\keyword 16-bit Floating Point Support\inmodule QtCore \inheaderfile QFloat16 More...

#include <qfloat16.h>

Collaboration diagram for qfloat16:

Public Types
using	NativeType = QtPrivate::NativeFloat16Type
using	NearestFloat = std::conditional_t<IsNative, NativeType, float>

Public Member Functions
constexpr	qfloat16 () noexcept
	qfloat16 (Qt::Initialization) noexcept
	qfloat16 (float f) noexcept
	operator float () const noexcept
template<typename T, typename = std::enable_if_t<std::is_arithmetic_v<T> && !std::is_same_v<T, NearestFloat>>>
constexpr	qfloat16 (T value) noexcept
bool	isInf () const noexcept
bool	isNaN () const noexcept
bool	isFinite () const noexcept
Q_CORE_EXPORT int	fpClassify () const noexcept
qfloat16	copySign (qfloat16 sign) const noexcept
constexpr bool	isNormal () const noexcept

Static Public Member Functions
static constexpr qfloat16	_limit_epsilon () noexcept
static constexpr qfloat16	_limit_min () noexcept
static constexpr qfloat16	_limit_denorm_min () noexcept
static constexpr qfloat16	_limit_max () noexcept
static constexpr qfloat16	_limit_lowest () noexcept
static constexpr qfloat16	_limit_infinity () noexcept
static constexpr qfloat16	_limit_quiet_NaN () noexcept

Static Public Attributes
static constexpr bool	IsNative = QFLOAT16_IS_NATIVE

Friends
qfloat16	copysign (qfloat16 mag, qfloat16 sign) noexcept
bool	signbit (qfloat16 x) noexcept
bool	qIsNull (qfloat16 f)
qfloat16	operator- (qfloat16 a) noexcept
qfloat16	operator+ (qfloat16 a, qfloat16 b) noexcept
qfloat16	operator- (qfloat16 a, qfloat16 b) noexcept
qfloat16	operator* (qfloat16 a, qfloat16 b) noexcept
qfloat16	operator/ (qfloat16 a, qfloat16 b) noexcept
size_t	qHash (qfloat16 key, size_t seed=0) noexcept
QF16_CONSTEXPR bool	comparesEqual (const qfloat16 &lhs, const qfloat16 &rhs) noexcept
QF16_CONSTEXPR Qt::partial_ordering	compareThreeWay (const qfloat16 &lhs, const qfloat16 &rhs) noexcept
template<typename T, if_type_is_integral< T > = true>
QF16_CONSTEXPR bool	comparesEqual (const qfloat16 &lhs, T rhs) noexcept
template<typename T, if_type_is_integral< T > = true>
QF16_CONSTEXPR Qt::partial_ordering	compareThreeWay (const qfloat16 &lhs, T rhs) noexcept
QT_WARNING_POP friend Q_CORE_EXPORT QDataStream &	operator<< (QDataStream &ds, qfloat16 f)
Q_CORE_EXPORT QDataStream &	operator>> (QDataStream &ds, qfloat16 &f)
Q_CORE_EXPORT QTextStream &	operator<< (QTextStream &ts, qfloat16 f)
Q_CORE_EXPORT QTextStream &	operator>> (QTextStream &ts, qfloat16 &f)

Related Symbols
(Note that these are not member symbols.)
bool	qIsInfqIsInf (qfloat16 f)(float)
	Returns true if the `qfloat16` {f} is equivalent to infinity.
bool	qIsNaNqIsNaN (qfloat16 f)(float)
	Returns true if the `qfloat16` {f} is not a number (NaN).
bool	qIsFiniteqIsFinite (qfloat16 f)(float)
	Returns true if the `qfloat16` {f} is a finite number.
int	qFpClassifyqFpClassify (qfloat16 val)(float)
int	qRoundqRound (qfloat16 value)(float)
	Rounds value to the nearest integer.
qint64	qRound64qRound64 (qfloat16 value)(float)
	Rounds value to the nearest 64-bit integer.
bool	qFuzzyCompareqFuzzyCompare (qfloat16 p1, qfloat16 p2)(float, float)
	Compares the floating point value p1 and p2 and returns `true` if they are considered equal, otherwise `false`.
Q_CORE_EXPORT void	qFloatToFloat16 (qfloat16 out, const float in, qsizetype len) noexcept
Q_CORE_EXPORT void	qFloatFromFloat16 (float out, const qfloat16 in, qsizetype len) noexcept

Detailed Description

\keyword 16-bit Floating Point Support

\inmodule QtCore \inheaderfile QFloat16

Provides 16-bit floating point support.

