5.47 Compiler and library support for half-precision floating-point numbers

Half-precision is a floating-point format that occupies 16 bits.

Half-precision floating-point numbers are provided by:

  • The Vector Floating-Point (VFP) Version 4 architecture.

  • An optional extension to the VFPv3 architecture.

If a VFP coprocessor is not available, or if a VFPv3 coprocessor is used that does not have the extension, half-precision floating-point numbers are supported through the floating-point library fplib.

Half-precision floating-point numbers can only be used when selected with the --fp16_format=format compiler command-line option.

The C++ name mangling for the half-precision data type is specified in the C++ generic Application Binary Interface (ABI).

Related concepts
5.41 Compiler support for floating-point arithmetic
5.42 Default selection of hardware or software floating-point support
5.43 Example of hardware and software support differences for floating-point arithmetic
5.44 Vector Floating-Point (VFP) architectures
5.45 Limitations on hardware handling of floating-point arithmetic
5.46 Implementation of Vector Floating-Point (VFP) support code
5.48 Half-precision floating-point number format
5.49 Compiler support for floating-point computations and linkage
5.50 Types of floating-point linkage
5.51 Compiler options for floating-point linkage and computations
Related reference
5.52 Floating-point linkage and computational requirements of compiler options
5.53 Processors and their implicit Floating-Point Units (FPUs)
8.84 --fp16_format=format
Related information
Floating-point Support
C++ ABI for the ARM Architecture
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