Developer Guide

Contents

Additional Data Types Provided by the
ap_float.hpp
Header File

The
ap_float.hpp
header file provides some aliases for certain data types that you can use instead of explicitly declaring an
ap_float
data type.
Data Type
Description
ihc::bfloat16
A 16-bit floating-point number with an 8-bit exponent and a 7-bit mantissa (equivalent to declaring
ihc::ap_float<8, 7>
).
On Intel® Agilex™ devices, dot product operations that involve the
bfloat16
(or
ihc::ap_float<8,7>
) data type are mapped to FP16 digital signaling blocks (DSPs). On other device families, dot product operations are mapped to adaptive logic modules (ALMs) and fixed-point 18-bit DSPs.
On all device families, all other math functions are mapped to ALMs and fixed-point 18-bit DSPs.
ihc::bfloat19
A 19-bit floating-point number with an 8-bit exponent and a 10-bit mantissa (equivalent to declaring
ihc::ap_float<8,10>
).
On Intel® Agilex™ devices, dot product operations that involve the
bfloat19
(or
ihc::ap_float<8,10>
) data type are mapped to FP19 digital signaling blocks (DSPs). On other device families, dot product operations are mapped to adaptive logic modules (ALMs) and fixed-point 18-bit DSPs.
On all device families, all other math functions are mapped to ALMs and fixed-point 18-bit DSPs.
ihc::FPsingle
A 32-bit floating-point number with an 8-bit exponent, a 23-bit mantissa, and a "Round to the nearest, tie break to even" rounding mode (equivalent to declaring
ihc::ap_float<8, 23, fp_config::FP_Round::RNE>
).
Math operations with
FPsingle
map to the same hardware as the native
float
data type when the native float data type uses IEEE-754 round nearest ties to even (RNE) mode. For information about controlling the rounding mode for native floating-point data types, refer to Modify the Rounding Mode of Floating-point Operations (-Xsrounding=<rounding_type>).
ihc::FPdouble
A 64-bit floating-point number with an 11-bit exponent, a 52-bit mantissa, and a "Round to the nearest, tie break to even" rounding mode (equivalent to declaring
ihc::ap_float<11, 52, fp_config::FP_Round::RNE>
).
When subnormal support is on, math operations with
FPdouble
map to the same hardware at the native
double
data type. For information about controlling the subnormal settings of
FPdouble
(and other
ap_float
data types), refer to Operations with Explicit Precision Controls.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.