1 // Copyright 2011 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 // Extra POSIX/ANSI routines for Win32 when using Visual Studio C++. Please 6 // refer to The Open Group Base Specification for specification of the correct 7 // semantics for these functions. 8 // (http://www.opengroup.org/onlinepubs/000095399/) 9 #if defined(_MSC_VER) && (_MSC_VER < 1800) 10 11 #include "src/base/win32-headers.h" 12 #include <float.h> // Required for DBL_MAX and on Win32 for finite() 13 #include <limits.h> // Required for INT_MAX etc. 14 #include <cmath> 15 #include "src/base/win32-math.h" 16 17 #include "src/base/logging.h" 18 19 20 namespace std { 21 22 // Test for a NaN (not a number) value - usually defined in math.h 23 int isnan(double x) { 24 return _isnan(x); 25 } 26 27 28 // Test for infinity - usually defined in math.h 29 int isinf(double x) { 30 return (_fpclass(x) & (_FPCLASS_PINF | _FPCLASS_NINF)) != 0; 31 } 32 33 34 // Test for finite value - usually defined in math.h 35 int isfinite(double x) { 36 return _finite(x); 37 } 38 39 40 // Test if x is less than y and both nominal - usually defined in math.h 41 int isless(double x, double y) { 42 return isnan(x) || isnan(y) ? 0 : x < y; 43 } 44 45 46 // Test if x is greater than y and both nominal - usually defined in math.h 47 int isgreater(double x, double y) { 48 return isnan(x) || isnan(y) ? 0 : x > y; 49 } 50 51 52 // Classify floating point number - usually defined in math.h 53 int fpclassify(double x) { 54 // Use the MS-specific _fpclass() for classification. 55 int flags = _fpclass(x); 56 57 // Determine class. We cannot use a switch statement because 58 // the _FPCLASS_ constants are defined as flags. 59 if (flags & (_FPCLASS_PN | _FPCLASS_NN)) return FP_NORMAL; 60 if (flags & (_FPCLASS_PZ | _FPCLASS_NZ)) return FP_ZERO; 61 if (flags & (_FPCLASS_PD | _FPCLASS_ND)) return FP_SUBNORMAL; 62 if (flags & (_FPCLASS_PINF | _FPCLASS_NINF)) return FP_INFINITE; 63 64 // All cases should be covered by the code above. 65 DCHECK(flags & (_FPCLASS_SNAN | _FPCLASS_QNAN)); 66 return FP_NAN; 67 } 68 69 70 // Test sign - usually defined in math.h 71 int signbit(double x) { 72 // We need to take care of the special case of both positive 73 // and negative versions of zero. 74 if (x == 0) 75 return _fpclass(x) & _FPCLASS_NZ; 76 else 77 return x < 0; 78 } 79 80 } // namespace std 81 82 #endif // _MSC_VER 83
