internal::fp Class Reference

#include <format-inl.h>

Public Member Functions
	fp ()
	fp (uint64_t f_val, int e_val)
template<typename Double >
	fp (Double d)
template<int SHIFT = 0>
void	normalize ()
void	compute_boundaries (fp &lower, fp &upper) const

Public Attributes
significand_type	f
int	e

Static Public Attributes
static FMT_CONSTEXPR_DECL const int	significand_size

Private Types
typedef uint64_t	significand_type

Static Private Attributes
static FMT_CONSTEXPR_DECL const int	char_size
static FMT_CONSTEXPR_DECL const int	double_significand_size
static FMT_CONSTEXPR_DECL const uint64_t	implicit_bit

Detailed Description

Definition at line 353 of file format-inl.h.

Member Typedef Documentation

typedef uint64_t internal::fp::significand_type

private

Definition at line 355 of file format-inl.h.

Constructor & Destructor Documentation

internal::fp::fp ( )

inline

Definition at line 374 of file format-inl.h.

: f(0), e(0) {}

internal::fp::fp ( uint64_t  f_val, int  e_val  )

inline

Definition at line 375 of file format-inl.h.

: f(f_val), e(e_val) {}

template<typename Double >

internal::fp::fp ( Double  d )

inlineexplicit

Definition at line 380 of file format-inl.h.

                        {
    // Assume double is in the format [sign][exponent][significand].
    typedef std::numeric_limits<Double> limits;
    const int double_size = static_cast<int>(sizeof(Double) * char_size);
    const int exponent_size =
      double_size - double_significand_size - 1;  // -1 for sign
    const uint64_t significand_mask = implicit_bit - 1;
    const uint64_t exponent_mask = (~0ull >> 1) & ~significand_mask;
    const int exponent_bias = (1 << exponent_size) - limits::max_exponent - 1;
    auto u = bit_cast<uint64_t>(d);
    auto biased_e = (u & exponent_mask) >> double_significand_size;
    f = u & significand_mask;
    if (biased_e != 0)
      f += implicit_bit;
    else
      biased_e = 1;  // Subnormals use biased exponent 1 (min exponent).
    e = static_cast<int>(biased_e - exponent_bias - double_significand_size);
  }

Member Function Documentation

void internal::fp::compute_boundaries ( fp &  lower, fp &  upper  ) const

inline

Definition at line 418 of file format-inl.h.

                                                      {
    lower = f == implicit_bit ?
          fp((f << 2) - 1, e - 2) : fp((f << 1) - 1, e - 1);
    upper = fp((f << 1) + 1, e - 1);
    upper.normalize<1>();  // 1 is to account for the exponent shift above.
    lower.f <<= lower.e - upper.e;
    lower.e = upper.e;
  }

template<int SHIFT = 0>

void internal::fp::normalize ( )

inline

Definition at line 401 of file format-inl.h.

                   {
    // Handle subnormals.
    auto shifted_implicit_bit = implicit_bit << SHIFT;
    while ((f & shifted_implicit_bit) == 0) {
      f <<= 1;
      --e;
    }
    // Subtract 1 to account for hidden bit.
    auto offset = significand_size - double_significand_size - SHIFT - 1;
    f <<= offset;
    e -= offset;
  }

Member Data Documentation

FMT_CONSTEXPR_DECL const int internal::fp::char_size

staticprivate

Initial value:

=
    std::numeric_limits<unsigned char>::digits

Definition at line 358 of file format-inl.h.

FMT_CONSTEXPR_DECL const int internal::fp::double_significand_size

staticprivate

Initial value:

=
    std::numeric_limits<double>::digits - 1

Definition at line 362 of file format-inl.h.

int internal::fp::e

Definition at line 369 of file format-inl.h.

significand_type internal::fp::f

Definition at line 368 of file format-inl.h.

FMT_CONSTEXPR_DECL const uint64_t internal::fp::implicit_bit

staticprivate

Initial value:

=
    1ull << double_significand_size

Definition at line 364 of file format-inl.h.

FMT_CONSTEXPR_DECL const int internal::fp::significand_size

static

Initial value:

=
    sizeof(significand_type) * char_size

Definition at line 371 of file format-inl.h.

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The documentation for this class was generated from the following file:

• wire-cell-build/util/inc/spdlog/fmt/bundled/format-inl.h