A multiplier, for example, can be designed and treated like a black box. The performance of the multiplier is only marginally influenced by the way it is used in a larger system. Adders, datapaths, binary valued words. Hierarchy and Abstraction Entire CAD design frameworks are based on this design philosophy. These have made it possible to achieve current design complexity.
Standard cells are a popular design style that makes layout generation easy.
Layouts of basic gates such as AND, OR, NAND, NOR, and NOT as well as arithmetic and memory modules are provided as input. These cells are designed with similar characteristics, such as constant height, and can be manipulated easily to generate a layout. More on this later. Reality is more complex and a knowledge of digital circuit design will be important for some time to come. Someone has to design and implement the module libraries.