Data Types - 2021.2 English

Vitis Unified Software Platform Documentation: Application Acceleration Development (UG1393)

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2021.2 English

As it is faster to write and verify the code by using native C data types such as int, float, or double, it is a common practice to use these data types when coding for the first time. However, the code is implemented in hardware and all the operator sizes used in the hardware are dependent on the data types used in the accelerator code. The default native C/C++ data types can result in larger and slower hardware resources that can limit the performance of the kernel. Instead, consider using bit-accurate data types to ensure the code is optimized for implementation in hardware. Using bit-accurate, or arbitrary precision data types, results in hardware operators which are smaller and faster. This allows more logic to be placed into the programmable logic and also allows the logic to execute at higher clock frequencies while using less power.

Consider using bit-accurate data types instead of native C/C++ data types in your code.

In the following sections, the two most common arbitrary precision data types (arbitrary precision integer type and arbitrary precision fixed-point type) supported by the Vitis compiler are discussed.

Note: These data types should be used for C/C++ kernels only, not for OpenCL kernel (or inside the host code)