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//===-- Common operations on floating point numbers -------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "BitPatterns.h"
#include "FloatOperations.h"
#include "FloatProperties.h"
#include "utils/CPP/TypeTraits.h"
#ifndef LLVM_LIBC_UTILS_FPUTIL_MANIPULATION_FUNCTIONS_H
#define LLVM_LIBC_UTILS_FPUTIL_MANIPULATION_FUNCTIONS_H
namespace __llvm_libc {
namespace fputil {
template <typename T,
cpp::EnableIfType<cpp::IsFloatingPointType<T>::Value, int> = 0>
static inline T frexp(T x, int &exp) {
using Properties = FloatProperties<T>;
using BitsType = typename Properties::BitsType;
auto bits = valueAsBits(x);
if (bitsAreInfOrNaN(bits))
return x;
if (bitsAreZero(bits)) {
exp = 0;
return x;
}
exp = getExponentFromBits(bits) + 1;
static constexpr BitsType resultExponent =
Properties::exponentOffset - BitsType(1);
// Capture the sign and mantissa part.
bits &= (Properties::mantissaMask | Properties::signMask);
// Insert the new exponent.
bits |= (resultExponent << Properties::mantissaWidth);
return valueFromBits(bits);
}
template <typename T,
cpp::EnableIfType<cpp::IsFloatingPointType<T>::Value, int> = 0>
static inline T modf(T x, T &iptr) {
auto bits = valueAsBits(x);
if (bitsAreZero(bits) || bitsAreNaN(bits)) {
iptr = x;
return x;
} else if (bitsAreInf(bits)) {
iptr = x;
return bits & FloatProperties<T>::signMask
? valueFromBits(BitPatterns<T>::negZero)
: valueFromBits(BitPatterns<T>::zero);
} else {
iptr = trunc(x);
if (x == iptr) {
// If x is already an integer value, then return zero with the right
// sign.
return bits & FloatProperties<T>::signMask
? valueFromBits(BitPatterns<T>::negZero)
: valueFromBits(BitPatterns<T>::zero);
} else {
return x - iptr;
}
}
}
template <typename T,
cpp::EnableIfType<cpp::IsFloatingPointType<T>::Value, int> = 0>
static inline T copysign(T x, T y) {
constexpr auto signMask = FloatProperties<T>::signMask;
auto xbits = valueAsBits(x);
auto ybits = valueAsBits(y);
return valueFromBits((xbits & ~signMask) | (ybits & signMask));
}
template <typename T,
cpp::EnableIfType<cpp::IsFloatingPointType<T>::Value, int> = 0>
static inline T logb(T x) {
auto bits = valueAsBits(x);
if (bitsAreZero(bits)) {
// TODO(Floating point exception): Raise div-by-zero exception.
// TODO(errno): POSIX requires setting errno to ERANGE.
return valueFromBits(BitPatterns<T>::negInf);
} else if (bitsAreInf(bits)) {
return valueFromBits(BitPatterns<T>::inf);
} else if (bitsAreNaN(bits)) {
return x;
} else {
return getExponentFromBits(bits);
}
}
} // namespace fputil
} // namespace __llvm_libc
#endif // LLVM_LIBC_UTILS_FPUTIL_MANIPULATION_FUNCTIONS_H
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