From: Chris Cain <chricainogithub@gmail.com>
Date: Tue, 6 Mar 2018 00:32:16 +0000 (+0100)
Subject: Introduce variadic make_bitboard()
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=3192b09fe0258ec7654aa2c13bbc17b8417e6964

Introduce variadic make_bitboard()

Adds a helper function to make a bitboard from a list of squares.

No functional change
---

diff --git a/src/bitboard.h b/src/bitboard.h
index cf948afc..9fc53ee7 100644
--- a/src/bitboard.h
+++ b/src/bitboard.h
@@ -150,7 +150,17 @@ inline Bitboard file_bb(Square s) {
 }
 
 
-/// shift() moves a bitboard one step along direction D. Mainly for pawns
+/// make_bitboard() returns a bitboard from a list of squares
+
+constexpr Bitboard make_bitboard() { return 0; }
+
+template<typename ...Squares>
+constexpr Bitboard make_bitboard(Square s, Squares... squares) {
+  return (1ULL << s) | make_bitboard(squares...);
+}
+
+
+/// shift() moves a bitboard one step along direction D (mainly for pawns)
 
 template<Direction D>
 constexpr Bitboard shift(Bitboard b) {
diff --git a/src/pawns.cpp b/src/pawns.cpp
index 42819e14..29a98751 100644
--- a/src/pawns.cpp
+++ b/src/pawns.cpp
@@ -236,11 +236,13 @@ Entry* probe(const Position& pos) {
 template<Color Us>
 Value Entry::shelter_storm(const Position& pos, Square ksq) {
 
-  const Color Them = (Us == WHITE ? BLACK : WHITE);
-  const Bitboard ShelterMask = (Us == WHITE ? 1ULL << SQ_A2 | 1ULL << SQ_B3 | 1ULL << SQ_C2 | 1ULL << SQ_F2 | 1ULL << SQ_G3 | 1ULL << SQ_H2
-                                            : 1ULL << SQ_A7 | 1ULL << SQ_B6 | 1ULL << SQ_C7 | 1ULL << SQ_F7 | 1ULL << SQ_G6 | 1ULL << SQ_H7);
-  const Bitboard StormMask   = (Us == WHITE ? 1ULL << SQ_A3 | 1ULL << SQ_C3 | 1ULL << SQ_F3 | 1ULL << SQ_H3
-                                            : 1ULL << SQ_A6 | 1ULL << SQ_C6 | 1ULL << SQ_F6 | 1ULL << SQ_H6);
+  constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+  constexpr Bitboard ShelterMask = 
+                Us == WHITE ? make_bitboard(SQ_A2, SQ_B3, SQ_C2, SQ_F2, SQ_G3, SQ_H2)
+                            : make_bitboard(SQ_A7, SQ_B6, SQ_C7, SQ_F7, SQ_G6, SQ_H7);
+  constexpr Bitboard StormMask =
+                Us == WHITE ? make_bitboard(SQ_A3, SQ_C3, SQ_F3, SQ_H3)
+                            : make_bitboard(SQ_A6, SQ_C6, SQ_F6, SQ_H6);
 
   enum { BlockedByKing, Unopposed, BlockedByPawn, Unblocked };