On the Use of Hierarchies in the MlMOLA Hardware Design System

Until recently, the use of hierarchies in CAD for VLSI has almost exclusively been restricted to layout and simulation problems. The paper describes representation and handling of design hierarchies in the MIMOLA design system, featuring RT-level synthesis, test program generation and retargetable code generation. A method of embedding these tools in a common design environment, providing access to the hierarchy, is described. Advantages of having a design hierarchy are presented for each of the tools. In addition, relevant features of the MIMOLA language are explained. The MSS, as described in [11], did not make use of design hierarchies. This paper describes our approach for extending the MSS towards a hierarchical, integrated design system. Two major issues have to be solved: that of suitable design language and that of a suitable design system. Let us first consider the language issue by briefly reviewing some relevant features of the present version (version 3.4) of MIMOLA.