v8/src/win32-math.cc
2014-06-05 12:14:47 +00:00

83 lines
2.3 KiB
C++

// Copyright 2011 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Extra POSIX/ANSI routines for Win32 when using Visual Studio C++. Please
// refer to The Open Group Base Specification for specification of the correct
// semantics for these functions.
// (http://www.opengroup.org/onlinepubs/000095399/)
#if defined(_MSC_VER) && (_MSC_VER < 1800)
#include "src/base/win32-headers.h"
#include <limits.h> // Required for INT_MAX etc.
#include <float.h> // Required for DBL_MAX and on Win32 for finite()
#include <cmath>
#include "src/win32-math.h"
#include "src/checks.h"
namespace std {
// Test for a NaN (not a number) value - usually defined in math.h
int isnan(double x) {
return _isnan(x);
}
// Test for infinity - usually defined in math.h
int isinf(double x) {
return (_fpclass(x) & (_FPCLASS_PINF | _FPCLASS_NINF)) != 0;
}
// Test for finite value - usually defined in math.h
int isfinite(double x) {
return _finite(x);
}
// Test if x is less than y and both nominal - usually defined in math.h
int isless(double x, double y) {
return isnan(x) || isnan(y) ? 0 : x < y;
}
// Test if x is greater than y and both nominal - usually defined in math.h
int isgreater(double x, double y) {
return isnan(x) || isnan(y) ? 0 : x > y;
}
// Classify floating point number - usually defined in math.h
int fpclassify(double x) {
// Use the MS-specific _fpclass() for classification.
int flags = _fpclass(x);
// Determine class. We cannot use a switch statement because
// the _FPCLASS_ constants are defined as flags.
if (flags & (_FPCLASS_PN | _FPCLASS_NN)) return FP_NORMAL;
if (flags & (_FPCLASS_PZ | _FPCLASS_NZ)) return FP_ZERO;
if (flags & (_FPCLASS_PD | _FPCLASS_ND)) return FP_SUBNORMAL;
if (flags & (_FPCLASS_PINF | _FPCLASS_NINF)) return FP_INFINITE;
// All cases should be covered by the code above.
ASSERT(flags & (_FPCLASS_SNAN | _FPCLASS_QNAN));
return FP_NAN;
}
// Test sign - usually defined in math.h
int signbit(double x) {
// We need to take care of the special case of both positive
// and negative versions of zero.
if (x == 0)
return _fpclass(x) & _FPCLASS_NZ;
else
return x < 0;
}
} // namespace std
#endif // _MSC_VER