MathUtil: fix IsQNAN()

The constants were one nibble too short and the lower 51 bits don't
actually have to be zero.

1 files changed, 25 insertions, 14 deletions

diff --git a/Source/Core/Common/MathUtil.h b/Source/Core/Common/MathUtil.h
index 0febed3014..9ddacd6e1c 100644
--- a/Source/Core/Common/MathUtil.h
+++ b/Source/Core/Common/MathUtil.h
@@ -20,16 +20,18 @@ inline void Clamp(T* val, const T& min, const T& max)
 		*val = max;
 }
 
+// The most significant bit of the fraction is an is-quiet bit on all architectures we care about.
 
 static const u64 DOUBLE_SIGN = 0x8000000000000000ULL,
-	DOUBLE_EXP  = 0x7FF0000000000000ULL,
-	DOUBLE_FRAC = 0x000FFFFFFFFFFFFFULL,
-	DOUBLE_ZERO = 0x0000000000000000ULL;
+                 DOUBLE_EXP  = 0x7FF0000000000000ULL,
+                 DOUBLE_FRAC = 0x000FFFFFFFFFFFFFULL,
+                 DOUBLE_ZERO = 0x0000000000000000ULL,
+                 DOUBLE_QBIT = 0x0008000000000000ULL;
 
 static const u32 FLOAT_SIGN = 0x80000000,
-	FLOAT_EXP  = 0x7F800000,
-	FLOAT_FRAC = 0x007FFFFF,
-	FLOAT_ZERO = 0x00000000;
+                 FLOAT_EXP  = 0x7F800000,
+                 FLOAT_FRAC = 0x007FFFFF,
+                 FLOAT_ZERO = 0x00000000;
 
 union IntDouble {
 	double d;
@@ -40,34 +42,41 @@ union IntFloat {
 	u32 i;
 };
 
+inline bool IsINF(double d)
+{
+	IntDouble x; x.d = d;
+	return (x.i & ~DOUBLE_SIGN) == DOUBLE_EXP;
+}
+
 inline bool IsNAN(double d)
 {
 	IntDouble x; x.d = d;
-	return ( ((x.i & DOUBLE_EXP) == DOUBLE_EXP) &&
-			 ((x.i & DOUBLE_FRAC) != DOUBLE_ZERO) );
+	return ((x.i & DOUBLE_EXP) == DOUBLE_EXP) &&
+	       ((x.i & DOUBLE_FRAC) != DOUBLE_ZERO);
 }
 
 inline bool IsQNAN(double d)
 {
 	IntDouble x; x.d = d;
-	return ( ((x.i & DOUBLE_EXP) == DOUBLE_EXP) &&
-		     ((x.i & 0x0007fffffffffffULL) == 0x000000000000000ULL) &&
-		     ((x.i & 0x000800000000000ULL) == 0x000800000000000ULL) );
+	return ((x.i & DOUBLE_EXP) == DOUBLE_EXP) &&
+	       ((x.i & DOUBLE_QBIT) == DOUBLE_QBIT);
 }
 
 inline bool IsSNAN(double d)
 {
 	IntDouble x; x.d = d;
-	return( ((x.i & DOUBLE_EXP) == DOUBLE_EXP) &&
-			((x.i & DOUBLE_FRAC) != DOUBLE_ZERO) &&
-			((x.i & 0x0008000000000000ULL) == DOUBLE_ZERO) );
+	return ((x.i & DOUBLE_EXP) == DOUBLE_EXP) &&
+	       ((x.i & DOUBLE_FRAC) != DOUBLE_ZERO) &&
+	       ((x.i & DOUBLE_QBIT) == DOUBLE_ZERO);
 }
 
 inline float FlushToZero(float f)
 {
 	IntFloat x; x.f = f;
 	if ((x.i & FLOAT_EXP) == 0)
+	{
 		x.i &= FLOAT_SIGN;  // turn into signed zero
+	}
 	return x.f;
 }
 
@@ -75,7 +84,9 @@ inline double FlushToZero(double d)
 {
 	IntDouble x; x.d = d;
 	if ((x.i & DOUBLE_EXP) == 0)
+	{
 		x.i &= DOUBLE_SIGN;  // turn into signed zero
+	}
 	return x.d;
 }