\compares partial \compareswith partial float double {long double} qint8 quint8 qint16 quint16 \ qint32 quint32 long {unsigned long} qint64 quint64 \endcompareswith \compareswith partial qint128 quint128 Comparison with 128-bit integral types is only supported if Qt provides these types. \endcompareswith

The qfloat16 class provides support for half-precision (16-bit) floating point data. It is fully compliant with IEEE 754 as a storage type. This implies that any arithmetic operation on a qfloat16 instance results in the value first being converted to a float. This conversion to and from float is performed by hardware when possible, but on processors that do not natively support half-precision, the conversion is performed through a sequence of lookup table operations.

qfloat16 should be treated as if it were a POD (plain old data) type. Consequently, none of the supported operations need any elaboration beyond stating that it supports all arithmetic operators incident to floating point types.

Note: On x86 and x86-64 that to get hardware accelerated conversions you must compile with F16C or AVX2 enabled, or use qFloatToFloat16() and qFloatFromFloat16() which will detect F16C at runtime.

Since: 5.9

Definition at line 55 of file qfloat16.h.

Member Typedef Documentation

◆ NativeType

using qfloat16::NativeType = QtPrivate::NativeFloat16Type

Definition at line 69 of file qfloat16.h.

◆ NearestFloat

using qfloat16::NearestFloat = std::conditional_t<IsNative, NativeType, float>

Definition at line 72 of file qfloat16.h.

Constructor & Destructor Documentation

◆ qfloat16() [1/4]

qfloat16::qfloat16 ( )

inlineconstexprnoexcept

Definition at line 74 of file qfloat16.h.

◆ qfloat16() [2/4]

qfloat16::qfloat16 ( Qt::Initialization )

inlineexplicitnoexcept

Since: 6.1

Constructs a qfloat16 without initializing the value.

Definition at line 75 of file qfloat16.h.

◆ qfloat16() [3/4]

qfloat16::qfloat16 ( float f )

inlinenoexcept

Definition at line 367 of file qfloat16.h.

◆ qfloat16() [4/4]

template<typename T, typename = std::enable_if_t<std::is_arithmetic_v<T> && !std::is_same_v<T, NearestFloat>>>

qfloat16::qfloat16 ( T value )

inlineexplicitconstexprnoexcept

Definition at line 85 of file qfloat16.h.

Member Function Documentation

◆ _limit_denorm_min()

constexpr qfloat16 qfloat16::_limit_denorm_min ( )

inlinestaticconstexprnoexcept

Definition at line 119 of file qfloat16.h.

◆ _limit_epsilon()

constexpr qfloat16 qfloat16::_limit_epsilon ( )

inlinestaticconstexprnoexcept

Definition at line 117 of file qfloat16.h.

◆ _limit_infinity()

constexpr qfloat16 qfloat16::_limit_infinity ( )

inlinestaticconstexprnoexcept

Definition at line 122 of file qfloat16.h.

◆ _limit_lowest()

constexpr qfloat16 qfloat16::_limit_lowest ( )

inlinestaticconstexprnoexcept

Definition at line 121 of file qfloat16.h.

◆ _limit_max()

constexpr qfloat16 qfloat16::_limit_max ( )

inlinestaticconstexprnoexcept

Definition at line 120 of file qfloat16.h.

◆ _limit_min()

constexpr qfloat16 qfloat16::_limit_min ( )

inlinestaticconstexprnoexcept

Definition at line 118 of file qfloat16.h.

◆ _limit_quiet_NaN()

constexpr qfloat16 qfloat16::_limit_quiet_NaN ( )

inlinestaticconstexprnoexcept

Definition at line 123 of file qfloat16.h.

◆ copySign()

qfloat16 qfloat16::copySign ( qfloat16 sign ) const

inlinenoexcept

Since: 5.15

\obsolete [6.11] Use the copysign() friend function instead.

Definition at line 93 of file qfloat16.h.

References copysign.

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◆ fpClassify()

int qfloat16::fpClassify ( ) const

noexcept

Since: 5.14 Implements qFpClassify() for qfloat16.

Definition at line 164 of file qfloat16.cpp.

◆ isFinite()

bool qfloat16::isFinite ( ) const

inlinenoexcept

Since: 5.14

Tests whether this qfloat16 value is finite.

Definition at line 90 of file qfloat16.h.

Referenced by qIsFinite().

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◆ isInf()

bool qfloat16::isInf ( ) const

inlinenoexcept

Since: 5.14

Tests whether this qfloat16 value is an infinity.

