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      1 // Copyright 2011 the V8 project authors. All rights reserved.
      2 // Redistribution and use in source and binary forms, with or without
      3 // modification, are permitted provided that the following conditions are
      4 // met:
      5 //
      6 //     * Redistributions of source code must retain the above copyright
      7 //       notice, this list of conditions and the following disclaimer.
      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
     10 //       disclaimer in the documentation and/or other materials provided
     11 //       with the distribution.
     12 //     * Neither the name of Google Inc. nor the names of its
     13 //       contributors may be used to endorse or promote products derived
     14 //       from this software without specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 
     28 // Extra POSIX/ANSI routines for Win32 when using Visual Studio C++. Please
     29 // refer to The Open Group Base Specification for specification of the correct
     30 // semantics for these functions.
     31 // (http://www.opengroup.org/onlinepubs/000095399/)
     32 #ifdef _MSC_VER
     33 
     34 #undef V8_WIN32_LEAN_AND_MEAN
     35 #define V8_WIN32_HEADERS_FULL
     36 #include "win32-headers.h"
     37 #include <limits.h>        // Required for INT_MAX etc.
     38 #include <math.h>
     39 #include <float.h>         // Required for DBL_MAX and on Win32 for finite()
     40 #include "win32-math.h"
     41 
     42 #include "checks.h"
     43 
     44 namespace v8 {
     45 
     46 // Test for finite value - usually defined in math.h
     47 int isfinite(double x) {
     48   return _finite(x);
     49 }
     50 
     51 }  // namespace v8
     52 
     53 
     54 // Test for a NaN (not a number) value - usually defined in math.h
     55 int isnan(double x) {
     56   return _isnan(x);
     57 }
     58 
     59 
     60 // Test for infinity - usually defined in math.h
     61 int isinf(double x) {
     62   return (_fpclass(x) & (_FPCLASS_PINF | _FPCLASS_NINF)) != 0;
     63 }
     64 
     65 
     66 // Test if x is less than y and both nominal - usually defined in math.h
     67 int isless(double x, double y) {
     68   return isnan(x) || isnan(y) ? 0 : x < y;
     69 }
     70 
     71 
     72 // Test if x is greater than y and both nominal - usually defined in math.h
     73 int isgreater(double x, double y) {
     74   return isnan(x) || isnan(y) ? 0 : x > y;
     75 }
     76 
     77 
     78 // Classify floating point number - usually defined in math.h
     79 int fpclassify(double x) {
     80   // Use the MS-specific _fpclass() for classification.
     81   int flags = _fpclass(x);
     82 
     83   // Determine class. We cannot use a switch statement because
     84   // the _FPCLASS_ constants are defined as flags.
     85   if (flags & (_FPCLASS_PN | _FPCLASS_NN)) return FP_NORMAL;
     86   if (flags & (_FPCLASS_PZ | _FPCLASS_NZ)) return FP_ZERO;
     87   if (flags & (_FPCLASS_PD | _FPCLASS_ND)) return FP_SUBNORMAL;
     88   if (flags & (_FPCLASS_PINF | _FPCLASS_NINF)) return FP_INFINITE;
     89 
     90   // All cases should be covered by the code above.
     91   ASSERT(flags & (_FPCLASS_SNAN | _FPCLASS_QNAN));
     92   return FP_NAN;
     93 }
     94 
     95 
     96 // Test sign - usually defined in math.h
     97 int signbit(double x) {
     98   // We need to take care of the special case of both positive
     99   // and negative versions of zero.
    100   if (x == 0)
    101     return _fpclass(x) & _FPCLASS_NZ;
    102   else
    103     return x < 0;
    104 }
    105 
    106 #endif  // _MSC_VER
    107