BFloat16 Class Reference

#include <BFloat16.hpp>

Public Member Functions
	BFloat16 ()
	BFloat16 (const BFloat16 &v)=default
	BFloat16 (uint16_t v)
	BFloat16 (float v)
	operator float () const
BFloat16 &	operator= (const BFloat16 &other)=default
BFloat16 &	operator= (float v)
bool	operator== (const BFloat16 &r) const
float	ToFloat32 () const
uint16_t	Val () const

Static Public Member Functions
static BFloat16	Float32ToBFloat16 (const float v)
static BFloat16	Max ()
static BFloat16	Nan ()
static BFloat16	Inf ()

Detailed Description

Definition at line 14 of file BFloat16.hpp.

Constructor & Destructor Documentation

BFloat16() [1/4]

BFloat16 ( )

inline

Definition at line 17 of file BFloat16.hpp.

Referenced by BFloat16::Inf(), BFloat16::Max(), and BFloat16::Nan().

    : m_Value(0)
    {}

BFloat16() [2/4]

BFloat16 ( const BFloat16 &  v )

default

BFloat16() [3/4]

BFloat16 ( uint16_t  v )

inlineexplicit

Definition at line 23 of file BFloat16.hpp.

    : m_Value(v)
    {}

BFloat16() [4/4]

BFloat16 ( float  v )

inlineexplicit

Definition at line 27 of file BFloat16.hpp.

References BFloat16::Float32ToBFloat16(), and BFloat16::Val().

    {
        m_Value = Float32ToBFloat16(v).Val();
    }

Member Function Documentation

Float32ToBFloat16()

static BFloat16 Float32ToBFloat16 ( const float  v )

inlinestatic

Definition at line 50 of file BFloat16.hpp.

References armnn::error, and BFloat16::Nan().

Referenced by BFloat16::BFloat16(), BOOST_AUTO_TEST_CASE(), and BFloat16::operator=().

    {
        if (std::isnan(v))
        {
            return Nan();
        }
        else
        {
            // Round value to the nearest even
            // Float32
            // S EEEEEEEE MMMMMMLRMMMMMMMMMMMMMMM
            // BFloat16
            // S EEEEEEEE MMMMMML
            // LSB (L): Least significat bit of BFloat16 (last bit of the Mantissa of BFloat16)
            // R: Rounding bit
            // LSB = 0, R = 0 -> round down
            // LSB = 1, R = 0 -> round down
            // LSB = 0, R = 1, all the rest = 0 -> round down
            // LSB = 1, R = 1 -> round up
            // LSB = 0, R = 1 -> round up
            const uint32_t* u32 = reinterpret_cast<const uint32_t*>(&v);
            uint16_t u16 = static_cast<uint16_t>(*u32 >> 16u);
            // Mark the LSB
            const uint16_t lsb = u16 & 0x0001;
            // Mark the error to be truncate (the rest of 16 bits of FP32)
            const uint16_t error = static_cast<uint16_t>((*u32 & 0x0000FFFF));
            if ((error > 0x8000 || (error == 0x8000 && lsb == 1)))
            {
                u16++;
            }
            BFloat16 b(u16);
            return b;
        }
    }

Inf()

static BFloat16 Inf ( )

inlinestatic

Definition at line 109 of file BFloat16.hpp.

References BFloat16::BFloat16().

Referenced by BOOST_AUTO_TEST_CASE().

    {
        uint16_t infVal = 0x7F80;
        return BFloat16(infVal);
    }

Max()

static BFloat16 Max ( )

inlinestatic

Definition at line 97 of file BFloat16.hpp.

References BFloat16::BFloat16().

    {
        uint16_t max = 0x7F7F;
        return BFloat16(max);
    }

Nan()

static BFloat16 Nan ( )

inlinestatic

Definition at line 103 of file BFloat16.hpp.

References BFloat16::BFloat16().

Referenced by BOOST_AUTO_TEST_CASE(), and BFloat16::Float32ToBFloat16().

    {
        uint16_t nan = 0x7FC0;
        return BFloat16(nan);
    }

operator float()

operator float ( ) const

inline

Definition at line 32 of file BFloat16.hpp.

References BFloat16::operator=(), and BFloat16::ToFloat32().

    {
        return ToFloat32();
    }

operator=() [1/2]

BFloat16& operator= ( const BFloat16 &  other )

default

Referenced by BFloat16::operator float().

operator=() [2/2]

BFloat16& operator= ( float  v )

inline

Definition at line 39 of file BFloat16.hpp.

References BFloat16::Float32ToBFloat16(), and BFloat16::Val().

    {
        m_Value = Float32ToBFloat16(v).Val();
        return *this;
    }

operator==()

bool operator== ( const BFloat16 &  r ) const

inline

Definition at line 45 of file BFloat16.hpp.

References BFloat16::Val().

    {
        return m_Value == r.Val();
    }

ToFloat32()

float ToFloat32 ( ) const

inline

Definition at line 85 of file BFloat16.hpp.

Referenced by BOOST_AUTO_TEST_CASE(), FloatingPointConverter::ConvertBFloat16ToFloat32(), BFloat16::operator float(), and armnn::operator<<().

    {
        const uint32_t u32 = static_cast<uint32_t>(m_Value << 16u);
        const float* f32 = reinterpret_cast<const float*>(&u32);
        return *f32;
    }

Val()

uint16_t Val ( ) const

inline

Definition at line 92 of file BFloat16.hpp.

Referenced by BFloat16::BFloat16(), BOOST_AUTO_TEST_CASE(), armnn::operator<<(), BFloat16::operator=(), and BFloat16::operator==().

    {
        return m_Value;
    }

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

• src/armnnUtils/BFloat16.hpp