The HDL Coder library includes blocks from other block libraries with defaults set for HDL code generation. The HDL Operations library provides HDL-optimized blocks that model common hardware components. Use HDL Operations blocks and other blocks from the HDL Coder library to design and simulate systems intended for HDL code generation. If you have an HDL Coder™ license, you can generate HDL code from these systems. If you do not have an HDL Coder license, you can design and simulate with these blocks, but cannot generate HDL code.