename number_of_moves() in number_of_evasions()

It is more clear that only in that case the move number is
correct, otherwise is only a partial quantity: the number of
moves of that phase.

In case of PH_EVASIONS instead we have only one phase.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

src/movepick.cpp

@@ -39,11 +39,23 @@
 
 namespace {
 
+  enum MovegenPhase {
+    PH_TT_MOVES,       // Transposition table move and mate killer
+    PH_GOOD_CAPTURES,  // Queen promotions and captures with SEE values >= 0
+    PH_KILLERS,        // Killer moves from the current ply
+    PH_NONCAPTURES,    // Non-captures and underpromotions
+    PH_BAD_CAPTURES,   // Queen promotions and captures with SEE values < 0
+    PH_EVASIONS,       // Check evasions
+    PH_QCAPTURES,      // Captures in quiescence search
+    PH_QCHECKS,        // Non-capture checks in quiescence search
+    PH_STOP
+  };
+
   CACHE_LINE_ALIGNMENT
-  const MovegenPhaseT MainSearchPhaseTable[] = { PH_TT_MOVES, PH_GOOD_CAPTURES, PH_KILLERS, PH_NONCAPTURES, PH_BAD_CAPTURES, PH_STOP};
-  const MovegenPhaseT EvasionsPhaseTable[] = { PH_EVASIONS, PH_STOP};
-  const MovegenPhaseT QsearchWithChecksPhaseTable[] = { PH_TT_MOVES, PH_QCAPTURES, PH_QCHECKS, PH_STOP};
-  const MovegenPhaseT QsearchWithoutChecksPhaseTable[] = { PH_TT_MOVES, PH_QCAPTURES, PH_STOP};
+  const uint8_t MainSearchPhaseTable[] = { PH_TT_MOVES, PH_GOOD_CAPTURES, PH_KILLERS, PH_NONCAPTURES, PH_BAD_CAPTURES, PH_STOP};
+  const uint8_t EvasionsPhaseTable[] = { PH_EVASIONS, PH_STOP};
+  const uint8_t QsearchWithChecksPhaseTable[] = { PH_TT_MOVES, PH_QCAPTURES, PH_QCHECKS, PH_STOP};
+  const uint8_t QsearchWithoutChecksPhaseTable[] = { PH_TT_MOVES, PH_QCAPTURES, PH_STOP};
 }
 
 
@@ -63,6 +75,9 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d,
                        const History& h, SearchStack* ss) : pos(p), H(h) {
   int searchTT = ttm;
   ttMoves[0].move = ttm;
+  finished = false;
+  lastBadCapture = badCaptures;
+
   if (ss)
   {
       ttMoves[1].move = (ss->mateKiller == ttm)? MOVE_NONE : ss->mateKiller;
@@ -72,9 +87,6 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d,
   } else
       ttMoves[1].move = killers[0].move = killers[1].move = MOVE_NONE;
 
-  finished = false;
-  lastBadCapture = badCaptures;
-
   Color us = pos.side_to_move();
 
   dc = p.discovered_check_candidates(us);
@@ -243,7 +255,7 @@ void MovePicker::score_evasions() {
 /// class. It returns a new legal move every time it is called, until there
 /// are no more moves left.
 /// It picks the move with the biggest score from a list of generated moves taking
-/// care not to return the tt move if that has already been serched previously.
+/// care not to return the tt move if has already been searched previously.
 
 Move MovePicker::get_next_move() {
 

src/movepick.h

@@ -37,20 +37,6 @@
 
 struct SearchStack;
 
-enum MovegenPhase {
-  PH_TT_MOVES,       // Transposition table move and mate killer
-  PH_GOOD_CAPTURES,  // Queen promotions and captures with SEE values >= 0
-  PH_KILLERS,        // Killer moves from the current ply
-  PH_NONCAPTURES,    // Non-captures and underpromotions
-  PH_BAD_CAPTURES,   // Queen promotions and captures with SEE values < 0
-  PH_EVASIONS,       // Check evasions
-  PH_QCAPTURES,      // Captures in quiescence search
-  PH_QCHECKS,        // Non-capture checks in quiescence search
-  PH_STOP
-};
-
-typedef uint8_t MovegenPhaseT;
-
 /// MovePicker is a class which is used to pick one legal move at a time from
 /// the current position. It is initialized with a Position object and a few
 /// moves we have reason to believe are good. The most important method is
@@ -67,7 +53,7 @@ public:
   MovePicker(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss = NULL);
   Move get_next_move();
   Move get_next_move(Lock& lock);
-  int number_of_moves() const;
+  int number_of_evasions() const;
   Bitboard discovered_check_candidates() const;
 
 private:
@@ -81,7 +67,7 @@ private:
   MoveStack ttMoves[2], killers[2];
   bool finished;
   int phase;
-  const MovegenPhaseT* phasePtr;
+  const uint8_t* phasePtr;
   MoveStack *curMove, *lastMove, *lastBadCapture;
   Bitboard dc, pinned;
   MoveStack moves[256], badCaptures[64];
@@ -92,12 +78,13 @@ private:
 //// Inline functions
 ////
 
-/// MovePicker::number_of_moves() simply returns the numOfMoves member
-/// variable. It is intended to be used in positions where the side to move
-/// is in check, for detecting checkmates or situations where there is only
-/// a single reply to check.
+/// MovePicker::number_of_evasions() simply returns the number of moves in
+/// evasions phase. It is intended to be used in positions where the side to
+/// move is in check, for detecting checkmates or situations where there is
+/// only a single reply to check.
+/// WARNING: It works as long as PH_EVASIONS is the _only_ phase for evasions.
 
-inline int MovePicker::number_of_moves() const {
+inline int MovePicker::number_of_evasions() const {
   return int(lastMove - moves);
 }
 

src/position.cpp

@@ -940,7 +940,7 @@ void Position::do_capture_move(Bitboard& key, PieceType capture, Color them, Squ
 
     // Update piece list, move the last piece at index[capsq] position
     //
-    // WARNING: this is a not perfectly revresible operation. When we
+    // WARNING: This is a not perfectly revresible operation. When we
     // will reinsert the captured piece in undo_move() we will put it
     // at the end of the list and not in its original place, it means
     // index[] and pieceList[] are not guaranteed to be invariant to a

src/search.cpp

@@ -1109,7 +1109,7 @@ namespace {
     {
       assert(move_is_ok(move));
 
-      bool singleReply = (isCheck && mp.number_of_moves() == 1);
+      bool singleReply = (isCheck && mp.number_of_evasions() == 1);
       bool moveIsCheck = pos.move_is_check(move, dcCandidates);
       bool moveIsCapture = pos.move_is_capture(move);
 
@@ -1366,7 +1366,7 @@ namespace {
     {
       assert(move_is_ok(move));
 
-      bool singleReply = (isCheck && mp.number_of_moves() == 1);
+      bool singleReply = (isCheck && mp.number_of_evasions() == 1);
       bool moveIsCheck = pos.move_is_check(move, dcCandidates);
       bool moveIsCapture = pos.move_is_capture(move);