Data Types

Bit-accurate data types offer a reliable mechanism to model exact hardware bit-widths and arithmetic precision in High-Level Synthesis (HLS) workflows. These types range from simple signed and unsigned integer representations, familiar to RTL designers, to fixed point data types with support for rounding and saturation modes, and even fully IEEE-compliant floating-point types with user-defined exponent and mantissa widths. This level of control ensures bit-exact behavior, maintaining alignment between C++/SystemC numerical models and the final RTL generated by the HLS tool.
Some organizations use proprietary or custom-developed bit-accurate types for modeling. However, two widely available open-source options are AC types and SystemC types they support robust C++/SystemC design styles and offer comprehensive integer and fixed-point modeling capabilities. AC Types have become especially popular due to their support for unlimited bit-length, consistent simulation semantics, and faster execution performance in compiled environments.