mirror of
https://github.com/ecency/ecency-mobile.git
synced 2024-12-22 21:01:31 +03:00
119 lines
3.9 KiB
C++
119 lines
3.9 KiB
C++
// Copyright 2010 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 DOUBLE_CONVERSION_DIY_FP_H_
|
|
#define DOUBLE_CONVERSION_DIY_FP_H_
|
|
|
|
#include "utils.h"
|
|
|
|
namespace double_conversion {
|
|
|
|
// This "Do It Yourself Floating Point" class implements a floating-point number
|
|
// with a uint64 significand and an int exponent. Normalized DiyFp numbers will
|
|
// have the most significant bit of the significand set.
|
|
// Multiplication and Subtraction do not normalize their results.
|
|
// DiyFp are not designed to contain special doubles (NaN and Infinity).
|
|
class DiyFp {
|
|
public:
|
|
static const int kSignificandSize = 64;
|
|
|
|
DiyFp() : f_(0), e_(0) {}
|
|
DiyFp(uint64_t f, int e) : f_(f), e_(e) {}
|
|
|
|
// this = this - other.
|
|
// The exponents of both numbers must be the same and the significand of this
|
|
// must be bigger than the significand of other.
|
|
// The result will not be normalized.
|
|
void Subtract(const DiyFp& other) {
|
|
ASSERT(e_ == other.e_);
|
|
ASSERT(f_ >= other.f_);
|
|
f_ -= other.f_;
|
|
}
|
|
|
|
// Returns a - b.
|
|
// The exponents of both numbers must be the same and this must be bigger
|
|
// than other. The result will not be normalized.
|
|
static DiyFp Minus(const DiyFp& a, const DiyFp& b) {
|
|
DiyFp result = a;
|
|
result.Subtract(b);
|
|
return result;
|
|
}
|
|
|
|
|
|
// this = this * other.
|
|
void Multiply(const DiyFp& other);
|
|
|
|
// returns a * b;
|
|
static DiyFp Times(const DiyFp& a, const DiyFp& b) {
|
|
DiyFp result = a;
|
|
result.Multiply(b);
|
|
return result;
|
|
}
|
|
|
|
void Normalize() {
|
|
ASSERT(f_ != 0);
|
|
uint64_t f = f_;
|
|
int e = e_;
|
|
|
|
// This method is mainly called for normalizing boundaries. In general
|
|
// boundaries need to be shifted by 10 bits. We thus optimize for this case.
|
|
const uint64_t k10MSBits = UINT64_2PART_C(0xFFC00000, 00000000);
|
|
while ((f & k10MSBits) == 0) {
|
|
f <<= 10;
|
|
e -= 10;
|
|
}
|
|
while ((f & kUint64MSB) == 0) {
|
|
f <<= 1;
|
|
e--;
|
|
}
|
|
f_ = f;
|
|
e_ = e;
|
|
}
|
|
|
|
static DiyFp Normalize(const DiyFp& a) {
|
|
DiyFp result = a;
|
|
result.Normalize();
|
|
return result;
|
|
}
|
|
|
|
uint64_t f() const { return f_; }
|
|
int e() const { return e_; }
|
|
|
|
void set_f(uint64_t new_value) { f_ = new_value; }
|
|
void set_e(int new_value) { e_ = new_value; }
|
|
|
|
private:
|
|
static const uint64_t kUint64MSB = UINT64_2PART_C(0x80000000, 00000000);
|
|
|
|
uint64_t f_;
|
|
int e_;
|
|
};
|
|
|
|
} // namespace double_conversion
|
|
|
|
#endif // DOUBLE_CONVERSION_DIY_FP_H_
|