Machine descriptions to build tools for embedded systems

Because of poor tools, developing embedded systems can be unnecessarily hard. Machine descriptions based on register-transfer lists (RTLs) have proven useful in building retargetable compilers, but not in building other retargetable tools. Simulators, assemblers, linkers, debuggers, and profilers are built by hand if at all—previous machine descriptions have lacked the detail and precision needed to generate them. This paper presents detailed and precise machine-description techniques that are based on a new formalization of RTLs. Unlike previous notations, these RTLs have a detailed, unambiguous, and machine-independent semantics, which makes them ideal for supporting automatic generation of retargetable tools. The paper also gives examples of λ-RTL, a notation that makes it possible for human beings to read and write RTLs without becoming overwhelmed by machine-dependent detail.