内容

• 公共函数
• 相关非成员
• 宏
• 详细描述

qfloat16 类

提供 16 位浮点支持。 更多...

头：	#include <QFloat16>
qmake:	QT += core
Since:	Qt 5.9

该类在 Qt 5.9 引入。

• 所有成员列表，包括继承成员

公共函数

qfloat16	copySign (qfloat16 sign ) const
bool	isNormal () const

相关非成员

void	qFloatFromFloat16 (float * out , const qfloat16 * in , qsizetype len )
void	qFloatToFloat16 (qfloat16 * out , const float * in , qsizetype len )
bool	qFuzzyCompare (qfloat16 p1 , qfloat16 p2 )
bool	qIsFinite (qfloat16 f )
bool	qIsInf (qfloat16 f )
bool	qIsNaN (qfloat16 f )
qint64	qRound64 (qfloat16 value )
int	qRound (qfloat16 value )

宏

QT_NO_FLOAT16_OPERATORS

详细描述

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.

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

成员函数文档编制

qfloat16 qfloat16:: copySign ( qfloat16 sign ) const

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

该函数在 Qt 5.15 引入。

bool qfloat16:: isNormal () const

返回 true 若此 qfloat16 值是有限的且采用正常形式。

该函数在 Qt 5.14 引入。

另请参阅 qFpClassify ().

相关非成员

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

转换 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.

该函数在 Qt 5.11 引入。

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

转换 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.

该函数在 Qt 5.11 引入。

bool qFuzzyCompare ( qfloat16 p1 , qfloat16 p2 )

比较浮点值 p1 and p2 并返回 true 若它们被认为相等，否则 false .

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

bool qIsFinite ( qfloat16 f )

返回 true 若 qfloat16 f 是有限数。

另请参阅 qIsFinite.

bool qIsInf ( qfloat16 f )

返回 true 若 qfloat16 f 相当于无穷大。

另请参阅 qIsInf.

bool qIsNaN ( qfloat16 f )

返回 true 若 qfloat16 f 是 NaN (非数字)。

另请参阅 qIsNaN.

qint64 qRound64 ( qfloat16 value )

圆整 value 到最近 64 位整数。

另请参阅 qRound64.

int qRound ( qfloat16 value )

圆整 value 到最近整数。

另请参阅 qRound.

宏文档编制

QT_NO_FLOAT16_OPERATORS

Defining this macro disables the arithmetic operators for qfloat16.

This is only necessary on Visual Studio 2017 (and earlier) when including <QFloat16> and <bitset> in the same translation unit, which would otherwise cause a compilation error due to a toolchain bug (see [QTBUG-72073]).

该函数在 Qt 5.12.4 引入。