As the sizes of general and special purpose processors increase rapidly, generating high quality manufacturing tests which can be run at native speeds is becoming a serious problem. One solution is a novel method for functional test generation in which a transformed module is built manually, and which embodies functional constraints described using virtual logic. Test generation is then performed on the transformed module using commercial tools and the transformed module patterns are translated back to the processor level. However, the technique is useful only if the virtual logic can be generated automatically. This paper describes an automatic functional constraint extraction algorithm and a procedure to build the transformed module. We describe the tool, FALCON, used to extract the functional constraints of a given embedded module fromaVerilog RTL model. The constraint extraction for embedded modules of benchmark processors using FALCON takes only a few seconds. We show that this method can generate functional patterns in a time several orders of magnitude less than one using a conventional, at view of the circuit. 1

As the sizes of general and special purpose processors increase rapidly, generating high quality manufacturing tests for them is becoming a serious problem in industry. This paper describes a novel method for hierarchical functional test generation for processors which targets one embedded module at a time and uses commercial ATPG tools to derive tests for faults within the module. Applying the technique to benchmark processor designs, we were able to obtain test efficiencies for the embedded modules of the processors which were extremely close to what the commercial ATPG could do with complete access to the module. The hierarchical approach used produced this result, using the same commercial tool, but required a CPU time several orders of magnitude less than when using a conventional, flat view of the circuit.