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
20namespace std {
21
22// Test for a NaN (not a number) value - usually defined in math.h
23int isnan(double x) {
24  return _isnan(x);
25}
26
27
28// Test for infinity - usually defined in math.h
29int 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
35int 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
41int 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
47int 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
53int 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
71int 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