X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fvalue.h;h=364844555abead4ca5b79d62a819f024c6cad5a8;hp=ee093a6e13dcc32ea4ef8adb1ac972812c4498be;hb=9e6d38d224e35e509521d9dced4a46cde021fd83;hpb=06f06a9be8b888c540e95bbc35a84b541fef4a34

diff --git a/src/value.h b/src/value.h
index ee093a6e..36484455 100644
--- a/src/value.h
+++ b/src/value.h
@@ -52,39 +52,43 @@ enum Value {
 };
 
 
-/// Score struct keeps a midgame and an endgame value in a single
-/// ScoreValue 64 bit union.
-
-union ScoreValue {
-    int64_t v64;
-    struct {
-      int32_t mgv;
-      int32_t egv;
-    } v32;
-};
+/// Score enum keeps a midgame and an endgame value in a single
+/// integer (enum), first LSB 16 bits are used to store endgame
+/// value, while upper bits are used for midgame value.
 
-struct Score {
+// Compiler is free to choose the enum type as long as can keep
+// its data, so ensure Score to be an integer type.
+enum Score { ENSURE_32_BITS_SIZE_P = (1 << 16), ENSURE_32_BITS_SIZE_N = -(1 << 16)};
 
-    Score() {}
-    Score(const Score& s) { v = s.v; }
-    Score(int mg, int eg) { v.v32.mgv = int32_t(mg); v.v32.egv = int32_t(eg); }
+// Extracting the _signed_ lower and upper 16 bits it not so trivial
+// because according to the standard a simple cast to short is
+// implementation defined and so is a right shift of a signed integer.
+inline Value mg_value(Score s) { return Value(((int(s) + 32768) & ~0xffff) / 0x10000); }
 
-    Score& operator=(const Score& s) { v = s.v; return *this; }
-    Score& operator+=(const Score& s) { v.v32.mgv += s.v.v32.mgv; v.v32.egv += s.v.v32.egv; return *this; }
-    Score& operator-=(const Score& s) { v.v32.mgv -= s.v.v32.mgv; v.v32.egv -= s.v.v32.egv; return *this; }
+// Unfortunatly on Intel 64 bit we have a small speed regression, so use a faster code in
+// this case, although not 100% standard compliant it seems to work for Intel and MSVC.
+#if defined(IS_64BIT) && (!defined(__GNUC__) || defined(__INTEL_COMPILER))
+inline Value eg_value(Score s) { return Value(int16_t(s & 0xffff)); }
+#else
+inline Value eg_value(Score s) { return Value((int)(unsigned(s) & 0x7fffu) - (int)(unsigned(s) & 0x8000u)); }
+#endif
 
-    Value mg() const { return Value(v.v32.mgv); }
-    Value eg() const { return Value(v.v32.egv); }
+inline Score make_score(int mg, int eg) { return Score((mg << 16) + eg); }
 
-private:
-    ScoreValue v;
-};
+inline Score operator-(Score s) { return Score(-int(s)); }
+inline Score operator+(Score s1, Score s2) { return Score(int(s1) + int(s2)); }
+inline Score operator-(Score s1, Score s2) { return Score(int(s1) - int(s2)); }
+inline void operator+=(Score& s1, Score s2) { s1 = Score(int(s1) + int(s2)); }
+inline void operator-=(Score& s1, Score s2) { s1 = Score(int(s1) - int(s2)); }
+inline Score operator*(int i, Score s) { return Score(i * int(s)); }
+
+// Division must be handled separately for each term
+inline Score operator/(Score s, int i) { return make_score(mg_value(s) / i, eg_value(s) / i); }
 
-inline Score operator*(int i, Score s) { return Score(i * s.mg(), i * s.eg()); }
-inline Score operator*(Score s, int i) { return s * i; }
-inline Score operator-(Score s) { return Score(-s.mg(), -s.eg()); }
+// Only declared but not defined. We don't want to multiply two scores due to
+// a very high risk of overflow. So user should explicitly convert to integer.
+inline Score operator*(Score s1, Score s2);
 
-extern std::ostream& operator<<(std::ostream& os, Score s);
 
 ////
 //// Constants and variables
@@ -131,7 +135,7 @@ const Value PieceValueEndgame[17] = {
 
 /// Bonus for having the side to move (modified by Joona Kiiski)
 
-const Score TempoValue = Score(48, 22);
+const Score TempoValue = make_score(48, 22);
 
 
 ////