| // Copyright 2006-2008 the V8 project authors. All rights reserved. |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following |
| // disclaimer in the documentation and/or other materials provided |
| // with the distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived |
| // from this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #ifndef V8_CONVERSIONS_INL_H_ |
| #define V8_CONVERSIONS_INL_H_ |
| |
| #include <math.h> |
| #include <float.h> // required for DBL_MAX and on Win32 for finite() |
| #include <stdarg.h> |
| |
| // ---------------------------------------------------------------------------- |
| // Extra POSIX/ANSI functions for Win32/MSVC. |
| |
| #include "conversions.h" |
| #include "platform.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| // The fast double-to-int conversion routine does not guarantee |
| // rounding towards zero. |
| static inline int FastD2I(double x) { |
| #ifdef __USE_ISOC99 |
| // The ISO C99 standard defines the lrint() function which rounds a |
| // double to an integer according to the current rounding direction. |
| return lrint(x); |
| #else |
| // This is incredibly slow on Intel x86. The reason is that rounding |
| // towards zero is implied by the C standard. This means that the |
| // status register of the FPU has to be changed with the 'fldcw' |
| // instruction. This completely stalls the pipeline and takes many |
| // hundreds of clock cycles. |
| return static_cast<int>(x); |
| #endif |
| } |
| |
| |
| // The fast double-to-unsigned-int conversion routine does not guarantee |
| // rounding towards zero. |
| static inline unsigned int FastD2UI(double x) { |
| // There is no unsigned version of lrint, so there is no fast path |
| // in this function as there is in FastD2I. Using lrint doesn't work |
| // for values of 2^31 and above. |
| |
| // Convert "small enough" doubles to uint32_t by fixing the 32 |
| // least significant non-fractional bits in the low 32 bits of the |
| // double, and reading them from there. |
| const double k2Pow52 = 4503599627370496.0; |
| bool negative = x < 0; |
| if (negative) { |
| x = -x; |
| } |
| if (x < k2Pow52) { |
| x += k2Pow52; |
| uint32_t result; |
| memcpy(&result, &x, sizeof(result)); // Copy low 32 bits. |
| return negative ? ~result + 1 : result; |
| } |
| // Large number (outside uint32 range), Infinity or NaN. |
| return 0x80000000u; // Return integer indefinite. |
| } |
| |
| |
| static inline double DoubleToInteger(double x) { |
| if (isnan(x)) return 0; |
| if (!isfinite(x) || x == 0) return x; |
| return (x >= 0) ? floor(x) : ceil(x); |
| } |
| |
| |
| int32_t NumberToInt32(Object* number) { |
| if (number->IsSmi()) return Smi::cast(number)->value(); |
| return DoubleToInt32(number->Number()); |
| } |
| |
| |
| uint32_t NumberToUint32(Object* number) { |
| if (number->IsSmi()) return Smi::cast(number)->value(); |
| return DoubleToUint32(number->Number()); |
| } |
| |
| |
| int32_t DoubleToInt32(double x) { |
| int32_t i = FastD2I(x); |
| if (FastI2D(i) == x) return i; |
| static const double two32 = 4294967296.0; |
| static const double two31 = 2147483648.0; |
| if (!isfinite(x) || x == 0) return 0; |
| if (x < 0 || x >= two32) x = modulo(x, two32); |
| x = (x >= 0) ? floor(x) : ceil(x) + two32; |
| return (int32_t) ((x >= two31) ? x - two32 : x); |
| } |
| |
| |
| } } // namespace v8::internal |
| |
| #endif // V8_CONVERSIONS_INL_H_ |