This paper describes a methodology for machine-description, intended to help develop processor specific tools in a generic
and reusable way. It is based on our work about retargetable compiler for embedded processors and is contributed to Architecture
Design Language (ADL). The processor described in our machine-description system is modeled in UML class diagram in 3-layer
architecture. The resulting machine-description is reusable for developers to create retargetable compilers.