An Algebraic Model of Correctness for Superscalar Microprocessors

A set of algebraic tools for microprocessors (Harman and Tucker [1995a], Harman and Tucker [1994], Fox and Harman [1996b]) are extended to accommodate superscalar processors, where instructions may be executed in parallel, or out of program order. This has implications for the representation of timing abstraction, the relationship between time at different levels of abstraction, and the concept of the correctness of one representation with respect to another. We illustrate our tools with a simple, superscalar example, and extend our one-step theorems for simplifying the formal verification of microprocessors (Harman and Tucker [1995a], Harman and Tucker [1994], Fox and Harman [1996b]) to superscalar processors.