Definition at line 88 of file qfloat16.h.

Referenced by qIsInf().

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◆ isNaN()

bool qfloat16::isNaN ( ) const

inlinenoexcept

Since: 5.14

Tests whether this qfloat16 value is "not a number".

Definition at line 89 of file qfloat16.h.

Referenced by qIsNaN().

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◆ isNormal()

bool qfloat16::isNormal ( ) const

inlineconstexprnoexcept

Since: 5.14

Returns true if this qfloat16 value is finite and in normal form.

See also: qFpClassify()

Definition at line 128 of file qfloat16.h.

◆ operator float()

qfloat16::operator float ( ) const

inlinenoexcept

Definition at line 407 of file qfloat16.h.

◆ comparesEqual [1/2]

QF16_CONSTEXPR bool comparesEqual	(	const qfloat16 &	lhs,
		const qfloat16 &	rhs )

friend

Definition at line 223 of file qfloat16.h.

◆ comparesEqual [2/2]

template<typename T, if_type_is_integral< T > = true>

QF16_CONSTEXPR bool comparesEqual	(	const qfloat16 &	lhs,
		T	rhs )

friend

Definition at line 247 of file qfloat16.h.

◆ compareThreeWay [1/2]

QF16_CONSTEXPR Qt::partial_ordering compareThreeWay	(	const qfloat16 &	lhs,
		const qfloat16 &	rhs )

friend

Definition at line 226 of file qfloat16.h.

◆ compareThreeWay [2/2]

template<typename T, if_type_is_integral< T > = true>

QF16_CONSTEXPR Qt::partial_ordering compareThreeWay	(	const qfloat16 &	lhs,
		T	rhs )

friend

Definition at line 250 of file qfloat16.h.

◆ copysign

qfloat16 copysign	(	qfloat16	x,
		qfloat16	sign )

friend

Since: 6.11

Returns a qfloat16 with the sign of sign but the rest of its value taken from {x}. Serves as qfloat16's equivalent of std::copysign().

See also: signbit()

Definition at line 95 of file qfloat16.h.

Referenced by copySign().

◆ operator*

qfloat16 operator*	(	qfloat16	a,
		qfloat16	b )

friend

Definition at line 169 of file qfloat16.h.

◆ operator+

qfloat16 operator+	(	qfloat16	a,
		qfloat16	b )

friend

Definition at line 167 of file qfloat16.h.

◆ operator- [1/2]

qfloat16 operator- ( qfloat16 a )

friend

Definition at line 160 of file qfloat16.h.

◆ operator- [2/2]

qfloat16 operator-	(	qfloat16	a,
		qfloat16	b )

friend

Definition at line 168 of file qfloat16.h.

◆ operator/

qfloat16 operator/	(	qfloat16	a,
		qfloat16	b )

friend

Definition at line 170 of file qfloat16.h.

◆ operator<< [1/2]

QT_WARNING_POP friend Q_CORE_EXPORT QDataStream & operator<<	(	QDataStream &	ds,
		qfloat16	f )

friend

Definition at line 421 of file qfloat16.cpp.

◆ operator<< [2/2]

Q_CORE_EXPORT QTextStream & operator<<	(	QTextStream &	ts,
		qfloat16	f )

friend

Definition at line 452 of file qfloat16.cpp.

◆ operator>> [1/2]

Q_CORE_EXPORT QDataStream & operator>>	(	QDataStream &	ds,
		qfloat16 &	f )

friend

Definition at line 438 of file qfloat16.cpp.

◆ operator>> [2/2]

Q_CORE_EXPORT QTextStream & operator>>	(	QTextStream &	ts,
		qfloat16 &	f )

friend

Definition at line 444 of file qfloat16.cpp.

◆ qFloatFromFloat16()

Q_CORE_EXPORT void qFloatFromFloat16	(	float *	out,
		const qfloat16 *	in,
		qsizetype	len )

Since: 5.11

Converts len qfloat16 from in to floats and stores them in out. Both in and out must have len allocated entries.

This function is faster than converting values one by one, and will do runtime F16C detection on x86 and x86-64 hardware.

Definition at line 389 of file qfloat16.cpp.

◆ qFloatToFloat16()

Q_CORE_EXPORT void qFloatToFloat16	(	qfloat16 *	out,
		const float *	in,
		qsizetype	len )

Since: 5.11

Converts len floats from in to qfloat16 and stores them in out. Both in and out must have len allocated entries.

This function is faster than converting values one by one, and will do runtime F16C detection on x86 and x86-64 hardware.

