From 5ea984ac3515946d952bd3c9cfe8e8baef7cc85d Mon Sep 17 00:00:00 2001
From: Marco Costalba <mcostalba@gmail.com>
Date: Sun, 16 Jun 2013 10:51:17 +0200
Subject: [PATCH] Don't calculate pawnsOnSquares twice

And reformat some code while there.

No functional change.
---
 src/pawns.cpp | 45 +++++++++++++++++++--------------------------
 1 file changed, 19 insertions(+), 26 deletions(-)

diff --git a/src/pawns.cpp b/src/pawns.cpp
index 861c421f..d05e8af0 100644
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -80,11 +80,12 @@ namespace {
   #undef V
 
   template<Color Us>
-  Score evaluate_pawns(const Position& pos, Bitboard ourPawns,
-                       Bitboard theirPawns, Pawns::Entry* e) {
+  Score evaluate(const Position& pos, Pawns::Entry* e) {
 
-    const Color Them = (Us == WHITE ? BLACK : WHITE);
-    const Square  Up = (Us == WHITE ? DELTA_N : DELTA_S);
+    const Color  Them  = (Us == WHITE ? BLACK    : WHITE);
+    const Square Up    = (Us == WHITE ? DELTA_N  : DELTA_S);
+    const Square Right = (Us == WHITE ? DELTA_NE : DELTA_SW);
+    const Square Left  = (Us == WHITE ? DELTA_NW : DELTA_SE);
 
     Bitboard b;
     Square s;
@@ -94,6 +95,16 @@ namespace {
     Score value = SCORE_ZERO;
     const Square* pl = pos.piece_list(Us, PAWN);
 
+    Bitboard ourPawns = pos.pieces(Us, PAWN);
+    Bitboard theirPawns = pos.pieces(Them, PAWN);
+
+    e->passedPawns[Us] = 0;
+    e->kingSquares[Us] = SQ_NONE;
+    e->semiopenFiles[Us] = 0xFF;
+    e->pawnAttacks[Us] = shift_bb<Right>(ourPawns) | shift_bb<Left>(ourPawns);
+    e->pawnsOnSquares[Us][BLACK] = popcount<Max15>(ourPawns & BlackSquares);
+    e->pawnsOnSquares[Us][WHITE] = pos.piece_count(Us, PAWN) - e->pawnsOnSquares[Us][BLACK];
+
     // Loop through all pawns of the current color and score each pawn
     while ((s = *pl++) != SQ_NONE)
     {
@@ -135,7 +146,7 @@ namespace {
             // Note that we are sure to find something because pawn is not passed
             // nor isolated, so loop is potentially infinite, but it isn't.
             while (!(b & (ourPawns | theirPawns)))
-                Us == WHITE ? b <<= 8 : b >>= 8;
+                b = shift_bb<Up>(b);
 
             // The friendly pawn needs to be at least two ranks closer than the
             // enemy pawn in order to help the potentially backward pawn advance.
@@ -175,15 +186,10 @@ namespace {
             value += CandidatePassed[relative_rank(Us, s)];
     }
 
-    e->pawnsOnSquares[Us][BLACK] = popcount<Max15>(ourPawns & BlackSquares);
-    e->pawnsOnSquares[Us][WHITE] = pos.piece_count(Us, PAWN) - e->pawnsOnSquares[Us][BLACK];
-
-    e->pawnsOnSquares[Them][BLACK] = popcount<Max15>(theirPawns & BlackSquares);
-    e->pawnsOnSquares[Them][WHITE] = pos.piece_count(Them, PAWN) - e->pawnsOnSquares[Them][BLACK];
-
     return value;
   }
-}
+
+} // namespace
 
 namespace Pawns {
 
@@ -196,24 +202,11 @@ Entry* probe(const Position& pos, Table& entries) {
   Key key = pos.pawn_key();
   Entry* e = entries[key];
 
-  // If e->key matches the position's pawn hash key, it means that we
-  // have analysed this pawn structure before, and we can simply return
-  // the information we found the last time instead of recomputing it.
   if (e->key == key)
       return e;
 
   e->key = key;
-  e->passedPawns[WHITE] = e->passedPawns[BLACK] = 0;
-  e->kingSquares[WHITE] = e->kingSquares[BLACK] = SQ_NONE;
-  e->semiopenFiles[WHITE] = e->semiopenFiles[BLACK] = 0xFF;
-
-  Bitboard wPawns = pos.pieces(WHITE, PAWN);
-  Bitboard bPawns = pos.pieces(BLACK, PAWN);
-  e->pawnAttacks[WHITE] = shift_bb<DELTA_NE>(wPawns) | shift_bb<DELTA_NW>(wPawns);
-  e->pawnAttacks[BLACK] = shift_bb<DELTA_SE>(bPawns) | shift_bb<DELTA_SW>(bPawns);
-
-  e->value =  evaluate_pawns<WHITE>(pos, wPawns, bPawns, e)
-            - evaluate_pawns<BLACK>(pos, bPawns, wPawns, e);
+  e->value = evaluate<WHITE>(pos, e) - evaluate<BLACK>(pos, e);
   return e;
 }
 
-- 
2.39.2