Datatypes

Bit-accurate datatypes provide a mechanism to model exact hardware bit-width and arithmetic precision. From simple signed and unsigned integer representations that are familiar to RTL designers, through fixed point datatypes with rounding and saturation modes, all the way to complete IEEE compliant user-specified exponent and mantissa floating point types, HLS ensures that there is no misunderstanding between the C++/SystemC numerical behavior and the resulting RTL created by HLS.

Some companies may have their own home-grown types for modeling bit-accuracy. There are two publicly available types in the AC Types and SystemC types. Both can be obtained without cost, and both support C++/SystemC design styles and provide integer and fixed point modeling. The AC Types have become particularly popular due to their true unlimited length, consistent behavior, and faster simulation speed in executables.