6f1d641fb6
Review URL: http://codereview.chromium.org/303034 git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3116 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
96 lines
3.5 KiB
C++
96 lines
3.5 KiB
C++
// Copyright 2006-2008 the V8 project authors. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following
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// disclaimer in the documentation and/or other materials provided
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// with the distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#ifndef V8_CONVERSIONS_INL_H_
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#define V8_CONVERSIONS_INL_H_
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#include <math.h>
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#include <float.h> // required for DBL_MAX and on Win32 for finite()
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#include <stdarg.h>
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// ----------------------------------------------------------------------------
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// Extra POSIX/ANSI functions for Win32/MSVC.
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#include "conversions.h"
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#include "platform.h"
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namespace v8 {
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namespace internal {
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// The fast double-to-int conversion routine does not guarantee
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// rounding towards zero.
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static inline int FastD2I(double x) {
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#ifdef __USE_ISOC99
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// The ISO C99 standard defines the lrint() function which rounds a
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// double to an integer according to the current rounding direction.
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return lrint(x);
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#else
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// This is incredibly slow on Intel x86. The reason is that rounding
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// towards zero is implied by the C standard. This means that the
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// status register of the FPU has to be changed with the 'fldcw'
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// instruction. This completely stalls the pipeline and takes many
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// hundreds of clock cycles.
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return static_cast<int>(x);
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#endif
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}
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static inline double DoubleToInteger(double x) {
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if (isnan(x)) return 0;
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if (!isfinite(x) || x == 0) return x;
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return (x >= 0) ? floor(x) : ceil(x);
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}
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int32_t NumberToInt32(Object* number) {
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if (number->IsSmi()) return Smi::cast(number)->value();
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return DoubleToInt32(number->Number());
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}
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uint32_t NumberToUint32(Object* number) {
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if (number->IsSmi()) return Smi::cast(number)->value();
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return DoubleToUint32(number->Number());
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}
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int32_t DoubleToInt32(double x) {
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int32_t i = FastD2I(x);
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if (FastI2D(i) == x) return i;
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static const double two32 = 4294967296.0;
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static const double two31 = 2147483648.0;
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if (!isfinite(x) || x == 0) return 0;
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if (x < 0 || x >= two32) x = modulo(x, two32);
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x = (x >= 0) ? floor(x) : ceil(x) + two32;
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return (int32_t) ((x >= two31) ? x - two32 : x);
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}
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} } // namespace v8::internal
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#endif // V8_CONVERSIONS_INL_H_
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