Provided by: opencl-1.2-man-doc_1.0~svn33624-5_all bug

NAME

       cl_khr_fp16 - Optional half floating-point support.

       #pragma OPENCL EXTENSION cl_khr_fp16 : enable

DESCRIPTION

       This extension adds support for half scalar and vector types as built-in types that can be
       used for arithmetic operations, conversions, etc. An application that wants to use half
       and halfn types will need to include the directive shown above.

       The list of built-in scalar and vector data types are extended to include the types in the
       table below.

       The built-in vector data types for halfn are also declared as appropriate types in the
       OpenCL API (and header files) that can be used by an application. The following table
       describes the built-in vector data types for halfn as defined in the OpenCL C programming
       language and the corresponding data type available to the application:

       ┌────────────────────────┬───────────────────────┬──────────────────────────┐
       │Type in OpenCL LanguageDescriptionAPI type for application │
       ├────────────────────────┼───────────────────────┼──────────────────────────┤
       │half2                   │ 2-component           │ cl_half2                 │
       │                        │ half-precision        │                          │
       │                        │ floating-point vector │                          │
       ├────────────────────────┼───────────────────────┼──────────────────────────┤
       │half3                   │ 3-component           │ cl_half3                 │
       │                        │ half-precision        │                          │
       │                        │ floating-point vector │                          │
       ├────────────────────────┼───────────────────────┼──────────────────────────┤
       │half4                   │ 4-component           │ cl_half4                 │
       │                        │ half-precision        │                          │
       │                        │ floating-point vector │                          │
       ├────────────────────────┼───────────────────────┼──────────────────────────┤
       │half8                   │ 8-component           │ cl_half8                 │
       │                        │ half-precision        │                          │
       │                        │ floating-point vector │                          │
       ├────────────────────────┼───────────────────────┼──────────────────────────┤
       │half16                  │ 16-component          │ cl_half16                │
       │                        │ half-precision        │                          │
       │                        │ floating-point vector │                          │
       └────────────────────────┴───────────────────────┴──────────────────────────┘

       The relational, equality, logical and logical unary operators(3clc) can be used with half
       scalar and halfn vector types and shall produce a scalar int and vector shortn result
       respectively.

       The OpenCL compiler accepts an h and H suffix on floating point literals, indicating the
       literal is typed as a half.

       The macro names given in the following list must use the values specified. These constant
       expressions are suitable for use in #if preprocessing directives.

       The following table also describes the corresponding macro names available to the
       application.

       Macro in OpenCL Language   value         Macro for application
       #define HALF_DIG           3             HALF_DIG
       #define HALF_MANT_DIG      11            HALF_MANT_DIG
       #define HALF_MAX_10_EXP    +4            HALF_MAX_10_EXP

       #define HALF_MAX_EXP       +16           HALF_MAX_EXP
       #define HALF_MIN_10_EXP    -4            HALF_MIN_10_EXP
       #define HALF_MIN_EXP       -13           HALF_MIN_EXP
       #define HALF_RADIX         2             HALF_RADIX
       #define HALF_MAX           0x1.ffcp15h   HALF_MAX
       #define HALF_MIN           0x1.0p-14h    HALF_MIN
       #define HALF_EPSILON       0x1.0p-10h    HALF_EPSILON

       The following constants are also available. They are of type half and are accurate within
       the precision of the half type.

       ┌─────────────┬──────────────────┐
       │ConstantDescription      │
       ├─────────────┼──────────────────┤
       │M_E_H        │ Value of e       │
       ├─────────────┼──────────────────┤
       │M_LOG2E_H    │ Value of log2 e  │
       ├─────────────┼──────────────────┤
       │M_LOG10E_H   │ Value of log10 e │
       ├─────────────┼──────────────────┤
       │M_LN2_H      │ Value of ln 2    │
       ├─────────────┼──────────────────┤
       │M_LN10_H     │ Value of ln 10   │
       ├─────────────┼──────────────────┤
       │M_PI_H       │ Value of π       │
       ├─────────────┼──────────────────┤
       │M_PI_2_H     │ Value of π / 2   │
       ├─────────────┼──────────────────┤
       │M_PI_4_H     │ Value of π / 4   │
       ├─────────────┼──────────────────┤
       │M_1_PI_H     │ Value of 1 / π   │
       ├─────────────┼──────────────────┤
       │M_2_PI_H     │ Value of 2 / π   │
       ├─────────────┼──────────────────┤
       │M_2_SQRTPI_H │ Value of 2 / √π  │
       ├─────────────┼──────────────────┤
       │M_SQRT2_H    │ Value of √2      │
       ├─────────────┼──────────────────┤
       │M_SQRT1_2_H  │ Value of 1 / √2  │
       └─────────────┴──────────────────┘

       Ann application may query the configuration information using the op-code
       CL_DEVICE_HALF_FP_CONFIG with clGetDeviceInfo(3clc) for an OpenCL device that supports
       half precision floating-point.

SPECIFICATION

       OpenCL Specification[1]

SEE ALSO

       EXTENSION(3clc), clGetDeviceInfo(3clc), mathFunctions(3clc), commonFunctions(3clc),
       geometricFunctions(3clc), relationalFunctions(3clc),
       vectorDataLoadandStoreFunctions(3clc), asyncCopyFunctions(3clc), imageFunctions(3clc)

AUTHORS

       The Khronos Group

COPYRIGHT

       Copyright © 2007-2011 The Khronos Group Inc.
       Permission is hereby granted, free of charge, to any person obtaining a copy of this
       software and/or associated documentation files (the "Materials"), to deal in the Materials
       without restriction, including without limitation the rights to use, copy, modify, merge,
       publish, distribute, sublicense, and/or sell copies of the Materials, and to permit
       persons to whom the Materials are furnished to do so, subject to the condition that this
       copyright notice and permission notice shall be included in all copies or substantial
       portions of the Materials.

NOTES

        1. OpenCL Specification
           page 14, section 9.5 - Half Floating-Point