No abstract

Abstract. The Verisoft project aims at the pervasive formal verification from the application layer over the system level software, comprising a microkernel and a compiler, down to the hardware. The different layers of the system give rise to various abstraction levels to conduct the reasoning steps efficiently. The lower the abstraction level the more details and invariants are necessary to ensure overall system correctness. Illustrated by a page-fault handler we discuss the layers and the trade-off between efficiency of reasoning at a more abstract layer versus the development of meta-theory to transfer the verification results between the layers.

No abstract

No abstract

In the spirit of the famous CLI stack project [2] the Verisoft project [31] aims at the pervasive verification of entire computer systems including hardware, system software, compiler, and communicating applications, with a special focus on industrial applications. The main programming language used in the Verisoft project is C0 (a subset of C which is similar to MISRA C [20]). This paper reports on (i) an operational small steps semantics for C0 which is formalized in Isabelle/HOL [25], (ii) the formal specification of a compiler from C0 to the DLX machine language [14, 23] in Isabelle/HOL, (iii) a paper and pencil correctness proof for this compiler and the status of the formal verification effort for this proof, and (iv) the implementation of the compiler in C0 and a formal proof in Isabelle/HOL that the implementation produces the same code as the specification. * Work supported by DFG Graduiertenkolleg "Leistungsgarantien für Rechnersysteme". † Work partially funded by the German Federal Ministry of Education and Research (BMBF) in the framework of the Verisoft project under grant 01 IS C38.