Bug 640494 part 2 - Use bit masking instead of signbit() to avoid problems when including some STL headers. r=luke

js/src/jsnum.h

@@ -41,12 +41,6 @@
 #define jsnum_h___
 
 #include <math.h>
-#if defined(XP_WIN) || defined(XP_OS2)
-#include <float.h>
-#endif
-#ifdef SOLARIS
-#include <ieeefp.h>
-#endif
 #include "jsvalue.h"
 
 #include "jsstdint.h"
@@ -85,37 +79,32 @@ typedef union jsdpun {
     jsdouble d;
 } jsdpun;
 
+/* Low-level floating-point predicates. See bug 640494. */
+
 static inline int
 JSDOUBLE_IS_NaN(jsdouble d)
 {
-#ifdef WIN32
-    return _isnan(d);
-#else
-    return isnan(d);
-#endif
+    jsdpun u;
+    u.d = d;
+    return (u.u64 & JSDOUBLE_EXPMASK) == JSDOUBLE_EXPMASK &&
+           (u.u64 & JSDOUBLE_MANTMASK) != 0;
 }
 
 static inline int
 JSDOUBLE_IS_FINITE(jsdouble d)
 {
-#ifdef WIN32
-    return _finite(d);
-#else
-    return finite(d);
-#endif
+    /* -0 is finite. NaNs are not. */
+    jsdpun u;
+    u.d = d;
+    return (u.u64 & JSDOUBLE_EXPMASK) != JSDOUBLE_EXPMASK;
 }
 
 static inline int
 JSDOUBLE_IS_INFINITE(jsdouble d)
 {
-#ifdef WIN32
-    int c = _fpclass(d);
-    return c == _FPCLASS_NINF || c == _FPCLASS_PINF;
-#elif defined(SOLARIS)
-    return !finite(d) && !isnan(d);
-#else
-    return isinf(d);
-#endif
+    jsdpun u;
+    u.d = d;
+    return (u.u64 & ~JSDOUBLE_SIGNBIT) == JSDOUBLE_EXPMASK;
 }
 
 #define JSDOUBLE_HI32_SIGNBIT   0x80000000
@@ -127,13 +116,9 @@ JSDOUBLE_IS_INFINITE(jsdouble d)
 static inline bool
 JSDOUBLE_IS_NEG(jsdouble d)
 {
-#ifdef WIN32
-    return JSDOUBLE_IS_NEGZERO(d) || d < 0;
-#elif defined(SOLARIS)
-    return copysign(1, d) < 0;
-#else
-    return signbit(d);
-#endif
+    jsdpun u;
+    u.d = d;
+    return (u.s.hi & JSDOUBLE_HI32_SIGNBIT) != 0;
 }
 
 static inline uint32

js/src/jsvalue.h

@@ -89,24 +89,19 @@
 
 /* To avoid a circular dependency, pull in the necessary pieces of jsnum.h. */
 
-#include <math.h>
-#if defined(XP_WIN) || defined(XP_OS2)
-#include <float.h>
-#endif
-#ifdef SOLARIS
-#include <ieeefp.h>
-#endif
+#define JSDOUBLE_SIGNBIT (((uint64) 1) << 63)
+#define JSDOUBLE_EXPMASK (((uint64) 0x7ff) << 52)
+#define JSDOUBLE_MANTMASK ((((uint64) 1) << 52) - 1)
 
-static inline int
+static JS_ALWAYS_INLINE JSBool
 JSDOUBLE_IS_NEGZERO(jsdouble d)
 {
-#ifdef WIN32
-    return (d == 0 && (_fpclass(d) & _FPCLASS_NZ));
-#elif defined(SOLARIS)
-    return (d == 0 && copysign(1, d) < 0);
-#else
-    return (d == 0 && signbit(d));
-#endif
+    union {
+        jsdouble d;
+        uint64 bits;
+    } x;
+    x.d = d;
+    return x.bits == JSDOUBLE_SIGNBIT;
 }
 
 static inline bool