Maintaining abstractions with verification

By use of the Boyer-Moore logic a microprocessor, an assembler and a compiler have been formally specified. Each of these provides a more abstract interface than that upon which they are implemented (e.g., the language of the compiler is more abstract than the language of the assembler that is the target of the compiler). In a simple prototype system, it is shown that it is possible to ensure that such abstractions are correctly maintained by verifying the correct implementation of the systems which support them. Because the components of the prototype system were designed as cooperating units, the abstractions supported can be composed to provide an environment for developing software systems for which the predictability of the high-level language programs is just as good as that of the Boolean logic hardware model.<>