Definition at line 370 of file qfloat16.cpp.

◆ qFpClassifyqFpClassify()

int qFpClassifyqFpClassify ( qfloat16 val )

Since: 5.14

Returns the floating-point class of val.

◆ qFuzzyCompareqFuzzyCompare()

bool qFuzzyCompareqFuzzyCompare	(	qfloat16	p1,
		qfloat16	p2 )

Compares the floating point value p1 and p2 and returns true if they are considered equal, otherwise false.

The two numbers are compared in a relative way, where the exactness is stronger the smaller the numbers are.

◆ qHash

size_t qHash	(	qfloat16	key,
		size_t	seed = 0 )

friend

Since: 6.5.3 \qhash{qfloat16}

Note: In Qt versions before 6.5, this operation was provided by the qHash(float) overload. In Qt versions 6.5.0 to 6.5.2, this functionality was broken in various ways. In Qt versions 6.5.3 and 6.6 onwards, this overload restores the Qt 6.4 behavior.

Definition at line 172 of file qfloat16.h.

◆ qIsFiniteqIsFinite()

bool qIsFiniteqIsFinite ( qfloat16 f )

Returns true if the qfloat16 {f} is a finite number.

◆ qIsInfqIsInf()

bool qIsInfqIsInf ( qfloat16 f )

Returns true if the qfloat16 {f} is equivalent to infinity.

◆ qIsNaNqIsNaN()

bool qIsNaNqIsNaN ( qfloat16 f )

Returns true if the qfloat16 {f} is not a number (NaN).

◆ qIsNull

bool qIsNull ( qfloat16 f )

friend

Definition at line 358 of file qfloat16.h.

◆ qRound64qRound64()

qint64 qRound64qRound64 ( qfloat16 value )

Rounds value to the nearest 64-bit integer.

◆ qRoundqRound()

int qRoundqRound ( qfloat16 value )

Rounds value to the nearest integer.

◆ signbit

bool signbit ( qfloat16 x )

friend

Since: 6.11

Returns true if qfloat16 x is negative, false otherwise. Note this function returns true for negative zero, negative infinity, and negative NaN values.

See also: copysign()

Definition at line 98 of file qfloat16.h.

Member Data Documentation

◆ b16

quint16 qfloat16::b16

Definition at line 138 of file qfloat16.h.

◆ IsNative

bool qfloat16::IsNative = QFLOAT16_IS_NATIVE

staticconstexpr

Definition at line 71 of file qfloat16.h.

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

qtbase/src/corelib/global/qfloat16.h (74b5e86f2a3f07d4d75b4e7d83e4ea15469c834a)
qtbase/src/corelib/global/qfloat16.cpp (74b5e86f2a3f07d4d75b4e7d83e4ea15469c834a)
qtbase/src/corelib/global/qfloat16tables.cpp (05fc3aef53348fb58be6308076e000825b704e58)

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Friends

Related Symbols

Detailed Description

Member Typedef Documentation

◆ NativeType

◆ NearestFloat

Constructor & Destructor Documentation

◆ qfloat16() [1/4]

◆ qfloat16() [2/4]

◆ qfloat16() [3/4]

◆ qfloat16() [4/4]

Member Function Documentation

◆ _limit_denorm_min()

◆ _limit_epsilon()

◆ _limit_infinity()

◆ _limit_lowest()

◆ _limit_max()

◆ _limit_min()

◆ _limit_quiet_NaN()

◆ copySign()

◆ fpClassify()

◆ isFinite()

◆ isInf()

◆ isNaN()

◆ isNormal()

◆ operator float()

Friends And Related Symbol Documentation

◆ comparesEqual [1/2]

◆ comparesEqual [2/2]

◆ compareThreeWay [1/2]

◆ compareThreeWay [2/2]

◆ copysign

◆ operator*

◆ operator+

◆ operator- [1/2]

◆ operator- [2/2]

◆ operator/

◆ operator<< [1/2]

◆ operator<< [2/2]

◆ operator>> [1/2]

◆ operator>> [2/2]

◆ qFloatFromFloat16()

◆ qFloatToFloat16()

◆ qFpClassifyqFpClassify()

◆ qFuzzyCompareqFuzzyCompare()

◆ qHash

◆ qIsFiniteqIsFinite()

◆ qIsInfqIsInf()

◆ qIsNaNqIsNaN()

◆ qIsNull

◆ qRound64qRound64()

◆ qRoundqRound()

◆ signbit

Member Data Documentation

◆ b16

◆ IsNative