We present two techniques, (1) placement-based timing-driven partitioner (PTP) and (2) virtual physical synthesis based budgeter (VSB), that support effective distributed physical synthesis.

We present a new abstraction refinement algorithm to better refine the abstract model for formal property verification. In previous work, refinements are selected either based on a set of counter examples of the current abstract model, as in [5][6][7][8][9][19][20], or independent of any counter examples, as in [17]. We (1) introduce a new "controllability" analysis that is independent of any particular counter examples, (2) apply a new "cooperativeness" analysis that extracts information from a particular set of counter examples and (3) combine both to better refine the abstract model. We implemented the algorithm and applied it to verify several real-world designs and properties. We compared the algorithm against the abstraction refinement algorithms in [19] and [20] and the interpolation-based reachability analysis in [14]. The experimental results indicate that the new algorithm outperforms the other three algorithms in terms of runtime, abstraction efficiency (as defined in [19]) and the number of proven properties.

Model checking is a practical tool for automated debugging of embedded software. In model checking, a high-level description of a system is compared against a logical correctness requirement to discover inconsistencies. Since model checking is based on exhaustive state-space exploration and the size of the state space of a design grows exponentially with the size of the description, scalability remains a challenge. We have thus developed techniques for exploiting modular design structure during model checking, and the model checker jMocha (Java MOdel-CHecking Algorithm) is based on this theme. Instead of manipulating unstructured state-transition graphs, it supports the hierarchical modeling framework of reactive modules. jMocha is a growing interactive software environment for specification, simulation and verification, and is intended as a vehicle for the development of new verification algorithms and approaches. It is written in Java and uses native C-code BDD libraries from VIS. jMocha offers: (1) a GUI that looks familiar to Windows/Java users; (2) a simulator that displays traces in a message sequence chart fashion; (3) requirements verification both by symbolic and enumerative model checking; (4) implementation verification by checking trace containment; (5) a proof manager that aids compositional and assume-guarantee reasoning; and (6) SLANG (Scripting LANGuage) for the rapid and structured development of new verification algorithms. jMocha is available publicly at; it is a successor and extension of the original Mocha tool that was entirely written in C.