Design of microprocessors with built-in on-line test

Control flow checking techniques are discussed. Invariant properties of the control flow can be checked at two different levels: verification of the sequencing in the controller of the microprocessor or verification of the control flow in the application program. Control flow checking has been implemented, at the two levels, in different versions of a 32-b microprocessor designed in a CMOS 1.5- mu technology. Integration of the monitors on silicon is detailed. The silicon overhead due to the different online test devices is precisely discussed. Different versions of this microprocessor have been designed and implemented in order to make real cost comparisons on components with identical functionality but different integrated monitors. Here only the hardware cost of concurrent checking is considered.<>